Chronic post-traumatic headache: clinical findings and possible mechanisms

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.

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.

A role of NLRP3 and MMP9 in migraine progression: a systematic review of translational study

Background

Migraines affect one billion individuals globally, with a higher occurrence among young adults and women. A significant survey in the United States indicated that 17.1% of women and 5.6% of men suffer from migraines. This study seeks to investigate the potential connection between NLRP3 and MMP9 in migraine pathology.

Methods

The research involved searching databases such as PubMed, Scopus, Science Direct, Google Scholar, and Proquest, with the search concluding on March 31, 2024. Following PRISMA guidelines, PICO data were collected, focusing exclusively on animal models induced by Nitroglycerine (10 mg/kg), while excluding clinical studies.

Results

The study, originally registered in Prospero Reg. No. CRD42022355893, conducted bias analysis using SYRCLE's RoB tool and evaluated author consensus using GraphPad v9.5.1. Out of 7,359 search results, 22 papers met the inclusion criteria. Inter-rater reliability among reviewers was assessed using Cohen's kappa statistics.

Conclusion

This review summarizes 22 preclinical studies on Nitroglycerin (NTG), NLRP3, MMP9, and related biomarkers in migraine. They reveal that NTG, especially at 10 mg/kg, consistently induces migraine-like symptoms in rodents by activating NLRP3 inflammasome and stimulating proinflammatory molecule production.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, CRD42022355893.

A case of SIADH following uncomplicated mild traumatic brain injury: Did cognitive bias delay treatment?

To optimize clinical care, it is imperative for providers to recognize their own inherent cognitive biases and the impact that has on their clinical decision making, thereby minimizing complications such as prolonged hospitalization, unnecessary healthcare spending, and impaired patient satisfaction and functional outcomes.

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.

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.

Strain in the Midbrain: Impact of Traumatic Brain Injury on the Central Serotonin System

Traumatic brain injury (TBI) is a pervasive public health crisis that severely impacts the quality of life of affected individuals. Like peripheral forms of trauma, TBI results from extraordinarily heterogeneous environmental forces being imparted on the cranial space, resulting in heterogeneous disease pathologies. This has made therapies for TBI notoriously difficult to develop, and currently, there are no FDA-approved pharmacotherapies specifically for the acute or chronic treatment of TBI. TBI is associated with changes in cognition and can precipitate the onset of debilitating psychiatric disorders like major depressive disorder (MDD), generalized anxiety disorder (GAD), and post-traumatic stress disorder (PTSD). Complicating these effects of TBI, FDA-approved pharmacotherapies utilized to treat these disorders often fail to reach the desired level of efficacy in the context of neurotrauma. Although a complicated association, decades of work have linked central serotonin (5-HT) neurotransmission as being involved in the etiology of a myriad of neuropsychiatric disorders, including MDD and GAD. 5-HT is a biogenic monoamine neurotransmitter that is highly conserved across scales of biology. Though the majority of 5-HT is isolated to peripheral sites such as the gastrointestinal (GI) tract, 5-HT neurotransmission within the CNS exerts exquisite control over diverse biological functions, including sleep, appetite and respiration, while simultaneously establishing normal mood, perception, and attention. Although several key studies have begun to elucidate how various forms of neurotrauma impact central 5-HT neurotransmission, a full determination of precisely how TBI disrupts the highly regulated dynamics of 5-HT neuron function and/or 5-HT neurotransmission has yet to be conceptually or experimentally resolved. The purpose of the current review is, therefore, to integrate the disparate bodies of 5-HT and TBI research and synthesize insight into how new combinatorial research regarding 5-HT neurotransmission and TBI may offer an informed perspective into the nature of TBI-induced neuropsychiatric complications.

Mechanisms and treatments of chronic pain after traumatic brain injury

While pain after trauma generally resolves, some trauma patients experience pain for months to years after injury. An example, relevant to both combat and civilian settings, is chronic pain after traumatic brain injury (TBI). Headache as well as pain in the back and extremities are common locations for TBI-related chronic pain to be experienced. TBI-related pain can exist alone or can exacerbate pain from other injuries long after healing has occurred. Consequences of chronic pain in these settings include increased suffering, higher levels of disability, serious emotional problems, and worsened cognitive deficits. The current review will examine recent evidence regarding dysfunction of endogenous pain modulatory mechanisms, neuroplastic changes in the trigeminal circuitry and alterations in spinal nociceptive processing as contributors to TBI-related chronic pain. Key pain modulatory centers including the locus coeruleus, periaqueductal grey matter, and rostroventromedial medulla are vulnerable to TBI. Both the rationales and existing evidence for the use of monoamine reuptake inhibitors, CGRP antagonists, CXCR2 chemokine receptor antagonists, and interventional therapies will be presented. While consensus guidelines for the management of chronic post-traumatic TBI-related pain are lacking, several approaches to this clinically challenging situation deserve focused evaluation and may prove to be viable therapeutic options.

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.

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.

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.

Sensory hypersensitivities are associated with post-traumatic headache-related disability

OBJECTIVE

To examine whether sensory hypersensitivity contributes to headache-related disability in a secondary analysis of patients with post-traumatic headache.

BACKGROUND

Up to one-third of individuals with traumatic brain injuries report persistent headache 3 months post-injury. High rates of allodynia and photophobia have been observed in clinical studies and animal models of post-traumatic headache, but we do not fully understand how sensory amplifications impact post-traumatic headache-related disability.

METHODS

We identified a cross-sectional sample of patients from the American Registry for Migraine Research database with new or worsening headaches post-head injury from 2016 to 2020 and performed a secondary analysis of those data. We modeled the relationship between sensory sensitivity and Migraine Disability Assessment scores using questionnaires. Candidate variables included data collection features (study site and year), headache-related and general clinical features (headache frequency, migraine diagnosis, abuse history, sex, age, cognitive and affective symptom scores), and sensory symptoms (related to light, sound, and touch sensitivity).

RESULTS

The final sample included 193 patients (median age 46, IQR 22; 161/193, 83.4% female). Migraine Disability Assessment scores ranged from 0 to 260 (median 47, IQR 87). The final model included allodynia, hyperacusis, photosensitivity, headache days per month, abuse history, anxiety and depression, cognitive dysfunction, and age (R2  = 0.43). An increase of one point in allodynia score corresponded to a 3% increase in headache disability (95% CI: 0%-7%; p = 0.027), an increase of one-tenth of a point in the photosensitivity score corresponded to a 12% increase (95% CI: 3%-25%; p = 0.002), and an increase of one point in the hyperacusis score corresponded to a 2% increase (95% CI: 0%-4%; p = 0.016).

