Persistent post-traumatic headache: a migrainous loop or not? The clinical evidence

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.

A review of the personality traits in post-concussion syndrome

INTRODUCTION

Various manifestations ranging from physical symptoms to cognitive and emotional impairments could often be seen following head concussions that lead to mild traumatic brain injury (mTBI). These symptoms are commonly comprising the post-concussion syndrome (PCS) and their resolution could be influenced by multiple factors. Personality traits have been suggested as potential risk factors for the emergence and persistence of PCS. In this study, we aimed to investigate the possible predisposition to PCS given by certain personality traits.

METHODS

Prospective cohort studies, observational studies, and cross-phenotype polygenic risk score analyses were selected from the main scientific databases (PubMed/Medline, Scopus, EMBASE, Web of Science) based on multiple-step screening, using keywords (such as "personality traits", "post-concussion syndrome", "traumatic brain injury", "anxiety", "depression", "resilience", and "somatization") and inclusion/exclusion criteria (English written studies available in full text presenting relevant data on TBI patients and their personality traits; reviews, animal studies, and studies not written in English, not available in full text, or not presenting full demographical and clinical data were excluded). The investigated personality traits included emotional reserve, somatic trait anxiety, embitterment, mistrust, parental anxiety, state anxiety, trait anxiety, anxiety sensitivity, pain catastrophizing, helplessness, sports-concussion symptom load, and cognitive resilience.

RESULTS

The reviewed data from 16 selected studies suggested that personality traits play an essential role in the development and persistence of PCS. Emotional reserve, cognitive resilience, and lower levels of somatic trait anxiety were associated with better outcomes in PCS. However, higher levels of anxiety sensitivity, pain catastrophizing, helplessness, and sports-concussion symptom load were associated with worse outcomes in PCS. Parental anxiety was not associated with persistent symptoms in children following concussion. Despite the statistical analysis regarding the included publications bias was low, further studies should further investigate the correlation between TBI and some personality traits, as some of the selected studies did not included healthy individuals and their psychological profiles for comparison and correlation analysis.

CONCLUSION

Personality traits may help predict the development and persistence of PCS following mTBI. Understanding the personality traits roles in PCS could assist the development of targeted interventions for the prevention and treatment of PCS. Further research is needed to better understand the complex interactions between personality traits, neurobiological factors, and psychosocial factors in PCS.

Epidemiology, Pathophysiology, and Treatment Strategies of Concussions: A Comprehensive Review

A concussion is a particular manifestation of a traumatic brain injury, which is the leading cause of mortality and disabilities across the globe. The global prevalence of traumatic brain injury is estimated to be 939 instances per 100,000 individuals, with approximately 5.48 million people per year experiencing severe traumatic brain injury. Epidemiology varies amongst different countries by socioeconomic status with diverse clinical manifestations. Additionally, classifying concussions is an ambiguous process as clinical diagnoses are the only current classification method, and morbidity rates differ by demographic location as well as populations examined. In this article, we critically reviewed the pathophysiology of concussions, classification methods, treatment options available including both pharmacologic and nonpharmacologic intervention methods, etiologies as well as global etiologic differences associated with them, and clinical manifestations along with their associated morbidities. Furthermore, analysis of the current research regarding the incidence of concussion based traumatic brain injuries and future directions are discussed. Investigation on the efficacy of new therapeutic-related interventions such as exosome therapy and electromagnetic field stimulation are warranted to properly manage and treat concussion-induced traumatic brain injury.

Frequency and predictors of headache in the first 12 months after traumatic brain injury: results from CENTER-TBI

BACKGROUND

Headache is a prevalent and debilitating symptom following traumatic brain injury (TBI). Large-scale, prospective cohort studies are needed to establish long-term headache prevalence and associated factors after TBI. This study aimed to assess the frequency and severity of headache after TBI and determine whether sociodemographic factors, injury severity characteristics, and pre- and post-injury comorbidities predicted changes in headache frequency and severity during the first 12 months after injury.

METHODS

A large patient sample from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) prospective observational cohort study was used. Patients were stratified based on their clinical care pathway: admitted to an emergency room (ER), a ward (ADM) or an intensive care unit (ICU) in the acute phase. Headache was assessed using a single item from the Rivermead Post-Concussion Symptoms Questionnaire measured at baseline, 3, 6 and 12 months after injury. Mixed-effect logistic regression analyses were applied to investigate changes in headache frequency and associated predictors.

RESULTS

A total of 2,291 patients responded to the headache item at baseline. At study enrolment, 59.3% of patients reported acute headache, with similar frequencies across all strata. Female patients and those aged up to 40 years reported a higher frequency of headache at baseline compared to males and older adults. The frequency of severe headache was highest in patients admitted to the ICU. The frequency of headache in the ER stratum decreased substantially from baseline to 3 months and remained from 3 to 6 months. Similar trajectory trends were observed in the ICU and ADM strata across 12 months. Younger age, more severe TBI, fatigue, neck pain and vision problems were among the predictors of more severe headache over time. More than 25% of patients experienced headache at 12 months after injury.

CONCLUSIONS

Headache is a common symptom after TBI, especially in female and younger patients. It typically decreases in the first 3 months before stabilising. However, more than a quarter of patients still experienced headache at 12 months after injury. Translational research is needed to advance the clinical decision-making process and improve targeted medical treatment for headache.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02210221.

Migraine Prevalence, Environmental Risk, and Comorbidities in Men and Women Veterans

Importance

Migraine is a prevalent and debilitating condition that substantially impacts quality of life. Investigating migraine prevalence, associated comorbidities, and potential military service exposures in veterans, focusing on gender differences, is crucial for targeted interventions and management strategies.

Objective

To determine the prevalence of migraine, associated health comorbidities, and potential military service and environmental exposures among men and women US veterans using a large-scale epidemiological sample from the Million Veteran Program (MVP).

