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Conservative Management of Acute Sports-Related Concussions: A Narrative Review

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12 December 2023

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13 December 2023

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Abstract
This review explores the application of the conservative management model for pain to sports-related concussions (SRCs), framing concussions as a distinct form of pain syndrome with a pathophysiological foundation in central sensitization. Drawing parallels with proven pain management models, we underscore the significance of a proactive approach to concussion management. Recognizing concussions as a pain syndrome allows for the tailoring of interventions in alignment with conservative principles. This review first covers the epidemiology and controversies surrounding prolonged concussion recovery and persistent post-concussion symptoms (PPCS). Next, the pathophysiology of concussions is presented within the central sensitization framework, emphasizing the need for early intervention to mitigate the neuroplastic changes that lead to heightened pain sensitivity. Five components of the central sensitization process specific to concussion injuries are highlighted as targets for conservative interventions in the acute period: peripheral sensitization, cerebral metabolic dysfunction, neuroinflammation, glymphatic system dysfunction, and pain catastrophizing. These proactive interventions are emphasized as pivotal in accelerating concussion recovery and reducing the risk of prolonged symptoms and PPCS, in line with the philosophy of conservative management.
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Subject: Medicine and Pharmacology  -   Clinical Medicine

1. Introduction

1.1. Conservative Management is Proactive in Nature

While conservative management paradigm starts with the Hippocratic principle of “first do no harm”, its mandate in sport medicine is much broader. Conservative management has evolved from mere avoidance strategies to ones that promote preventative interventions for sports-related injuries according to “the philosophy of active conservative care” [1]. In other words, conservative management in sports medicine is fundamentally proactive.

1.2. Conservative Principles in Pain Management

The conservative paradigm is applicable to pain management for sports injuries. While pain is an injury symptom in the acute period, it can become uncoupled in the sub-acute phase from the injury that first caused it, evolving into its own distinct disease state [2]. The concept of “pain as a disease” is acknowledged in the 2017 International Olympic Committee consensus statement on the treatment of pain in elite athletes. The Committee notes that pain management should address “all contributors to pain including underlying pathophysiology, biomechanical abnormalities and psychosocial issues” [3]. This is in accordance with the so-called “biopsychosocial” model of pain, a multidimensional approach used to understand and treat the complexities of chronic pain [4]. The consensus statement also emphasizes prevention as a primary goal of pain management, in line with the conservative care principles.

1.3. Central Sensitization and Conservative Pain Management

“Central sensitization” is the accepted model of pain chronification. It involves pathophysiological and neurobehavioral mechanisms that potentiate the transition from acute to chronic pain [5]. The International Association for the Study of Pain (IASP) has termed central sensitization-related pain “nociplastic”, a distinct category of pain [6].
The central sensitization framework can be used to guide conservative interventions, and clinical researchers have used it to guide treatment in several areas of sports medicine, including chronic low back pain [7,8,9], shoulder pain [10], knee pain [11], chronic myofascial pain [12], tendinopathy [13,14], temporomandibular disorders [15], migraines [16], and post-traumatic headaches [17]. The key insight of the central sensitization model is that chronic pain syndromes can be prevented through early proactive interventions, using the biopsychosocial model of pain as a guide.

1.4. Applying the Conservate Care Paradigm in Concussion Injuries

Concussions, or mild traumatic brain injuries (mTBIs), are a concerning problem for sports medicine. Approximately 3.8 million sports and recreational concussions are reported annually in the USA, with the number potentially much larger since approximately 50% of concussions are not reported [18]. In 2022, the International Conference on Concussions in Sport – Amsterdam released its refined definition of concussion:
“Sport-related concussion is a traumatic brain injury caused by a direct blow to the head, neck or body resulting in an impulsive force being transmitted to the brain that occurs in sports and exercise-related activities. This initiates a neurotransmitter and metabolic cascade, with possible axonal injury, blood flow change, and inflammation affecting the brain. Symptoms and signs may present immediately, or evolve over minutes or hours, and commonly resolve within days, but may be prolonged [emphasis added]” [19].
Importantly, prolonged concussion symptoms is one of the primary complications of concussion injuries and the prevention of prolonged symptoms should be seen as a primary goal of conservative management of concussions.
The trend of current research is to recognize prolonged concussion symptoms as a form of nociplastic pain (i.e. pain secondary to central sensitization) [17,20,21,22]. PPSS follows the typical dynamic sequence of central sensitization; peripheral insult, to peripheral sensitization, to prolonged neuroinflammation and neuroplasticity, to centrally-mediated chronic pain [23]. Recognizing PPCS as a nociplastic pain syndrome allows for the tailoring of conservative, biopsychosocial interventions that, when applied promptly after injury, may prevent its development.
Multiple studies now demonstrate that early, proactive care significantly improves concussion outcomes (Table 1) [24]. This goal of this paper is to first outline the central sensitization model of pain chronification as it pertains to concussions, and to then explore how early, proactive interventions, targeting specific steps in the central sensitization process, can improve outcomes.

2. Persistent Post-Concussive Symptoms (PPCS) and Prolonged Recovery

2.1. Defining PPCS

Formerly referred to as “post-concussion syndrome”, the term PPCS was forwarded in the Berlin Consensus Statement on Concussion in Sport (2016), in part due to the stigma surrounding the term “syndrome” [30]. This was loosely defined as concussion symptoms lasting longer than 2 weeks in children and 4 weeks in adults; a definition later adopted by the American Medical Society for Sports Medicine (AMSSM) in 2019 [31]. In the latest Amsterdam consensus statement, the PPCS definition was updated to denote symptoms lasting for > 4 weeks in all age groups.
Adding to the confusion, the term “post-concussion syndrome” was removed from the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), referred to instead as “neurocognitive symptoms associated with traumatic brain injury”. Meanwhile, the 2024 International Classification of Diseases – Tenth Revision (ICD-10) diagnosis code F07.81 still describes the condition as “post concussional syndrome” [32]. The ICD-10 criteria is applied loosely in many studies, with the original descriptor: “Head injury usually sufficiently severe to result in loss of consciousness and then development within four weeks of at least three of the eight following symptoms: headache, dizziness, fatigue, irritability, sleep problems, concentration problems, memory disorders and emotion perturbations” [33,34,35]. The notation that concussions are “usually sufficiently severe to result in loss of consciousness” is largely ignored, as less than 10% of concussions result in loss of consciousness [36].

2.2. The Epidemiology of PCSS

Epidemiological studies on the prevalence of PPCS are conflicting due to shifting definitions of the condition itself. A typical estimate of the prevalence of PPCS repeated in the literature is 15-30% [37], but this number can change dramatically depending on the criteria and timing used. For instance, one study showed that 64% of mTBIs were positive for PPCS at the three month mark by ICD-10 criteria vs. 11% when using the old DSM-IV criteria [33]. Furthermore, several large prospective studies now show that mTBI symptoms can persist for over a year in around 50% of cases [38,39].

2.3. The Epidemiology of Prolonged Symptoms

In sports medicine, the prevalence of prolonged single symptoms are arguably of more importance than the prevalence of PPCS. This is because return to play (RTP) criteria, by consensus (and in some cases by law), calls for the complete resolution of concussion-related symptoms [19]. Importantly, the relatively low PPCS prevalence reported in numerous publications may distort expectations on how long it should take for athletes to return to sports.
For high-quality evidence on single prolonged symptoms, the Transforming Research and Clinical Knowledge in TBI (TRACK-TBI), a multi-center prospective cohort study, is an excellent resource. In this study, participants were evaluated at the 2-week mark, and then 3-, 6-, and 12-months post-injury. In this cohort of over 2000 patients, the percentage of participants who reported at least one new or worsened symptoms after mTBI was 90% at 2 weeks, 78% at 3 months, 74% at 6 months, and 71% at 12 months. If the ICD-10 criteria of 3 or more symptoms was applied to this data set, 53% would be diagnostically positive at the one-year mark [40]. One problem with these numbers is that the TRACK-TBI cohort includes roughly 15% moderate to severe TBI cases, the 85% balance being mTBI cases.
Another source of data is the prospective, multicenter Predicting and Preventing Post-concussive Problems in Pediatrics (5P) cohort study of 3063 children 5–17 years of age, presenting within 48 hours of a concussion injury. In this study, 50% of participants still had at least one symptom at the 28-day mark. Fatigue and headaches were the most common complaints. Notably, 68% of the concussions in this study were sports-related [41].

2.4. Controversies in the Prevalence of Prolonged Symptoms

The above findings conflict with the clinical literature on collegiate sports-related concussions (SRCs), which reports a much faster recovery rate. For instance, in one cohort study of 1974 SRCs in college and club sport members, only 11.7% had symptoms lasting beyond 35 days [42]. Another source of data, the Concussion Assessment, Research, and Education (CARE) Consortium, is a 30-site study with 1751 collegiate athlete participants with SRCs. In this study, 80% of athletes were asymptomatic within 14 days of recovery, with a median time to recovery of 6.4 days and median RTP time of 12.8 days. Only 22.8% experienced “slow recovery”, which was defined in the study as symptoms lasting beyond 14 days or a RTP longer than 24 days [43].
There are several possible explanations for this conflicting data. First, non-sports concussions may take longer to recover than SRCs due to factors like age, mechanism of injury, or litigation intent. The effect of age on symptom resolution can appreciated by examining the prospective Toronto Concussion Study of 473 adults, where 39% were deemed to be unrecovered by physician evaluation at the 4 week mark [44]. Likewise, litigation intent has been shown to influence the rate of symptom resolution [45]. Still, these factors cannot fully explain the gap between the 5P study and the preponderance of collegiate data. Second, SRCs in competitive sports are known to be subject to significant underreporting, with one study showing that 68% of college football players had at least one concussion they did not disclose [46]. The high rate of misreporting and underreporting in competitive-level sport most certainly distorts the data on symptom recovery time. This controversy deserves more attention in future research.

2.5. Risk Factors of Prolonged Recovery

Understanding risk factors for PPCS can alert practitioners to be particularly vigilant and proactive in the acute period for at-risk athletes. A variety of risk factors have been identified in the clinical literature, some of which are not always consistent. The most commonly reported preinjury risk factors are having prior concussions, female gender, mood disorders, learning disorders, attention deficit hyperactivity disorder (ADHD), and a personal or family history of migraines [47,48,49,50]. When looking at post-injury risk factors, the commonly cited factors include injury severity, retrograde amnesia, a high symptom score, “feeling in a fog”, delayed reporting, and the presence of sleep disturbances [39,46,51,52].

2.6. The Time-Course Pattern of Symptom Recovery

The time-course of mTBI symptom resolution underscores the importance of early intervention. There is a definitive “hockey-stick” pattern in the resolution of symptoms, with rapid resolution happening in the first weeks after concussion, followed by very little resolution after this period.
In a prospective study of PPCS, it was found that being symptomatic at one month was significantly predictive of being symptomatic at one year [53]. This is in line with the findings of the TRACK-TBI study, where there was only a 7% drop in those with one symptom from the 3-month to 12-month mark. Expressed another way, symptoms decreased steadily at ~1.7 symptom score points per month in the first 3 months, but then only 0.2 points per month for the rest of the year [40].
This distinctive time-course pattern correlates with the development of nociplastic pain and the phenomenon of central sensitization. When symptoms linger, central neuroplastic changes occur, and the symptoms become chronic. This underscores the notion that a therapeutic window for conservative interventions exists in the early period, but this closes once the deleterious neuroplastic changes in central sensitization become established.

3. Central Sensitization and Symptom Chronification in Concussions

3.1. Defining Central Sensitization

Central sensitization describes the dynamics of chronic pain development, a process where amplification of the perception of pain is ascribed to alterations in central nervous system (CNS) sensory processing. Woolf, one of the pioneers of the central sensitization model, explains:
“Central sensitization is where the CNS can change, distort, or amplify pain, increasing its degree, duration, and spatial extent in a manner that no longer directly reflects the specific qualities of peripheral noxious stimuli, but rather the particular functional states of circuits in the CNS… This does not mean that the pain is not real, just that it is not activated by noxious stimuli” [54].
In other words, central sensitization is the process by which pain transitions from a symptom of injury to a disease state.

3.2. The Neurobiological Sequence of Central Sensitization

In the central sensitization, the neurobiological sequence begins when an insult to peripheral tissues triggers “peripheral sensitization”, a state marked by heightened responsiveness and excitability of nociceptors, an increased signaling rate, and strengthened synaptic transmission. When this is sustained, glial cells, activated by calcitonin gene-related peptide (CGRP) and other neuropeptides, propagate a neuroinflammatory response, enhancing sensitization in higher order neurons and initiating neuroplasticity [55]. Descending facilitation from the brainstem amplifies pain signals, and cortical plasticity in higher brain centers contributes to heightened and prolonged pain perception. Stress, anxiety, and pain catastrophizing intensify and stabilize neural pain signaling pathways through the neuroendocrine system [56] and the "nociceptive amygdala" [57]. The cumulative result is CNS remodeling (neuroplasticity), leading to pathologically elevated pain and sensory hypersensitivity, independent of the original source of peripheral injury.