CONCLUSIONS

Increased photosensitivity, allodynia, and hyperacusis were associated with increased headache-related disability in this sample of patients with post-traumatic headache. Symptoms of sensory amplification likely contribute to post-traumatic headache-related disability and merit an ongoing investigation into their potential as disease markers and treatment targets.

Persistent Changes in Mechanical Nociception in Rats With Traumatic Brain Injury Involving Polytrauma

Traumatic brain injury (TBI) survivors often experience debilitating consequences. Due to the high impact nature of TBI, patients often experience concomitant peripheral injuries (ie, polytrauma). A common, yet often overlooked, comorbidity of TBI is chronic pain. Therefore, this study investigated how common concomitant peripheral injuries (ie, femoral fracture and muscle crush) can affect long-term behavioral and structural TBI outcomes with a particular focus on nociception. Rats were randomly assigned to 1 of 4 groups: polytrauma (POLY; ie, fracture + muscle crush + TBI), peripheral injury (PERI; ie, fracture + muscle crush + sham TBI), TBI (ie, sham fracture + sham muscle crush + TBI), and sham-injured (SHAM; ie, sham fracture + sham muscle crush + sham TBI). Rats underwent behavioral testing at 3-, 6-, and 11-weeks postinjury, and were then euthanized for postmortem magnetic resonance imaging (MRI). POLY rats had a persisting increase in pain sensitivity compared to all groups on the von Frey test. MRI revealed that POLY rats also had abnormalities in the cortical and subcortical brain structures involved in nociceptive processing. These findings have important implications and provide a foundation for future studies to determine the underlying mechanisms and potential treatment strategies for chronic pain in TBI survivors. PERSPECTIVE: Rats with TBI and concomitant peripheral trauma displayed chronic nociceptive pain and MRI images also revealed damaged brain structures/pathways that are involved in chronic pain development. This study highlights the importance of polytrauma and the affected brain regions for developing chronic pain.

Neuropsychological Function in Traumatic Brain Injury and the Influence of Chronic Pain

Cognitive dysfunction, pain, and psychological morbidity all present unique challenges to those living with traumatic brain injury (TBI). In this study we examined (a) the impact of pain across domains of attention, memory, and executive function, and (b) the relationships between pain and depression, anxiety, and post-traumatic stress disorder (PTSD) in persons with chronic TBI. Our sample included 86 participants with a TBI and chronic pain (n = 26), patients with TBI and no chronic pain (n = 23), and a pain-free control group without TBI (n = 37). Participants visited the laboratory and completed a comprehensive battery of neuropsychological tests as part of a structured interview. Multivariate analysis of covariance using education as a covariate, failed to detect a significant group difference for neuropsychological composite scores of attention, memory, and executive function (p = .165). A follow-up analysis using multiple one-way analysis of variance (ANOVA) was conducted for individual measures of executive function. Post-hoc testing indicated that those in both TBI groups preformed significantly worse on measures of semantic fluency when compared to controls (p < 0.001, ηρ2 = .16). Additionally, multiple ANOVAs indicated that those with TBI and pain scored significantly worse across all psychological assessments (p < .001). We also found significant associations between measures of pain and most psychological symptoms. A follow-up stepwise linear regression among those in the TBI pain group indicated that post concussive complaints, pain severity, and neuropathic pain symptoms differentially contributed to symptoms of depression, anxiety, and PTSD. These findings suggest deficits in verbal fluency among those living with chronic TBI, with results also reinforcing the multidimensional nature of pain and its psychological significance in this population.

Gut instinct: Sex differences in the gut microbiome are associated with changes in adolescent nociception following maternal separation in rats

Adolescent chronic pain is a growing public health epidemic. Our understanding of its etiology is limited; however, several factors can increase susceptibility, often developing in response to an acute pain trigger such as a surgical procedure or mild traumatic brain injury (mTBI), or an adverse childhood experience (ACE). Additionally, the prevalence and manifestation of chronic pain is sexually dimorphic, with double the rates in females than males. Despite this, the majority of pre-clinical pain research focuses on males, leaving a gap in mechanistic understanding for females. Given that emerging evidence has linked the gut microbiome and the brain-gut-immune axis to various pain disorders, we aimed to investigate sex-dependent changes in taxonomic and functional gut microbiome features following an ACE and acute injury as chronic pain triggers. Male and female Sprague Dawley rat pups were randomly assigned to either a maternal separation (MS) or no stress paradigm, then further into a sham, mTBI, or surgery condition. Chronically, the von Frey test was used to measure mechanical nociception, and fecal samples were collected for 16S rRNA sequencing. Animals in the surgery group had an increase in pain sensitivity when compared to mTBI and sham groups, and this was complemented by changes to the gut microbiome. In addition, significant sex differences were identified in gut microbiome composition, which were exacerbated in response to MS. Overall, we provide preliminary evidence for sex differences and ACE-induced changes in bacterial composition that, when combined, may be contributing to heterogeneity in pain outcomes.

Enhanced education for adult patients with persistent post-concussion headaches: a randomized controlled trial

Aim & Patients

We conducted a randomized clinical trial to determine if an e-learning intervention can enhance recovery in adult patients with persistent post-concussion headaches (PPCH).

Materials & Methods

The intervention consisted of three e-learning modules administered at baseline, 6 and 12 weeks. Data were collected on symptoms, community integration, quality of life and healthcare utilization at baseline and 12-week follow-up. ANCOVA was conducted to compare changes.

Results

No statistically significant difference was observed on symptoms although we observed a trend toward reduced healthcare utilization and improved quality of life in the intervention group.

Conclusion

E-learning modules for patients experiencing PPCH warrant further investigation with data on participant compliance and measures focusing on simpler short-term outcomes.Clinical Trial Registration: NCT03391583 (ClinicalTrials.gov).

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.

Concomitant Brain Injury and Spinal Cord Injury Management Strategies: A Narrative Review

Spinal cord injury (SCI) is a catastrophic event with multiple comorbidities including spastic paralysis, sensory loss, autonomic dysfunction with sympathetic blunting, neurogenic orthostatic hypotension, neurogenic restrictive and obstructive lung disease, neuropathic pain, spasticity, neurogenic bladder, neurogenic bowel, immobilization hypercalcemia, osteopenia/osteoporosis, neurogenic obesity, and metabolic dysfunction. Cervical and thoracic SCI is all too often accompanied by traumatic brain injury (TBI), which carries its own set of comorbidities including headaches, seizures, paroxysmal sympathetic hyperactivity, aphasia, dysphagia, cognitive dysfunction, memory loss, agitation/anxiety, spasticity, bladder and bowel incontinence, and heterotopic ossification. This manuscript will review the etiology and epidemiology of dual diagnoses, assessment of both entities, and discuss some of the most common comorbidities and management strategies to optimize functional recovery.