Design, Setting, and Participants

This cross-sectional study analyzed self-report survey data from the MVP, a large epidemiological sample of US veterans that was started in 2011 and has ongoing enrollment. Eligible participants were selected from the MVP database in 2023. The study included 491 604 veterans to examine migraine prevalence, health comorbidities, demographic characteristics, military service history, and environmental exposures. Data were analyzed from December 2022 to July 2023.

Exposures

Military service and environmental factors, such as chemical or biological warfare exposure, were considered.

Main Outcomes and Measures

The primary outcome was migraine prevalence among men and women veterans, assessed through self-reported diagnoses. Secondary outcomes included the association between migraine and health comorbidities, demographic characteristics, military service history, and environmental exposures.

Results

Of the 491 604 veterans included in this study, 450 625 (91.8%) were men and 40 979 (8.2%) were women. The lifetime prevalence of migraine was significantly higher in women (12 324 of 40 979 [30.1%]) than in men (36 816 of 450 625 [8.2%]). Migraine prevalence varied by race and ethnicity, with the highest prevalence in Hispanic or Latinx women (1213 of 3495 [34.7%]). Veterans with migraine reported worse general health, higher levels of pain, increased pain interference with work, a higher likelihood of psychiatric and neurological health conditions, and greater lifetime opioid use. Specific aspects of military service, including service post-September 2001 and deployment in Operation Enduring Freedom and Operation Iraqi Freedom, and environmental factors, including Agent Orange, chemical and biological welfare, and antinerve agent pills history, were significantly associated with migraine prevalence.

Conclusions and Relevance

In this cross-sectional study of migraine, the results highlighted gender differences in migraine prevalence and associated health comorbidities among US veterans. The findings emphasized the need for interdisciplinary approaches to migraine management, increased awareness and education efforts, and population-based screening strategies, particularly for women and Hispanic veterans who are at greater risk. Our findings encourage further research into tailored interventions for specific subpopulations and the impact of military service and environmental exposures on migraine and related health conditions.

Application of biomechanical principles to upper cervical spine anatomy to alleviate symptoms of intermittent cranial nerve IX irritation. Directions for successful self-management of headache post-concussion? A case series

BACKGROUND

The neck has been implicated as a potential generator of symptoms such as dizziness and headache in individuals with persistent symptoms post concussion. Anatomically, the neck could also be a potential trigger for autonomic or cranial nerve symptoms. The glossopharyngeal nerve which innervates the upper pharynx is one possible autonomic trigger that might be affected by the upper cervical spine.

CASE DESCRIPTION

This is a case series of three individuals with persistent post-traumatic headache (PPTH) and symptoms of autonomic dysregulation who also had signs of intermittent glossopharyngeal nerve irritation associated with certain neck positions or movements. Biomechanical principles were applied to anatomical research on the path of the glossopharyngeal nerve, in relation to the upper cervical spine and the dura mater, to alleviate these intermittent symptoms. The patients were provided techniques to be used as tools to immediately alleviate the intermittent dysphagia, which also alleviated the constant headache at the same time. As part of the overall long-term management program, patients were also taught daily exercises to improve upper cervical and dural stability and mobility.

OUTCOME

The result was a decrease in intermittent dysphagia, headache, and autonomic symptoms in the long term in persons with PPTH following concussion.

DISCUSSION

Autonomic and dysphagia symptoms may provide clues as to the origin of symptoms in a subgroup of individuals with PPTH.

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.

Phenotype of new daily persistent headache: subtypes and comparison to transformed chronic daily headache

BACKGROUND

It is unknown whether new daily persistent headache (NDPH) is a single disorder or heterogenous group of disorders, and whether it is a unique disorder from chronic migraine and chronic tension-type headache. We describe a large group of patients with primary NDPH, compare its phenotype to transformed chronic daily headache (T-CDH), and use cluster analysis to reveal potential sub-phenotypes in the NDPH group.

METHODS

We performed a case-control study using prospectively collected clinical data in patients with primary NDPH and T-CDH (encompassing chronic migraine and chronic tension-type headache). We used logistic regression with propensity score matching to compare demographics, phenotype, comorbidities, and treatment responses between NDPH and T-CDH. We used K-means cluster analysis with Gower distance to identify sub-clusters in the NDPH group based on a combination of demographics, phenotype, and comorbidities.

RESULTS

We identified 366 patients with NDPH and 696 with T-CDH who met inclusion criteria. Patients with NDPH were less likely to be female (62.6% vs. 73.3%, p < 0.001). Nausea, vomiting, photophobia, phonophobia, motion sensitivity, vertigo, and cranial autonomic symptoms were all significantly less frequent in NDPH than T-CDH (p value for all < 0.001). Acute treatments appeared less effective in NDPH than T-CDH, and medication overuse was less common (16% vs. 42%, p < 0.001). Response to most classes of oral preventive treatments was poor in both groups. The most effective treatment in NDPH was doselupin in 45.7% patients (95% CI 34.8-56.5%). Cluster analysis identified three subgroups of NDPH. Cluster 1 was older, had a high proportion of male patients, and less severe headaches. Cluster 2 was predominantly female, had severe headaches, and few associated symptoms. Cluster 3 was predominantly female with a high prevalence of migrainous symptoms and headache triggers.

CONCLUSIONS

Whilst there is overlap in the phenotype of NDPH and T-CDH, the differences in migrainous, cranial autonomic symptoms, and vulnerability to medication overuse suggest that they are not the same disorder. NDPH may be fractionated into three sub-phenotypes, which require further investigation.

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.

Sub-occipital muscle pressure pain thresholds correlate to direction of symptomatic active comfortable sustained neck rotation testing in post-concussive headache: a retrospective observational cross-sectional study

OBJECTIVES

To compare sub-occipital muscle pressure sub pain thresholds (PPTs) in individuals with persistent-post-traumatic-headache (PPTH) in relation to the presence or not of cranial nerve and/or autonomic symptoms reported during sustained neck rotation (SNR).