3.3. Central Sensitization and Chronic Pain

Importantly, when central sensitization has occurred, susceptibility to other chronic pain conditions is elevated. This phenomenon is seen in mTBIs, where more than 50% of people report developing issues with chronic pain [58] and there is a nearly 5 times increased risk of experiencing persistent pain [59]. Again, litigation intent is an important factor to remember in this context.
The clinical hallmarks of central sensitization are noted in mTBI patients [60], including heightened sensitivity to painful stimuli (hyperalgesia), pain from usually nonpainful stimuli (allodynia), and increased sensitivity to both external and internal stimuli (global sensory hyperresponsiveness) [61]. Importantly, chronic central sensitization-related pain is also associated with an increased risk of opioid abuse [62]. Along these lines, clinical studies show that the odds of prescription opioid abuse are 1.5-2.9 times higher in previously concussed adolescents [63,64].

3.4. Central Sensitivity Syndromes

The central sensitization process extends beyond the perception of pain. For instance, in clinical studies, fatigue is predicted by signs of central sensitization, independent of the presence of pain [65]. In addition, people with central sensitization conditions often present with multiple overlapping symptoms, including physical and cognitive fatigue, mood disorders, dysautonomia, sensory hypersensitivity, and sleep disorders [66]. To characterize conditions with these shared features, terms like Central Sensitivity Syndrome (CSS) and Chronic Overlapping Pain Conditions (COPCs) have been introduced [67]. Long-COVID is considered to be a CS-mediated disease, featuring the typical pattern of overlapping symptoms including pain, fatigue, headache, difficulty concentrating, mood disorders, and sleep problems [68]. Like long-COVID, PPCS follows a classic central sensitization pattern with a similar constellation of symptoms.

4. Potential Targets for Conservative Interventions for Acute Concussions

By viewing PPCS as a form of nociplastic pain secondary to central sensitization, it reveals a time-dependent process that can potentially be interrupted. Recognizing this temporal dimension is key, as it points to a critical therapeutic window for early intervention. The strategic goal is to prevent the neuroplastic changes that are responsible for pain chronification, in line with the International Olympic Committee consensus statement referred to above [3].
Here we cover five components of the central sensitization process specific to concussions that can be targeted with conservative treatments in the acute period: peripheral sensitization, cerebral metabolic dysfunction, neuroinflammation, glymphatic system dysfunction, and pain catastrophizing. As will become clear, certain interventions can potentially positively affect multiple central sensitization-related targets (see Table 2).

4.1. Reducing Peripheral Sensitization

Sustained peripheral pain signaling and peripheral sensitization are the initiating mechanisms of the central sensitization process. Animal models of central sensitization highlight the need for ongoing nociceptive input to drive this phenomenon, suggesting a therapeutic benefit in aggressively reducing such input in the acute period. This approach, particularly in perioperative medicine, has shown promise in mitigating central sensitization-related chronic pain [67].
Since the peripheral source of pain in concussion is primarily through the ophthalmic branches of the trigeminal nerve (V1) that innervate the meninges and cranial periosteum [78] and secondarily through CGRP-mediated activation of the trigeminal ganglion and trigeminocervical nucleus , treatment of peripheral trigeminal hypersensitivity may help abort the development of PPCS [79,80,81].

4.1.1. Exercise

The clinical data on early exercise in the past decade has revolutionized the treatment of concussion injuries, with high quality evidence supporting this intervention [69,82]. One of the many benefits of exercise is that it reduces peripheral sensitization through mechanisms such as endorphin release and changes in pain modulation systems [83]. Importantly, symptom-limited exercise should be prescribed, as overexertion may lead to symptom exacerbation and worsening of peripheral sensitization [84].

4.1.2. Analgesics

Analgesic therapy can be effective at decreasing peripheral sensitization. Non-steroidal anti-inflammatory drugs (NSAIDs) normalize the heightened pain threshold linked to inflammation by inhibiting prostaglandin formation at peripheral and central sites [85]. Acetaminophen achieves peripheral prostaglandin inhibition and can positively affect several central anti-nociception processes [86]. The perioperative use of preventative analgesia with these and other drugs successfully reduces central sensitization-related chronic pain after surgery [87,88].
In the concussion literature, a randomized clinical trial found that a combination of NSAIDs and acetaminophen showed the most promising results in terms of reducing the number of headache days and return to school time [89]. On the other hand, the 5P cohort study (refenced above) showed that emergency room administration of the OTC oral analgesics had no impact on the presence of headaches at the 7 day follow up. There was no mention of whether it was a one-time dose or if treatment was continued at home [90].

4.1.3. Cold Therapy

Cold therapy to the head and neck may potentially reduce peripheral sensitization. Cold compresses alleviate pain by slowing pain signal transmission to the central nervous system and cell metabolism. Additionally, cold reduces inflammation, constricts vessels, and decreases the release of chemical pain mediators, leading to an increased pain threshold and reduced pain [91].
In concussions, branches of the trigeminal nerve that innervate the cranial periosteum show an acute inflammatory response after closed head trauma [79], suggesting that topical cooling may mediate acute trigeminal hypersensitivity in the cutaneous nerves of the scalp and neck. In the clinical literature, one study found that concussed subjects self-reported temporary relief from physical symptoms after head cooling [92]. In another group of studies, players receiving head-neck cooling have shorter time to return-to-play than controls in several studies [72,93].

4.1.4. Physical Therapy

Physical therapy can help reduce hypersensitivity of the balance system. Vestibular therapy has shown promising results when instituted early in cases where there are balance issues. In vertiginous states, there is hypersensitivity in the balance organs, just as there is with other sensory inputs. Just like with exercise, the goal of vestibular therapy is to engage in symptom-limited movements to challenge and reset the hypersensitivity in the balance system. Cervical therapy has also been shown to be beneficial in select cases when started early. Importantly, the neck has cross signaling from trigeminal inputs in the cervicotrigeminal nucleus.

4.1.5. Sensory Protection

Photophobia is common in the acute period after concussion [94], reflecting underlying trigeminal sensory nerve hypersensitivity. Because intrinsically photosensitive retinal ganglion cells (ipRGCs) are sensitive to 480nm light, FL-41 glasses and other tinted lenses are being applied in cases of post-concussive photophobia [95,96]. The use of ear plugs in phonophobia may be helpful in the short term, but there is no data to support this. For sensory hypersensitivity, treatment involves gradual and systematic sound desensitization rather than total deprivation [97].
Table 3. Conservative measures to reduce peripheral sensitization.
Table 3. Conservative measures to reduce peripheral sensitization.
Intervention Rationale
Exercise Activate endogenous pain reduction mechanisms.
Analgesics Interrupt prostaglandin-mediated pain signaling.
Cold Therapy Reduce hypersensitivity of cutaneous trigeminal nerves.
Physical Therapy Reduce hypersensitive of vestibular and cervical inputs.
Sensory Protection Prevent sensory overstimulation.

4.2. Addressing Cerebral Metabolic Dysfunction

The neurometabolic consequences of concussion drive central sensitization-related changes by amplifying peripheral sensitization and secondary injury in the brain. Numerous ionic, metabolic, and physiological changes occur acutely after concussions which contribute to migraine-phenotype symptoms [98]. Cortical spreading depolarization, like those seen in migraine, may represent the initiating event in this cascading metabolic dysfunction [99]. Depolarization results in excess glutamate, which in turn triggers an ionic imbalance that leads to overactivity of sodium-potassium pumps, causing an increase in energy demand in the form of adenosine triphosphate (ATP). This intensifies the need for glucose metabolism and oxygen at a time when cerebral blood flow (CBF) is impaired [23]. These changes overload mitochondria, altering their membrane permeability, and triggering oxidative stress through the production of reactive oxygen species (ROS) [98,100]. This neurometabolic cascade coincides with the first week after injury, the window of time when clinical symptoms are the most severe after concussions and when central sensitization-related changes begin to occur.

4.2.1. Mitochondrial Support

Interventions for acute mitochondrial dysfunction in concussions is a promising and exciting area of study. Because early mitochondrial dysfunction is seen in acute mTBI [101], addressing mitochondrial impairment may enhance mTBI outcomes [102]. Creatine supplementation may help with the metabolic crisis after concussions [103]. In addition to its role in sustaining ATP concentrations and cellular bioenergetics [104], creatine is believed to contribute to preserving mitochondrial membrane potential and reducing intramitochondrial reactive oxygen species and calcium [105]. There is only limited human trial data on creatine in TBI patients, but the results were uniformly positive [106,107].
Ketogenic diets are also being explored for their ability to mitigate mTBI-related glucose hypometabolism [108], with pilot clinical trials in PPCS patients showing promising results [108,109]. Like creatine, ketone bodies serve as an energy substrate, bypassing glycolysis to undergo direct metabolism via the tricarboxylic acid cycle. This process enhances oxygen metabolism, supports mitochondrial function, and reduces oxidative stress and glutamate-induced injury [110].
Another compound of interest is ubiquinol (coenzyme Q-10), which has been shown to preserve mitochondria and reduce oxidative stress in animal TBI models [111].
Vitamin D is now known to be a critical mitochondrial transcription factor and in preclinical models of neurodegenerative disease, it rescues mitochondria from oxidative stress [112,113].

4.2.2. Exercise

Exercise is a powerful intervention for the post-concussion metabolic crisis because it increases CBF, which in turn increases oxygen and glucose delivery [114]. Multiple studies have documented that CBF is decreased in the acute and subacute periods after SRCs [115]. While not quantified in any studies, the beneficial effects seen with early post-concussion exercise may be related to its ability to increase CBF.

4.2.3. Deep Breathing

Clinical evidence shows that regular deep breathing exercises significantly increases blood oxygen levels [116]. Furthermore, breathing exercises have been shown to decrease mitochondrial-related biomarkers of oxidative stress in a variety of clinical contexts [117].

4.2.4. Cold Therapy

Vigorous exercise may lead to hyperthermia, which can exacerbate concussion-related glucose hypometabolism. Therefore, cooling after exercise may improve outcomes in this regard by reducing hyperthermia-related neurometabolic burden [118].
Table 4. Conservative measures to address cerebral metabolic dysfunction.
Table 4. Conservative measures to address cerebral metabolic dysfunction.
Intervention Rationale
Mitochondrial support Use supplements to both provide alternative sources of energy (creatine, ketones) and protect mitochondria (coenzyme Q10, vitamin D).
Exercise Increase CBF for enhanced oxygen and glucose delivery.
Deep breathing Improve blood oxygenation and relieve mitochondrial stress.
Cold Therapy Prevent hyperthermia-related increase in glucose demand.

4.3. Decreasing Neuroinflammation

Neuroinflammation is a pivotal component in the initiation of nociplastic pain after concussions because inflammatory mediators and cytokines drive the sensitization of neurons within the CNS [119]. In traumatic brain injuries, CGRP is an integral player in this process by amplifying the microglial response and priming neurons for neuroplastic changes in the trigeminal system [120]. CGRP levels increase after concussions due to an increased expression in trigeminal nociceptors and in response to post-injury cortical spreading depolarization [121]. In animal models, CGRP inhibitors prevent the development of PPCS-like hypersensitivity when delivered in the first two weeks after injury, but not after this period [21]. Clinically, there is evidence that CGRP polymorphism can partially explain clinical outcomes after concussions [122]. Another study found that intravenous infusion of CGRP triggers migraine-like headaches in people with PPCS, highlighting the significant role of CGRP in the genesis of post-traumatic headaches [123]. These connections suggest that targeting neuroinflammation early after concussion injuries may disrupt the cascade of events, potentially preventing PPCS development [124].

4.3.1. Nutraceuticals

Several nutraceuticals may be beneficial at reducing concussion-induced neuroinflammation. For instance, Vitamin D may reduce neuroinflammatory and secondary injury effects after concussions [125]. Preclinical studies demonstrate that vitamin D improves post-mTBI neuroinflammation and oxidative stress [126,127]. Vitamin D has also been shown to decrease CGRP levels in migraineurs [128]. Importantly, TBI patients low vitamin D levels are noted to have significantly worse cognitive impairment and poor functional outcomes [77,129], whereas early vitamin D supplementation in deficient patients leads to significant improvement in clinical outcomes [130]. Ubiquinol (coenzyme Q-10) has been shown to decrease oxidative stress and neurodegeneration in TBI animal models [131]. It also has been shown to decrease CGRP and neuroinflammatory markers in migraineurs [132,133]. Other nutraceuticals that have been shown to significantly decrease CGRP in human trials for migraine include melatonin [134] and curcumin (turmeric) [135]. Preclinical data shows that omega oils prevent the neuroinflammatory changes in microglia to a pro-inflammatory phenotype, activate neuroprotective cytokines, and mitigate TBI-related blood brain barrier disruption [136,137].

