Post-traumatic headache: epidemiology and pathophysiological insights

Low-Dose Interleukin-2 Reverses Traumatic Brain Injury-Induced Cognitive Deficit and Pain in a Murine Model

OBJECTIVE

Despite the high prevalence, mild traumatic brain injury (mTBI)-induced chronic headache and cognitive deficits are poorly understood and lack effective treatments. Low-dose interleukin-2 (LD-IL-2) treatment soon after mTBI or overexpressing IL-2 in brain astrocytes prior to injury protects mice from developing post-traumatic headache (PTH)-related behaviors and cognitive decline. The present study addresses a clinically relevant knowledge gap: whether LD-IL-2 treatment long after the initial injury is still effective for chronic PTH and cognitive deficits.

METHODS

mTBI was induced by a noninvasive closed-head weight drop method. LD-IL-2 was administered 4-6 weeks post-mTBI to assess its effects on chronic PTH-related facial mechanical hypersensitivity as well as mTBI-induced impairment in novel object recognition and object location tests. Endogenous regulatory T (Treg) cells were depleted to investigate the mechanism of action of LD-IL-2.

RESULTS

Delayed LD-IL-2 treatment abolished chronic PTH-related behaviors. It also completely reversed mTBI-induced cognitive impairment in both male and female mice. Treg cell depletion not only prolonged PTH-related behaviors but also abolished the effects of LD-IL-2. Interestingly, LD-IL-2 treatment significantly increased the number of Treg cells in dura but not in brain tissues.

INTERPRETATION

These results suggest that the beneficial effects of LD-IL-2 treatment are mediated through the expansion of meningeal Treg cells. Collectively, our study identifies Treg as a cellular target and LD-IL-2 as a promising therapy for both chronic PTH and mTBI-induced cognitive impairment for both males and females, with a wide therapeutic time window and the potential of reducing polypharmacy in mTBI treatment. ANN NEUROL 2024;96:508-525.

Headache management in traumatic brain injury

Traumatic brain injury (TBI) is estimated to rank as the third most important disease burden worldwide. About 60% of the survivors develop chronic headaches and visual symptoms, and the long-term management of headaches in these patients is controversial. Importantly, the care pathway of most patients is fragmented, complicating conclusive headache management. Here we review the epidemiology and aetiology of post traumatic headaches (PTH), discuss the diagnostic work up and summarise the acute and long-term management.

Management of Pain and Headache After Traumatic Brain Injury

This article will identify common causes of pain following traumatic brain injury (TBI), discuss current treatment strategies for these complaints, and help tailor treatments for both acute and chronic settings. We will also briefly discuss primary and secondary headache disorders, followed by common secondary pain disorders that may be related to trauma.

American Headache Society white paper on treatment of post-traumatic headache from concussion in youth

OBJECTIVE

To provide healthcare professionals guidance on youth at risk for prolonged recovery and post-traumatic headache (PTH), and on pharmacologic and non-pharmacologic management of PTH due to concussion and mild traumatic brain injury.

BACKGROUND

Headache is the most common persistent post-concussive symptom affecting 8% of youth for >3 months after concussion. Over the past decade, many studies have explored the treatment of PTH in youth, but there are no established guidelines.

METHODS

This white paper is based on a synthesis of an updated systematic review of the literature on treatment of PTH and a narrative review of the literature on risk factors for prolonged recovery and health disparities. Results were interpreted by a group of expert providers in PTH in children and adolescents through collaboration of the PTH and pediatric special interest groups of the American Headache Society.

RESULTS

Factors that consistently were associated with prolonged recovery from concussion and persistent PTH included female sex, a high number of acute symptoms, and adolescent age. Social determinants of health also likely play an important role in PTH and deserve consideration in the clinical and research settings. A total of 33 studies met the criteria for inclusion in the systematic review of PTH treatment in youth, although most were retrospective and of fair-to-poor quality. Treatment strategies included acute and preventive pharmacologic management, procedures, neuro-modulatory devices, physical therapy, physical activity, and behavioral health support. A collaborative care approach that includes a thoughtful combination of these management strategies is likely most effective.

CONCLUSIONS

This white paper provides a roadmap for tailoring the treatment of PTH based on factors influencing prolonged headache, the timing of therapies, and therapies with the most evidence for treating PTH in youth. We also highlight research needed for developing more definitive guidelines on PTH management in youth.

Evaluating the Phenotypic Patterns of Post-Traumatic Headache: A Systematic Review of Military Personnel

INTRODUCTION

Mild traumatic brain injury (TBI) affects a significant number of military personnel, primarily because of physical impact, vehicle incidents, and blast exposure. Post-traumatic headache (PTH) is the most common symptom reported following mild TBI and can persist for several years. However, the current International Classification of Headache Disorders lacks phenotypic characterization for this specific headache disorder. It is important to appropriately classify the headache sub-phenotypes as it may enable more targeted management approaches. This systematic review seeks to identify the most common sub-phenotype of headaches in military personnel with PTH attributed to mild TBI.

METHODS

We conducted a systematic search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines, focusing on the military population. PubMed, Web of Science, Cochrane, and Clinicaltrials.gov databases were searched. Abstracts and full texts were independently reviewed by two authors using predefined inclusion and exclusion criteria. Data extraction was performed using a standardized form. The risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

Eight papers related to the military population were included in this review. Migraine was the most commonly reported headache sub-phenotype, with a prevalence ranging from 33 to 92%. Additionally, one military study identified tension-type headaches as the most prevalent headache phenotype. Although not the primary phenotype, one military cohort reported that approximately one-third of their cohort experienced trigeminal autonomic cephalalgias, which were associated with exposure to blast injuries and prior concussions.

CONCLUSION

This systematic review demonstrated that PTH in the military population frequently exhibit migraine-like features. Tension-type headache and trigeminal autonomic cephalalgias also occur, although less commonly reported. Sub-phenotyping PTH may be important for initiating effective treatment since different phenotypes may respond differently to medications. The study populations analyzed in this systematic review display heterogeneity, underscoring the necessity for additional research features, more stringent criteria and comprehensive recording of baseline characteristics. Characterizing headaches following injury is crucial for an accurate diagnosis to enable effective management and rehabilitation planning for our armed forces.

Exploring Symptom Overlaps: Post-COVID-19 Neurological Syndrome and Post-Concussion Syndrome in Athletes

The COVID-19 pandemic has introduced new challenges in managing neurological conditions, particularly among athletes. This paper explores the intersection of post-COVID-19 neurological syndrome (PCNS/PASC) and post-concussion syndrome (PCS), focusing on their implications in sports medicine. Our analysis covers the symptomatology, pathophysiology, and management strategies for PCNS/PASC and PPCS, with special attention paid to the unique challenges faced by athletes recovering from these conditions, including the risk of symptom exacerbation and prolonged recovery. Key findings reveal that both PCNS/PASC and PPCS present with overlapping symptoms such as cognitive difficulties, exercise intolerance, and mental health issues, but differ in specific manifestations like anosmia and ageusia, unique to COVID-19. Pathophysiological analysis reveals similarities in blood-brain barrier disruption (BBB) but differences in the extent of immune activation. Management strategies emphasize a gradual increase in physical activity, close symptom monitoring, and psychological support, with a tailored approach for athletes. Specific interventions include progressive aerobic exercises, resistance training, and cognitive rehabilitation. Furthermore, our study highlights the importance of integrating neurology, psychiatry, physical therapy, and sports medicine to develop comprehensive care strategies. Our findings underscore the dual challenge of COVID-19 and concussion in athletes, necessitating a nuanced, interdisciplinary approach to effective management. Future research should focus on the long-term neurological effects of both conditions and optimizing treatment protocols to improve patient outcomes. This comprehensive understanding is crucial for advancing the management of athletes affected by these overlapping conditions and ensuring their safe return to sports.

Inhibition of 2-AG hydrolysis alleviates posttraumatic headache attributed to mild traumatic brain injury

BACKGROUND

Posttraumatic headache (PTH) is a common and debilitating symptom following repetitive mild traumatic brain injury (rmTBI), and it mainly resembles a migraine-like phenotype. While modulation of the endocannabinoid system (ECS) is effective in treating TBI and various types of pain including migraine, the role of augmentation of endocannabinoids in treating PTH has not been investigated.

METHODS

Repetitive mild TBI was induced in male C57BL/6J mice using the non-invasive close-head impact model of engineered rotational acceleration (CHIMERA). Periorbital allodynia was assessed using von Frey filaments and determined by the "Up-Down" method. Immunofluorescence staining was employed to investigate glial cell activation and calcitonin gene-related peptide (CGRP) expression in the trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC) of the rmTBI mice. Levels of 2-arachidonoyl glycerol (2-AG), anandamide (AEA), and arachidonic acid (AA) in the TG, medulla (including TNC), and periaqueductal gray (PAG) were measured by mass spectrometry. The therapeutic effect of endocannabinoid modulation on PTH was also assessed.

RESULTS

The rmTBI mice exhibited significantly increased cephalic pain hypersensitivity compared to the sham controls. MJN110, a potent and selective inhibitor of the 2-AG hydrolytic enzyme monoacylglycerol lipase (MAGL), dose-dependently attenuated periorbital allodynia in the rmTBI animals. Administration of CGRP at 0.01 mg/kg reinstated periorbital allodynia in the rmTBI animals on days 33 and 45 post-injury but had no effect in the sham and MJN110 treatment groups. Activation of glial cells along with increased production of CGRP in the TG and TNC at 7 and 14 days post-rmTBI were attenuated by MJN110 treatment. The anti-inflammatory and anti-nociceptive effects of MJN110 were partially mediated by cannabinoid receptor activation, and the pain-suppressive effect of MJN110 was completely blocked by co-administration of DO34, an inhibitor of 2-AG synthase. The levels of 2-AG in TG, TNC and PAG were decreased in TBI animals, significantly elevated and further reduced by the selective inhibitors of 2-AG hydrolytic and synthetic enzymes, respectively.