BACKGROUND

Previously 81% of military service members with PPTH demonstrated symptoms with SNR up to 60 seconds. Of these, 54% reported symptoms in one (Uni-Symp) and 46% in both directions of rotation (Bi-Symp). Sub-occipital PPTs, in relation to SNR direction, were of interest.

METHODS

Retrospective review of records of 77 individuals, with PPTH with both SNR and PPTs. Average suboccipital and scalene PPTs were compared between Asymptomatic (n = 13), upon SNR testing, or Symptomatic (Uni-Symp, n = 32, Bi-Symp, n = 32), groups.

RESULTS

The Bi-Symp group had significantly reduced sub-occipital PPTs relative to the Asymptomatic group on both sides [p < 0.009] with no side-to-side differences in either group. The Uni-Symp group had significantly lower sub-occipital PPTs on the symptomatic SNR test direction compared to the asymptomatic side [t(31) = 3.37, p = 0.002]. There were no differences within or between groups in the scalene PPTs(p's > 0.08).

CONCLUSIONS

An upper cervical mechanical trigger of symptoms during SNR tests in some individuals with PPTH is possible. The direction of symptomatic SNR tests may indicate direction of guarded hypermobile dysfunction and direct treatment.

Patient-Centered Approaches to Cognitive Assessment in Acute TBI

PURPOSE OF THE REVIEW

The purpose of this article is to help clinicians understand how underlying pathophysiologies and medical comorbidities associated with acute traumatic brain injury (TBI) can impact assessment of cognition during the initial stages of recovery. Clinicians can use information from this article to develop assessment plans rooted in patient-centered care.

RECENT FINDINGS

The authors conducted a review of the literature related to the assessment of cognition in acute TBI, focusing on pathophysiology, medical comorbidities, and assessment approaches. Results indicated that TBI pathophysiologies associated with white and gray matter changes make many patients vulnerable to cognitive deficits. Acute comorbidities such as psychological and pain status influence cognitive abilities as well. The current approaches to cognitive assessment can be limited in many ways, though by using the patient's neuropathological profile, noted comorbidities, and other patient specific factors, clinicians can potentially improve the effectiveness of assessment.

A multicenter, longitudinal survey of headaches and concussions among youth athletes in the United States from 2009 to 2019

OBJECTIVE/ BACKGROUND

Chronic headaches and sports-related concussions are among the most common neurological morbidities in adolescents and young adults. Given that the two can overlap in presentation, studying the effects of one on another has proven difficult. In this longitudinal study, we sought to assess the relationship between chronic headaches and concussions, analyzing the role of historic concussions on chronic headaches, as well as that of premorbid headaches on future concussion incidence, severity, and recovery.

METHODS

This multi-center, longitudinal cohort study followed 7,453 youth athletes who were administered demographic and clinical surveys as well as a total of 25,815 Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) assessments between 2009 and 2019. ImPACT was administered at baseline. Throughout the season concussions were examined by physicians and athletic trainers, followed by re-administration of ImPACT post-injury (PI), and at follow-up (FU), a median of 7 days post-concussion. Concussion incidence was calculated as the total number of concussions per patient years. Concussion severity and recovery were calculated as standardized deviations from baseline to PI and then FU in Symptom Score and the four neurocognitive composite ImPACT scores: Verbal Memory, Visual Memory, Processing Speed, and Reaction Time. Data were collected prospectively in a well-organized electronic format supervised by a national research-oriented organization with rigorous quality assurance. Analysis was preformed retrospectively.

RESULTS

Of the eligible athletes, 1,147 reported chronic headaches (CH) at the start of the season and 6,306 reported no such history (NH). Median age of the cohort was 15.4 ± 1.6 years, and students were followed for an average of 1.3 ± 0.6 years. A history of concussions (OR 2.31, P < 0.0001) was associated with CH. Specifically, a greater number of past concussions (r2 = 0.95) as well as concussions characterized by a loss of consciousness (P < 0.0001) were associated with more severe headache burden. The CH cohort had a greater future incidence of concussion than the NH cohort (55.6 vs. 43.0 per 100 patient-years, P < 0.0001). However, multivariate analysis controlling for demographic, clinical, academic, and sports-related variables yielded no such effect (OR 0.99, P = 0.85). On multivariable analysis the CH cohort did have greater deviations from baseline to PI and FU in Symptom Score (PI OR per point 1.05, P = 0.01, FU OR per point 1.11, P = 0.04) and Processing Speed (OR per point 1.08, P = 0.04), suggesting greater concussion severity and impaired symptomatic recovery as compared to the NH cohort.

CONCLUSION

A history of concussions was a significant contributor to headache burden among American adolescents and young adults. However, those with chronic headaches were not more likely to be diagnosed with a concussion, despite presenting with more severe concussions that had protracted recovery. Our findings not only suggest the need for conservative management among youth athletes with chronic headaches, they also indicate a potential health care gap in this population, in that those with chronic headaches may be referred for concussion diagnosis and management at lower rates than those with no such comorbidity.

Intermediate cervical plexus block in the management of treatment resistant chronic cluster headache following whiplash trauma in three patients: a case series

OBJECTIVES

Cluster headaches are an intensely painful and debilitating headache disorder. Conventional management includes abortive and preventative agents. A fifth of patients with chronic cluster headaches can be refractory to conventional treatment. Cluster headache can develop following whiplash trauma to the head and neck.

CASE PRESENTATION

Three patients were referred to a tertiary pain medicine unit in a university teaching hospital with treatment-resistant chronic cluster headache. They were treated with a novel intervention namely, ultrasound-guided intermediate cervical plexus block with depot methylprednisolone. Patient one reported chronic cluster headache for three years. Patient two reported episodic cluster headache that appeared to be evolving into chronic cluster headache. Patient three reported bilateral cluster headache following a motor vehicle accident. Intermediate cervical plexus block provided significant and durable relief in three patients with treatment resistant chronic cluster headache.

CONCLUSIONS

The novel intervention may have played a role in aborting and preventing chronic cluster headaches.

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.