Cognitive Behavioral Therapy for Veterans With Comorbid Posttraumatic Headache and Posttraumatic Stress Disorder Symptoms: A Randomized Clinical Trial

Question

Do cognitive behavioral therapies for posttraumatic headache and posttraumatic stress disorder (PTSD) symptoms improve headache-related disability in veterans compared with treatment per usual?

Findings

A randomized clinical trial of 193 post-9/11 combat veterans with posttraumatic headache and PTSD symptoms found headache disability was significantly improved with cognitive behavioral therapy for headaches compared with treatment per usual. Though participants randomly assigned to cognitive processing therapy reported significantly greater improvement in PTSD symptom severity compared with treatment per usual, there was no significant effect of cognitive processing therapy on headache disability.

Meaning

Cognitive behavioral therapies are efficacious treatments for veterans with comorbid posttraumatic headache and PTSD symptoms.

Importance

Posttraumatic headache is the most disabling complication of mild traumatic brain injury. Posttraumatic stress disorder (PTSD) symptoms are often comorbid with posttraumatic headache, and there are no established treatments for this comorbidity.

Objective

To compare cognitive behavioral therapies (CBTs) for headache and PTSD with treatment per usual (TPU) for posttraumatic headache attributable to mild traumatic brain injury.

Design, Setting, and Participants

This was a single-site, 3–parallel group, randomized clinical trial with outcomes at posttreatment, 3-month follow-up, and 6-month follow-up. Participants were enrolled from May 1, 2015, through May 30, 2019; data collection ended on October 10, 2019. Post-9/11 US combat veterans from multiple trauma centers were included in the study. Veterans had comorbid posttraumatic headache and PTSD symptoms. Data were analyzed from January 20, 2020, to February 2, 2022.

Interventions

Patients were randomly assigned to 8 sessions of CBT for headache, 12 sessions of cognitive processing therapy for PTSD, or treatment per usual for headache.

Main Outcomes and Measures

Co–primary outcomes were headache-related disability on the 6-Item Headache Impact Test (HIT-6) and PTSD symptom severity on the PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (PCL-5) assessed from treatment completion to 6 months posttreatment.

Results

A total of 193 post-9/11 combat veterans (mean [SD] age, 39.7 [8.4] years; 167 male veterans [87%]) were included in the study and reported severe baseline headache-related disability (mean [SD] HIT-6 score, 65.8 [5.6] points) and severe PTSD symptoms (mean [SD] PCL-5 score, 48.4 [14.2] points). For the HIT-6, compared with usual care, patients receiving CBT for headache reported −3.4 (95% CI, −5.4 to −1.4; P < .01) points lower, and patients receiving cognitive processing therapy reported −1.4 (95% CI, −3.7 to 0.8; P = .21) points lower across aggregated posttreatment measurements. For the PCL-5, compared with usual care, patients receiving CBT for headache reported −6.5 (95% CI, −12.7 to −0.3; P = .04) points lower, and patients receiving cognitive processing therapy reported −8.9 (95% CI, −15.9 to −1.9; P = .01) points lower across aggregated posttreatment measurements. Adverse events were minimal and similar across treatment groups.

Conclusions and Relevance

This randomized clinical trial demonstrated that CBT for headache was efficacious for disability associated with posttraumatic headache in veterans and provided clinically significant improvement in PTSD symptom severity. Cognitive processing therapy was efficacious for PTSD symptoms but not for headache disability.

Trial Registration

ClinicalTrials.gov Identifier: NCT02419131

Multicenter and prospective trial of anti-epileptics for early seizure prevention in mild traumatic brain injury with a positive computed tomography scan

Background:

Posttraumatic seizures (PTSs) are a major source of disability after traumatic brain injury (TBI). The Brain Trauma Foundation Guidelines recommend prophylactic anti-epileptics (AEDs) for early PTS in severe TBI, but high-quality evidence is lacking in mild TBI.

Methods:

To determine the benefit of administering prophylactic AEDs, we performed a prospective and multicenter study evaluating consecutive patients who presented to a Level 1 trauma center from January 2017 to December 2020. We included all patients with mild TBI defined as Glasgow Coma Scale (GCS) 13–15 and a positive head computed tomography (CT). Patients were excluded for previous seizure history, current AED use, or a neurosurgical procedure. Patients were given a prophylactic 7-day course of AEDs on a week-on versus week-off basis and followed with in-person clinic visits, in-hospital evaluation, or a validated phone questionnaire.

Results:

Four hundred and ninety patients were enrolled, 349 (71.2%) had follow-up, and 139 (39.8%) were given prophylactic AEDs. There was no difference between seizure rates for the prophylactic AED group (0.7%) and those without (2.9%; P = 0.25). Patients who had a PTS were on average older (81.4 years) than patients without a seizure (64.8 years; P = 0.02). Seizure rate increased linearly by age groups: <60 years old (0%); 60–70 years old (1.7%); 70–80 years old (2.3%); and >80 years old (4.6%).

Conclusion:

Prophylactic AEDs did not provide a benefit for PTS reduction in mild TBI patients with a positive CT head scan.

Preclinical assessment of onabotulinumtoxinA for the treatment of mild traumatic brain injury-related acute and persistent post-traumatic headache

Objective

Investigation of onabotulinumtoxinA in a murine model of acute and persistent post-traumatic headache.

Methods

Mild traumatic brain injury was induced with a weight drop method. Periorbital and hindpaw cutaneous allodynia were measured for 14 days. Mice were then exposed to bright light stress and allodynia was reassessed. OnabotulinumtoxinA (0.5 U) was injected subcutaneously over the cranial sutures at different post-injury time points.

Results

After milt traumatic brain injury, mice exhibited periorbital and hindpaw allodynia that lasted for approximately 14 days. Allodynia could be reinstated on days 14–67 by exposure to stress only in previously injured mice. OnabotulinumtoxinA administration at 2 h after mild traumatic brain injury fully blocked both transient acute and stress-induced allodynia up to day 67. When administered 72 h post-mild traumatic brain injury, onabotulinumtoxinA reversed acute allodynia, but only partially prevented stress-induced allodynia. OnabotulinumtoxinA administration at day 12, when initial allodynia was largely resolved, produced incomplete and transient prevention of stress-induced allodynia. The degree of acute allodynia correlated positively with subsequent stress-induced allodynia.