4.3.2. Dietary Changes

There is an increasing interest in the impact of diet on concussion outcomes [109,138,139]. Diets rich in red meat, saturated and trans fats, refined sugars, and carbohydrates are associated with neuroinflammation, while neuroprotective and anti-inflammatory effects are linked to diets high in unsaturated, polyunsaturated, and monounsaturated fats, as well as ketogenic and Mediterranean diets, and intermittent fasting [140]. The effects on anti-neuroinflammatory (ANI) diets on TBI outcomes are being worked out in both preclinical [141] and clinical studies [109,142]. Specific supplements have been extensive studied, most notably the use of omega oils [143,144,145]. There is also interest in the impact of TBI on the gut microbiome [146]. Other recommendations include low glutamate, low tyramine, and low histamine diet combined with the elimination of caffeine from the diet.

4.3.3. Exercise

Regular moderate-intensity exercise is associated with anti-inflammatory effects [147]. Animal models of TBI support that early exercise reduces markers of neuroinflammation and nociceptive sensitization [148,149]. Further research is being proposed on the role of exercise immunology in TBI outcomes [150].

4.3.4. Stress Reduction

There is a direct association between psychological stress and neuroinflammation [151]. Stress-reducing interventions like deep breathing and mindfulness-based stress reduction (MBSR) have been shown to decrease biomarkers of neuroinflammation in clinical trials of central sensitization-related symptoms [152]. Multiple clinical trials suggest that mindfulness-based interventions are supportive of mTBI recovery [153].
Table 4. Conservative measures to decrease neuroinflammation.
Table 4. Conservative measures to decrease neuroinflammation.
Intervention Rationale
Nutraceuticals Use supplements that target CGRP (vitamin D, coenzyme q10, melatonin, turmeric) and other pro-inflammatory processes (omega oils).
Dietary Changes Reduce proinflammatory foods, reduce glutamate, tyramine, histamine, increase anti-inflammatory foods, and provide gut microbiome support (probiotics). Eliminate caffeine.
Exercise Moderate intensity exercise reduces neuroinflammation.
Stress Reduction Mindfulness and deep breathing to reduce stress-related contributions to neuroinflammation.

4.4. Optimizing Glymphatic System Functioning

The prolonged presence of neuroinflammation in concussions may be associated with dysfunction in the glymphatic system during the acute phase following the injury [154]. The glymphatic system, a waste clearance pathway in the central nervous system, plays a crucial role in removing metabolic byproducts and cellular debris after concussion [155]. Damage-associated molecular patterns (DAMPs) are due to normally intracellular proteins that, when released into the extracellular space after trauma, elicit an immune response. The release of DAMPs is linked to adverse post-TBI outcomes, including diminished memory, altered motor coordination, and cognitive impairments [100]. This debris is normally cleared by the glymphatic system, but in the aftermath of a concussion, the glymphatic system functioning is decreased by up to 60% [156]. This compromised waste removal process contributes to the sustained inflammatory response to neurotoxic proteins (like tau), which in turn is permissive of central sensitization-related neuroplasticity [157]. This is concerning, as cumulative tau deposition around intracerebral vessels is the histological definition of chronic traumatic encephalopathy (CTE) [158]. Therefore, optimizing glymphatic function in the acute period after concussions is an important therapeutic goal [17].

4.4.1. Circadian therapy

The glymphatic system is linked to sleep and the circadian system, with over 80% of glymphatic system clearance occurring during deep sleep [159,160,161]. Because sleep is also pathologically disturbed after concussion injuries [162,163], circadian therapy interventions are important early interventions. Melatonin has been extensively studied as an adjuvant therapy for concussions, with a meta-analysis showing positive sleep-related outcomes in 8 of 9 studies [75]. Limiting blue light via screen-time restriction positively impacts concussion recovery time [164]. Morning blue light therapy is associated with improvement in multiple concussion outcomes in patients with established PPCS [165]. Finally, because sleep apnea significantly disrupts glymphatic function [166] and is associated with poor outcomes in concussion [167], screening for and treatment of sleep apnea is recommended in concussion injuries. Other interventions along these lines include sleep hygiene, cognitive behavioral therapy (CBT), and prescribed exercise [17].

4.4.2. Omega oils

Numerous studies demonstrate the positive impact of omega oils on sleep quality and their influence on circadian variations in blood pressure, potentially through direct effects on melatonin release and norepinephrine regulation [168,169]. Additionally, in a TBI animal model, omega oils were found to enhance glymphatic drainage, reducing neurological impairment after simulated injury; this effect was directly related to improved glymphatic clearance [137].

4.4.3. Exercise and Deep Breathing

Because exercise increases blood pressure and CSF flow, it has a positive effect on glymphatic functioning [170,171]. Similarly, deep breathing influences glymphatic clearance by increasing the flow magnitude of CSF [172].
Table 5. Conservative measures to optimize the glymphatic system.
Table 5. Conservative measures to optimize the glymphatic system.
Intervention Rationale
Circadian Therapy 80% of glymphatic clearance occurs during sleep. Methods to improve deep sleep include melatonin, screen and evening light restriction, morning blue light exposure, and sleep hygiene.
Omega oils Omega oils directly enhance glymphatic clearance through their effect on aquaporin channels. Indirectly, they improve the glymphatic system by their positive influence on sleep.
Exercise and Deep Breathing Exercise increases blood pressure and heart rate, which then increases CSF flow. Deep breathing also increases CSF flow.

4.5. Pain Catastrophizing

Another possible target to prevent the central sensitization process after concussion is pain catastrophizing in the acute period [173]. Pain catastrophizing is the putative link between trait anxiety and post-concussion symptoms [174]. Pain catastrophizing involves an exaggerated negative mental outlook toward pain, magnifying its threat, fostering feelings of helplessness, and contributing to increased distress and disability. Several orthopedic studies have linked pain catastrophizing with the development of nociplastic pain and central sensitization [175,176,177].
In concussion research, pain catastrophizing subscales (rumination, magnification, and helplessness) show significant correlations with pain severity, the number of reported post-concussion symptoms, psychological distress, and functional levels [178]. These findings are related to studies on the relationship between trait resilience (arguably the opposite of pain catastrophizing) and concussion outcomes. Reduced resilience is linked to increased symptoms and a prolonged recovery from SRCs, whereas high resilience shows the opposite [179,180].

4.5.1. Mindfulness, Meditation, and Deep Breathing

There is significant clinical evidence that trait mindfulness is negatively associated with pain catastrophizing [181,182] and that mindfulness exercises may help abort pain catastrophizing [152,183,184]. A recent meta-analysis examining the impact of post-mTBI interventions like mindfulness, meditation, and yoga revealed substantial improvement in overall symptoms when compared to control groups, including improvements in mental health, physical well-being, cognitive performance, and overall quality of life [73]. In a pilot study, deep breathing exercises in concussion patients was associated with decreased stress and tension [71].

4.5.2. Coaching

The use of coaching in pain management is gaining interest. Clinical trials of health coaching to aid with stress management and goal-setting in chronic pain patients show reduced psychological stress and improved resilience [185]. In the concussion literature, web-based resources combined with weekly coaching sessions produced improved outcomes and high patient satisfaction rates [186]. In a randomized trial, collaborative care, where coping skills, relaxation strategies, sleep hygiene, and positive thinking techniques were coached, showed significantly improved results in PPCS patients [187]. In another randomized trial, the addition of weekly motivational interviewing and CBT significantly improved multiple mTBI outcome measures [188]. Another randomized trial showed that regular telephonic follow-up using motivational and behavioral activation approaches resulted in significantly lower depression scores, including in those with preexisting depression [189].

4.5.3. Exercise

There is evidence that exercise can improve pain catastrophizing by influencing the fear center of the brain. Voluntary exercise stimulates neurons in the mesolimbic system, including in the amygdala. This has been suggested as the mechanism by which exercise aids in overcoming fear-avoidance behaviors associated with chronic pain conditions [190].
Table 6. Conservative measures to address pain catastrophizing.
Table 6. Conservative measures to address pain catastrophizing.
Intervention Rationale
Mindfulness, Deep Breathing Trait mindfulness is the key to aborting pain catastrophizing. Deep breathing is in essence a form of mindfulness.
Coaching Coaching helps maintain motivation and promotes resilience. Human contact is also healing, the “social” in biopsychosocial care.
Exercise Moderate intensity exercise reduces neuroinflammation.

5. Conclusion

In outlining PPCS as a form of chronic pain, and by examining the mechanisms for how chronic pain develops using the central sensitization model, several interventions for the prevention of prolonged symptoms and PPCS emerge. These include methods designed to reduce peripheral sensitization, address cerebral metabolic dysfunction, mitigate post-concussion neuroinflammation, optimize glymphatic system functioning, and reduce pain catastrophizing. This proactive program is in line with the principles of conservative management in sports medicine.
There are several inherent limitations in the current review. First, any review of this type is limited by the author’s awareness of all potentially relevant research. In addition, apart from exercise, there is a shortage of high-quality evidence-based research supporting many of the potentially promising interventions mentioned above.
Despite this limitations, theory-informed treatments and insights from preclinical studies, particularly those grounded in the central sensitization model, can still play a pivotal role in developing a program for proactive conservative care. Our hope is that this review contributes meaningfully to addressing empirical and knowledge gaps in the concussion literature and guiding strategic interventions in concussion management.

Author Contributions

Conceptualization, H.D., J.F., and S.K.; methodology, H.D; software, N/A; validation, N/A.; formal analysis, H.D.; investigation, J.F. and M.M.; resources, H.D.; data curation, J.F.; writing—original draft preparation, H.D., J.F., and M.M.; writing—review and editing, M.M and S.K.; visualization, N/A; supervision, H.D.; project administration, S.K.; funding acquisition, N/A. All authors have read and agreed to the published version of the manuscript.”.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data available online.

Acknowledgments

Brian McGuire, for general support.

Conflicts of Interest

The authors of this review article are currently engaged in the clinical treatment of concussions in a for-profit setting. The associated organization is TBI Virtual, a telehealth clinic that specializes in concussion care (www.tbivirtual.com).