Relationship Between Headache Characteristics and a Remote History of TBI in Veterans: A 10-Year Retrospective Chart Review

BACKGROUND AND OBJECTIVES

The objective of this work was to examine the association between deployment-related traumatic brain injury (TBI) severity, frequency, and other injury characteristics with headache outcomes in veterans evaluated at a Veterans Administration (VA) polytrauma support clinic.

METHODS

We conducted a retrospective chart review of 594 comprehensive TBI evaluations between 2011 and 2021. Diagnostic criteria were based on the Department of Defense/VA Consensus-Based Classification of Closed TBI. Adjusted odds ratios (AORs) and 95% CIs were estimated for headache prevalence (logistic), headache severity (ordinal), and prevalence of migraine-like features (logistic) with multiple regression analysis. Regression models were adjusted for age, sex, race/ethnicity, time since injury, and mental health diagnoses.

RESULTS

TBI severity groups were classified as sub concussive exposure (n = 189) and mild (n = 377), moderate (n = 28), and severe TBI (n = 0). Increased headache severity was reported in veterans with mild TBI (AOR 1.72 [95% CI 1.15, 2.57]) and moderate TBI (AOR 3.89 [1.64, 9.15]) compared to those with subconcussive exposure. A history of multiple mild TBIs was associated with more severe headache (AOR 2.47 [1.34, 4.59]) and migraine-like features (AOR 5.95 [2.55, 13.77]). No differences were observed between blast and nonblast injuries; however, greater headache severity was reported in veterans with both primary and tertiary blast effects (AOR 2.56 [1.47, 4.49]). Alteration of consciousness (AOC) and posttraumatic amnesia (PTA) >30 minutes were associated with more severe headache (AOR 3.37 [1.26, 9.17] and 5.40 [2.21, 13.42], respectively). The length of time between the onset of last TBI and the TBI evaluation was associated with headache severity (AOR 1.09 [1.02, 1.17]) and prevalence of migraine-like features (AOR 1.27 [1.15, 1.40]). Last, helmet use was associated with less severe headache (AOR 0.42 [0.23, 0.75]) and lower odds of migraine-like features (AOR 0.45 [0.21, 0.98]).

DISCUSSION

Our data support the notion of a dose-response relationship between TBI severity and headache outcomes. A history of multiple mild TBIs and longer duration of AOC and PTA are unique risk factors for poor headache outcomes in veterans. Furthermore, this study sheds light on the poor headache outcomes associated with subconcussive exposure. Past TBI characteristics should be considered when developing headache management plans for veterans.

Reframing postconcussional syndrome as an interface disorder of neurology, psychiatry and psychology

Persistent symptoms following a minor head injury can cause significant morbidity, yet the underlying mechanisms for this are poorly understood. The shortcomings of the current terminology that refer to non-specific symptom clusters is discussed. This update considers the need for a multi-dimensional approach for the heterogenous mechanisms driving persistent symptoms after mild traumatic brain injury. Relevant pathophysiology is discussed to make the case for mild traumatic brain injury to be conceptualized as an interface disorder spanning neurology, psychiatry and psychology. The relevance of pre-injury factors, psychological co-morbidities and their interaction with the injury to produce persistent symptoms are reviewed. The interplay with psychiatric diagnoses, functional and somatic symptom disorder presentations and the influence of the medicolegal process is considered. The judicious use and interpretation of investigations given the above complexity is discussed, with suggestions of how the explanation of the diagnostic formulation to the patient can be tailored, including insight into the above processes, to aid recovery. Moving beyond the one-dimensional concept of 'postconcussional syndrome' and reframing the cause of persistent symptoms following mild traumatic brain injury in a bio-psycho-socio-ecological model will hopefully improve understanding of the underlying contributory mechanistic interactions and facilitate treatment.

Equity and Disparities in Diagnosis, Management, and Research of Post-Traumatic Headache

PURPOSE OF REVIEW

There are notable health disparities and inequities in individuals with traumatic brain injury (TBI) and concussion by race, ethnicity, gender, socioeconomic status, and geography. This review will evaluate these disparities and inequities and assess the social determinants of health that drive outcomes for post-traumatic headache. Interventions for achieving this are also discussed.

RECENT FINDINGS

Significant disparities and inequities exist in TBI and concussion among people of different races, socioeconomic status, and geographic locations. Migraine is a common symptom post-concussion, for which disparities and social determinants of health are also discussed. Overall, multi-level interventions to reduce these disparities and inequities are reviewed for post-traumatic headache but require further investigation. Interventions are needed to reduce disparities and inequities including public health initiatives, improvements in clinical care, diversity/inclusion training, and research efforts. As literature expands, we can form guidance to identify solutions for eliminating disparities in care of diverse populations.

Post-traumatic headache: Pathophysiology and management - A review

Background

Post-traumatic headache (PTH) is a common secondary headache due to traumatic brain injury. In the past, significant research has been conducted to understand the pathophysiology and treatment options for PTH. However, PTH still lacks evidence-based treatment, and most of the management depends on the primary phenotype observed in the patient.

Objective

The main objective of this review is to provide a single reference that covers the current understanding of the pathophysiology and the treatment options available for PTH.

Methods

A detailed literature search on PubMed was performed, and a narrative review was prepared.

Results

The pathophysiology of PTH is multifactorial. Acute PTH may be attributed to increased peripheral pain sensitization with impaired pain inhibiting pathways. Chronic or persistent PTH may be due to a chronic inflammatory response and peripheral as well as central sensitization. The mechanism responsible for the transition of acute to persistent PTH is unknown. The migraine-like phenotype is reported to be the most prevalent headache type seen in PTH. New targets for preventive treatment have been identified in recent years, such as neuropeptides like calcitonin-gene-related peptide (CGRP), nitric oxide, and glutamate. The preventive pharmacological and non-pharmacological strategies employed for migraine (e.g. anti-CGRP monoclonal antibodies, onabotulinumtoxinA, physical therapy, cognitive and behavioral treatment, and neurostimulation techniques) have shown in preliminary studies that they are potentially efficacious, but large, randomized, double blind, placebo controlled trials are needed to further establish these as treatment options for PTH.