Conclusion

Mild traumatic brain injury induced transient headache-like pain followed by long lasting sensitization and persistent vulnerability to a normally innocuous stress stimulus, respectively modeling acute and persistent post-traumatic headache.. Administration of onabotulinumtoxinA following the resolution of acute post-traumatic headache diminished persistent post-traumatic headache but the effects were transient, suggesting that underlying persistent mild traumatic brain injury-induced maladaptations were not reversed. In contrast, early onabotulinumtoxinA administration fully blocked both acute post-traumatic headache as well as the transition to persistent post-traumatic headache suggesting prevention of neural adaptations that promote vulnerability to headache-like pain. Additionally, the degree of acute post-traumatic headache was predictive of risk of persistent post-traumatic headache.

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.

Exploring Vestibular Assessment in Patients with Headache and Dizziness

Patients often report symptoms of headache and dizziness concomitantly. Symptoms of dizziness can be explored with a comprehensive vestibular assessment, allowing for the investigation of central and peripheral vestibular system contributions to symptoms of dizziness. Patients who report both symptoms of headache and dizziness demonstrate abnormalities of the vestibular system which can be measured quantitatively. Completion of comprehensive vestibular testing can help to guide diagnosis and strategies for intervention.

Headache Diary Mobile Application for Monitoring and Characterizing Posttraumatic Headaches

OBJECTIVE

This study analyzed the data collected using a headache diary mobile application to characterize posttraumatic headaches (PTHs) in a sample of US veterans. Specifically, we measured patient engagement with the mobile application and compared our findings with previous literature regarding PTHs.

SETTING

A Headache Center of Excellence (HCoE) in a Veterans Health Administration facility.

PARTICIPANTS

Forty-nine veterans currently being treated for ongoing PTH-related complaints with English fluency, reliable access to the internet, and a mobile phone.

DESIGN

Observational study of PTH characteristics using the mobile application over the course of 1 year.

MEASURES

Main outcome measures were collected via a headache diary mobile application developed for patients to track headache-associated symptoms, headache location, triggers, type, intensity, and duration. Patients also completed a baseline Headache Impact Test (HIT-6) survey.

RESULTS

In total, 1569 entries were completed during the first year of application deployment. On average, patients completed 2.5 entries per week and used the application for 70 days. They frequently reported associated PTH symptoms of photophobia (56.7%) and headaches triggered by emotional stress (35.1%). Network analyses revealed patterns of co-occurrence in triggers of headache pain, associated symptoms, and headache pain location. Headache pain severity and impact ratings from the headache diary demonstrated convergent validity with the established HIT-6 measure.

CONCLUSIONS

Headache diary mobile applications are a promising tool for monitoring and characterizing PTHs in veterans. Present results mirror past studies of PTH characteristics. Mobile application headache diaries may be used in both clinical and research settings to monitor headache symptoms and communicate the functional impact of headaches in real time.

Persistent posttraumatic headaches and functioning in veterans: Injury type can matter

OBJECTIVE

To characterize the relationship between head trauma types (blast injury, blunt injury, combined blast+blunt injury) with subsequent headache presentations and functioning.

BACKGROUND

Posttraumatic headaches (PTHs), the most common sequelae of traumatic brain injury (TBI), are painful and disabling. More than 400,000 veterans report having experienced a TBI, and understanding the predictors of PTHs may guide treatment developments.

METHODS

This study used a nested-cohort design analyzing baseline data from a randomized clinical trial of cognitive behavioral therapy for PTH (N = 190). Participants had PTH (from blast and/or blunt head trauma) and symptoms of posttraumatic stress disorder (PTSD). The Structured Diagnostic Interview for Headache-Revised and Ohio State University Traumatic Brain Injury Identification Method were used to phenotype headaches and head injury histories, respectively.

RESULTS

Individuals with persistent PTHs after a combined blast and blunt head trauma were more likely (OR =3.45; 95% CI [1.41, 8.4]) to experience chronic (vs. episodic) PTHs compared with the blunt trauma only group (23/33, 70% vs. 26/65, 40%, respectively); and they were more likely (OR =2.51; 95% CI [1.07, 5.9]) to experience chronic PTH compared with the blast trauma only group (44/92, 48%). There were no differences between head injury type on headache-related disability, depression symptoms, or severity of PTSD symptoms.

CONCLUSION

The combination of blast and blunt injuries was associated with headache chronicity, but not headache disability. Considering the refractory nature of chronic headaches, the potential added and synergistic effects of distinct head injuries warrant further study.

Suicide Attempts in US Veterans with Chronic Headache Disorders: A 10-Year Retrospective Cohort Study

Objectives

A large-scale retrospective analysis of veterans with chronic pain was conducted to examine (1) the annual incidence of suicide attempts (SA) in veterans with chronic headache and other chronic pain conditions, and (2) the risk of SA in men and women with chronic headache and chronic headache concurrent with traumatic brain injury (TBI) as compared to non-headache chronic pain.

Methods

This retrospective study (N=3,247,621) analyzed National Veterans Affair Health Administrative data of patients diagnosed with chronic head, neck, back and other chronic pain from 2000 to 2010. Multivariable Poisson regression was used to explore the relative risks of SA in veterans with chronic headache and chronic headache concurrent with TBI as stratified by sex.

Results

Veterans with chronic headaches had the highest annual incidence of SA (329 to 491 per 100,000) each year among all identified types of chronic pain conditions. Compared to other non-headache chronic pain, chronic headache is associated with increased risk of SA [men RR (1.48), CI (1.37,1.59); women RR (1.64), CI (1.28,2.09)], after adjusting for demographic factors, TBI, and psychiatric comorbidities. The risk increased further when chronic headache is comorbid with TBI [men RR (2.82), CI (2.60, 3.05); women RR (2.16, CI (1.67-2.78)].

Conclusion

Veterans with chronic headache have a higher risk of SA than those with other chronic pain and women with chronic headache are at a higher risk than men with chronic headache. Chronic headache concurrent with TBI further heightened this risk, especially in men. Our data underscore the importance of identifying specific types of chronic pain in veterans with comorbid TBI and sex disparity associated with SA when targeting suicide prevention measures.

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.