References

  1. Bober, S. Conservative Management of Sports Injuries 2nd Edition. J. Can. Chiropr. Assoc. 2009, 53, 216–217.
  2. Treede, R.-D.; Rief, W.; Barke, A.; Aziz, Q.; Bennett, M.I.; Benoliel, R.; Cohen, M.; Evers, S.; Finnerup, N.B.; First, M.B.; et al. Chronic Pain as a Symptom or a Disease: The IASP Classification of Chronic Pain for the International Classification of Diseases (ICD-11). PAIN 2019, 160, 19. [CrossRef]
  3. Hainline, B.; Derman, W.; Vernec, A.; Budgett, R.; Deie, M.; Dvořák, J.; Harle, C.; Herring, S.A.; McNamee, M.; Meeuwisse, W.; et al. International Olympic Committee Consensus Statement on Pain Management in Elite Athletes. Br. J. Sports Med. 2017, 51, 1245–1258. [CrossRef]
  4. Clauw, D.J.; Essex, M.N.; Pitman, V.; Jones, K.D. Reframing Chronic Pain as a Disease, Not a Symptom: Rationale and Implications for Pain Management. Postgrad. Med. 2019, 131, 185–198. [CrossRef]
  5. Igolnikov, I.; Gallagher, R.M.; Hainline, B. Sport-Related Injury and Pain Classification. Handb. Clin. Neurol. 2018, 158, 423–430. [CrossRef]
  6. Nijs, J.; Lahousse, A.; Kapreli, E.; Bilika, P.; Saraçoğlu, İ.; Malfliet, A.; Coppieters, I.; De Baets, L.; Leysen, L.; Roose, E.; et al. Nociplastic Pain Criteria or Recognition of Central Sensitization? Pain Phenotyping in the Past, Present and Future. J. Clin. Med. 2021, 10, 3203. [CrossRef]
  7. Winslow, J.J.; Jackson, M.; Getzin, A.; Costello, M. Rehabilitation of a Young Athlete With Extension-Based Low Back Pain Addressing Motor-Control Impairments and Central Sensitization. J. Athl. Train. 2018, 53, 168–173. [CrossRef]
  8. Steinmetz, A.; Hacke, F.; Delank, K.-S. Pressure Pain Thresholds and Central Sensitization in Relation to Psychosocial Predictors of Chronicity in Low Back Pain. Diagn. Basel Switz. 2023, 13, 786. [CrossRef]
  9. Li, W.; Gong, Y.; Liu, J.; Guo, Y.; Tang, H.; Qin, S.; Zhao, Y.; Wang, S.; Xu, Z.; Chen, B. Peripheral and Central Pathological Mechanisms of Chronic Low Back Pain: A Narrative Review. J. Pain Res. 2021, 14, 1483–1494. [CrossRef]
  10. Bilika, P.; Nijs, J.; Fandridis, E.; Dimitriadis, Z.; Strimpakos, N.; Kapreli, E. In the Shoulder or in the Brain? Behavioral, Psychosocial and Cognitive Characteristics of Unilateral Chronic Shoulder Pain with Symptoms of Central Sensitization. Healthcare 2022, 10, 1658. [CrossRef]
  11. Rankin, J.; Rudy-Froese, B.; Hoyt, C.; Ramsahoi, K.; Gareau, L.; Howatt, W.; Carlesso, L. Quantitative Sensory Testing Protocols to Evaluate Central and Peripheral Sensitization in Knee OA: A Scoping Review. Pain Med. Malden Mass 2022, 23, 526–557. [CrossRef]
  12. San-Antolín, M.; Rodríguez-Sanz, D.; Becerro-de-Bengoa-Vallejo, R.; Losa-Iglesias, M.E.; Casado-Hernández, I.; López-López, D.; Calvo-Lobo, C. Central Sensitization and Catastrophism Symptoms Are Associated with Chronic Myofascial Pain in the Gastrocnemius of Athletes. Pain Med. Malden Mass 2020, 21, 1616–1625. [CrossRef]
  13. Coombes, B.K.; Bisset, L.; Vicenzino, B. Management of Lateral Elbow Tendinopathy: One Size Does Not Fit All. J. Orthop. Sports Phys. Ther. 2015, 45, 938–949. [CrossRef]
  14. Raney, E.B.; Thankam, F.G.; Dilisio, M.F.; Agrawal, D.K. Pain and the Pathogenesis of Biceps Tendinopathy. Am. J. Transl. Res. 2017, 9, 2668–2683.
  15. Ferrillo, M.; Giudice, A.; Marotta, N.; Fortunato, F.; Di Venere, D.; Ammendolia, A.; Fiore, P.; de Sire, A. Pain Management and Rehabilitation for Central Sensitization in Temporomandibular Disorders: A Comprehensive Review. Int. J. Mol. Sci. 2022, 23, 12164. [CrossRef]
  16. Suzuki, K.; Suzuki, S.; Shiina, T.; Kobayashi, S.; Hirata, K. Central Sensitization in Migraine: A Narrative Review. J. Pain Res. 2022, 15, 2673–2682. [CrossRef]
  17. Kureshi, S.; Stowe, C.; Francis, J.; Djalilian, H. Circadian Therapy Interventions for Glymphatic Dysfunction in Concussions Injuries: A Narrative Review. Sci. Prog. 2023, 106, 368504231189536. [CrossRef]
  18. Harmon, K.G.; Drezner, J.A.; Gammons, M.; Guskiewicz, K.M.; Halstead, M.; Herring, S.A.; Kutcher, J.S.; Pana, A.; Putukian, M.; Roberts, W.O. American Medical Society for Sports Medicine Position Statement: Concussion in Sport. Br. J. Sports Med. 2013, 47, 15–26. [CrossRef]
  19. Patricios, J.S.; Schneider, K.J.; Dvorak, J.; Ahmed, O.H.; Blauwet, C.; Cantu, R.C.; Davis, G.A.; Echemendia, R.J.; Makdissi, M.; McNamee, M.; et al. Consensus Statement on Concussion in Sport: The 6th International Conference on Concussion in Sport-Amsterdam, October 2022. Br. J. Sports Med. 2023, 57, 695–711. [CrossRef]
  20. Cortez, M.M.; Millsap, L.; Rea, N.A.; Sciarretta, C.; Brennan, K.C. Photophobia and Allodynia in Persistent Post-Traumatic Headache Are Associated with Higher Disease Burden. Cephalalgia Int. J. Headache 2021, 41, 1089–1099. [CrossRef]
  21. Navratilova, E.; Rau, J.; Oyarzo, J.; Tien, J.; Mackenzie, K.; Stratton, J.; Remeniuk, B.; Schwedt, T.; Anderson, T.; Dodick, D.; et al. CGRP-Dependent and Independent Mechanisms of Acute and Persistent Post-Traumatic Headache Following Mild Traumatic Brain Injury in Mice. Cephalalgia Int. J. Headache 2019, 39, 1762–1775. [CrossRef]
  22. Tanaka, M.; Zhang, Y. Preclinical Studies of Posttraumatic Headache and the Potential Therapeutics. Cells 2022, 12, 155. [CrossRef]
  23. Neumann, K.D.; Broshek, D.K.; Newman, B.T.; Druzgal, T.J.; Kundu, B.K.; Resch, J.E. Concussion: Beyond the Cascade. Cells 2023, 12, 2128. [CrossRef]
  24. Wingerson, M.J.; Magliato, S.N.; Smulligan, K.L.; Wilson, J.C.; Little, C.C.; Howell, D.R. Predicting Time to Evaluation After Pediatric Concussion: Factors Affecting Specialty Concussion Care. Orthop. J. Sports Med. 2023, 11, 23259671231186430. [CrossRef]
  25. Bock, S.; Grim, R.; Barron, T.F.; Wagenheim, A.; Hu, Y.E.; Hendell, M.; Deitch, J.; Deibert, E. Factors Associated with Delayed Recovery in Athletes with Concussion Treated at a Pediatric Neurology Concussion Clinic. Childs Nerv. Syst. ChNS Off. J. Int. Soc. Pediatr. Neurosurg. 2015, 31, 2111–2116. [CrossRef]
  26. Cassimatis, M.; Orr, R.; Fyffe, A.; Browne, G. Early Injury Evaluation Following Concussion Is Associated with Improved Recovery Time in Children and Adolescents. J. Sci. Med. Sport 2021, 24, 1235–1239. [CrossRef]
  27. Eagle, S.R.; Puligilla, A.; Fazio-Sumrok, V.; Kegel, N.; Collins, M.W.; Kontos, A.P. Association of Time to Initial Clinic Visit with Prolonged Recovery in Pediatric Patients with Concussion. J. Neurosurg. Pediatr. 2020, 26, 165–170. [CrossRef]
  28. Kontos, A.P.; Jorgensen-Wagers, K.; Trbovich, A.M.; Ernst, N.; Emami, K.; Gillie, B.; French, J.; Holland, C.; Elbin, R.J.; Collins, M.W. Association of Time Since Injury to the First Clinic Visit With Recovery Following Concussion. JAMA Neurol. 2020, 77, 435–440. [CrossRef]
  29. Pratile, T.; Marshall, C.; DeMatteo, C. Examining How Time from Sport-Related Concussion to Initial Assessment Predicts Return-to-Play Clearance. Phys. Sportsmed. 2022, 50, 132–140. [CrossRef]
  30. McCrory, P.; Meeuwisse, W.; Dvořák, J.; Aubry, M.; Bailes, J.; Broglio, S.; Cantu, R.C.; Cassidy, D.; Echemendia, R.J.; Castellani, R.J.; et al. Consensus Statement on Concussion in Sport-the 5th International Conference on Concussion in Sport Held in Berlin, October 2016. Br. J. Sports Med. 2017, 51, 838–847. [CrossRef]
  31. Harmon, K.G.; Clugston, J.R.; Dec, K.; Hainline, B.; Herring, S.; Kane, S.F.; Kontos, A.P.; Leddy, J.J.; McCrea, M.; Poddar, S.K.; et al. American Medical Society for Sports Medicine Position Statement on Concussion in Sport. Br. J. Sports Med. 2019, 53, 213–225. [CrossRef]
  32. Auxéméry, Y.; Gayraud, F. Post-Concussion Syndrome: Still Forgotten? From the Disappearance of the DSM-5 to a Multidisciplinary Consultation. L’Encephale 2021, 47, 491–494. [CrossRef]
  33. Boake, C.; McCauley, S.R.; Levin, H.S.; Pedroza, C.; Contant, C.F.; Song, J.X.; Brown, S.A.; Goodman, H.; Brundage, S.I.; Diaz-Marchan, P.J. Diagnostic Criteria for Postconcussional Syndrome After Mild to Moderate Traumatic Brain Injury. J. Neuropsychiatry Clin. Neurosci. 2005, 17, 350–356. [CrossRef]
  34. Heslot, C.; Azouvi, P.; Perdrieau, V.; Granger, A.; Lefèvre-Dognin, C.; Cogné, M. A Systematic Review of Treatments of Post-Concussion Symptoms. J. Clin. Med. 2022, 11, 6224. [CrossRef]
  35. Organization, W.H. The ICD-10 Classification of Mental and Behavioural Disorders: Clinical Descriptions and Diagnostic Guidelines; World Health Organization, 1992; ISBN 978-92-4-154422-1.
  36. Zimmerman, K.A.; Cournoyer, J.; Lai, H.; Snider, S.B.; Fischer, D.; Kemp, S.; Karton, C.; Hoshizaki, T.B.; Ghajari, M.; Sharp, D.J. The Biomechanical Signature of Loss of Consciousness: Computational Modelling of Elite Athlete Head Injuries. Brain 2022, 146, 3063–3078. [CrossRef]
  37. Hou, R.; Moss-Morris, R.; Peveler, R.; Mogg, K.; Bradley, B.P.; Belli, A. When a Minor Head Injury Results in Enduring Symptoms: A Prospective Investigation of Risk Factors for Postconcussional Syndrome after Mild Traumatic Brain Injury. J. Neurol. Neurosurg. Psychiatry 2012, 83, 217–223. [CrossRef]
  38. Theadom, A.; Parag, V.; Dowell, T.; McPherson, K.; Starkey, N.; Barker-Collo, S.; Jones, K.; Ameratunga, S.; Feigin, V.L. Persistent Problems 1 Year after Mild Traumatic Brain Injury: A Longitudinal Population Study in New Zealand. Br. J. Gen. Pract. 2016, 66, e16–e23. [CrossRef]
  39. Nelson, L.D.; Temkin, N.R.; Dikmen, S.; Barber, J.; Giacino, J.T.; Yuh, E.; Levin, H.S.; McCrea, M.A.; Stein, M.B.; Mukherjee, P.; et al. Recovery After Mild Traumatic Brain Injury in Patients Presenting to US Level I Trauma Centers. JAMA Neurol. 2019, 76, 1049–1059. [CrossRef]
  40. Machamer, J.; Temkin, N.; Dikmen, S.; Nelson, L.D.; Barber, J.; Hwang, P.; Boase, K.; Stein, M.B.; Sun, X.; Giacino, J.; et al. Symptom Frequency and Persistence in the First Year after Traumatic Brain Injury: A TRACK-TBI Study. J. Neurotrauma 2022, 39, 358–370. [CrossRef]
  41. Lyons, T.W.; Mannix, R.; Tang, K.; Yeates, K.O.; Sangha, G.; Burns, E.C.; Beer, D.; Dubrovsky, A.S.; Gagnon, I.; Gravel, J.; et al. Paediatric Post-Concussive Symptoms: Symptom Clusters and Clinical Phenotypes. Br. J. Sports Med. 2022, 56, 785–791. [CrossRef]