Conclusions

The lack of evidence-based treatment for PTH has created a need for future large trials to confirm the safety and efficacy of the currently employed treatments.

Effects of acupuncture treatment on posttraumatic headache after traumatic brain injury in patients: A protocol for systematic review

BACKGROUND

Posttraumatic headache (PTH) after traumatic brain injury (TBI) is a common clinical symptom, which refers to a headache that occurs after TBI. Acupuncture is often used for the treatment of such patients in China, and significant clinical effects have been achieved. However, to date, its efficacy has not been methodically evaluated. The purpose of this systematic review is to provide evidence to prove the effectiveness of acupuncture in the treatment of PTH in patients with TBI.

METHODS

This systematic review will be conducted in accordance with the preferred reporting items for systematic review and meta-analysis protocols. The following electronic databases will be searched from their inception to February 2022: PubMed, Web of Science, Embase, PsycINFO, the Cochrane Library, and Chinese databases such as Chinese Biomedical Literature (CBM), Chinese Medical Current Content (CMCC), Chinese Scientific Journal Database (VIP), WanFang Database, and China National Knowledge Infrastructure (CNKI). No language restrictions will be applied to the search strategy. Randomized controlled trials and cohort and case-control studies that met the inclusion and exclusion criteria will be included in this study. The meta-analysis will be performed using RevMan 5.3 software. Each session of this systematic review will be conducted independently by 2 members.

RESULTS

This review evaluates the efficacy of acupuncture in the treatment of PTH after TBI.

CONCLUSION

This review provides substantial evidence for the clinical application of acupuncture in PTH treatment after TBI.

ETHICS AND DISSEMINATION

Since the data in this study will be retrieved from published trials, therefore the Patient Consent Statement and Ethical Approval are not required. We will disseminate our results by publishing the research in a peer-reviewed journal.

TRAIL REGISTRATION NUMBER

The protocol was registered in INPLASY (INPLASY 202220073).

Neuro-Visual and Vestibular Manifestations of Concussion and Mild TBI

PURPOSE OF REVIEW

Mild traumatic brain injury, or concussion, is a major cause of disability. Vestibular and visual dysfunction following concussion is common and can negatively affect patients' well-being and prolong recovery. Etiologies of visual and vestibular symptoms are numerous, including ocular, neuro-ophthalmic, otologic, and neuro-vestibular conditions. Some etiologies are benign and may be treatable, while others are potentially vision or life-threatening, making a focused history and examination essential. This review offers an approach to the evaluation and treatment of the most common neuro-visual and vestibular impairments that may result from concussion.

RECENT FINDINGS

Treatment of concussion including exercise, computerized programs, transcranial magnetic stimulation, gene therapy, stem cell therapy, and nanoparticles has shown promise. Many novel therapies are in the pipework for visual and vestibular recovery after concussion; however, the treatment mainstay remains therapy and evaluation for co-existing diseases.

Vestibular Rehabilitation Therapy for the Treatment of Vestibular Migraine, and the Impact of Traumatic Brain Injury on Outcome: A Retrospective Study

INTRODUCTION

Vestibular migraine (VM) is a common condition; individuals experience dizziness with migraine symptoms. Vestibular rehabilitation therapy (VRT) has been reported as an effective treatment for VM, however, evidence is limited. VM and traumatic brain injury (TBI) can co-occur, and some suggest that TBI can induce VM. There is limited evidence on the effect a history of TBI has on VRT in patients with VM.

METHODS

Retrospective case series of 93 (f = 63, m = 30) participants with VM and underwent VRT (mean age 48.62; SD 15.92). Pre- and post-treatment self-reported outcome measures and functional gait assessment were extracted from the participants health records and evaluated. The impact of TBI on VRT outcome in participants with VM was analyzed. Individuals with TBI and no history of migraine (n = 40) were also extracted to act as a control.

RESULTS

VRT significantly improved self-reported dizziness on the Dizziness Handicap Inventory (DHI), with a mean change of -18 points (p < 0.000) and +5 points on the functional gait assessment (FGA) (p < 0.000) in patients with VM. A history of TBI significantly impacted outcome on the DHI (p = 0.018) in patients with VM.VRT significantly improved all outcome measures for individuals with TBI, with a mean change of -16 points on the DHI (p = 0.001) and +5 points on the FGA (p < 0.000). VM presence significantly impacted outcome.

CONCLUSION

VRT should be considered as a treatment option to reduce dizziness and the risk of falls in individuals with VM. TBI may negatively impact VRT outcomes in individuals with VM.

Prevalence of post-traumatic stress disorder in the United States: a systematic literature review

OBJECTIVE

This study synthesized evidence regarding the prevalence of post-traumatic stress disorder (PTSD) in the United States (US).

METHODS

A systematic literature review (SLR) identified recently published (2015-2019) observational studies of PTSD prevalence in the US via the MEDLINE, EMBASE, and PsycINFO databases. Eligible studies' most recent data were collected no earlier than 2013. Data elements extracted included study design, sample size, location, data source/year(s), study population(s), traumatic event type, prevalance estimates with corresponding look-back periods, and clinical metrics.

RESULTS

Data from 38 identified articles were categorized by population, diagnostic criteria, and lookback period. Among civilians, point prevalence ranged from 8.0% to 56.7%, 1-year prevalence from 2.3% to 9.1%, and lifetime prevalence from 3.4% to 26.9%. In military populations, point prevalence ranged from 1.2% to 87.5%, 1-year prevalence from 6.7% to 50.2%, and lifetime prevalence from 7.7% to 17.0%. Within these ranges, several estimates were derived from relatively high quality data; these articles are highlighted in the review. Prevalence was elevated in subpopulations including emergency responders, refugees, American Indian/Alaska Natives, individuals with heavy substance use, individuals with a past suicide attempt, trans-masculine individuals, and women with prior military sexual trauma. Female sex, lower income, younger age, and behavioral health conditions were identified as risk factors for PTSD.