A narrative review of biopsychosocial factors which impact overweight and obesity for individuals with acquired brain injury

Primary Objective: To discuss the biopsychosocial factors that affect being overweight or obese after acquired brain injury (ABI)Research Design: Narrative reviewMethods and Procedures: Based on the biopsychosocial model, we discuss the unique injury-specific factors that can affect bring overweight or obese among individuals with ABI including: (1) biological, (2) psychological and (3) social/ecological factors.Main Outcomes and Results: Injury-specific factors that impact being overweight or obese following ABI include endocrine dysfunction, pain, bowel and bladder incontinence, balance problems and motor impairment, medications, sleep quality and fatigue, alcohol and tobacco use, psychological disorders and symptoms, cognitive changes, social support, isolation, participation, transportation, independence, and knowledge. These factors may also compound general factors impacting weight management, making it difficult for individuals with ABI to maintain a healthy lifestyle.Conclusions: It is important to recognize the biopsychosocial factors that impact weight-loss and lifestyle change after ABI so that interventions can be tailored to meet individuals' unique needs. Empirical research is needed to better understand how biopsychosocial factors interact and impact overweight/ obesity after ABI.

Possible effects of agent orange and posttraumatic stress disorder on hyperglycemia in Korean veterans from the US-Vietnam war

This study was conducted to examine whether Korean veterans from the US-Vietnam War who had a diagnosis of type II diabetes mellitus (T2DM) as well as past history of exposure to agent orange (AO) are vulnerable to hyperglycemia when receiving intra-articular corticosteroid injection (IACI) for pain relief.The current study included a total of 49 patients (n = 49) who received an injection of triamcinolone 20 or 40 mg to the shoulder under sonographic guidance or did that of dexamethasone 10 mg or triamcinolone 40 mg combined with dexamethasone 20 mg to the spine under fluoroscopic guidance. Their 7-day fasting blood glucose (FBG) levels were measured and then averaged, serving as baseline levels. This is followed by measurement of FBG levels for 14 days of IACI. Respective measurements were compared with baseline levels. The patients were also evaluated for whether there are increases in FBG levels depending on insulin therapy as well as HbA1c ≥ 7% or HbA1c < 7%.Overall, there were significant increases in FBG levels by 64.7 ± 42.5 mg/dL at 1 day of IACI from baseline (P < .05). HbA1c ≥ 7% and HbA1c < 7% showed increases in FBG levels by 106.1 ± 49.0 mg/dL and 46.5 ± 3.8 mg/dL, respectively, at 1 day of IACI from baseline (P < .05). In the presence and absence of insulin therapy, there were significant increases in them by 122.6 ± 48.7 mg/dL and 48.0 ± 20.4 mg/dL, respectively, at 1 day of IACI from baseline (P < .05). But there were decreases in them to baseline levels at 2 days of IACI.Clinicians should consider the possibility of hyperglycemia when using corticosteroids for relief of musculoskeletal pain in Korean veterans from the US-Vietnam War who had a history of exposure to AO.

Botulinum Toxin Type A for the Treatment of Post-traumatic Headache: A Randomized, Placebo-Controlled, Cross-over Study

INTRODUCTION

Botulinum toxin type A (BoNT/A) is an approved treatment for chronic migraine and has been shown to be effective in reducing number, days, and severity of headache in other headache disorders. Whether botulinum toxin is a safe and effective treatment specifically for post-traumatic headache (PTH), however, is unknown. This study sought to determine whether treatment with BoNT/A improved symptoms of PTH in military veterans.

MATERIALS AND METHODS

Forty subjects with PTH were randomized to receive treatment of either BoNT/A or a saline placebo. Sixteen weeks post-treatment or at return to baseline headache severity, subjects were crossed over to receive treatment with the other medication than previously treated with in the first session. Subjects recorded number of headaches, number of headache days, and headache pain severity in daily diaries. Outcome measures included change in the weekly number of headaches, number of headache days per week, and headache pain severity compared to baseline, and the change in number of headaches and number of headaches days at baseline compared to the rating scores averaged across weeks 6-11.

RESULTS

The number of headaches per week significantly decreased by 2.24 (43.3%) with BoNT/A treatment (P < .001) and significantly increased by 1.28 (35.1%) with placebo (P = .02) at the end of the 16 weeks and the difference between groups was also significant (P < .001). The number of headache days per week also significantly decreased by 2.24 (44.4%) at the end of 16 weeks with BoNT/A treatment (P < .001), was not significantly changed with placebo, and the difference between the two groups was significant (P < .001). Both the change in number of headaches and number of headache days averaged across weeks 6-11 compared to baseline were significantly decreased in the BoNT/A group (1.6 and 1.4, respectively) compared to a significant increase of 0.3 in number of weekly headaches and a nonsignificant decrease of 0.1 in number of headache days for the placebo group (P = .048 and P = .005, respectively). Headache pain severity was significantly reduced by 0.06 with botulinum toxin treatment (P = .02) and was not significantly increased by 0.04 in the placebo group with a significant difference between groups (P = .006).

CONCLUSIONS

Treatment with BoNT/A clinically and significantly improved the frequency and pain severity of PTH compared to placebo in military veterans. Limitations of the study include subject dropout, adherence to documenting variables daily in the dairy, and only one treatment of BoNT/A. Strengths include the cross-over study design, which demonstrated that BoNT/A was effective regardless of treatment order. This dataset is the first prospective study to evaluate BoNT/A as an intervention for symptoms of PTH and provides evidence that larger-scale and multiple treatment studies evaluating BoNT/A for this headache type are warranted.

Identifying oxidized lipid mediators as prognostic biomarkers of chronic posttraumatic headache

Chronic posttraumatic headache (PTH) is among the most common and disabling sequelae of traumatic brain injury (TBI). Current PTH treatments are often only partially effective and have problematic side effects. We previously showed in a small randomized trial of patients with chronic nontraumatic headaches that manipulation of dietary fatty acids decreased headache frequency, severity, and pain medication use. Pain reduction was associated with alterations in oxylipins derived from n-3 and n-6 fatty acids, suggesting that oxylipins could potentially mediate clinical pain reduction. The objective of this study was to investigate whether circulating oxylipins measured in the acute setting after TBI could serve as prognostic biomarkers for developing chronic PTH. Participants enrolled in the Traumatic Head Injury Neuroimaging Classification Protocol provided serum within 3 days of TBI and were followed up at 90 days postinjury with a neurobehavioral symptom inventory (NSI) and satisfaction with life survey. Liquid chromatography-tandem mass spectrometry methods profiled 39 oxylipins derived from n-3 docosahexaenoic acid (DHA), and n-6 arachidonic acid and linoleic acid. Statistical analyses assessed the association of oxylipins with headache severity (primary outcome, measured by headache question on NSI) as well as associations between oxylipins and total NSI or satisfaction with life survey scores. Among oxylipins, 4-hydroxy-DHA and 19,20-epoxy-docosapentaenoate (DHA derivatives) were inversely associated with headache severity, and 11-hydroxy-9-epoxy-octadecenoate (a linoleic acid derivative) was positively associated with headache severity. These findings support a potential for DHA-derived oxylipins as prognostic biomarkers for development of chronic PTH.