  42. Bretzin, A.C.; Esopenko, C.; D’Alonzo, B.A.; Wiebe, D.J. Clinical Recovery Timelines After Sport-Related Concussion in Men’s and Women’s Collegiate Sports. J. Athl. Train. 2022, 57, 678–687. [CrossRef]
  43. McAllister, T.W.; Broglio, S.P.; Katz, B.P.; Perkins, S.M.; LaPradd, M.; Zhou, W.; McCrea, M.A. Characteristics and Outcomes of Athletes With Slow Recovery From Sports-Related Concussion. Neurology 2023, 100, e1510–e1519. [CrossRef]
  44. Comper, P.; Foster, E.; Chandra, T.; Langer, L.; Wiseman-Hakes, C.; Mochizuki, G.; Ruttan, L.; Lawrence, D.W.; Inness, E.L.; Gladstone, J.; et al. The Toronto Concussion Study: A Prospective Investigation of Characteristics in a Cohort of Adults from the General Population Seeking Care Following Acute Concussion, 2016–2020. Front. Neurol. 2023, 14, 1152504. [CrossRef]
  45. Mikolic, A.; Panenka, W.J.; Iverson, G.L.; Cotton, E.; Burke, M.J.; Silverberg, N.D. Litigation, Performance Validity Testing, and Treatment Outcomes in Adults With Mild Traumatic Brain Injury. J. Head Trauma Rehabil. 2023. [CrossRef]
  46. Kerr, Z.Y.; Zuckerman, S.L.; Wasserman, E.B.; Vander Vegt, C.B.; Yengo-Kahn, A.; Buckley, T.A.; Solomon, G.S.; Sills, A.K.; Dompier, T.P. Factors Associated with Post-Concussion Syndrome in High School Student-Athletes. J. Sci. Med. Sport 2018, 21, 447–452. [CrossRef]
  47. Cuff, S.; Maki, A.; Feiss, R.; Young, J.; Shi, J.; Hautmann, A.; Yang, J. Risk Factors for Prolonged Recovery from Concussion in Young Patients. Br. J. Sports Med. 2022, 56, 1345–1352. [CrossRef]
  48. Martin, A.K.; Petersen, A.J.; Sesma, H.W.; Koolmo, M.B.; Ingram, K.M.; Slifko, K.B.; Nguyen, V.N.; Doss, R.C.; Linabery, A.M. Learning and Attention Deficit/Hyperactivity Disorders as Risk Factors for Prolonged Concussion Recovery in Children and Adolescents. J. Int. Neuropsychol. Soc. JINS 2022, 28, 109–122. [CrossRef]
  49. Langer, L.; Levy, C.; Bayley, M. Increasing Incidence of Concussion: True Epidemic or Better Recognition? J. Head Trauma Rehabil. 2020, 35, E60–E66. [CrossRef]
  50. Nolan, K.E.; Caccese, J.B.; Kontos, A.P.; Buckley, T.A.; Garcia, G.-G.P.; Port, N.; Broglio, S.P.; McAllister, T.W.; McCrea, M.; Pasquina, P.F.; et al. Primary and Secondary Risk Factors Associated With Concussion Symptom Clusters in Collegiate Athletes: Results From the NCAA-DoD Grand Alliance CARE Consortium. Orthop. J. Sports Med. 2023, 11, 23259671231163581. [CrossRef]
  51. Cassimatis, M.; Orr, R.; Fyffe, A.; Browne, G. Association of Sleep Disturbance With Neurocognition, Symptom Severity, and Recovery in Pediatric Concussion: A 10-Year Retrospective Analysis of a Tertiary Referral Concussion Clinic. J. Head Trauma Rehabil. 2023, 38, 231–239. [CrossRef]
  52. Robinson, M.; Johnson, A.M.; Fischer, L.K.; MacKenzie, H.M. Two Symptoms to Triage Acute Concussions: Using Decision Tree Modeling to Predict Prolonged Recovery After a Concussion. Am. J. Phys. Med. Rehabil. 2022, 101, 135–138. [CrossRef]
  53. Wäljas, M.; Iverson, G.L.; Lange, R.T.; Hakulinen, U.; Dastidar, P.; Huhtala, H.; Liimatainen, S.; Hartikainen, K.; Öhman, J. A Prospective Biopsychosocial Study of the Persistent Post-Concussion Symptoms Following Mild Traumatic Brain Injury. J. Neurotrauma 2015, 32, 534–547. [CrossRef]
  54. Woolf, C.J. Central Sensitization: Implications for the Diagnosis and Treatment of Pain. Pain 2011, 152, S2-15. [CrossRef]
  55. Afroz, S.; Arakaki, R.; Iwasa, T.; Oshima, M.; Hosoki, M.; Inoue, M.; Baba, O.; Okayama, Y.; Matsuka, Y. CGRP Induces Differential Regulation of Cytokines from Satellite Glial Cells in Trigeminal Ganglia and Orofacial Nociception. Int. J. Mol. Sci. 2019, 20, E711. [CrossRef]
  56. Staniszewski, K.; Lygre, H.; Bifulco, E.; Kvinnsland, S.; Willassen, L.; Helgeland, E.; Berge, T.; Rosén, A. Temporomandibular Disorders Related to Stress and HPA-Axis Regulation. Pain Res. Manag. 2018, 2018, 7020751. [CrossRef]
  57. Bowen, A.J.; Huang, Y.W.; Chen, J.Y.; Pauli, J.L.; Campos, C.A.; Palmiter, R.D. Topographic Representation of Current and Future Threats in the Mouse Nociceptive Amygdala. Nat. Commun. 2023, 14, 196. [CrossRef]
  58. Robayo, L.E.; Govind, V.; Vastano, R.; Felix, E.R.; Fleming, L.; Cherup, N.P.; Widerström-Noga, E. Multidimensional Pain Phenotypes after Traumatic Brain Injury. Front. Pain Res. 2022, 3.
  59. Kumar, R.G.; Ornstein, K.A.; Corrigan, J.D.; Sayko Adams, R.; Dams-O’Connor, K. Association between Lifetime History of Traumatic Brain Injury, Prescription Opioid Use, and Persistent Pain: A Nationally Representative Study. J. Neurotrauma 2021, 38, 2284–2290. [CrossRef]
  60. Ofek, H.; Defrin, R. The Characteristics of Chronic Central Pain after Traumatic Brain Injury. Pain 2007, 131, 330–340. [CrossRef]
  61. Volcheck, M.M.; Graham, S.M.; Fleming, K.C.; Mohabbat, A.B.; Luedtke, C.A. Central Sensitization, Chronic Pain, and Other Symptoms: Better Understanding, Better Management. Cleve. Clin. J. Med. 2023, 90, 245–254. [CrossRef]
  62. Kuisell, C.; Ploutz-Snyder, R.; Williams, D.A.; Voepel-Lewis, T.; Hutchinson, R.J.; Dudding, K.M.; Bridges, C.; Lavoie Smith, E.M. Adolescents and Young Adults With Sickle Cell Disease: Nociplastic Pain and Pain Catastrophizing as Predictors of Pain Interference and Opioid Consumption. Clin. J. Pain 2023, 39, 326–333. [CrossRef]
  63. Tham, S.W.; Palermo, T.M.; Chrisman, S.; Groenewald, C.B. Prescription Opioid Misuse and Sports-Related Concussion among High School Students in the United States. J. Head Trauma Rehabil. 2021, 36, 338–344. [CrossRef]
  64. Ilie, G.; Mann, R.E.; Hamilton, H.; Adlaf, E.M.; Boak, A.; Asbridge, M.; Rehm, J.; Cusimano, M.D. Substance Use and Related Harms Among Adolescents With and Without Traumatic Brain Injury. J. Head Trauma Rehabil. 2015, 30, 293–301. [CrossRef]
  65. Druce, K.L.; McBeth, J. Central Sensitization Predicts Greater Fatigue Independently of Musculoskeletal Pain. Rheumatology 2019, 58, 1923–1927. [CrossRef]
  66. Fern, J.; ez-Sola Central Sensitization: A Pathogenic Mechanism in Complex Undefined Diseases. 2019, 9, 2485–2490. [CrossRef]
  67. Harte, S.E.; Harris, R.E.; Clauw, D.J. The Neurobiology of Central Sensitization. J. Appl. Biobehav. Res. 2018, 23, e12137. [CrossRef]
  68. Goudman, L.; De Smedt, A.; Roggeman, S.; Fernández-de-Las-Peñas, C.; Hatem, S.M.; Schiltz, M.; Billot, M.; Roulaud, M.; Rigoard, P.; Moens, M. Association between Experimental Pain Measurements and the Central Sensitization Inventory in Patients at Least 3 Months after COVID-19 Infection: A Cross-Sectional Pilot Study. J. Clin. Med. 2023, 12, 661. [CrossRef]
  69. Leddy, J.J.; Burma, J.S.; Toomey, C.M.; Hayden, A.; Davis, G.A.; Babl, F.E.; Gagnon, I.; Giza, C.C.; Kurowski, B.G.; Silverberg, N.D.; et al. Rest and Exercise Early after Sport-Related Concussion: A Systematic Review and Meta-Analysis. Br. J. Sports Med. 2023, 57, 762–770. [CrossRef]
  70. Grool, A.M.; Aglipay, M.; Momoli, F.; Meehan, W.P.; Freedman, S.B.; Yeates, K.O.; Gravel, J.; Gagnon, I.; Boutis, K.; Meeuwisse, W.; et al. Association Between Early Participation in Physical Activity Following Acute Concussion and Persistent Postconcussive Symptoms in Children and Adolescents. JAMA 2016, 316, 2504–2514. [CrossRef]
  71. Cook, N.E.; Huebschmann, N.A.; Iverson, G.L. Safety and Tolerability of an Innovative Virtual Reality-Based Deep Breathing Exercise in Concussion Rehabilitation: A Pilot Study. Dev. Neurorehabilitation 2021, 24, 222–229. [CrossRef]
  72. Al-Husseini, A.; Fazel Bakhsheshi, M.; Gard, A.; Tegner, Y.; Marklund, N. Shorter Recovery Time in Concussed Elite Ice Hockey Players by Early Head-and-Neck Cooling: A Clinical Trial. J. Neurotrauma 2022. [CrossRef]
  73. Acabchuk, R.L.; Brisson, J.M.; Park, C.L.; Babbott-Bryan, N.; Parmelee, O.A.; Johnson, B.T. Therapeutic Effects of Meditation, Yoga, and Mindfulness-Based Interventions for Chronic Symptoms of Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis. Appl. Psychol. Health Well-Being 2021, 13, 34–62. [CrossRef]
  74. Barlow, K.M.; Esser, M.J.; Veidt, M.; Boyd, R. Melatonin as a Treatment after Traumatic Brain Injury: A Systematic Review and Meta-Analysis of the Pre-Clinical and Clinical Literature. J. Neurotrauma 2019, 36, 523–537. [CrossRef]
  75. Cassimatis, M.; Browne, G.; Orr, R. The Utility of Melatonin for the Treatment of Sleep Disturbance After Traumatic Brain Injury: A Scoping Review. Arch. Phys. Med. Rehabil. 2022, S0003-9993(22)01656-2. [CrossRef]
  76. Miller, S.M.; Zynda, A.J.; Sabatino, M.J.; Jo, C.; Ellis, H.B.; Dimeff, R.J. A Pilot Randomized Controlled Trial of Docosahexaenoic Acid for the Treatment of Sport-Related Concussion in Adolescents. Clin. Pediatr. (Phila.) 2022, 61, 785–794. [CrossRef]
  77. Choudhary, A.; Kumar, A.; Sharma, R.; Khurana, L.; Jain, S.; Sharma, S.; Kumar, D.; Sharma, S. Optimal Vitamin D Level Ameliorates Neurological Outcome and Quality of Life after Traumatic Brain Injury: A Clinical Perspective. Int. J. Neurosci. 2023, 133, 417–425. [CrossRef]
  78. Zhao, J.; Levy, D. The Sensory Innervation of the Calvarial Periosteum Is Nociceptive and Contributes to Headache-like Behavior. PAIN® 2014, 155, 1392–1400. [CrossRef]
  79. Benromano, T.; Defrin, R.; Ahn, A.H.; Zhao, J.; Pick, C.G.; Levy, D. Mild Closed Head Injury Promotes a Selective Trigeminal Hypernociception: Implications for the Acute Emergence of Post-Traumatic Headache. Eur. J. Pain Lond. Engl. 2015, 19, 621–628. [CrossRef]
  80. Daiutolo, B.V.; Tyburski, A.; Clark, S.W.; Elliott, M.B. Trigeminal Pain Molecules, Allodynia, and Photosensitivity Are Pharmacologically and Genetically Modulated in a Model of Traumatic Brain Injury. J. Neurotrauma 2016, 33, 748–760. [CrossRef]
  81. Tyburski, A.L.; Cheng, L.; Assari, S.; Darvish, K.; Elliott, M.B. Frequent Mild Head Injury Promotes Trigeminal Sensitivity Concomitant with Microglial Proliferation, Astrocytosis, and Increased Neuropeptide Levels in the Trigeminal Pain System. J. Headache Pain 2017, 18, 16. [CrossRef]
  82. Lal, A.; Kolakowsky-Hayner, S.A.; Ghajar, J.; Balamane, M. The Effect of Physical Exercise After a Concussion: A Systematic Review and Meta-Analysis. Am. J. Sports Med. 2018, 46, 743–752. [CrossRef]
  83. Manojlović, D.; Kopše, E.I. The Effectiveness of Aerobic Exercise for Pain Management in Patients with Fibromyalgia. Eur. J. Transl. Myol. 2023, 33, 11423. [CrossRef]