CONCLUSIONS

PTSD prevalence estimates varied widely, partly due to different study designs, populations, and methodologies, and recent nationally representative estimates were lacking. Efforts to increase PTSD screening and improve disease awareness may allow for a better detection and management of PTSD.

Somatosensory dysfunction in patients with posttraumatic headache: A systematic review

OBJECTIVES

Aim of the review is to summarize the knowledge about the sensory function and pain modulatory systems in posttraumatic headache and discuss its possible role in patients with posttraumatic headache.

BACKGROUND

Posttraumatic headache is the most common complication after traumatic brain injury, and significantly impacts patients' quality of life. Even though it has a high prevalence, its origin and pathophysiology are poorly understood. Thereby, the existing treatment options are insufficient. Identifying its mechanisms can be an important step forward to develop target-based personalized treatment.

METHODS

We searched the PubMed database for studies examining pain modulation and/or quantitative sensory testing in individuals with headache after brain injury.

RESULTS

The studies showed heterogenous alterations in sensory profiles (especially in heat and pressure pain perception) compared to healthy controls and headache-free traumatic brain injury-patients. Furthermore, pain inhibition capacity was found to be diminished in subjects with posttraumatic headache.

CONCLUSIONS

Due to the small number of heterogenous studies a distinct sensory pattern for patients with posttraumatic headache could not be identified. Further research is needed to clarify the underlying mechanisms and biomarkers for prediction of development and persistence of posttraumatic headache.

Mild traumatic brain injury affects the features of migraine

BACKGROUND

Headache is one of the most common symptoms after concussion, and mild traumatic brain injury (mTBI) is a risk factor for chronic migraine (CM). However, there remains a paucity of data regarding the impact of mTBI on migraine-related symptoms and clinical course.

METHODS

Of 2161 migraine patients who participated in the American Registry for Migraine Research between February 2016 and March 2020, 1098 completed questions assessing history of TBI (50.8%). Forty-four patients reported a history of moderate to severe TBI, 413 patients reported a history of mTBI. Patients' demographics, headache symptoms and triggers, history of physical abuse, allodynia symptoms (ASC-12), migraine disability (MIDAS), depression (PHQ-2), and anxiety (GAD-7) were compared between migraine groups with (n = 413) and without (n = 641) a history of mTBI. Either the chi-square-test or Fisher's exact test, as appropriate, was used for the analyses of categorical variables. The Mann-Whitney test was used for the analyses of continuous variables. Logistic regression models were used to compare variables of interest while adjusting for age, gender, and CM.

RESULTS

A significantly higher proportion of patients with mTBI had CM (74.3% [307/413] vs. 65.8% [422/641], P = 0.004), had never been married or were divorced (36.6% [147/402] vs. 29.4% [187/636], P = 0.007), self-reported a history of physical abuse (24.3% [84/345] vs. 14.3% [70/491], P <  0.001), had mild to severe anxiety (50.5% [205/406] vs. 41.0% [258/630], P = 0.003), had headache-related vertigo (23.0% [95/413] vs. 15.9% [102/640], P = 0.009), and difficulty finding words (43.0% [174/405] vs. 32.9% [208/633], P <  0.001) in more than half their attacks, and headaches triggered by lack of sleep (39.4% [155/393] vs. 32.6% [198/607], P = 0.018) and reading (6.6% [26/393] vs. 3.0% [18/607], P = 0.016), compared to patients without mTBI. Patients with mTBI had significantly greater ASC-12 scores (median [interquartile range]; 5 [1-9] vs. 4 [1-7], P < 0.001), MIDAS scores (42 [18-85] vs. 34.5 [15-72], P = 0.034), and PHQ-2 scores (1 [0-2] vs. 1 [0-2], P = 0.012).

CONCLUSION

Patients with a history of mTBI are more likely to have a self-reported a history of physical abuse, vertigo, and allodynia during headache attacks, headaches triggered by lack of sleep and reading, greater headache burden and headache disability, and symptoms of anxiety and depression. This study suggests that a history of mTBI is associated with the phenotype, burden, clinical course, and associated comorbid diseases in patients with migraine, and highlights the importance of inquiring about a lifetime history of mTBI in patients being evaluated for migraine.

Position Paper on Post-Traumatic Headache: The Relationship Between Head Trauma, Stress Disorder, and Migraine

Traumatic brain injury (mTBI) is a major public health concern, with mild TBI (mTBI) constituting the vast majority of the injuries. Post-traumatic headache (PTH) is one of the most frequent symptoms that follow a mTBI, occurring in isolation with a tension-type or migraine phenotype, or more often as part of a complex neurobehavioural array of symptoms. The existence of PTH as a separate entity from the primary headaches is still a matter of debate. Classification issues and a lack of methodologically robust epidemiological and clinical studies have made it difficult to elucidate the mechanisms underlying acute and even more persistent PTH (PPTH). Furthermore, psychiatric comorbidities such as post-traumatic stress disorder (PTSD), previous history of migraine, and legal issues often reported by PPTH patients have complicated the understanding of this condition, hence treatment approaches for PTH remain problematic. Recent findings from structural and functional neuroimaging studies have attempted to describe the brain architecture of PPTH, suggesting the involvement of different networks compared to migraine. It also seems that calcitonin gene-related peptide (CGRP) levels are not particularly raised in PPTH, although CGRP monoclonal antibodies have obtained positive initial open-label evidence of efficacy in PPTH, and more trials assessing the efficacy of this class of treatments are underway. The broad overlap between PTH, migraine, and PTSD suggests that research in this field should start with a re-appraisal of the diagnostic criteria, followed by methodologically sound epidemiological and clinical studies. Preclinical research should strive to create more reliable PTH models to support human neuroimaging, neurochemical, and neurogenetic studies, aiming to underpin new pathophysiological hypotheses that may expand treatment targets and improve the management of PTH patients.