Cerebrovascular Reactivity Measures Are Associated With Post-traumatic Headache Severity in Chronic TBI; A Retrospective Analysis

OBJECTIVE

To characterize the relationship between persistent post-traumatic headache (pPTH) and traumatic cerebrovascular injury (TCVI) in chronic traumatic brain injury (TBI). Cerebrovascular reactivity (CVR), a measure of the cerebral microvasculature and endothelial cell function, is altered both in individuals with chronic TBI and migraine headache disorder (Amyot et al., 2017; Lee et al., 2019b). The pathophysiologies of pPTH and migraine are believed to be associated with chronic microvascular dysfunction. We therefore hypothesize that TCVI may contribute to the underlying migraine-like mechanism(s) of pPTH.

MATERIALS AND METHODS

22 moderate/severe TBI participants in the chronic stage (>6 months) underwent anatomic and functional magnetic resonance imaging (fMRI) scanning with hypercapnia gas challenge to measure CVR as well as the change in CVR (ΔCVR) after single-dose treatment of a specific phosphodiesterase-5 (PDE-5) inhibitor, sildenafil, which potentiates vasodilation in response to hypercapnia in impaired endothelium, as part of a Phase2a RCT of sildenafil in chronic TBI (NCT01762475). CVR and ΔCVR measures of each participant were compared with the individual's pPTH severity measured by the headache impact test-6 (HIT-6) survey.

RESULTS

There was a moderate correlation between HIT-6 and both CVR and ΔCVR scores [Spearman's correlation = -0.50 (p = 0.018) and = 0.46 (p = 0.03), respectively], indicating that a higher headache burden is associated with decreased endothelial function in our chronic TBI population.

CONCLUSION

There is a correlation between PTH and CVR in chronic moderate-severe TBI. This relationship suggests that chronic TCVI may underlie the pathobiology of pPTH. Further, our results suggest that novel treatment strategies that target endothelial function and vascular health may be beneficial in refractory pPTH.

fMRI findings in MTBI patients with headaches following rTMS

Mild Traumatic Brain Injury (MTBI) patients with persistent headaches are known to have diminished supraspinal modulatory connectivity from their prefrontal cortices. Repetitive transcranial magnetic stimulation (rTMS) is able to alleviate MTBI-related headache (MTBI-HA). This functional magnetic resonance imaging (fMRI) study assessed supraspinal correlates associated with the headache analgesic effect of rTMS at left prefrontal cortex (LPFC), hypothesizing real rTMS would significantly increase modulatory functions at LPFC in comparison to sham treatment. Subjects with MTBI-HA were randomized to receive either real or sham rTMS treatments and subjected to pre- and post-treatment resting state and evoked heat-pain fMRI as described in a prior study. Real rTMS consisted of 2000 pulses delivered at 10 Hz and 80% of the resting motor threshold at left dorsolateral prefrontal cortex, whereas sham treatment was delivered with same figure-of-eight coil turned 180 degrees. Follow-up fMRI was performed one-week post-treatment. All fMRI data was processed using BrainVoyager QX Software. 14 subjects receiving real and 12 subjects receiving sham treatments completed the study. The REAL group demonstrated significant (P < 0.02) decreases in headache frequency and intensity at one week following treatment. fMRI scans in the REAL group showed increased evoked heat pain activity (P < 0.002) and resting functional connectivity (P < 0.0001) at the LPFC after rTMS. Neither this significant analgesic effect nor these fMRI findings were seen in the sham group. Sham treatment was, however, associated with a decrease in resting state activity at the LPFC (P < 0.0001). This study correlates the demonstrated analgesic effect of rTMS in the treatment of MTBI-HA with enhanced supraspinal functional connectivity in the left prefrontal cortex, which is known to be involved in “top-down” pain inhibition along the descending midbrain-thalamic-cingulate pathway.

Trial Registration: This study was registered on September 24, 2013, on ClinicalTrials.gov with the identifier: NCT01948947. https://clinicaltrials.gov/ct2/show/NCT01948947.

Photophobia and allodynia in persistent post-traumatic headache are associated with higher disease burden

OBJECTIVE

To assess photophobia and allodynia in subjects with post-traumatic headache and examine how these sensory hypersensitivities associate with clinical measures of disease burden.

BACKGROUND

Post-traumatic headache is the most frequent and disabling long-term consequence of mild traumatic brain injury. There is evidence of sensory dysfunction in acute post-traumatic headache, and it is known from other headache conditions that sensory amplifications correlate with more severe disease. However, systematic studies in post-traumatic headache are surprisingly scarce.

METHODS

We tested light and tactile sensitivity, along with measures of disease burden, in 30 persistent post-traumatic headache subjects and 35 controls.

RESULTS

In all, 79% of post-traumatic headache subjects exhibited sensory hypersensitivity based on psychophysical assessment. Of those exhibiting hypersensitivity, 54% exhibited both light and tactile sensitivity. Finally, sensory thresholds were correlated across modalities, as well as with headache attack frequency.

CONCLUSIONS

In this study, post-traumatic headache subjects with both light and tactile sensitivity had significantly higher headache frequencies and lower sensitivity thresholds to both modalities, compared to those with single or no sensory hypersensitivity. This pattern suggests that hypersensitivity across multiple modalities may be functionally synergistic, reflect a higher disease burden, and may serve as candidate markers of disease.

Decreased grey matter volume in mTBI patients with post-traumatic headache compared to headache-free mTBI patients and healthy controls: a longitudinal MRI study

Traumatic brain injury (TBI) occurs in 1.7 million people annually and many patients go on to develop persistent disorders including post-traumatic headache (PTH). PTH is considered chronic if it continues past 3 months. In this study we aimed to identify changes in cerebral grey matter volume (GMV) associated with PTH in mild TBI patients. 50 mTBI patients (31 Non-PTH; 19 PTH) underwent MRI scans: within 10 days post-injury, 1 month, 6 months and 18 months. PTH was assessed at visit 4 by a post-TBI headache questionnaire. Healthy controls (n = 21) were scanned twice 6 months apart. Compared to non-PTH, PTH patients had decreased GMV across two large clusters described as the right anterior-parietal (p = 0.012) and left temporal-opercular (p = 0.027). Compared to healthy controls non-PTH patients had decreased GMV in the left thalamus (p = 0.047); PTH patients had decreased GMV in several extensive clusters: left temporal-opercular (p = 0.003), temporal-parietal (p = 0.041), superior frontal gyrus (p = 0.008) and right middle frontal/superior frontal gyrus (0.004) and anterior-parietal (p = 0.003). Differences between PTH and non-PTH patients were most striking at early time points. These early changes may be associated with an increased risk of PTH. Patients with these changes should be monitored for chronic PTH.