  84. Leddy, J.J.; Haider, M.N.; Ellis, M.J.; Mannix, R.; Darling, S.R.; Freitas, M.S.; Suffoletto, H.N.; Leiter, J.; Cordingley, D.M.; Willer, B. Early Subthreshold Aerobic Exercise for Sport-Related Concussion: A Randomized Clinical Trial. JAMA Pediatr. 2019, 173, 319–325. [CrossRef]
  85. Burian, M.; Geisslinger, G. COX-Dependent Mechanisms Involved in the Antinociceptive Action of NSAIDs at Central and Peripheral Sites. Pharmacol. Ther. 2005, 107, 139–154. [CrossRef]
  86. Jóźwiak-Bebenista, M.; Nowak, J.Z. Paracetamol: Mechanism of Action, Applications and Safety Concern. Acta Pol. Pharm. 2014, 71, 11–23.
  87. Fregoso, G.; Wang, A.; Tseng, K.; Wang, J. Transition from Acute to Chronic Pain: Evaluating Risk for Chronic Postsurgical Pain. Pain Physician 2019, 22, 479–488.
  88. Pak, D.J.; Yong, R.J.; Kaye, A.D.; Urman, R.D. Chronification of Pain: Mechanisms, Current Understanding, and Clinical Implications. Curr. Pain Headache Rep. 2018, 22, 9. [CrossRef]
  89. Petrelli, T.; Farrokhyar, F.; McGrath, P.; Sulowski, C.; Sobhi, G.; DeMatteo, C.; Giglia, L.; Singh, S.K. The Use of Ibuprofen and Acetaminophen for Acute Headache in the Postconcussive Youth: A Pilot Study. Paediatr. Child Health 2017, 22, 2–6. [CrossRef]
  90. Ledoux, A.-A.; Tang, K.; Freedman, S.B.; Gravel, J.; Boutis, K.; Yeates, K.O.; Mannix, R.C.; Richer, L.R.; Bell, M.J.; Zemek, R.L.; et al. Early Analgesic Administration and Headache Presence 7 Days Post-Concussion in Children. CJEM 2022, 24, 876–884. [CrossRef]
  91. Hatefi, F.; Kazemi, M.; Manglian, P.; Shahi Moridi, D.; Heydari, S.; Hasani, H. The Effects of Cold Compress and Transcutaneous Electrical Nerve Stimulation on the Pain Associated with Chest Tube Removal among Patients with Coronary Bypass Grafting. J. Cardiothorac. Surg. 2023, 18, 186. [CrossRef]
  92. Walter, A.; Finelli, K.; Bai, X.; Johnson, B.; Neuberger, T.; Seidenberg, P.; Bream, T.; Hallett, M.; Slobounov, S. Neurobiological Effect of Selective Brain Cooling after Concussive Injury. Brain Imaging Behav. 2018, 12, 891–900. [CrossRef]
  93. Gard, A.; Tegner, Y.; Bakhsheshi, M.F.; Marklund, N. Selective Head-Neck Cooling after Concussion Shortens Return-to-Play in Ice Hockey Players. Concussion Lond. Engl. 2021, 6, CNC90. [CrossRef]
  94. Merezhinskaya, N.; Mallia, R.K.; Park, D.; Millian-Morell, L.; Barker, F.M. Photophobia Associated with Traumatic Brain Injury: A Systematic Review and Meta-Analysis. Optom. Vis. Sci. Off. Publ. Am. Acad. Optom. 2021, 98, 891–900. [CrossRef]
  95. Bansal, S.; Green, K. Application of Colored Filters in Patients Post-Traumatic Brain Injury: A Review. NeuroRehabilitation 2022, 50, 321–330. [CrossRef]
  96. Abusamak, M.; Alrawashdeh, H.M. Post-Concussion Syndrome Light Sensitivity: A Case Report and Review of the Literature. Neuro-Ophthalmol. Aeolus Press 2022, 46, 85–90. [CrossRef]
  97. Henry, J.A.; Theodoroff, S.M.; Edmonds, C.; Martinez, I.; Myers, P.J.; Zaugg, T.L.; Goodworth, M.-C. Sound Tolerance Conditions (Hyperacusis, Misophonia, Noise Sensitivity, and Phonophobia): Definitions and Clinical Management. Am. J. Audiol. 2022, 31, 513–527. [CrossRef]
  98. Giza, C.C.; Hovda, D.A. The New Neurometabolic Cascade of Concussion. Neurosurgery 2014, 75 Suppl 4, S24-33. [CrossRef]
  99. Pacheco, J.M.; Hines-Lanham, A.; Stratton, C.; Mehos, C.J.; McCurdy, K.E.; Pinkowski, N.J.; Zhang, H.; Shuttleworth, C.W.; Morton, R.A. Spreading Depolarizations Occur in Mild Traumatic Brain Injuries and Are Associated with Postinjury Behavior. eNeuro 2019, 6. [CrossRef]
  100. Howell, D.R.; Southard, J. THE MOLECULAR PATHOPHYSIOLOGY OF CONCUSSION. Clin. Sports Med. 2021, 40, 39–51. [CrossRef]
  101. Hubbard, W.B.; Joseph, B.; Spry, M.; Vekaria, H.J.; Saatman, K.E.; Sullivan, P.G. Acute Mitochondrial Impairment Underlies Prolonged Cellular Dysfunction after Repeated Mild Traumatic Brain Injuries. J. Neurotrauma 2019, 36, 1252–1263. [CrossRef]
  102. Ahluwalia, M.; Kumar, M.; Ahluwalia, P.; Rahimi, S.; Vender, J.R.; Raju, R.P.; Hess, D.C.; Baban, B.; Vale, F.L.; Dhandapani, K.M.; et al. Rescuing Mitochondria in Traumatic Brain Injury and Intracerebral Hemorrhages - A Potential Therapeutic Approach. Neurochem. Int. 2021, 150, 105192. [CrossRef]
  103. Dolan, E.; Gualano, B.; Rawson, E.S. Beyond Muscle: The Effects of Creatine Supplementation on Brain Creatine, Cognitive Processing, and Traumatic Brain Injury. Eur. J. Sport Sci. 2019, 19, 1–14. [CrossRef]
  104. Marshall, R.P.; Droste, J.-N.; Giessing, J.; Kreider, R.B. Role of Creatine Supplementation in Conditions Involving Mitochondrial Dysfunction: A Narrative Review. Nutrients 2022, 14, 529. [CrossRef]
  105. Forbes, S.C.; Cordingley, D.M.; Cornish, S.M.; Gualano, B.; Roschel, H.; Ostojic, S.M.; Rawson, E.S.; Roy, B.D.; Prokopidis, K.; Giannos, P.; et al. Effects of Creatine Supplementation on Brain Function and Health. Nutrients 2022, 14, 921. [CrossRef]
  106. Sakellaris, G.; Nasis, G.; Kotsiou, M.; Tamiolaki, M.; Charissis, G.; Evangeliou, A. Prevention of Traumatic Headache, Dizziness and Fatigue with Creatine Administration. A Pilot Study. Acta Paediatr. Oslo Nor. 1992 2008, 97, 31–34. [CrossRef]
  107. Sakellaris, G.; Kotsiou, M.; Tamiolaki, M.; Kalostos, G.; Tsapaki, E.; Spanaki, M.; Spilioti, M.; Charissis, G.; Evangeliou, A. Prevention of Complications Related to Traumatic Brain Injury in Children and Adolescents with Creatine Administration: An Open Label Randomized Pilot Study. J. Trauma 2006, 61, 322–329. [CrossRef]
  108. Rippee, M.; Chen, J.; Taylor, M. The Ketogenic Diet in the Treatment of Post-Concussion Syndrome—A Feasibility Study. Front. Nutr. 2020, 7.
  109. Ryan, T.; Nagle, S.; Daly, E.; Pearce, A.J.; Ryan, L. A Potential Role Exists for Nutritional Interventions in the Chronic Phase of Mild Traumatic Brain Injury, Concussion and Sports-Related Concussion: A Systematic Review. Nutrients 2023, 15, 3726. [CrossRef]
  110. Demers-Marcil, S.; Coles, J.P. Cerebral Metabolic Derangements Following Traumatic Brain Injury. Curr. Opin. Anaesthesiol. 2022, 35, 562–569. [CrossRef]
  111. Pierce, J.D.; Gupte, R.; Thimmesch, A.; Shen, Q.; Hiebert, J.B.; Brooks, W.M.; Clancy, R.L.; Diaz, F.J.; Harris, J.L. Ubiquinol Treatment for TBI in Male Rats: Effects on Mitochondrial Integrity, Injury Severity, and Neurometabolism. J. Neurosci. Res. 2018, 96, 1080–1092. [CrossRef]
  112. Gezen-Ak, D.; Alaylıoğlu, M.; Yurttaş, Z.; Çamoğlu, T.; Şengül, B.; İşler, C.; Yaşar Kına, Ü.; Keskin, E.; Atasoy, İ.L.; Kafardar, A.M.; et al. Vitamin D Receptor Regulates Transcription of Mitochondrial DNA and Directly Interacts with Mitochondrial DNA and TFAM. J. Nutr. Biochem. 2023, 116, 109322. [CrossRef]
  113. Araújo de Lima, L.; Oliveira Cunha, P.L.; Felicio Calou, I.B.; Tavares Neves, K.R.; Facundo, H.T.; Socorro de Barros Viana, G. Effects of Vitamin D (VD3) Supplementation on the Brain Mitochondrial Function of Male Rats, in the 6-OHDA-Induced Model of Parkinson’s Disease. Neurochem. Int. 2022, 154, 105280. [CrossRef]
  114. Leddy, J.J.; Haider, M.N.; Ellis, M.; Willer, B.S. Exercise Is Medicine for Concussion. Curr. Sports Med. Rep. 2018, 17, 262–270. [CrossRef]
  115. Li, F.; Lu, L.; Shang, S.; Chen, H.; Wang, P.; Haidari, N.A.; Chen, Y.-C.; Yin, X. Cerebral Blood Flow and Its Connectivity Deficits in Mild Traumatic Brain Injury at the Acute Stage. Neural Plast. 2020, 2020, 2174371. [CrossRef]
  116. Urell, C.; Emtner, M.; Hedenström, H.; Tenling, A.; Breidenskog, M.; Westerdahl, E. Deep Breathing Exercises with Positive Expiratory Pressure at a Higher Rate Improve Oxygenation in the Early Period after Cardiac Surgery--a Randomised Controlled Trial. Eur. J. Cardio-Thorac. Surg. Off. J. Eur. Assoc. Cardio-Thorac. Surg. 2011, 40, 162–167. [CrossRef]
  117. Li, T.; Wang, H.; Zhang, H.; Zhang, P.; Zhang, M.; Feng, H.; Duan, X.; Liu, W.; Wang, X.; Sun, Z. Effect of Breathing Exercises on Oxidative Stress Biomarkers in Humans: A Systematic Review and Meta-Analysis. Front. Med. 2023, 10, 1121036. [CrossRef]
  118. Blaya, M.; Truettner, J.; Zhao, W.; Bramlett, H.; Dietrich, W.D. Mild Hyperthermia Aggravates Glucose Metabolic Consequences in Repetitive Concussion. Int. J. Mol. Sci. 2020, 21, 609. [CrossRef]
  119. Ji, R.-R.; Nackley, A.; Huh, Y.; Terrando, N.; Maixner, W. Neuroinflammation and Central Sensitization in Chronic and Widespread Pain. Anesthesiology 2018, 129, 343–366. [CrossRef]
  120. Mehkri, Y.; Hanna, C.; Sriram, S.; Lucke-Wold, B.; Johnson, R.D.; Busl, K. Calcitonin Gene-Related Peptide and Neurologic Injury: An Emerging Target for Headache Management. Clin. Neurol. Neurosurg. 2022, 220, 107355. [CrossRef]
  121. Close, L.N.; Eftekhari, S.; Wang, M.; Charles, A.C.; Russo, A.F. Cortical Spreading Depression as a Site of Origin for Migraine: Role of CGRP. Cephalalgia 2019, 39, 428–434. [CrossRef]
  122. La Fountaine, M.F.; Hohn, A.N.; Leahy, C.L.; Weir, J.P.; Testa, A.J. Observations from a Prospective Small Cohort Study Suggest That CGRP Genes Contribute to Acute Posttraumatic Headache Burden after Concussion. Front. Neurol. 2022, 13, 947524. [CrossRef]
  123. Ashina, H.; Iljazi, A.; Al-Khazali, H.M.; Do, T.P.; Eigenbrodt, A.K.; Larsen, E.L.; Andersen, A.M.; Hansen, K.J.; Bräuner, K.B.; Chaudhry, B.A.; et al. CGRP-Induced Migraine-like Headache in Persistent Post-Traumatic Headache Attributed to Mild Traumatic Brain Injury. J. Headache Pain 2022, 23, 135. [CrossRef]
  124. Ashina, H.; Dodick, D.W. Post-Traumatic Headache: Pharmacologic Management and Targeting CGRP Signaling. Curr. Neurol. Neurosci. Rep. 2022, 22, 105–111. [CrossRef]
  125. Saadatmand, K.; Khan, S.; Hassan, Q.; Hautamaki, R.; Ashouri, R.; Lua, J.; Doré, S. Benefits of Vitamin D Supplementation to Attenuate TBI Secondary Injury? Transl. Neurosci. 2021, 12, 533–544. [CrossRef]
  126. Jiang, H.; Yang, X.; Wang, Y.; Zhou, C. Vitamin D Protects against Traumatic Brain Injury via Modulating TLR4/MyD88/NF-κB Pathway-Mediated Microglial Polarization and Neuroinflammation. BioMed Res. Int. 2022, 2022, 3363036. [CrossRef]
  127. Scrimgeour, A.G.; Condlin, M.L.; Loban, A.; DeMar, J.C. Omega-3 Fatty Acids and Vitamin D Decrease Plasma T-Tau, GFAP, and UCH-L1 in Experimental Traumatic Brain Injury. Front. Nutr. 2021, 8, 685220. [CrossRef]