Post-traumatic Headache and Mild Traumatic Brain Injury: Brain Networks and Connectivity

PURPOSE OF REVIEW

Post-traumatic headache (PTH) consequent to mild traumatic brain injury (mTBI) is a complex, multidimensional, chronic neurological disorder. The purpose of this review is to evaluate the current neuroimaging studies on mTBI and PTH with a specific focus on brain networks and connectivity patterns.

RECENT FINDINGS

We present findings on PTH incidence and prevalence, as well as the latest neuroimaging research findings on mTBI and PTH. Additionally, we propose a new strategy in studying PTH following mTBI. The diversity and heterogeneity of pathophysiological mechanisms underlying mild traumatic brain injury pose unique challenges on how we interpret neuroimaging findings in PTH. Evaluating alterations in the intrinsic brain network connectivity patterns using novel imaging and analytical techniques may provide additional insights into PTH disease state and therefore inform effective treatment strategies.

The role of deficient pain modulatory systems in the development of persistent post-traumatic headaches following mild traumatic brain injury: an exploratory longitudinal study

BACKGROUND

Post-traumatic headache (PTH) is one of the most common and long-lasting symptoms following mild traumatic brain injury (TBI). However, the pathological mechanisms underlying the development of persistent PTH remain poorly understood. The primary purpose of this prospective pilot study was to evaluate whether early pain modulatory profiles (sensitization and endogenous pain inhibitory capacity) and psychological factors after mild TBI predict the development of persistent PTH in mild TBI patients.

METHODS

Adult mild TBI patients recruited from Level I Emergency Department Trauma Centers completed study sessions at 1-2 weeks, 1-month, and 4-months post mild TBI. Participants completed the following outcome measures during each session: conditioned pain modulation to measure endogenous pain inhibitory capacity, temporal summation of pain and pressure pain thresholds of the head to measure sensitization of the head, Pain Catastrophizing Scale, Center for Epidemiological Studies - Depression Scale, and a standardized headache survey. Participants were classified into persistent PTH (PPTH) and no-PPTH groups based on the 4-month data.

RESULTS

The results revealed that mild TBI patients developing persistent PTH exhibited significantly diminished pain inhibitory capacity, and greater depression and pain catastrophizing following injury compared to those who do not develop persistent PTH. Furthermore, logistic regression indicated that headache pain intensity at 1-2 weeks and pain inhibitory capacity on the conditioned pain modulation test at 1-2 weeks predicted persistent PTH classification at 4 months post injury.

CONCLUSIONS

Overall, the results suggested that persistent PTH is characterized by dysfunctional alterations in endogenous pain modulatory function and psychological processes in the early stages following mild TBI, which likely exacerbate risk for the maintenance of PTH.

Headache complexity (number of symptom features) differentiates post-traumatic from non-traumatic headaches

BACKGROUND

Post-traumatic headaches are a common sequela of mild traumatic brain injury (concussion). It is unclear whether or how these headaches differ phenotypically from primary headaches.

OBJECTIVE

Determine whether there is an overarching unobserved latent trait that drives the expression of observed features of post-traumatic headache and other headaches.

METHODS

Data from this post-hoc analysis come from the Warrior Strong Cohort Study conducted from 2010 through 2015. Approximately 25,000 soldiers were screened for concussion history at routine post-deployment health assessments. A random sample was invited to participate, enrolling 1567. Twelve observed headache phenotypic features were used to measure "headache complexity", the latent trait of clinical interest, using single factor confirmatory factor analysis. We compared headache complexity between groups and determined whether headache complexity predicted accessing medical care for headache.

RESULTS

Of 1094 soldiers with headaches, 198 were classified as having post-traumatic headache. These headaches were compared to those in the other soldiers (647 without concussion history and 249 with concussion history). Soldiers with post-traumatic headache had greater endorsement of all 12 headache features compared to the soldiers with non-concussive headaches. The confirmatory factor analysis showed good model fit (χ² (51) = 95.59, p = 0.0002, RMSEA = 0.03, comparative fit index = 0.99, and Tucker-Lewis index = 0.99), providing empirical support for the headache complexity construct. Soldier groups differed in their mean headache complexity level (p < 0.001) such that post-traumatic headache soldiers had greater headache complexity compared to non-concussed soldiers (standardized mean difference = 0.91, 95% confidence interval: 0.72-1.09, p < 0.001 and to concussed soldiers with coincidental headaches standardized mean difference = 0.75, 95% confidence interval: 0.53-0.96, p < 0.001). Increasing headache complexity predicted medical encounters for headache (odds ratio = 1.87, 95% confidence interval: 1.49-2.35, p < 0.001) and migraine (odds ratio = 3.74, 95% confidence interval: 2.33-5.98, p < 0.001) during the year following deployment.Conclusions and relevance: The current study provided support for a single latent trait, characterized by observed headache symptoms, that differentiates between concussive and non-concussive headaches and predicts use of medical care for headache. The single trait confirmatory factor analysis suggests that post-traumatic headaches differ from non-concussive headaches by severity more than kind, based on the symptoms assessed.ClinicalTrials.gov identifier NCT01847040.

Interrelations between migraine-like headache and persistent post-traumatic headache attributed to mild traumatic brain injury: a prospective diary study

BACKGROUND

Persistent post-traumatic headache (PTH) is a common sequela of mild traumatic brain injury (TBI) and retrospective assessments have found a migraine-like phenotype to be very frequent. This has raised a discussion of shared underlying mechanisms and whether persistent PTH is simply trauma-triggered migraine.

METHODS

A 28-day prospective diary study with daily entries and acquisition of data on headache characteristics, associated symptoms, and acute medication use. A total of 64 patients with persistent PTH were enrolled from April 2019 to August 2019. Outcomes were the proportion of monthly headache days of any intensity that met the criteria for a migraine-like day or TTH-like day, as well as the corresponding figures for monthly headache days of moderate to severe intensity. Headache phenotypes were initially assigned based on diagnostic evaluation by semi-structured interview, whilst final headache phenotypes were assigned by diary review.