CONCLUSION

Enhancing endogenous levels of 2-AG appears to be an effective strategy for the treatment of PTH by attenuating pain initiation and transmission in the trigeminal pathway and facilitating descending pain inhibitory modulation.

Posttraumatic headache: pain related evoked potentials (PREP) and conditioned pain modulation (CPM) to assess the pain modulatory function

Posttraumatic headache (PTH) is common following traumatic brain injury and impacts quality of life. We investigated descending pain modulation as one possible mechanism for PTH and correlated it to clinical measures. Pain-related evoked potentials (PREP) were recorded in 26 PTH-patients and 20 controls after electrical stimulation at the right hand and forehead with concentric surface electrodes. Conditioned pain modulation (CPM) was assessed using painful cutaneous electric stimulation (PCES) on the right hand as test stimulus and immersion of the left hand into 10 °C-cold water bath as conditioning stimulus based on changes in pain intensity and in amplitudes of PCES-evoked potentials. All participants completed questionnaires assessing depression, anxiety, and pain catastrophising. PTH-patients reported significantly higher pain ratings during PREP-recording in both areas despite similar stimulus intensity at pain threshold. N1P1-amplitudes during PREP and CPM-assessment were lower in patients in both areas, but statistically significant only on the hand. Both, PREP-N1-latencies and CPM-effects (based on the N1P1-amplitudes and pain ratings) were similar in both groups. Patients showed significantly higher ratings for anxiety and depression, which did not correlate with the CPM-effect. Our results indicate generalized hyperalgesia for electrical stimuli in both hand and face in PTH. The lacking correlation between pain ratings and EEG parameters indicates different mechanisms of pain perception and nociception.

Abnormal longitudinal changes of structural covariance networks of cortical thickness in mild traumatic brain injury with posttraumatic headache

BACKGROUND

It is widely acknowledged that mild traumatic brain injury (MTBI) leads to either functionally or anatomically abnormal brain regions. Structural covariance networks (SCNs) that depict coordinated regional maturation patterns are commonly employed for investigating brain structural abnormalities. However, the dynamic nature of SCNs in individuals with MTBI who suffer from posttraumatic headache (PTH) and their potential as biomarkers have hitherto not been investigated.

METHODS

This study included 36 MTBI patients with PTH and 34 well-matched healthy controls (HCs). All participants underwent magnetic resonance imaging scans and were assessed with clinical measures during the acute and subacute phases. Structural covariance matrices of cortical thickness were generated for each group, and global as well as nodal network measures of SCNs were computed.

RESULTS

MTBI patients with PTH demonstrated reduced headache impact and improved cognitive function from the acute to subacute phase. In terms of global network metrics, MTBI patients exhibited an abnormal normalized clustering coefficient compared to HCs during the acute phase, although no significant difference in the normalized clustering coefficient was observed between the groups during the subacute phase. Regarding nodal network metrics, MTBI patients displayed alterations in various brain regions from the acute to subacute phase, primarily concentrated in the prefrontal cortex (PFC).

CONCLUSIONS

These findings indicate that the cortical thickness topography in the PFC determines the typical structural-covariance topology of the brain and may serve as an important biomarker for MTBI patients with PTH.

Hypersensitivity to BKCa channel opening in persistent post-traumatic headache

BACKGROUND

Large conductance  calcium-activated potassium (BKCa) channels have been implicated in the neurobiological underpinnings of migraine. Considering the clinical similarities between migraine and persistent post-traumatic headache (PPTH), we aimed to examine whether MaxiPost (a BKCa channel opener) could induce migraine-like headache in persons with PPTH.

METHODS

This is a randomized double-blind, placebo-controlled, two-way crossover study from September 2023 to December 2023. Eligible participants were adults with PPTH after mild traumatic brain injury who reported having no personal history of migraine. The randomized participants received a single dose of either MaxiPost (0.05 mg/min) or placebo (isotonic saline) that was infused intravenously over 20 minutes. The two experiment sessions were scheduled at least one week apart to avoid potential carryover effects. The primary endpoint was the induction of migraine-like headache after MaxiPost as compared to placebo within 12 hours of drug administration. The secondary endpoint was the area under the curve (AUC) values for headache intensity scores between MaxiPost and placebo over the same 12-hour observation period.

RESULTS

Twenty-one adult participants (comprising 14 females and 7 males) with PPTH were enrolled and completed both experiment sessions. The proportion of participants who developed migraine-like headache was 11 (52%) of 21 participants after MaxiPost infusion, in contrast to four (19%) participants following placebo (P = .02). Furthermore, the median headache intensity scores, represented by AUC values, were higher following MaxiPost than after placebo (P < .001).

CONCLUSIONS

Our results indicate that BKCa channel opening can elicit migraine-like headache in persons with PPTH. Thus, pharmacologic blockade of BKCa channels might present a novel avenue for drug discovery. Additional investigations are nonetheless needed to confirm these insights and explore the therapeutic prospects of BKCa channel blockers in managing PPTH.

CLINICALTRIALS

GOV IDENTIFIER

NCT05378074.

Ultrasound guided platelet rich plasma injections for post-traumatic greater occipital neuralgia following concussion: a pilot randomized controlled trial

Background

Treatment for post-traumatic greater occipital neuralgia (GON) includes serial injections of steroid/anesthetic. While these injections can alleviate pain, effects can be transient, frequently lasting only 1 month. As a potential alternative, platelet-rich plasma (PRP) injections are an emerging biological treatment with beneficial effects in peripheral nerve disorders. We investigated the feasibility, safety, and effectiveness of a single PRP injection for post-traumatic GON in comparison to saline or steroid/anesthetic injection.

Methods

In this pilot randomized, double-blinded, placebo-controlled trial, 32 adults with post-traumatic GON were allocated 1:1:1 to receive a single ultrasound-guided injection of (1) autologous PRP (2) steroid/anesthetic or (3) normal saline. Our primary outcome was feasibility (recruitment, attendance, retention) and safety (adverse events). Exploratory measures included headache intensity and frequency (daily headache diaries) and additional questionnaires (headache impact, and quality of life) assessed at pre-injection, 1 week, 1 month, and 3 months post-injection.

Results

We screened 67 individuals, 55% were eligible and 95% of those participated. Over 80% of daily headache diaries were completed with 91% of participants completing the 3-month outcome questionnaires. No serious adverse events were reported. There were no significant differences between groups for headache intensity or frequency. Headache impact on function test-6 scores improved at 3 month in the PRP (β = -9.7, 95% CI [-15.6, -3.74], p = 0.002) and saline (β = -6.7 [-12.7, -0.57], p = 0.033) groups but not steroid/anesthetic group (p = 0.135).

Conclusion

PRP is a feasible and safe method for treating post-traumatic GON with comparable results to saline and steroid/anaesthetic. Further trials with larger sample sizes are required.Clinical trial registration:https://clinicaltrials.gov/, identifier NCT04051203.

Posttraumatic headache is a distinct headache type from migraine

PURPOSE OF REVIEW

Posttraumatic headache (PTH), a headache that develops within 7 days of a causative injury, is one of the most common secondary headaches, mostly attributed to mild traumatic brain injury (mTBI). Because presence of preinjury headache is a risk factor for developing PTH and PTH symptoms often resemble migraine or tension-type headache, the association between PTH and primary headaches has attracted attention from clinicians and scientists.

RECENT FINDINGS

Recent studies on epidemiological aspects, headache features, risk factors, imaging characteristics, and response to treatment, suggest overlapping features and distinct objective findings in PTH compared to migraine.

SUMMARY

We argue that PTH is distinct from migraine. Therefore, PTH epidemiology, pathophysiology, diagnosis, treatment, and prognosis should continue to be investigated separately from migraine.

The Postconcussion Syndrome and Posttraumatic Headaches in Civilians, Soldiers, and Athletes

Posttraumatic headaches are one of the most common and controversial secondary headache types. After a mild traumatic brain, an estimated 11% to 82% of people develop a postconcussion syndrome, which has been controversial for more than 160 years. Headache is estimated as present in 30% to 90% of patients after a mild head injury. Most headaches are tension-type-like or migraine-like. Headaches in civilians, soldiers, athletes, and postcraniotomy are reviewed. The treatments are the same as for the primary headaches. Persistent posttraumatic headaches can continue for many years.

Effects of PDE-3 inhibition in persistent post-traumatic headache: evidence of cAMP-dependent signaling

BACKGROUND

Phosphodiesterase 3 (PDE-3) inhibition have been implicated in the neurobiologic underpinnings of migraine. Considering the clinical similarities between migraine and persistent post-traumatic headache (PPTH), we aimed to ascertain whether PDE-3 inhibition can elicit migraine-like headache in persons with PPTH.

METHODS

We tested cilostazol, which inhibits PDE-3, in a randomized, double-blind, placebo-controlled, two-way crossover study involving persons with PPTH attributed to mild traumatic brain injury. The randomized participants were allocated to receive oral administration of either 200-mg cilostazol or placebo (calcium tablet) on two separate experiment days. The primary end point was the incidence of migraine-like headache during a 12-hour observation window post-ingestion. The secondary endpoint was the area under the curve (AUC) for reported headache intensity scores during the same observation window.