  128. Ghorbani, Z.; Rafiee, P.; Fotouhi, A.; Haghighi, S.; Rasekh Magham, R.; Ahmadi, Z.S.; Djalali, M.; Zareei, M.; Razeghi Jahromi, S.; Shahemi, S.; et al. The Effects of Vitamin D Supplementation on Interictal Serum Levels of Calcitonin Gene-Related Peptide (CGRP) in Episodic Migraine Patients: Post Hoc Analysis of a Randomized Double-Blind Placebo-Controlled Trial. J. Headache Pain 2020, 21, 22. [CrossRef]
  129. Jung, E.; Ro, Y.S.; Park, J.H.; Moon, S.B.; Lee, S.G.W.; Park, G.J.; Ryu, H.H.; Shin, S.D. Vitamin D Deficiency and Prognosis after Traumatic Brain Injury with Intracranial Injury: A Multi-Center Observational Study. J. Neurotrauma 2022, 39, 1408–1416. [CrossRef]
  130. Lee, J.M.; Jeong, S.W.; Kim, M.Y.; Park, J.B.; Kim, M.S. The Effect of Vitamin D Supplementation in Patients with Acute Traumatic Brain Injury. World Neurosurg. 2019, 126, e1421–e1426. [CrossRef]
  131. Kalayci, M.; Unal, M.M.; Gul, S.; Acikgoz, S.; Kandemir, N.; Hanci, V.; Edebali, N.; Acikgoz, B. Effect of Coenzyme Q10 on Ischemia and Neuronal Damage in an Experimental Traumatic Brain-Injury Model in Rats. BMC Neurosci. 2011, 12, 75. [CrossRef]
  132. Dahri, M.; Tarighat-Esfanjani, A.; Asghari-Jafarabadi, M.; Hashemilar, M. Oral Coenzyme Q10 Supplementation in Patients with Migraine: Effects on Clinical Features and Inflammatory Markers. Nutr. Neurosci. 2019, 22, 607–615. [CrossRef]
  133. Sazali, S.; Badrin, S.; Norhayati, M.N.; Idris, N.S. Coenzyme Q10 Supplementation for Prophylaxis in Adult Patients with Migraine—a Meta-Analysis. BMJ Open 2021, 11, e039358. [CrossRef]
  134. Ansari, M.; Karkhaneh, A.; Kheirollahi, A.; Emamgholipour, S.; Rafiee, M.H. The Effect of Melatonin on Gene Expression of Calcitonin Gene-Related Peptide and Some Proinflammatory Mediators in Patients with Pure Menstrual Migraine. Acta Neurol. Belg. 2017, 117, 677–685. [CrossRef]
  135. Rezaie, S.; Askari, G.; Khorvash, F.; Tarrahi, M.J.; Amani, R. Effects of Curcumin Supplementation on Clinical Features and Inflammation, in Migraine Patients: A Double-Blind Controlled, Placebo Randomized Clinical Trial. Int. J. Prev. Med. 2021, 12, 161. [CrossRef]
  136. Lin, L.; Zheng, S.; Lai, J.; Ye, D.; Huang, Q.; Wu, Z.; Chen, X.; Wang, S. Omega-3 Polyunsaturated Fatty Acids Protect Neurological Function After Traumatic Brain Injury by Suppressing Microglial Transformation to the Proinflammatory Phenotype and Activating Exosomal NGF/TrkA Signaling. Mol. Neurobiol. 2023, 60, 5592–5606. [CrossRef]
  137. Zhang, E.; Wan, X.; Yang, L.; Wang, D.; Chen, Z.; Chen, Y.; Liu, M.; Zhang, G.; Wu, J.; Han, H.; et al. Omega-3 Polyunsaturated Fatty Acids Alleviate Traumatic Brain Injury by Regulating the Glymphatic Pathway in Mice. Front. Neurol. 2020, 11, 707. [CrossRef]
  138. Patel, P.R.; Armistead-Jehle, P.; Eltman, N.R.; Heath, K.M.; Cifu, D.X.; Swanson, R.L. Brain Injury: How Dietary Patterns Impact Long-Term Outcomes. Curr. Phys. Med. Rehabil. Rep. 2023, 11, 367–376. [CrossRef]
  139. Tabor, J.B.; McCrea, M.A.; Meier, T.B.; Emery, C.A.; Debert, C.T. Hiding in Plain Sight: Factors Influencing the Neuroinflammatory Response to Sport-Related Concussion. Neurotrauma Rep. 2022, 3, 200–206. [CrossRef]
  140. Kip, E.; Parr-Brownlie, L.C. Healthy Lifestyles and Wellbeing Reduce Neuroinflammation and Prevent Neurodegenerative and Psychiatric Disorders. Front. Neurosci. 2023, 17, 1092537. [CrossRef]
  141. Yu, J.; Zhu, H.; Taheri, S.; Mondy, W.; Perry, S.; Kindy, M.S. Impact of Nutrition on Inflammation, Tauopathy, and Behavioral Outcomes from Chronic Traumatic Encephalopathy. J. Neuroinflammation 2018, 15, 277. [CrossRef]
  142. McGeown, J.P.; Hume, P.A.; Theadom, A.; Quarrie, K.L.; Borotkanics, R. Nutritional Interventions to Improve Neurophysiological Impairments Following Traumatic Brain Injury: A Systematic Review. J. Neurosci. Res. 2021, 99, 573–603. [CrossRef]
  143. Miller, S.M.; Zynda, A.J.; Sabatino, M.J.; Ellis, H.B.; Dimeff, R. DOCOSAHEXAENOIC ACID (DHA) FOR THE TREATMENT OF PEDIATRIC SPORT-RELATED CONCUSSION: RESULTS OF A FEASIBILITY TRIAL. Orthop. J. Sports Med. 2019, 7, 2325967119S00004. [CrossRef]
  144. Heileson, J.L.; Anzalone, A.J.; Carbuhn, A.F.; Askow, A.T.; Stone, J.D.; Turner, S.M.; Hillyer, L.M.; Ma, D.W.L.; Luedke, J.A.; Jagim, A.R.; et al. The Effect of Omega-3 Fatty Acids on a Biomarker of Head Trauma in NCAA Football Athletes: A Multi-Site, Non-Randomized Study. J. Int. Soc. Sports Nutr. 2021, 18, 65. [CrossRef]
  145. Patch, C.S.; Hill-Yardin, E.L.; Lewis, M.; Ryan, L.; Daly, E.; Pearce, A.J. The More, the Better: High-Dose Omega-3 Fatty Acids Improve Behavioural and Molecular Outcomes in Preclinical Models in Mild Brain Injury. Curr. Neurol. Neurosci. Rep. 2021, 21, 45. [CrossRef]
  146. Aghakhani, N. Relationship between Mild Traumatic Brain Injury and the Gut Microbiome: A Scoping Review. J. Neurosci. Res. 2022, 100, 827–834. [CrossRef]
  147. Wang, M.; Zhang, H.; Liang, J.; Huang, J.; Chen, N. Exercise Suppresses Neuroinflammation for Alleviating Alzheimer’s Disease. J. Neuroinflammation 2023, 20, 76. [CrossRef]
  148. Rafie, F.; Khaksari, M.; Amiresmaili, S.; Soltani, Z.; Pourranjbar, M.; Shirazpour, S.; Jafari, E. Protective Effects of Early Exercise on Neuroinflammation, and Neurotoxicity Associated by Traumatic Brain Injury: A Behavioral and Neurochemical Approach. Int. J. Neurosci. 2022, 1–14. [CrossRef]
  149. Bharadwaj, V.N.; Sahbaie, P.; Shi, X.; Irvine, K.-A.; Yeomans, D.C.; Clark, J.D. Effect of Voluntary Exercise on Endogenous Pain Control Systems and Post-Traumatic Headache in Mice. J. Pain 2023, 24, 1859–1874. [CrossRef]
  150. Singaravelu Jaganathan, K.; Sullivan, K.A. Traumatic Brain Injury Rehabilitation: An Exercise Immunology Perspective. Exerc. Immunol. Rev. 2022, 28, 90–97.
  151. Calcia, M.A.; Bonsall, D.R.; Bloomfield, P.S.; Selvaraj, S.; Barichello, T.; Howes, O.D. Stress and Neuroinflammation: A Systematic Review of the Effects of Stress on Microglia and the Implications for Mental Illness. Psychopharmacology (Berl.) 2016, 233, 1637–1650. [CrossRef]
  152. Diez, G.G.; Anitua, E.; Castellanos, N.; Vázquez, C.; Galindo-Villardón, P.; Alkhraisat, M.H. The Effect of Mindfulness on the Inflammatory, Psychological and Biomechanical Domains of Adult Patients with Low Back Pain: A Randomized Controlled Clinical Trial. PloS One 2022, 17, e0276734. [CrossRef]
  153. Lovette, B.C.; Kanaya, M.R.; Bannon, S.M.; Vranceanu, A.-M.; Greenberg, J. “Hidden Gains”? Measuring the Impact of Mindfulness-Based Interventions for People with Mild Traumatic Brain Injury: A Scoping Review. Brain Inj. 2022, 36, 1059–1070. [CrossRef]
  154. Simon, D.W.; McGeachy, M.; Bayır, H.; Clark, R.S.B.; Loane, D.J.; Kochanek, P.M. Neuroinflammation in the Evolution of Secondary Injury, Repair, and Chronic Neurodegeneration after Traumatic Brain Injury. Nat. Rev. Neurol. 2017, 13, 171–191. [CrossRef]
  155. Park, J.H.; Bae, Y.J.; Kim, J.S.; Jung, W.S.; Choi, J.W.; Roh, T.H.; You, N.; Kim, S.-H.; Han, M. Glymphatic System Evaluation Using Diffusion Tensor Imaging in Patients with Traumatic Brain Injury. Neuroradiology 2023, 65, 551–557. [CrossRef]
  156. Iliff, J.J.; Chen, M.J.; Plog, B.A.; Zeppenfeld, D.M.; Soltero, M.; Yang, L.; Singh, I.; Deane, R.; Nedergaard, M. Impairment of Glymphatic Pathway Function Promotes Tau Pathology after Traumatic Brain Injury. J. Neurosci. 2014, 34, 16180–16193. [CrossRef]
  157. Ishida, K.; Yamada, K.; Nishiyama, R.; Hashimoto, T.; Nishida, I.; Abe, Y.; Yasui, M.; Iwatsubo, T. Glymphatic System Clears Extracellular Tau and Protects from Tau Aggregation and Neurodegeneration. J. Exp. Med. 2022, 219, e20211275. [CrossRef]
  158. Ruchika, F.N.U.; Shah, S.; Neupane, D.; Vijay, R.; Mehkri, Y.; Lucke-Wold, B. Understanding the Molecular Progression of Chronic Traumatic Encephalopathy in Traumatic Brain Injury, Aging and Neurodegenerative Disease. Int. J. Mol. Sci. 2023, 24. [CrossRef]
  159. Piantino, J.; Schwartz, D.L.; Luther, M.; Newgard, C.; Silbert, L.; Raskind, M.; Pagulayan, K.; Kleinhans, N.; Iliff, J.; Peskind, E. Link between Mild Traumatic Brain Injury, Poor Sleep, and Magnetic Resonance Imaging: Visible Perivascular Spaces in Veterans. J. Neurotrauma 2021, 38, 2391–2399. [CrossRef]
  160. Piantino, J.A.; Iliff, J.J.; Lim, M.M. The Bidirectional Link Between Sleep Disturbances and Traumatic Brain Injury Symptoms: A Role for Glymphatic Dysfunction? Biol. Psychiatry 2022, 91, 478–487. [CrossRef]
  161. Hablitz, L.M.; Plá, V.; Giannetto, M.; Vinitsky, H.S.; Stæger, F.F.; Metcalfe, T.; Nguyen, R.; Benrais, A.; Nedergaard, M. Circadian Control of Brain Glymphatic and Lymphatic Fluid Flow. Nat. Commun. 2020, 11, 4411. [CrossRef]
  162. Hughes, C.; Hunt, K.; Cox, B.; Raybon, J.; Lopez, R.M. Sleep Dysfunction in Adolescents With Prolonged Postconcussion Symptoms: A Reciprocal Coupling of Traumatic Brain Injury and Sleep-Related Problems. J. Sport Rehabil. 2022, 31, 809–814. [CrossRef]
  163. Blaney, N.A.; Trbovich, A.; Ernst, N.; Eagle, S.R.; Collins, M.W.; Kontos, A.P. Influence of Sleep Dysfunction on Concussion Assessment Outcomes Among Adolescent Athletes After Concussion and Healthy Controls. Clin. J. Sport Med. Off. J. Can. Acad. Sport Med. 2021, 31, 481–487. [CrossRef]
  164. Macnow, T.; Curran, T.; Tolliday, C.; Martin, K.; McCarthy, M.; Ayturk, D.; Babu, K.M.; Mannix, R. Effect of Screen Time on Recovery From Concussion: A Randomized Clinical Trial. JAMA Pediatr. 2021, 175, 1124–1131. [CrossRef]
  165. Raikes, A.C.; Dailey, N.S.; Shane, B.R.; Forbeck, B.; Alkozei, A.; Killgore, W.D.S. Daily Morning Blue Light Therapy Improves Daytime Sleepiness, Sleep Quality, and Quality of Life Following a Mild Traumatic Brain Injury. J. Head Trauma Rehabil. 2020, 35, E405–E421. [CrossRef]
  166. Wang, J.; Tian, Y.; Qin, C.; Meng, L.; Feng, R.; Xu, S.; Zhai, Y.; Liang, D.; Zhang, R.; Tian, H.; et al. Impaired Glymphatic Drainage Underlying Obstructive Sleep Apnea Is Associated with Cognitive Dysfunction. J. Neurol. 2023, 270, 2204–2216. [CrossRef]
  167. Santos, A.; Walsh, H.; Anssari, N.; Ferreira, I.; Tartaglia, M.C. Post-Concussion Syndrome and Sleep Apnea: A Retrospective Study. J. Clin. Med. 2020, 9, 691. [CrossRef]