RESULTS

After diary review, we found that monthly headache days were exclusively migraine-like in 24 of 64 patients (38%) and exclusively TTH-like days in 8 of 64 patients (13%). Considering only monthly headache days of moderate to severe intensity, the corresponding figures were 35 of 64 patients (55%) for migraine-like days and 8 of 64 patients (13%) for TTH-like days. The following headache phenotypes were assigned based on diary review: chronic migraine-like (n = 47, 73%), combined episodic migraine-like and chronic TTH-like (n = 9, 13%), and 'pure' chronic TTH-like (n = 8, 13%).

CONCLUSIONS

A migraine-like phenotype is common in patients most adversely affected by persistent PTH, although some patients did have a pure chronic TTH-like phenotype. At minimum, these findings suggest that persistent PTH is - at least in some - not 'trauma-triggered migraine'.

Reason to doubt the ICHD-3 7-day inclusion criterion for mild TBI-related posttraumatic headache: A nested cohort study

Background

Posttraumatic headache is difficult to define and there is debate about the specificity of the 7-day headache onset criterion in the current definition. There is limited evidence available to guide decision making about this criterion.

Method

A nested cohort study of 193 treatment-seeking veterans who met criteria for persistent headache attributed to mild traumatic injury to the head, including some veterans with delayed headache onset up to 90 days post-injury, was undertaken. Survival analysis examined the proportion of participants reporting headache over time and differences in these proportions based on sex, headache phenotype, and mechanism of injury.

Result

127 participants (66%; 95% CI: 59–72%) reported headache onset within 7 days of head injury and 65 (34%) reported headache onset between 8 days and 3 months after head injury. Fourteen percent of participants reported pre-existing migraine before head injury, and there was no difference in the proportion of veterans with pre-existing migraine based on headache onset. Headache onset times were not associated with sex, headache phenotype, or mechanism of injury. There were no significant differences in proportion of veterans with headache onset within 7 days of head injury based on headache phenotype (70% migraine onset within 7 days, 70% tension-type headache within 7 days, 56% cluster headache within 7 days; p ≥ .364). Similar findings were observed for head injury (64% blast, 60% blunt; p = .973). There were no significant differences observed between headache onset groups for psychiatric symptoms (Posttraumatic Stress Disorder Checklist for DSM-5 = 1.3, 95% CI = −27.5, 30.1; Patient Health Questionnaire-9 Item = 3.5, 95% CI = −6.3, 3.7; Generalized Anxiety Disorder Screener = 6.5, 95% CI = −2.7, 15.6).

Conclusions

Although most of the sample reported headache onset within 7 days of head injury, one-third experienced an onset outside of the diagnostic range. Additionally, veterans with headache onset within 7 days of head injury were not meaningfully different from those with later onset based on sex, headache phenotype, or mechanism of head injury. The ICHD-3 diagnostic criteria for 7-day headache onset should be expanded to 3 months.

ClinicalTrials.gov Identifier

NCT02419131

Persistent post-traumatic headache: a migrainous loop or not? The preclinical evidence

Background

According to the International Classification of Headache Disorders 3, post-traumatic headache (PTH) attributed to traumatic brain injury (TBI) is a secondary headache reported to have developed within 7 days from head injury, regaining consciousness following the head injury, or discontinuation of medication(s) impairing the ability to sense or report headache following the head injury. It is one of the most common secondary headache disorders, and it is defined as persistent when it lasts more than 3 months.

Main body

Currently, due to the high prevalence of this disorder, several preclinical studies have been conducted using different animal models of mild TBI to reproduce conditions that engender PTH. Despite representing a simplification of a complex disorder and displaying different limitations concerning the human condition, animal models are still a mainstay to study in vivo the mechanisms of PTH and have provided valuable insight into the pathophysiology and possible treatment strategies. Different models reproduce different types of trauma and have been ideated in order to ensure maximal proximity to the human condition and optimal experimental reproducibility.

Conclusion

At present, despite its high prevalence, PTH is not entirely understood, and the differential contribution of pathophysiological mechanisms, also observed in other conditions like migraine, has to be clarified. Although facing limitations, animal models are needed to improve understanding of PTH. The knowledge of currently available models is necessary to all researchers who want to investigate PTH and contribute to unravel its mechanisms.

The Relation between Persistent Post-Traumatic Headache and PTSD: Similarities and Possible Differences

Post-traumatic headache (PTH) may be considered a secondary headache, which is linked to severe disability and psychosocial impairment. Interestingly, nearly 30% of subjects with persistent post-traumatic headache (PPTH) also suffer from post-traumatic stress disorder (PTSD). Although existing studies demonstrated the existence of common pathophysiological characteristics in subjects with migraine and PPTH, the differences and similarities between these complex diseases are currently poorly understood and are yet to be comprehensively elucidated. Thus, the present review aimed to systematically investigate the nature of PPTH in the effort to better identify both the neurobiological and clinical aspects underlying this condition. Overall, the included studies reported that: (1) the predictors for persistent acute traumatic injury to the head were female gender, persistent symptoms related to mild post-traumatic brain injury (mTBI), PTSD, elevated inflammatory markers, prior mild traumatic brain injury, being injured while suffering from alcohol abuse; (2) static/dynamic functional connectivity differences, white matter tract abnormalities, and morphology changes were found between PPTH and migraine in brain regions involved in pain processing; and (3) clinical differences which were most prominent at early time points when they were linked to the increased risk of PPTH. Based on the selected reports, the relation between migraine and PPTH needs to be considered bidirectionally, but PTSD may play a critical role in this relation. The main implications of these findings, with a specific focus on PTSD, are discussed. Further longitudinal studies are needed to reveal the exact nature of this relation, as well as to clarify the distinct clinical characteristics of migraine, PPTH, and PTSD.