RESULTS

Twenty-one persons underwent randomization and completed both experiment days. The mean participants' age was 41.4 years, and most (n = 17) were females. During the 12-hour observation window, 14 (67%) of 21 participants developed migraine-like headache post-cilostazol, in contrast to three (14%) participants after placebo (P =.003). The headache intensity scores were higher post-cilostazol than after placebo (P <.001).

CONCLUSIONS

Our results provide novel evidence showing that PDE-3 inhibition can elicit migraine-like headache in persons with PPTH. Given that PDE-3 inhibition increases intracellular cAMP levels, our findings allude to the potential therapeutic value of targeting cAMP-dependent signaling pathways in the management of PPTH. Further investigations are imperative to substantiate these insights and delineate the importance of cAMP-dependent signaling pathways in the neurobiologic mechanisms underlying PPTH.

CLINICALTRIALS

GOV IDENTIFIER

NCT05595993.

Hypersensitivity to PACAP-38 in post-traumatic headache: a randomized clinical trial

Pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38), known for its role in migraine pathogenesis, has been identified as a novel drug target. Given the clinical parallels between post-traumatic headache (PTH) and migraine, we explored the possible role of PACAP-38 in the pathogenesis of PTH. To this end, we conducted a randomized, double-blind, placebo-controlled, two-way crossover trial involving adult participants diagnosed with persistent PTH resulting from mild traumatic brain injury. Participants were randomly assigned to receive a 20-min continuous intravenous infusion of either PACAP-38 (10 pmol/kg/min) or placebo (isotonic saline) on two separate experimental days, with a 1-week washout period in between. The primary outcome was the difference in incidence of migraine-like headache between PACAP-38 and placebo during a 12-h observational period post-infusion. The secondary outcome was the difference in the area under the curve (AUC) for baseline-corrected median headache intensity scores during the same 12-h observational period. Of 49 individuals assessed for eligibility, 21 were enrolled and completed the trial. The participants had a mean age of 35.2 years, and 16 (76%) were female. Most [19 of 21 (90%)] had a migraine-like phenotype. During the 12-h observational period, 20 of 21 (95%) participants developed migraine-like headache after intravenous infusion of PACAP-38, compared with two (10%) participants after placebo (P < 0.001). Furthermore, the baseline-corrected AUC values for median headache intensity scores during the 12-h observational period was higher after PACAP-38 than placebo (P < 0.001). These compelling results demonstrate that PACAP-38 is potent inducer of migraine-like headache in people with persistent PTH. Thus, targeting PACAP-38 signalling might be a promising avenue for the treatment of PTH.

Posttraumatic Headache

OBJECTIVE

This article provides an overview of the epidemiology, diagnosis, clinical presentation, pathophysiology, prognosis, and treatment of posttraumatic headache attributed to mild traumatic brain injury (mTBI).

LATEST DEVELOPMENTS

The International Classification of Headache Disorders, Third Edition requires that posttraumatic headache begin within 7 days of the inciting trauma. Although posttraumatic headache characteristics and associated symptoms vary, most commonly there is substantial overlap with symptoms of migraine or tension-type headache. New insights into posttraumatic headache pathophysiology suggest roles for neuroinflammation, altered pain processing and modulation, and changes in brain structure and function. Although the majority of posttraumatic headache resolves during the acute phase, about one-third of individuals have posttraumatic headache that persists for at least several months. Additional work is needed to identify predictors and early markers of posttraumatic headache persistence, but several potential predictors have been identified such as having migraine prior to the mTBI, the total number of TBIs ever experienced, and the severity of initial symptoms following the mTBI. Few data are available regarding posttraumatic headache treatment; studies investigating different treatments and the optimal timing for initiating posttraumatic headache treatment are needed.

ESSENTIAL POINTS

Posttraumatic headache begins within 7 days of the causative injury. The characteristics of posttraumatic headache most commonly resemble those of migraine or tension-type headache. Posttraumatic headache persists for 3 months or longer in about one-third of individuals. Additional studies investigating posttraumatic headache treatment are needed.

Inflammation, brain connectivity, and neuromodulation in post-traumatic headache

Post-traumatic headache (PTH) is a debilitating condition that affects individuals with different levels of traumatic brain injury (TBI) severity. The difficulties in developing an effective treatment are related to a lack of understanding the complicated mechanisms and neurobiological changes in brain function after a brain injury. Preclinical studies have indicated that peripheral and central sensitization of the trigeminal nociceptive pathways contributes to PTH. While recent brain imaging studies have uncovered widespread changes in brain functional connectivity following trauma, understanding exactly how these networks contribute to PTH after injury remains unknown. Stimulation of peripheral (trigeminal or vagus) nerves show promising efficacies in PTH experimental animals, likely mediated by influencing TBI-induced pathological plasticity by decreasing neuroinflammation and neuronal apoptosis. Non-invasive brain stimulations, such as transcranial magnetic or direct current stimulations, show analgesia for multiple chronic pain conditions, including PTH. Better mechanistic understanding of analgesia achieved by neuromodulations can define peripheral and central mechanisms involved in the development, the resolution, and the management of PTH.

What Are the Predictors for and Psychosocial Correlates of Chronic Headache After Moderate to Severe Traumatic Brain Injury?

OBJECTIVE

Although headache (HA) is a common sequela of traumatic brain injury (TBI), early predictors of chronic HA after moderate to severe TBI are not well established, and the relationship chronic HA has with psychosocial functioning is understudied. Thus, we sought to (1) determine demographic and injury predictors of chronic HA 1 or more years after moderate to severe TBI and (2) examine associations between chronic HA and psychosocial outcomes.

SETTING

Community.

PARTICIPANTS

Participants in the TBI Model System (TBIMS) with moderate to severe TBI who consented for additional chronic pain questionnaires at the time of TBIMS follow-up.

DESIGN

Multisite, observational cohort study using LASSO (least absolute shrinkage and selection operator) regression for prediction modeling and independent t tests for psychosocial associations.

MAIN OUTCOME MEASURES

Chronic HA after TBI at year 1 or 2 postinjury and more remotely (5 or more years).

RESULTS

The LASSO model for chronic HA at 1 to 2 years achieved acceptable predictability (cross-validated area under the curve [AUC] = 0.70). At 5 or more years, predictability was nearly acceptable (cross-validated AUC = 0.68), but much more complex, with more than twice as many variables contributing. Injury characteristics had stronger predictive value at postinjury years 1 to 2 versus 5 or more years, especially sustained intracranial pressure elevation (odds ratio [OR] = 3.8) and skull fragments on head computed tomography (CT) (OR = 2.5). Additional TBI(s) was a risk factor at both time frames, as were multiple socioeconomic characteristics, including lower education level, younger age, female gender, and Black race. Lower education level was a particularly strong predictor at 5 or more years (OR up to 3.5). Emotional and participation outcomes were broadly poorer among persons with chronic HA after moderate to severe TBI.

CONCLUSIONS

Among people with moderate to severe TBI, chronic HA is associated with significant psychosocial burden. The identified risk factors will enable targeted clinical screening and monitoring strategies to enhance clinical care pathways that could lead to better outcomes. They may also be useful as stratification or covariates in future clinical trial research on treatments.

Idiopathic intracranial hypertension: a step change in understanding the disease mechanisms

The understanding of idiopathic intracranial hypertension (IIH) has evolved over the past few years. Previously, IIH was considered a disease exclusively affecting the neuro-ophthalmic axis, characterized by raised intracranial pressure, headache and papilloedema, and resulting in the risk of severe and permanent visual loss and life-changing disabling headaches. Recent advances have begun to redefine IIH as a probable metabolic disease involving a range of systemic manifestations. More than 95% of individuals affected by the disease are women of reproductive age with obesity. The incidence is rapidly rising and parallels the escalating worldwide obesity rates. Contemporary insights identify associations with insulin resistance, type 2 diabetes and a twofold increased risk of cardiovascular disease in excess of that driven by obesity alone. Adipose distribution in people with IIH, like that in other metabolic diseases, is preferentially centripetal and is associated with changes in intracranial pressure. Evidence now demonstrates adipose tissue dysfunction in people with IIH, involving transcriptional and metabolic priming for lipogenesis and weight gain. Hormonal perturbations are also observed, including a unique phenotype of androgen excess that promotes cerebrospinal fluid secretion. Knowledge of these additional disease features is driving research into novel therapeutic targets and altering the approach to multidisciplinary care.

Identification of brain areas in mice with peak neural activity across the acute and persistent phases of post-traumatic headache

BACKGROUND

Post-traumatic headache is very common after a mild traumatic brain injury. Post-traumatic headache may persist for months to years after an injury in a substantial proportion of people. The pathophysiology underlying post-traumatic headache remains unknown but is likely distinct from other headache disorders. Identification of brain areas activated in acute and persistent phases of post-traumatic headache can provide insights into the underlying circuits mediating headache pain. We used an animal model of mild traumatic brain injury-induced post-traumatic headache and c-fos immunohistochemistry to identify brain regions with peak activity levels across the acute and persistent phases of post-traumatic headache.

METHODS

Male and female C57BL/6 J mice were briefly anesthetized and subjected to a sham procedure or a weight drop closed-head mild traumatic brain injury . Cutaneous allodynia was assessed in the periorbital and hindpaw regions using von Frey filaments. Immunohistochemical c-fos based neural activity mapping was then performed on sections from whole brain across the development of post-traumatic headache (i.e. peak of the acute phase at 2 days post- mild traumatic brain injury), start of the persistent phase (i.e. >14 days post-mild traumatic brain injury) or after provocation with stress (bright light). Brain areas with consistent and peak levels of c-fos expression across mild traumatic brain injury induced post-traumatic headache were identified and included for further analysis.