  168. Yokoi-Shimizu, K.; Yanagimoto, K.; Hayamizu, K. Effect of Docosahexaenoic Acid and Eicosapentaenoic Acid Supplementation on Sleep Quality in Healthy Subjects: A Randomized, Double-Blinded, Placebo-Controlled Trial. Nutrients 2022, 14, 4136. [CrossRef]
  169. Bhardwaj, K.; Verma, N.; Trivedi, R.; Bhardwaj, S. Effect of Essential Fatty Acid Blend on Circadian Variations of Ambulatory Blood Pressure in Patients with Essential Hypertension and Coronary Artery Disease Risk Markers. J. Hum. Hypertens. 2022, 36, 289–298. [CrossRef]
  170. von Holstein-Rathlou, S.; Petersen, N.C.; Nedergaard, M. Voluntary Running Enhances Glymphatic Influx in Awake Behaving, Young Mice. Neurosci. Lett. 2018, 662, 253–258. [CrossRef]
  171. He, X.-F.; Liu, D.-X.; Zhang, Q.; Liang, F.-Y.; Dai, G.-Y.; Zeng, J.-S.; Pei, Z.; Xu, G.-Q.; Lan, Y. Voluntary Exercise Promotes Glymphatic Clearance of Amyloid Beta and Reduces the Activation of Astrocytes and Microglia in Aged Mice. Front. Mol. Neurosci. 2017, 10, 144. [CrossRef]
  172. Kollmeier, J.M.; Gürbüz-Reiss, L.; Sahoo, P.; Badura, S.; Ellebracht, B.; Keck, M.; Gärtner, J.; Ludwig, H.-C.; Frahm, J.; Dreha-Kulaczewski, S. Deep Breathing Couples CSF and Venous Flow Dynamics. Sci. Rep. 2022, 12, 2568. [CrossRef]
  173. Naugle, K.M.; Carey, C.; Evans, E.; Saxe, J.; Overman, R.; White, F.A. The Role of Deficient Pain Modulatory Systems in the Development of Persistent Post-Traumatic Headaches Following Mild Traumatic Brain Injury: An Exploratory Longitudinal Study. J. Headache Pain 2020, 21, 138. [CrossRef]
  174. Greenberg, J.; Mace, R.A.; Funes, C.J.; Silverberg, N.D.; Iverson, G.L.; Caplan, D.N.; Vranceanu, A.-M. Pain Catastrophizing and Limiting Behavior Mediate the Association Between Anxiety and Postconcussion Symptoms. Psychosomatics 2020, 61, 49–55. [CrossRef]
  175. Bech, N.H.; Sierevelt, I.N.; de Rooij, A.; Kerkhoffs, G.M.M.J.; Haverkamp, D. The Influence of Pain Catastrophizing and Central Sensitization on the Reported Pain after Hip Arthroscopy. Knee Surg. Sports Traumatol. Arthrosc. Off. J. ESSKA 2021, 29, 2837–2842. [CrossRef]
  176. Campbell, C.M.; Buenaver, L.F.; Finan, P.; Bounds, S.C.; Redding, M.; McCauley, L.; Robinson, M.; Edwards, R.R.; Smith, M.T. Sleep, Pain Catastrophizing, and Central Sensitization in Knee Osteoarthritis Patients With and Without Insomnia. Arthritis Care Res. 2015, 67, 1387–1396. [CrossRef]
  177. Balasch-Bernat, M.; Dueñas, L.; Aguilar-Rodríguez, M.; Falla, D.; Schneebeli, A.; Navarro-Bosch, M.; Lluch, E.; Barbero, M. The Spatial Extent of Pain Is Associated with Pain Intensity, Catastrophizing and Some Measures of Central Sensitization in People with Frozen Shoulder. J. Clin. Med. 2021, 11, 154. [CrossRef]
  178. Chaput, G.; Lajoie, S.P.; Naismith, L.M.; Lavigne, G. Pain Catastrophizing Correlates with Early Mild Traumatic Brain Injury Outcome. Pain Res. Manag. 2016, 2016, 2825856. [CrossRef]
  179. Hassan, A.; Brooks, B.L.; McArthur, B.A.; Beauchamp, M.H.; Craig, W.; Doan, Q.; Zemek, R.; Yeates, K.O. Dynamic Relations Between Psychological Resilience and Post-Concussion Symptoms in Children With Mild Traumatic Brain Injury Versus Orthopedic Injury: An A-CAP Study. J. Neurotrauma 2023. [CrossRef]
  180. Bunt, S.C.; Meredith-Duliba, T.; Didehhani, N.; Hynan, L.S.; LoBue, C.; Stokes, M.; Miller, S.M.; Bell, K.; Batjer, H.; Cullum, C.M. Resilience and Recovery from Sports Related Concussion in Adolescents and Young Adults. J. Clin. Exp. Neuropsychol. 2021, 43, 677–688. [CrossRef]
  181. Conti, Y.; Vatine, J.-J.; Levy, S.; Levin Meltz, Y.; Hamdan, S.; Elkana, O. Pain Catastrophizing Mediates the Association Between Mindfulness and Psychological Distress in Chronic Pain Syndrome. Pain Pract. Off. J. World Inst. Pain 2020, 20, 714–723. [CrossRef]
  182. Jones, M.I.; Parker, J.K. Mindfulness Mediates the Relationship between Mental Toughness and Pain Catastrophizing in Cyclists. Eur. J. Sport Sci. 2018, 18, 872–881. [CrossRef]
  183. Day, M.A.; Ward, L.C.; Thorn, B.E.; Burns, J.; Ehde, D.M.; Barnier, A.J.; Mattingley, J.B.; Jensen, M.P. Mechanisms of Mindfulness Meditation, Cognitive Therapy, and Mindfulness-Based Cognitive Therapy for Chronic Low Back Pain. Clin. J. Pain 2020, 36, 740–749. [CrossRef]
  184. Bagheri, S.; Naderi, A.; Mirali, S.; Calmeiro, L.; Brewer, B.W. Adding Mindfulness Practice to Exercise Therapy for Female Recreational Runners With Patellofemoral Pain: A Randomized Controlled Trial. J. Athl. Train. 2021, 56, 902–911. [CrossRef]
  185. Gmuca, S.; Weiss, P.F.; McGill, M.; Xiao, R.; Ward, M.; Nelson, M.; Sherry, D.D.; Cronholm, P.F.; Gerber, J.S.; Palermo, T.M.; et al. The Feasibility and Acceptability of Resilience Coaching for Adolescent Chronic Musculoskeletal Pain: A Single-Arm Pilot Trial. Child. Basel Switz. 2022, 9, 1432. [CrossRef]
  186. Curran, D.; Lauzon, J.; Quon, D.; Marshall, S. Feasibility of an Interactive Coaching App to Enhance Post-Concussion Outpatient Care. Front. Med. Technol. 2021, 3, 660540. [CrossRef]
  187. McCarty, C.A.; Zatzick, D.; Stein, E.; Wang, J.; Hilt, R.; Rivara, F.P. Collaborative Care for Adolescents With Persistent Postconcussive Symptoms: A Randomized Trial. Pediatrics 2016, 138, e20160459. [CrossRef]
  188. Ponsford, J.; Lee, N.K.; Wong, D.; McKay, A.; Haines, K.; Alway, Y.; Downing, M.; Furtado, C.; O’Donnell, M.L. Efficacy of Motivational Interviewing and Cognitive Behavioral Therapy for Anxiety and Depression Symptoms Following Traumatic Brain Injury. Psychol. Med. 2016, 46, 1079–1090. [CrossRef]
  189. Bombardier, C.H.; Bell, K.R.; Temkin, N.R.; Fann, J.R.; Hoffman, J.; Dikmen, S. The Efficacy of a Scheduled Telephone Intervention for Ameliorating Depressive Symptoms during the First Year after Traumatic Brain Injury. J. Head Trauma Rehabil. 2009, 24, 230–238. [CrossRef]
  190. Kami, K.; Tajima, F.; Senba, E. Brain Mechanisms of Exercise-Induced Hypoalgesia: To Find a Way Out from “Fear-Avoidance Belief.” Int. J. Mol. Sci. 2022, 23, 2886. [CrossRef]
Table 1. Studies documenting the impact of early intervention for concussion outcomes.
Table 1. Studies documenting the impact of early intervention for concussion outcomes.
Author Study Design Summary of Findings
Bock, et al. (2015) [25] RS, n=366 Being seen by a concussion specialist <7 days after injury resulted in significantly shorter recovery time (p < 0.05).
Cassimatis, et al. (2021) [26] RS, n=341 Late evaluation (>28 days) athletes took three times longer to recover (mean 148.0 days, 95% CI: 121.1-173.9) compared to early evaluation (<14 days) athletes (mean 38.7 days, 95% CI: 30.7-46.7).
Eagle, et al. (2020) [27] RS, n=218 The odds of having prolonged recovery (>30 days) was nearly 10x greater (OR=9.8) when seen 8-20 days after recovery vs <7 days.
Kontos, et al. (2020) [28] RS, n=162 The adjusted odds ratio of having prolonged recovery was nearly 6x greater (aOR=5.8 [95% CI, 1.9-17.6]; P = .001) when seen 8-20 days after recovery vs <7 days. Those seen early (<7days) recovered a mean of 20 days earlier than those seen late (8-20 days).
Pratile, et al. (2022) [29] CS, n=1213 Athletes assessed <10 days after the injury recovered in 23.5 days (95% CI, 22.5, 24.5) vs. 37.1 days (95% CI, 33.7, 40.5) for those assessed 10-30 days after injury.
* RS = retrospective study, CS = cohort study.
Table 2. Selected interventions that address multiple CS-related targets.
Table 2. Selected interventions that address multiple CS-related targets.
Intervention Target Author, Study Details Summary of Findings
Early Exercise PS, CN, NI, GO, PC Leddy, et al. (2023) [69]; MA (n=9432) Early physical activity and prescribed exercise improved recovery by a mean of −4.64 days (95% CI −6.69, –2.59).
Grool, et al. (2016) [70];
CS (n=2413)
Early participation (<7 days) in physical activity compared with no physical activity was associated with lower risk of PPCS (413 [24.6%] patients vs 320 [43.5%] patients; RR, 0.75 [95% CI, 0.70-0.80].
Deep Breathing CN, NI, GO, PC Cook et al. (2021) [71];
PS (n=15)
Following deep breathing exercises, participants reported significant reduction in stress (r =.57), tension (r =.73), fatigue (r =.73), and confusion (r =.67), with large effect sizes.
Cold Therapy PS, CN Al-Husseini, et al. (2022) [72], RCT (n=132) The proportion of players with prolonged symptoms (> 14 days) was 24.7% in the cold therapy intervention group and 43.7% in controls (p < 0.05)
Mindfulness NI, PC Acabchuk, et al. (2021) [73], MA (n=532) Meditation, yoga, and mindfulness-based interventions lead to significant improvement of overall symptoms compared to controls (d = 0.41; 95% CI [0.04, 0.77]; τ2 = 0.06).
Melatonin NI, GO Barlow, et al. (2019) [74], MA (n=15) Meta-analysis of pre-clinical data showed a positive effect of melatonin on neurobehavioural outcome (SMD = 1.51 (95% CI: 1.06-1.96)), neurological status (SMD = 1.35 (95% CI: 0.83-1.88)), and cognition (SMD = 1.16 (95% CI: 0.4-1.92)) after TBI.
Cassimatis, et al. (2022) [75], MA (n=251) Eight of 9 mTBI studies reported positive sleep outcomes after melatonin treatment, with significant improvements in subjective sleep quality, objective sleep efficiency, and total sleep, and reductions in self-reported fatigue, anxiety, and depressive symptoms.
Omega oils NI, GO Miller, et al. (2022) [76], RCT (n=40) In SRCs, the treatment group took 2g of docosahexaenoic acid (DHA) daily for 12 weeks. The DHA group were symptom-free earlier than the placebo group (11.0 vs 16.0 days, P = .08) and had a shorter RTP time (14.0 vs 19.5 days, P = .12).
Vitamin D CN, NI Sharma, et al. (2020) [77], RCT (n=35) In moderate to severe TBI, Vitamin D bolus in the acute period showed significant improvements in cognitive and physiological outcomes. Inflammatory markers were also significantly decreased in the treatment group (IL-6 p = 0.08, TNF-α p = 0.02).
* PS = peripheral sensitization, CN = cerebral neurometabolism, NI = neuroinflammation, GO = glymphatic optimization, PC = pain catastrophizing. ** CS = cohort study, MA = meta-analysis, RCT = randomized clinical trial, PS = pilot study.
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