Study design for a randomized clinical trial of cognitive-behavioral therapy for posttraumatic headache

Posttraumatic headache (PTH) is a common debilitating condition arising from head injury and is highly prevalent among military service members and veterans with traumatic brain injury (TBI). Diagnosis and treatment for PTH is still evolving, and surprisingly little is known about the putative mechanisms that drive these headaches. This manuscript describes the design of a randomized clinical trial of two nonpharmacological (i.e., behavioral) interventions for posttraumatic headache. Design of this trial required careful consideration of PTH diagnosis and inclusion criteria, which was challenging due to the lack of standard clinical characteristics in PTH unique from other types of headaches. The treatments under study differed in clinical focus and dose (i.e., number of treatment sessions), but the trial was designed to balance the treatments as well as possible. Finally, while the primary endpoints for pain research can vary from assessments of pain intensity to objective and subjective functional measures, this trial of PTH interventions chose carefully to establish clinically relevant endpoints and to maximize the opportunity to detect significant differences between groups with two primary outcomes. All these issues are discussed in this manuscript.

CGRP monoclonal antibody prevents the loss of diffuse noxious inhibitory controls (DNIC) in a mouse model of post-traumatic headache

AIM

Determine the role of calcitonin-gene related peptide in promoting post-traumatic headache and dysregulation of central pain modulation induced by mild traumatic brain injury in mice.

METHODS

Mild traumatic brain injury was induced in lightly anesthetized male C57BL/6J mice by a weight drop onto a closed and unfixed skull, which allowed free head rotation after the impact. We first determined possible alterations in the diffuse noxious inhibitory controls, a measure of net descending pain inhibition called conditioned pain modulation in humans at day 2 following mild traumatic brain injury. Diffuse noxious inhibitory control was assessed as the latency to a thermally induced tail-flick that served as the test stimulus in the presence of right forepaw capsaicin injection that provided the conditioning stimulus. Post-traumatic headache-like behaviors were assessed by the development of cutaneous allodynia in the periorbital and hindpaw regions after mild traumatic brain injury. We then determined if intraperitoneal fremanezumab, an anti-calcitonin-gene related peptide monoclonal antibody or vehicle administered 2 h after sham or mild traumatic brain injury induction could alter cutaneous allodynia or diffuse noxious inhibitory control responses on day 2 post mild traumatic brain injury.

RESULTS

In naïve and sham mice, capsaicin injection into the forepaw elevated the latency to tail-flick, reflecting the antinociceptive diffuse noxious inhibitory control response. Periorbital and hindpaw cutaneous allodynia, as well as a loss of diffuse noxious inhibitory control, was observed in mice 2 days after mild traumatic brain injury. Systemic treatment with fremanezumab blocked mild traumatic brain injury-induced cutaneous allodynia and prevented the loss of diffuse noxious inhibitory controls in mice subjected to a mild traumatic brain injury.

INTERPRETATION

Sequestration of calcitonin-gene related peptide in the initial stages following mild traumatic brain injury blocked the acute allodynia that may reflect mild traumatic brain injury-related post-traumatic headache and, additionally, prevented the loss of net descending inhibition within central pain modulation pathways. As loss of conditioned pain modulation has been linked to multiple persistent pain conditions, dysregulation of descending modulatory pathways may contribute to the persistence of post-traumatic headache. Additionally, evaluation of the conditioned pain modulation/diffuse noxious inhibitory controls response may serve as a biomarker of vulnerability for chronic/persistent pain. These findings suggest that early anti-calcitonin-gene related peptide intervention has the potential to be effective both for the treatment of mild traumatic brain injury-induced post-traumatic headache, as well as inhibiting mechanisms that may promote post-traumatic headache persistence.

Severities in persistent mild traumatic brain injury related headache is associated with changes in supraspinal pain modulatory functions

Emerging evidence suggests mild traumatic brain injury related headache (MTBI-HA) is a form of neuropathic pain state. Previous supraspinal mechanistic studies indicate patients with MTBI-HA demonstrate a dissociative state with diminished levels of supraspinal prefrontal pain modulatory functions and enhanced supraspinal sensory response to pain in comparison to healthy controls. However, the relationship between supraspinal pain modulatory functional deficit and severity of MTBI-HA is largely unknown. Understanding this relationship may provide enhanced levels of insight about MTBI-HA and facilitate the development of treatments. This study assessed pain related supraspinal resting states among MTBI-HA patients with various headache intensity phenotypes with comparisons to controls via functional magnetic resonance imaging (fMRI). Resting state fMRI data was analyzed with self-organizing-group-independent-component-analysis in three MTBI-HA intensity groups (mild, moderate, and severe) and one control group (n = 16 per group) within a pre-defined supraspinal pain network based on prior studies. In the mild-headache group, significant increases in supraspinal function were observed in the right premotor cortex (T = 3.53, p < 0.001) and the left premotor cortex (T = 3.99, p < 0.0001) when compared to the control group. In the moderate-headache group, a significant (T = -3.05, p < 0.01) decrease in resting state activity was observed in the left superior parietal cortex when compared to the mild-headache group. In the severe-headache group, significant decreases in resting state supraspinal activities in the right insula (T = -3.46, p < 0.001), right premotor cortex (T = -3.30, p < 0.01), left premotor cortex (T = -3.84, p < 0.001), and left parietal cortex (T = -3.94, p < 0.0001), and an increase in activity in the right secondary somatosensory cortex (T = 4.05, p < 0.0001) were observed when compared to the moderate-headache group. The results of the study suggest that the increase in MTBI-HA severity may be associated with an imbalance in the supraspinal pain network with decline in supraspinal pain modulatory function and enhancement of sensory/pain decoding.