RESULTS

Following mild traumatic brain injury, periorbital and hindpaw allodynia was observed in both male and female mice. This allodynia was transient and subsided within the first 14 days post-mild traumatic brain injury and is representative of acute post-traumatic headache. After this acute post-traumatic headache phase, exposure of mild traumatic brain injury mice to a bright light stress reinstated periorbital and hindpaw allodynia for several hours - indicative of the development of persistent post-traumatic headache. Acute post-traumatic headache was coincident with an increase in neuronal c-fos labeling in the spinal nucleus of the trigeminal caudalis, primary somatosensory cortex, and the nucleus accumbens. Neuronal activation returned to baseline levels by the persistent post-traumatic headache phase in the spinal nucleus of the trigeminal caudalis and primary somatosensory cortex but remained elevated in the nucleus accumbens. In the persistent post-traumatic headache phase, coincident with allodynia observed following bright light stress, we observed bright light stress-induced c-fos neural activation in the spinal nucleus of the trigeminal caudalis, primary somatosensory cortex, and nucleus accumbens.

CONCLUSION

Examination of mild traumatic brain injury-induced changes in peak c-fos expression revealed brain regions with significantly increased neural activity across the acute and persistent phases of post-traumatic headache. Our findings suggest mild traumatic brain injury-induced post-traumatic headache produces neural activation along pain relevant pathways at time-points matching post-traumatic headache-like pain behaviors. These observations suggest that the spinal nucleus of the trigeminal caudalis, primary somatosensory cortex, and nucleus accumbens may contribute to both the induction and maintenance of post-traumatic headache.

Hypersensitivity to opening of ATP-sensitive potassium channels in post-traumatic headache

OBJECTIVE

To investigate whether levcromakalim (a KATP channel opener) induces migraine-like headache in people with persistent post-traumatic headache who had no known history of migraine.

METHODS

In a randomized, double-blind, placebo-controlled, 2-way crossover trial, participants were randomly assigned to receive a 20-minute continuous intravenous infusion of levcromakalim (50 µg/mL) or placebo (isotonic saline) on two separate experimental days with a 1-week wash-out period in between. The primary endpoint was the difference in incidence of migraine-like headache between levcromakalim and placebo during a 12-hour observational period after infusion start. The secondary endpoint was the difference in area under the curve for baseline-corrected median headache intensity scores between levcromakalim and placebo during the 12-hour observational period.

RESULTS

A total of 21 participants with persistent post-traumatic headache were randomized and completed the trial. During the 12-hour observational period, 12 (57%) of 21 participants reported experiencing migraine-like headache following the levcromakalim infusion, compared with three after placebo (P = 0.013). Moreover, the baseline-corrected median headache intensity scores were higher following the levcromakalim infusion than after placebo (P = 0.003).

CONCLUSION

Our findings suggest that KATP channels play an important role in the pathogenesis of migraine-like headache in people with persistent post-traumatic headache. This implies that KATP channel blockers might represent a promising avenue for drug development. Further research is warranted to explore the potential therapeutic benefits of KATP channel blockers in managing post-traumatic headache.Trial Registration: ClinicalTrials.gov Identifier: NCT05243953.

Does Physiologic Post-Concussion Disorder Cause Persistent Post-Traumatic Headache?

PURPOSE OF REVIEW

One system classifies patients with symptoms after concussion into physiologic, vestibulo-ocular, cervicogenic, and mood/cognition post-concussion disorders (PCD) based upon the preponderance of specific symptoms and physical impairments. This review discusses physiologic PCD and its potential relationship to the development of persistent post-traumatic headaches (PPTH).

RECENT FINDINGS

Headache is the most reported symptom after a concussion. Headaches in physiologic PCD are suspected to be due to abnormal cellular metabolism, subclinical neuroinflammation, and dysfunction of the autonomic nervous system (ANS). These abnormalities have been linked to the development of migraine-like and neuralgia-related PPTH. Physiologic PCD is a potential cause of PPTH after a concussion. Future research should focus on how to prevent PPTH in patients with physiologic PCD.

Multimodal Migraine Management and the Pursuit of Migraine Freedom: A Narrative Review

Migraine is a neurologic disease with a complex pathophysiology that can be controlled with current treatment options but not cured. Therefore, treatment expectations are highly variable. The concept of migraine freedom was recently introduced and can mean different things, with some, for example, expecting complete freedom from headache and associated symptoms and others accepting the occasional migraine attack if it does not impact functioning. Therefore, migraine management should be optimized so that patients can have the best opportunity to achieve their optimal treatment goals. With migraine freedom as a goal and, given the complex pathophysiology of migraine and the high incidence of comorbidities among individuals with migraine, treatment with a single modality may be insufficient, as it may not achieve migraine freedom in those with more frequent or disabling attacks. In this clinical perspective article, we have identified four key, partially overlapping principles of multimodal migraine treatment: (1) manage common comorbidities; (2) control modifiable risk factors for progression by addressing medication and caffeine overuse; (3) diagnose and treat secondary causes of headache, if present; and (4) individualize acute and preventive treatments to minimize pain, functional disability, and allodynia. There are many barriers to pursuing migraine freedom, and strategies to overcome them should be optimized. Migraine freedom should be an aspirational goal both at the individual attack level and for the disease overall. We believe that a comprehensive and multimodal approach that addresses all barriers people with migraine face could move patients closer to migraine freedom.

Effect of Voluntary Exercise on Endogenous Pain Control Systems and Post-traumatic Headache in Mice

Traumatic brain injury (TBI) can cause acute and chronic pain along with motor, cognitive, and emotional problems. Although the mechanisms are poorly understood, previous studies suggest disruptions in endogenous pain modulation may be involved. Voluntary exercise after a TBI has been shown to reduce some consequences of injury including cognitive impairment. We hypothesized, therefore, that voluntary exercise could augment endogenous pain control systems in a rodent model of TBI. For these studies, we used a closed-head impact procedure in male mice modeling mild TBI. We investigated the effect of voluntary exercise on TBI-induced hindpaw nociceptive sensitization, diffuse noxious inhibitory control failure, and periorbital sensitization after bright light stress, a model of post-traumatic headache. Furthermore, we investigated the effects of exercise on memory, circulating markers of brain injury, neuroinflammation, and spinal cord gene expression. We observed that exercise significantly reduced TBI-induced hindpaw allodynia and periorbital allodynia in the first week following TBI. We also showed that exercise improved the deficits associated with diffuse noxious inhibitory control and reduced bright light stress-induced allodynia up to 2 months after TBI. In addition, exercise preserved memory and reduced TBI-induced increases in spinal BDNF, CXCL1, CXCL2, and prodynorphin expression, all genes previously linked to TBI-induced nociceptive sensitization. Taken together, our observations suggest that voluntary exercise may reduce pain after TBI by reducing TBI-induced changes in nociceptive signaling and preserving endogenous pain control systems. PERSPECTIVE: This article evaluates the effects of exercise on pain-related behaviors in a preclinical model of traumatic brain injury (TBI). The findings show that exercise reduces nociceptive sensitization, loss of diffuse noxious inhibitory control, memory deficits, and spinal nociception-related gene expression after TBI. Exercise may reduce or prevent pain after TBI.

Prevalence of and Risk Factors for Post-traumatic Headache in Civilian Patients After Mild Traumatic Brain Injury: A TRACK-TBI Study

OBJECTIVE

To ascertain the prevalence of and risk factors for post-traumatic headache (PTH) attributed to mild traumatic brain injury (mTBI).

PATIENTS AND METHODS

A prospective, longitudinal, multicenter cohort study of patients with mTBI and orthopedic trauma controls who were enrolled from February 26, 2014, to August 8, 2018. The baseline assessment was conducted as soon as possible following evaluation at the emergency department. Follow-ups were scheduled at 2 weeks, 3 months, 6 months, and 12 months postinjury. Eligible patients with mTBI included those 18 years of age or older who presented to the emergency department within 24 hours of head injury warranting evaluation by noncontrast head computed tomography scan. Acute PTH was considered present when a patient reported a headache score of greater than or equal to 2 on the Rivermead Post-concussion Questionnaire at 2 weeks postinjury (ie, headache is at least a mild problem compared with pre-injury). Persistent PTH was defined when a patient with acute PTH reported a Rivermead Post-concussion Questionnaire headache score of greater than or equal to 2 at the scheduled follow-up examinations.

RESULTS

Acute PTH was reported by 963 (60.4%) of 1594 patients with mTBI at 2 weeks postinjury. Among those with acute PTH, 439 (52.4%) of 837 patients reported persistent PTH at 3 months postinjury. This figure decreased over time and 278 (37.5%) of 742 patients continued to report persistent PTH at 6 months, whereas 187 (28.9%) of 646 patients did so as well at 12 months postinjury. Risk factors for acute PTH included younger age, female sex, fewer years of formal education, computed tomography-positive scans, alteration of consciousness, psychiatric history, and history of migraine. Risk factors for persistent PTH included female sex, fewer years of formal education, and history of migraine.

CONCLUSION

Post-traumatic headache is a prevalent sequela of mTBI that persists for at least 12 months in a considerable proportion of affected individuals. The attributable burden necessitates better patient follow-up, disease characterization, improved awareness of PTH in clinical practice, and identification of effective therapies.

Headache among combat-exposed veterans and service members and its relation to mild traumatic brain injury history and other factors: a LIMBIC-CENC study

Background

Headache (HA) is a common persistent complaint following mild traumatic brain injury (mTBI), but the association with remote mTBI is not well established, and risk factors are understudied.

Objective

Determine the relationship of mTBI history and other factors with HA prevalence and impact among combat-exposed current and former service members (SMs).

Design

Secondary cross-sectional data analysis from the Long-Term Impact of Military-Relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium prospective longitudinal study.

Methods

We examined the association of lifetime mTBI history, demographic, military, medical and psychosocial factors with (1) HA prevalence ("lately, have you experienced headaches?") using logistic regression and (2) HA burden via the Headache Impact Test-6 (HIT-6) using linear regression. Each lifetime mTBI was categorized by mechanism (blast-related or not) and setting (combat deployed or not). Participants with non-credible symptom reporting were excluded, leaving N = 1,685 of whom 81% had positive mTBI histories.

Results

At a median 10 years since last mTBI, mTBI positive participants had higher HA prevalence (69% overall, 78% if 3 or more mTBIs) and greater HA burden (67% substantial/severe impact) than non-TBI controls (46% prevalence, 54% substantial/severe impact). In covariate-adjusted analysis, HA prevalence was higher with greater number of blast-related mTBIs (OR 1.81; 95% CI 1.48, 2.23), non-blast mTBIs while deployed (OR 1.42; 95% CI 1.14, 1.79), or non-blast mTBIs when not deployed (OR 1.23; 95% CI 1.02, 1.49). HA impact was only higher with blast-related mTBIs. Female identity, younger age, PTSD symptoms, and subjective sleep quality showed effects in both prevalence and impact models, with the largest mean HIT-6 elevation for PTSD symptoms. Additionally, combat deployment duration and depression symptoms were factors for HA prevalence, and Black race and Hispanic/Latino ethnicity were factors for HA impact. In sensitivity analyses, time since last mTBI and early HA onset were both non-significant.

Conclusion

The prevalence of HA symptoms among formerly combat-deployed veterans and SMs is higher with more lifetime mTBIs regardless of how remote. Blast-related mTBI raises the risk the most and is uniquely associated with elevated HA burden. Other demographic and potentially modifiable risk factors were identified that may inform clinical care.

Which headache disorders can be diagnosed concurrently? An analysis of ICHD3 criteria using prime encoding system

Introduction

Real-life headache presentations may fit more than one ICHD3 diagnosis. This project seeks to exhaustively list all logically consistent "co-diagnoses" according to the ICHD3 criteria. We limited our project to cases of two concurrent diagnoses.

Methods

We included the criteria for "Migraine" (1.1, 1.2, 1.3), "Tension-type headache" (2.1, 2.2, 2.3, 2.4), "Trigeminal autonomic cephalalgias" (3.1, 3.2, 3.3, 3.4, 3.5), and "Other primary headache disorders." We also excluded "probable" diagnosis criteria. Each characteristic in the above criteria is assigned a unique prime number. We then encoded each ICHD3 criteria into integers through multiplication in a list format; we called these criteria representations. "Codiagnoses representations" were generated by multiplying all possible pairings of criteria representations. We then manually encoded a list of logically inconsistent characteristics through multiplication. All co-diagnoses representations divisible by any inconsistency representations were filtered out, generating a list of co-diagnoses representations that were logically consistent. This list was then translated back into ICHD3 diagnoses.

Results

We used a total of 103 prime numbers to encode 578 ICHD3 criteria. Once illogical characteristics were excluded, we obtained 145 dual diagnoses. Of the dual diagnoses, two contained intersecting characteristics due to subset relationships, 14 contained intersecting characteristics without subset relationships, and 129 contained dual diagnoses as a result of non-intersecting characteristics.

Conclusion

Analysis of dual diagnosis in headaches offers insight into "loopholes" in the ICHD3 as well as a potential explanation for the source of a number of controversies regarding headache disorders. The existence of dual diagnoses and their identification may carry implications for future developments and testing of machine-learning diagnostic algorithms for headaches.

Evaluating Headache and Facial Pain in a Headache Diagnostic Laboratory: Experiences from the Danish Headache Center

BACKGROUND

Diagnostic tests are not routinely used for the diagnosis of primary headaches. It is possible that laboratory tests could be developed and implemented at tertiary headache centers to be an integrated part of the diagnosis and management of headache patients, and laboratory tests that can be used on-site at headache centers could help in evaluating patients with secondary headache disorders.

METHODS

In this narrative review, we present some of the studies that have been made so far at the Headache Diagnostic Laboratory at the Danish Headache Center that aim to investigate and phenotype primary headaches and investigate secondary headaches as well as improve management.

RESULTS

Semi-structured interviews and deep phenotyping, quantitative sensory testing, and provocation studies have been shown to be valuable in categorizing primary and secondary headache subtypes, possible pathophysiology, and defining needs for further research. In patients suspected of increased intracranial pressure, transorbital ultrasound with measurement of the optic sheath diameter may be useful in monitoring patients. The management of headache patients needs to be critically evaluated to optimize treatment continuously.

CONCLUSION

A Headache Diagnostic Laboratory is very useful and should be an integrated part of headache care and management at tertiary headache centers.

Functional Overlay Model of Persistent Post-Concussion Syndrome

Persistent post-concussion syndrome (PPCS) is a complex and debilitating condition that can develop after head concussions or mild traumatic brain injury (mTBI). PPCS is characterized by a wide range of symptoms, including headaches, dizziness, fatigue, cognitive deficits, and emotional changes, that can persist for months or even years after the initial injury. Despite extensive research, the underlying mechanisms of PPCS are still poorly understood; furthermore, there are limited resources to predict PPCS development in mTBI patients and no established treatment. Similar to PPCS, the etiology and pathogenesis of functional neurological disorders (FNDs) are not clear neither fully described. Nonspecific multifactorial interactions that were also seen in PPCS have been identified as possible predispositions for FND onset and progression. Thus, we aimed to describe a functional overlay model of PPCS that emphasizes the interplay between functional and structural factors in the development and perpetuation of PPCS symptoms. Our model suggests that the initial brain injury triggers a cascade of physiological and psychological processes that disrupt the normal functioning of the brain leading to persistent symptoms. This disruption can be compounded by pre-existing factors, such as genetics, prior injury, and psychological distress, which can increase the vulnerability to PPCS. Moreover, specific interventions, such as cognitive behavioral therapy, neurofeedback, and physical exercise can target the PPCS treatment approach. Thus, the functional overlay model of PPCS provides a new framework for understanding the complex nature of this condition and for developing more effective treatments. By identifying and targeting specific functional factors that contribute to PPCS symptoms, clinicians and researchers can improve the diagnosis, management, and ultimately, outcomes of patients with this condition.

Post-Traumatic Headache: A Review of Prevalence, Clinical Features, Risk Factors, and Treatment Strategies

Post-traumatic headache (PTH) is a common and debilitating consequence of mild traumatic brain injury (mTBI) that can occur over one year after the head impact event. Thus, better understanding of the underlying pathophysiology and risk factors could facilitate early identification and management of PTH. There are several factors that could influence the reporting of PTH prevalence, including the definition of concussion and PTH. The main risk factors for PTHs include a history of migraines or headaches, female gender, younger age, greater severity of the head injury, and co-occurring psychological symptoms, such as anxiety and depression. PTH clinical profiles vary based on onset, duration, and severity: tension-type headache, migraine headaches, cervicogenic headache, occipital neuralgia, and new daily persistent headache. Pharmacological treatments often consist of analgesics and non-steroidal anti-inflammatory drugs, tricyclic antidepressants, or antiepileptic medication. Cognitive behavioral therapy, relaxation techniques, biofeedback, and physical therapy could also be used for PTH treatment. Our work highlighted the need for more rigorous studies to better describe the importance of identifying risk factors and patient-centered treatments and to evaluate the effectiveness of the existing treatment options. Clinicians should consider a multidisciplinary approach to managing PTH, including pharmacotherapy, cognitive behavioral therapy, and lifestyle changes.

Repeat mild traumatic brain injuries (RmTBI) modify nociception and disrupt orexinergic connectivity within the descending pain pathway

Repeat mild traumatic brain injuries (RmTBI) result in substantial burden to the public health system given their association with chronic post-injury pathologies, such as chronic pain and post-traumatic headache. Although this may relate to dysfunctional descending pain modulation (DPM), it is uncertain what mechanisms drive changes within this pathway. One possibility is altered orexinergic system functioning, as orexin is a potent anti-nociceptive neuromodulator. Orexin is exclusively produced by the lateral hypothalamus (LH) and receives excitatory innervation from the lateral parabrachial nucleus (lPBN). Therefore, we used neuronal tract-tracing to investigate the relationship between RmTBI and connectivity between lPBN and the LH, as well as orexinergic projections to a key site within the DPM, the periaqueductal gray (PAG). Prior to injury induction, retrograde and anterograde tract-tracing surgery was performed on 70 young-adult male Sprague Dawley rats, targeting the lPBN and PAG. Rodents were then randomly assigned to receive RmTBIs or sham injuries before undergoing testing for anxiety-like behaviour and nociceptive sensitivity. Immunohistochemical analysis identified distinct and co-localized orexin and tract-tracing cell bodies and projections within the LH. The RmTBI group exhibited altered nociception and reduced anxiety as well as a loss of orexin cell bodies and a reduction of hypothalamic projections to the ventrolateral nucleus of the PAG. However, there was no significant effect of injury on neuronal connectivity between the lPBN and orexinergic cell bodies within the LH. Our identification of structural losses and the resulting physiological changes in the orexinergic system following RmTBI begins to clarify acute post-injury mechanistic changes that drive may drive the development of post-traumatic headache and the chronification of pain.

Randomized controlled pilot trial of prazosin for prophylaxis of posttraumatic headaches in active-duty service members and veterans

OBJECTIVE

Evaluate the efficacy and tolerability of prazosin for prophylaxis of headaches following mild traumatic brain injury in active-duty service members and military veterans.

BACKGROUND

Prazosin is an alpha-1 adrenoreceptor antagonist that reduces noradrenergic signaling. An open-label trial in which prazosin reduced headache frequency in veterans following mild traumatic brain injury provided the rationale for this pilot study.

METHODS

A 22-week parallel-group randomized controlled trial  which included 48 military veterans and active-duty service members with mild traumatic brain injury-related headaches was performed. The study design was based on International Headache Society consensus guidelines for randomized controlled trials for chronic migraine. Following a pre-treatment baseline phase, participants with at least eight qualifying headache days per 4 weeks were randomized 2:1 to prazosin or placebo. After a 5-week titration to a maximum possible dose of 5 mg (morning) and 20 mg (evening), participants were maintained on the achieved dose for 12 weeks. Outcome measures were evaluated in 4-week blocks during the maintenance dose phase. The primary outcome measure was change in 4-week frequency of qualifying headache days. Secondary outcome measures were percent participants achieving at least 50% reduction in qualifying headache days and change in Headache Impact Test-6 scores.

RESULTS

Intent-to-treat analysis of randomized study participants (prazosin N = 32; placebo N = 16) demonstrated greater benefit over time in the prazosin group for all three outcome measures. In prazosin versus placebo participants, reductions from baseline to the final rating period for 4-week headache frequency were -11.9 ± 1.0 (mean ± standard error) versus -6.7 ± 1.5, a prazosin minus placebo difference of -5.2 (-8.8, -1.6 [95% confidence interval]), p = 0.005 and for Headache Impact Test-6 scores were -6.0 ± 1.3 versus +0.6 ± 1.8, a difference of -6.6 (-11.0, -2.2), p = 0.004. The mean predicted percent of participants at 12 weeks with ≥50% reduction in headache days/4 weeks, baseline to final rating, was 70 ± 8% for prazosin (21/30) versus 29 ± 12% for placebo (4/14), odds ratio 5.8 (1.44, 23.6), p = 0.013. The trial completion rate of 94% in the prazosin group (30/32) and 88% in the placebo group (14/16) indicated that prazosin was generally well tolerated at the administered dose regimen. Morning drowsiness/lethargy was the only adverse effect that differed significantly between groups, affecting 69% of the prazosin group (22/32) versus 19% of the placebo group (3/16), p = 0.002.

CONCLUSIONS

This pilot study provides a clinically meaningful efficacy signal for prazosin prophylaxis of posttraumatic headaches. A larger randomized controlled trial is needed to confirm and extend these promising results.

Temporal Changes of the Oral and Fecal Microbiota after Mild Traumatic Brain Injury in Rats by 16S rRNA Sequencing

A mild traumatic brain injury (mTBI) can increase the risk of neurodegenerative-related disease, and serious long-term outcomes are often overlooked. In forensic science, the accurate identification of mTBIs can directly affect the application of evidence in practice cases. Recent research has revealed that the oral cavity and fecal microbiota play a fundamental role in deeply interconnecting the gut and brain injury. Therefore, we investigated the relationship between the temporal changes of the oral cavity and fecal bacterial communities with damage identification and post-injury time estimation after mTBI. In this study, we analyzed the oral cavity and fecal bacterial communities in mTBI rats under 12 different post-injury times (sham, 0 h, 2 h, 6 h, 12 h, 24 h, 2 d, 3 d, 5 d, 7 d, 10 d, and 14 d post-injury) using 16S rRNA sequencing technology. The sequence results revealed bacteria belonging to 36 phyla, 82 classes, 211 orders, 360 families, 751 genera, and 1398 species. Compared to the sham group, the relative abundance of the bacterial communities varied markedly in the post-injury groups. Importantly, our data demonstrated that Fusobacteria, Prevotellaceae, Ruminococcaceae, and Lactobacillaceae might be the potential candidates for mTBI identification, and 2 h post-injury was a critical time point to explore the temporal changes of mTBI injury-time estimation. The results also provide new ideas for mTBI treatment in the clinic.

Imaging the brain and vascular reactions to headache treatments: a systematic review

BACKGROUND

Neuroimaging studies have made an important contribution to our understanding of headache pathophysiology. This systematic review aims to provide a comprehensive overview and critical appraisal of mechanisms of actions of headache treatments and potential biomarkers of treatment response disclosed by imaging studies.

MAIN BODY

We performed a systematic literature search on PubMed and Embase databases for imaging studies investigating central and vascular effects of pharmacological and non-pharmacological treatments used to abort and prevent headache attacks. Sixty-three studies were included in the final qualitative analysis. Of these, 54 investigated migraine patients, 4 cluster headache patients and 5 patients with medication overuse headache. Most studies used functional magnetic resonance imaging (MRI) (n = 33) or molecular imaging (n = 14). Eleven studies employed structural MRI and a few used arterial spin labeling (n = 3), magnetic resonance spectroscopy (n = 3) or magnetic resonance angiography (n = 2). Different imaging modalities were combined in eight studies. Despite of the variety of imaging approaches and results, some findings were consistent. This systematic review suggests that triptans may cross the blood-brain barrier to some extent, though perhaps not sufficiently to alter the intracranial cerebral blood flow. Acupuncture in migraine, neuromodulation in migraine and cluster headache patients, and medication withdrawal in patients with medication overuse headache could promote headache improvement by reverting headache-affected pain processing brain areas. Yet, there is currently no clear evidence for where each treatment acts, and no firm imaging predictors of efficacy. This is mainly due to a scarcity of studies and heterogeneous treatment schemes, study designs, subjects, and imaging techniques. In addition, most studies used small sample sizes and inadequate statistical approaches, which precludes generalizable conclusions.

CONCLUSION

Several aspects of headache treatments remain to be elucidated using imaging approaches, such as how pharmacological preventive therapies work, whether treatment-related brain changes may influence therapy effectiveness, and imaging biomarkers of clinical response. In the future, well-designed studies with homogeneous study populations, adequate sample sizes and statistical approaches are needed.

Remotely supervised at-home tDCS for veterans with persistent post-traumatic headache: a double-blind, sham-controlled randomized pilot clinical trial

Background

Currently, there are no FDA approved therapies for persistent post-traumatic headache (PPTH) secondary to traumatic brain injury (TBI). As such neither headache nor TBI specialists have an effective means to manage PPTH. Thus, the objective of the present pilot trial was to evaluate the feasibility and preliminary efficacy of a four-week at-home remotely supervised transcranial direct current stimulation (RS-tDCS) intervention for veterans with PPTH.

Methods

Twenty-five (m = 46.6 ± 8.7 years) veterans with PPTH were randomized into two groups and received either active (n = 12) or sham (n = 13) RS-tDCS, with anodal stimulation over left dlPFC and cathodal over occipital pole. Following a four-week baseline, participants completed 20-sessions of active or sham RS-tDCS with real-time video monitoring over a period of four-weeks. Participants were assessed again at the end of the intervention and at four-weeks post-intervention. Primary outcomes were overall adherence rate (feasibility) and change in moderate-to-severe headache days per month (efficacy). Secondary outcomes were changes in total number of headache days, and PPTH-related functional outcomes.

Results

Adherence rate was high with 88% of participants (active = 10/12; sham = 12/13) fully completing tDCS interventions. Importantly, there was no significant difference in adherence between active and sham groups (p = 0.59). Moderate-to-severe headache days were significantly reduced within the active RS-tDCS group (p = 0.004), compared to sham during treatment (-2.5 ± 3.5 vs. 2.3 ± 3.4), and 4-week follow-up (-3.9 ± 6.4 vs. 1.2 ± 6.5). Total number of headache days was significantly reduced within the active RS-tDCS (p = 0.03), compared to sham during-treatment (-4.0 ± 5.2 vs. 1.5 ± 3.8), and 4-week follow-up (-2.1 ± 7.2 vs. -0.2 ± 4.4).

Conclusion

The current results indicate our RS-tDCS paradigm provides a safe and effective means for reducing the severity and number of headache days in veterans with PPTH. High treatment adherence rate and the remote nature of our paradigm indicate RS-tDCS may be a feasible means to reduce PPTH, especially for veterans with limited access to medical facilities.Clinical Trial Registration: ClinicalTrials.gov, identifier [NCT04012853].

Post-Traumatic Headache in Children after Minor Head Trauma: Incidence, Phenotypes, and Risk Factors

Minor head trauma (MHT) is very frequent in children and post-traumatic headache (PTH) is one of its most common complications; however, its management is still a challenge. We aimed to assess the incidence and clinical characteristics of, and risk factors for, PTH among children referred to our pediatric emergency department (PED) for MHT. A total of 193 patients aged 3–14 years evaluated for MTH were enrolled and followed up for 6 months through phone calls and/or visits. PTH occurred in 25/193 patients (13%). PTH prevalence was significantly higher in school-aged (≥6 years) than in pre-school-aged children (21.6% vs. 4.9%, respectively, p < 0.009). Females were found to be more affected. The median time of onset was 4.6 days after MHT; resolution occurred in a median of 7 weeks. In 83.3% of patients, PTH subsided in <3 months, while in 16.7% it persisted longer. A total of 25% of children exhibited the migraine and 75% the tension-type variant. Our analysis indicates the presence of headache upon arrival in PED, isolated or associated with nausea and dizziness, as a factor predisposing the patient to the development of PTH. Our findings could be useful to identify children at risk for PTH for specific follow-up, family counseling, and treatment.

The NMDA receptor antagonists memantine and ketamine as anti-migraine agents

Migraine is a debilitating disorder affecting females more frequently than males. There is some evidence that drugs targeting glutamate receptors: memantine and ketamine might be beneficial in the therapy of this entity. Therefore, the purpose of this work is to present NMDA receptor antagonists, memantine and ketamine, as potential anti-migraine agents. We searched PubMed/MEDLINE, Embase, and clinical trials submitted to ClinicalTrials.gov to find publications describing eligible trials published between database inception and December 31, 2021. This comprehensive literature review summarizes data on the use of the NMDA receptor antagonists memantine and ketamine in the pharmacotherapy of migraine. Results from 20 previous and recent preclinical experiments are discussed and correlated with 19 clinical trials (including case series, open-label, and randomized placebo-controlled trials). For the purposes of this review, the authors hypothesized that the propagation of SD is a major mechanism in the pathophysiology of migraine. In several animal studies and in vitro studies, memantine and ketamine inhibited or reduced propagation of the SD. In addition, the results of clinical trials suggest that memantine or ketamine may be an effective treatment option for migraine. However, most studies on these agents lack control group. Although further clinical trials are needed, the results suggest that ketamine or memantine may be promising molecules for the treatment of severe migraine. Particular attention should be paid to people who have a treatment-resistant form of migraine with aura or have exhausted existing treatment options. For them, the drugs under discussion could represent an interesting alternative in the future.

Association of Posttraumatic Headache With Symptom Burden After Concussion in Children

Importance

Headache is the most common symptom after pediatric concussion.

Objectives

To examine whether posttraumatic headache phenotype is associated with symptom burden and quality of life 3 months after concussion.

Design, Setting, and Participants

This was a secondary analysis of the Advancing Concussion Assessment in Pediatrics (A-CAP) prospective cohort study, conducted September 2016 to July 2019 at 5 Pediatric Emergency Research Canada (PERC) network emergency departments. Children aged 8.0-16.99 years presenting with acute (<48 hours) concussion or orthopedic injury (OI) were included. Data were analyzed from April to December 2022.

Exposure

Posttraumatic headache was classified as migraine or nonmigraine headache, or no headache, using modified International Classification of Headache Disorders, 3rd edition, diagnostic criteria based on self-reported symptoms collected within 10 days of injury.

Main Outcomes and Measures

Self-reported postconcussion symptoms and quality-of-life were measured at 3 months after concussion using the validated Health and Behavior Inventory (HBI) and Pediatric Quality of Life Inventory-Version 4.0 (PedsQL-4.0). An initial multiple imputation approach was used to minimize potential biases due to missing data. Multivariable linear regression evaluated the association between headache phenotype and outcomes compared with the Predicting and Preventing Postconcussive Problems in Pediatrics (5P) clinical risk score and other covariates and confounders. Reliable change analyses examined clinical significance of findings.

Results

Of 967 enrolled children, 928 (median [IQR] age, 12.2 [10.5 to 14.3] years; 383 [41.3%] female) were included in analyses. HBI total score (adjusted) was significantly higher for children with migraine than children without headache (estimated mean difference [EMD], 3.36; 95% CI, 1.13 to 5.60) and children with OI (EMD, 3.10; 95% CI, 0.75 to 6.62), but not children with nonmigraine headache (EMD, 1.93; 95% CI, -0.33 to 4.19). Children with migraine were more likely to report reliable increases in total symptoms (odds ratio [OR], 2.13; 95% CI, 1.02 to 4.45) and somatic symptoms (OR, 2.70; 95% CI, 1.29 to 5.68) than those without headache. PedsQL-4.0 subscale scores were significantly lower for children with migraine than those without headache only for physical functioning (EMD, -4.67; 95% CI, -7.86 to -1.48).

Conclusions and Relevance

In this cohort study of children with concussion or OI, those with posttraumatic migraine symptoms after concussion had higher symptom burden and lower quality of life 3 months after injury than those with nonmigraine headache. Children without posttraumatic headache reported the lowest symptom burden and highest quality of life, comparable with children with OI. Further research is warranted to determine effective treatment strategies that consider headache phenotype.

White matter hyperintensities and cerebral microbleeds in persistent post-traumatic headache attributed to mild traumatic brain injury: a magnetic resonance imaging study

OBJECTIVE

To examine whether white matter hyperintensities (WMHs) and cerebral microbleeds (CMBs) are more prevalent in people with persistent post-traumatic headache attributed to mild traumatic brain injury (TBI), compared with healthy controls.

METHODS

A magnetic resonance imaging (MRI) study of adults with persistent post-traumatic headache attributed to mild TBI and age- and gender-matched healthy controls. A semi-structured interview and validated self-report instruments were used to record data on demographics, clinical characteristics, and comorbidities. Imaging data were obtained on a 3T MRI Scanner using a 32-channel head coil. Participants and controls underwent a single MRI session, in which fluid-attenuated inversion recovery was used to visualize WMHs, and susceptibility-weighted imaging was used to detect CMBs. The primary outcomes were (I) the difference in the mean number of WMHs between participants with persistent post-traumatic headache and healthy controls and (II) the difference in the mean number of CMBs between participants with persistent post-traumatic headache and healthy controls. All images were examined by a certified neuroradiologist who was blinded to the group status of the participants and controls.

RESULTS

A total of 97 participants with persistent post-traumatic headache and 96 age- and gender-matched healthy controls provided imaging data eligible for analyses. Among 97 participants with persistent post-traumatic headache, 43 (44.3%) participants presented with ≥ 1 WMH, and 3 (3.1%) participants presented with ≥ 1 CMB. Compared with controls, no differences were found in the mean number of WMHs (2.7 vs. 2.1, P = 0.58) and the mean number of CMBs (0.03 vs. 0.04, P = 0.98).

CONCLUSIONS

WMHs and CMBs were not more prevalent in people with persistent post-traumatic headache than observed in healthy controls. Future studies should focus on other MRI techniques to identify radiologic biomarkers of post-traumatic headache.

Use of Rimegepant in the Management of Cervicogenic Headache Secondary to Trauma: A Case Series

A cervicogenic headache (CH) originates from a cervical source. Multiple diagnostic criteria and treatment strategies for CH are present. Rimegepant is a calcitonin gene-related peptide receptor (CGRP) antagonist. We present a case series of three patients with CH who reported varying degrees of decreased headache intensity after using rimegepant.

The value of brain MRI functional connectivity data in a machine learning classifier for distinguishing migraine from persistent post-traumatic headache

Background

Post-traumatic headache (PTH) and migraine often have similar phenotypes. The objective of this exploratory study was to develop classification models to differentiate persistent PTH (PPTH) from migraine using clinical data and magnetic resonance imaging (MRI) measures of brain structure and functional connectivity (fc).

Methods

Thirty-four individuals with migraine and 48 individuals with PPTH attributed to mild TBI were included. All individuals completed questionnaires assessing headache characteristics, mood, sensory hypersensitivities, and cognitive function and underwent brain structural and functional imaging during the same study visit. Clinical features, structural and functional resting-state measures were included as potential variables. Classifiers using ridge logistic regression of principal components were fit on the data. Average accuracy was calculated using leave-one-out cross-validation. Models were fit with and without fc data. The importance of specific variables to the classifier were examined.

Results

With internal variable selection and principal components creation the average accuracy was 72% with fc data and 63.4% without fc data. This classifier with fc data identified individuals with PPTH and individuals with migraine with equal accuracy.

Conclusion

Multivariate models based on clinical characteristics, fc, and brain structural data accurately classify and differentiate PPTH vs. migraine suggesting differences in the neuromechanism and clinical features underlying both headache disorders.

Comparison of continuous headache features in youth with migraine, new daily persistent headache, and persistent post-traumatic headache

OBJECTIVE

To compare clinical features in youth with continuous headache from migraine, persistent post-traumatic headache, and new daily persistent headache to determine if they are similar, contrary to their distinction in the International Classification of Headache Disorders.

METHODS

We pursued a single center age- and sex-matched observational study comparing the clinical characteristics of 150 youth (11 - 17 years old) with continuous headache from migraine, persistent post-traumatic headache, and new daily persistent headache. A diagnostic algorithm based on international classification of headache disorders criteria was used to identify those with migraine (headache features of migraine with gradual onset), and persistent post-traumatic headache and new daily persistent headache (based on the circumstances of headache onset regardless of headache features). Fifty participants each with migraine, persistent post-traumatic headache, and new daily persistent headache were matched by age and sex. Participant survey responses on headache characteristics were compared.

RESULTS

Median usual headache severity was 6.0 [95%CI 6.0, 6.0] and was not different across diagnostic groups (H statistic = 1.2, p = 0.55). Headache exacerbation frequency, disability, associated symptoms, and most triggers were not significantly different across groups. The majority of persistent post-traumatic headache and new daily persistent headache had headache features consistent with a diagnose of migraine (72% and 62%, respectively).

CONCLUSION

Our findings suggest that most persistent post-traumatic headache and new daily persistent headache may represent abrupt onset of migraine.

Traumatic brain injury: Mechanisms, manifestations, and visual sequelae

Traumatic brain injury (TBI) results when external physical forces impact the head with sufficient intensity to cause damage to the brain. TBI can be mild, moderate, or severe and may have long-term consequences including visual difficulties, cognitive deficits, headache, pain, sleep disturbances, and post-traumatic epilepsy. Disruption of the normal functioning of the brain leads to a cascade of effects with molecular and anatomical changes, persistent neuronal hyperexcitation, neuroinflammation, and neuronal loss. Destructive processes that occur at the cellular and molecular level lead to inflammation, oxidative stress, calcium dysregulation, and apoptosis. Vascular damage, ischemia and loss of blood brain barrier integrity contribute to destruction of brain tissue. This review focuses on the cellular damage incited during TBI and the frequently life-altering lasting effects of this destruction on vision, cognition, balance, and sleep. The wide range of visual complaints associated with TBI are addressed and repair processes where there is potential for intervention and neuronal preservation are highlighted.

Safety and efficacy of peripheral nerve blocks to treat refractory headaches after aneurysmal subarachnoid hemorrhage - A pilot observational study

Objectives

Headache after aneurysmal subarachnoid hemorrhage (HASH) is common, severe, and often refractory to conventional treatments. Current treatment standards include medications including opioids, until the pain is mitigated. Peripheral nerve blocks (PNBs) may be an effective therapeutic option for HASH. We conducted a small before-and-after study of PNBs to determine safety, feasibility, and efficacy in treatment of HASH.

Methods

We conducted a pilot before-and-after observational study and collected data for 5 patients in a retrospective control group and 5 patients in a prospective intervention PNB group over a 12-month period. All patients received a standard treatment of medications including acetaminophen, magnesium, gabapentin, dexamethasone and anti-spasmodics or anti-emetics as needed. Patients in the intervention group received bilateral greater occipital, lesser occipital, and supraorbital PNBs in addition to medications. The primary outcome was pain severity, measured by Numeric pain rating scale (NPRS). All patients were followed for 1 week following enrollment.

Results

The mean ages in the PNB group and control group were 58.6 and 57.4, respectively. One patient in the control group developed radiographic vasospasm. Three patients in both groups had radiographic hydrocephalus and IVH, requiring external ventricular drain (EVD) placement. The PNB group had an average reduction in mean raw pain score of 2.76 (4.68, 1.92 p = 0.024), and relative pain score by 0.26 (0.48, 0.22 p = 0.026), compared to the control group. The reduction occurred immediately after PNB administration.

Conclusion

PNB can be a safe, feasible and effective treatment modality for HASH. Further investigations with a larger sample size are warranted.

Preclinical Studies of Posttraumatic Headache and the Potential Therapeutics

Posttraumatic headache (PTH) attributed to traumatic brain injury (TBI) is a secondary headache developed within 7 days after head injury, and in a substantial number of patients PTH becomes chronic and lasts for more than 3 months. Current medications are almost entirely relied on the treatment of primary headache such as migraine, due to its migraine-like phenotype and the limited understanding on the PTH pathogenic mechanisms. To this end, increasing preclinical studies have been conducted in the last decade. We focus in this review on the trigeminovascular system from the animal studies since it provides the primary nociceptive sensory afferents innervating the head and face region, and the pathological changes in the trigeminal pathway are thought to play a key role in the development of PTH. In addition to the pathologies, PTH-like behaviors induced by TBI and further exacerbated by nitroglycerin, a general headache inducer through vasodilation are reviewed. We will overview the current pharmacotherapies including calcitonin gene-related peptide (CGRP) monoclonal antibody and sumatriptan in the PTH animal models. Given that modulation of the endocannabinoid (eCB) system has been well-documented in the treatment of migraine and TBI, the therapeutic potential of eCB in PTH will also be discussed.

Emerging Roles of Type-I Interferons in Neuroinflammation, Neurological Diseases, and Long-Haul COVID

Interferons (IFNs) are pleiotropic cytokines originally identified for their antiviral activity. IFN-α and IFN-β are both type I IFNs that have been used to treat neurological diseases such as multiple sclerosis. Microglia, astrocytes, as well as neurons in the central and peripheral nervous systems, including spinal cord neurons and dorsal root ganglion neurons, express type I IFN receptors (IFNARs). Type I IFNs play an active role in regulating cognition, aging, depression, and neurodegenerative diseases. Notably, by suppressing neuronal activity and synaptic transmission, IFN-α and IFN-β produced potent analgesia. In this article, we discuss the role of type I IFNs in cognition, neurodegenerative diseases, and pain with a focus on neuroinflammation and neuro-glial interactions and their effects on cognition, neurodegenerative diseases, and pain. The role of type I IFNs in long-haul COVID-associated neurological disorders is also discussed. Insights into type I IFN signaling in neurons and non-neuronal cells will improve our treatments of neurological disorders in various disease conditions.

Brain Connectivity Predicts Chronic Pain in Acute Mild Traumatic Brain Injury

OBJECTIVES

Previous studies have established the role of the cortico-mesolimbic and descending pain modulation systems in chronic pain prediction. Mild traumatic brain injury (mTBI) is an acute pain model where chronic pain is prevalent and complicated for prediction. In this study, we set out to study whether functional connectivity (FC) of the nucleus accumbens (NAc) and the periaqueductal gray matter (PAG) is predictive of pain chronification in early-acute mTBI.

METHODS

To estimate FC, resting-state functional magnetic resonance imaging (fMRI) of 105 participants with mTBI following a motor vehicle collision was acquired within 72 hours post-accident. Participants were classified according to pain ratings provided at 12-months post-collision into chronic pain (head/neck pain ≥30/100, n = 44) and recovery (n = 61) groups, and their FC maps were compared.

RESULTS

The chronic pain group exhibited reduced negative FC between NAc and a region within the primary motor cortex corresponding with the expected representation of the area of injury. A complementary pattern was also demonstrated between PAG and the primary somatosensory cortex. PAG and NAc also shared increased FC to the rostral anterior cingulate cortex (rACC) within the recovery group. Brain connectivity further shows high classification accuracy (area under the curve [AUC] = .86) for future chronic pain, when combined with an acute pain intensity report.

INTERPRETATION

FC features obtained shortly after mTBI predict its transition to long-term chronic pain, and may reflect an underlying interaction of injury-related primary sensorimotor cortical areas with the mesolimbic and pain modulation systems. Our findings indicate a potential predictive biomarker and highlight targets for future early preventive interventions. ANN NEUROL 2022;92:819-833.

CGRP-induced migraine-like headache in persistent post-traumatic headache attributed to mild traumatic brain injury

OBJECTIVE

To ascertain whether intravenous infusion of calcitonin gene-related peptide (CGRP) can induce migraine-like headache in people with persistent post-traumatic headache attributed to mild traumatic brain injury (TBI) and no pre-existing migraine.

METHODS

A non-randomized, single-arm, open-label study at a single site in Denmark. Eligible participants were aged 18 to 65 years and had a known history of persistent post-traumatic headache attributed to mild TBI for ≥ 12 months. All participants received continuous intravenous infusion of CGRP (1.5 µg/min) over 20 min. A headache diary was used to collect outcome data until 12 h after the start of CGRP infusion. The primary end point was the incidence of migraine-like headache during 12-hour observational period.

RESULTS

A total of 60 participants completed the study protocol and provided data for the analysis of the primary end point. The median age was 32.5 (IQR, 25.5-43.0) years; 43 participants (72%) were female. Following CGRP infusion, 43 (72%) of 60 participants developed migraine-like headache during the 12-hour observational period. The median time to peak headache intensity was 40 min (IQR, 20-60), and the median peak headache intensity was 6 (IQR, 5-8) on the 11-point numeric rating scale.

CONCLUSION

Intravenous infusion of CGRP is a potent inducer of migraine-like headache in people with persistent post-traumatic headache attributed to mild TBI. This observation underscores the importance of CGRP in the genesis of migraine-like headache that is often experienced by individuals who are afflicted by persistent post-traumatic headache. Further research is warranted to ascertain whether other signaling molecules also contribute to the disease mechanisms underlying post-traumatic headache.

Glutamate, GABA and glutathione in adults with persistent post-concussive symptoms

Persistent post-concussive symptoms (PPCS) are debilitating and endure beyond the usual recovery period after mild traumatic brain injury (mTBI). Altered neurotransmission, impaired energy metabolism and oxidative stress have been examined acutely post-injury but have not been explored extensively in those with persistent symptoms. Specifically, the antioxidant glutathione (GSH) and the excitatory and inhibitory metabolites, glutamate (Glu) and γ-aminobutyric acid (GABA), are seldom studied together in the clinical mTBI literature. While Glu can be measured using conventional magnetic resonance spectroscopy (MRS) methods at 3 Tesla, GABA and GSH require the use of advanced MRS methods. Here, we used the recently established Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy (HERMES) to simultaneously measure GSH and GABA and short-echo time point resolved spectroscopy (PRESS) to measure Glu to gain new insight into the pathophysiology of PPCS. Twenty-nine adults with PPCS (mean age: 45.69 years, s.d.: 10.73, 22 females, 7 males) and 29 age- and sex-matched controls (mean age: 43.69 years, s.d.: 11.00) completed magnetic resonance spectroscopy scans with voxels placed in the anterior cingulate and right sensorimotor cortex. Relative to controls, anterior cingulate Glu was significantly reduced in PPCS. Higher anterior cingulate GABA was significantly associated with a higher number of lifetime mTBIs, suggesting GABA may be upregulated with repeated incidence of mTBI. Furthermore, GSH in both regions of interest was positively associated with symptoms of sleepiness and headache burden. Collectively, our findings suggest that the antioxidant defense system is active in participants with PPCS, however this may be at the expense of other glutamatergic functions such as cortical excitation and energy metabolism.