Bypassing TBI: Metabolic Surgery and the Link between Obesity and Traumatic Brain Injury-a Review

Obesity is a common outcome of traumatic brain injury (TBI) that exacerbates principal TBI symptom domains identified as common areas of post-TBI long-term dysfunction. Obesity is also associated with increased risk of later-life dementia and Alzheimer's disease. Patients with obesity and chronic TBI may be more vulnerable to long-term mental abnormalities. This review explores the question of whether weight loss induced by bariatric surgery could delay or perhaps even reverse the progression of mental deterioration. Bariatric surgery, with its induction of weight loss, remission of type 2 diabetes, and other expressions of the metabolic syndrome, improves metabolic efficiency, leads to reversal of brain lesions seen on imaging studies, and improves function. These observations suggest that metabolic/bariatric surgery may be a most effective therapy for TBI.

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

Feasibility of Smartphone-Delivered Progressive Muscle Relaxation in Persistent Post-Traumatic Headache Patients

Persistent post-traumatic headache (PPTH) is often the most common injury after mild traumatic brain injury (mTBI), reported by 47-95% of patients. Progressive muscle relaxation (PMR) has level A evidence in preventing migraine and tension headaches. However, research on this behavioral therapy for PPTH, let alone smartphone delivered, is limited. We performed a single-arm study of prospective patients calling our Concussion Center between June 2017 and July 2018. Inclusion criteria were that subjects had to meet International Classification of Headache Disorders, 3rd Edition criteria for PPTH secondary to mTBI, have four or more headache days a month, be age 18-85 years and 3-12 months post-injury, own a smartphone, and not tried headache behavioral therapy within the year. We recorded baseline headache and neuropsychiatric data. Using the RELAXaHEAD smartphone application, which has a headache diary and PMR audio files, participants were instructed to record headache symptoms and practice 20 min of PMR daily. There were three monthly follow-up assessments. There were 49 subjects enrolled. Basic demographics were: 33 (67%) female with mean age 40.1 ± 14.6 [20, 75] years. Of the 49 subjects, 15 (31%) had pre-existing headaches. In 11 (22%) subjects, mTBI was sports related. Subjects reported 17.7 ± 9.3 [4, 31] headache days in the month before enrollment, and 49 (100%) experienced over three concussion symptoms. Participants inputted data in the RELAXaHEAD app on average 18.3 ± 12.0 days [0, 31] the first month. Number of participants who did PMR over four times per week was 12 (24.5%) the first month, 9 (22.5%) the second month, and 6 (15%) the third month. After 3 months, 17 (42.5 %) participants continued doing PMR. Participants cited time constraints, forgetfulness, application glitches, and repetitiveness as obstacles to practicing PMR. It is feasible to get PPTH subjects to practice behavioral therapy through low-cost smartphone-based PMR two times weekly. Future work will assess efficacy and examine how to optimize barriers to PMR.

Traumatic brain injury neuroelectrochemical monitoring: behind-the-ear micro-instrument and cloud application

Background

Traumatic Brain Injury (TBI) is a leading cause of fatality and disability worldwide, partly due to the occurrence of secondary injury and late interventions. Correct diagnosis and timely monitoring ensure effective medical intervention aimed at improving clinical outcome. However, due to the limitations in size and cost of current ambulatory bioinstruments, they cannot be used to monitor patients who may still be at risk of secondary injury outside the ICU.

Methods

We propose a complete system consisting of a wearable wireless bioinstrument and a cloud-based application for real-time TBI monitoring. The bioinstrument can simultaneously record up to ten channels including both ECoG biopotential and neurochemicals (e.g. potassium, glucose and lactate), and supports various electrochemical methods including potentiometry, amperometry and cyclic voltammetry. All channels support variable gain programming to automatically tune the input dynamic range and address biosensors’ falling sensitivity. The instrument is flexible and can be folded to occupy a small space behind the ear. A Bluetooth Low-Energy (BLE) receiver is used to wirelessly connect the instrument to a cloud application where the recorded data is stored, processed and visualised in real-time. Bench testing has been used to validate device performance.

Results

The instrument successfully monitored spreading depolarisations (SDs) - reproduced using a signal generator - with an SNR of 29.07 dB and NF of 0.26 dB. The potentiostat generates a wide voltage range from -1.65V to +1.65V with a resolution of 0.8mV and the sensitivity of the amperometric AFE was verified by recording 5 pA currents. Different potassium, glucose and lactate concentrations prepared in lab were accurately measured and their respective working curves were constructed. Finally,the instrument achieved a maximum sampling rate of 1.25 ksps/channel with a throughput of 105 kbps. All measurements were successfully received at the cloud.

Conclusion

The proposed instrument uniquely positions itself by presenting an aggressive optimisation of size and cost while maintaining high measurement accuracy. The system can effectively extend neuroelectrochemical monitoring to all TBI patients including those who are mobile and those who are outside the ICU. Finally, data recorded in the cloud application could be used to help diagnosis and guide rehabilitation.

Use of CGRP receptor blocker erenumab in the management of post-traumatic headache: a case series of 5 women

CONTEXT

Post-traumatic headache (PTH) is a disabling headache disorder and the most common sequela of mild traumatic brain injury. The pathophysiology of PTH is poorly understood and there is limited available evidence to guide prophylactic medication selection. Emerging understanding of the pathophysiology of migraine headaches has led to the development of monoclonal antibodies, including erenumab. Erenumab has shown promise for the prevention of primary migraine headache; however, it has not yet been studied in PTH.

CASE SERIES

five women (average age 43.0 ± 17.9y) received treatment with erenumab for PTH secondary to mTBI. The average duration of PTH prior to starting erenumab was 32.0 ± 18.2 months. All patients were taking at least one daily headache prophylactic therapy prior to erenumab. The average pre-erenumab headache intensity was 86/100. On erenumab, the average reported reduction in headache intensity was 51.1%. After starting erenumab, all five patients were able to discontinue one or more medication(s). The most common side effect was constipation (three patients). There were no serious adverse events after an average follow-up of 3.4 ± 1.5 months. One patient discontinued erenumab during this period of follow-up after the resolution of her headaches.

CONCLUSION

Erenumab appears to be safe and effective for the management of PTH.

Addressing chronic persistent headaches after MTBI as a neuropathic pain state

An increasing number of patients with chronic persistent post-traumatic headache (PPTH) after mild traumatic brain injury (MTBI) are being referred to headache or pain specialists as conventional treatment options for primary headache disorders have not been able to adequately alleviate their debilitating headache symptoms. Evolving clinical and mechanistic evidences support the notation that chronic persistent MTBI related headaches (MTBI-HA) carry the hallmark characteristics of neuropathic pain. Thus, in addition to conventional treatment options applicable to non-traumatic primary headache disorders, other available treatment modalities for neuropathic pain should be considered. In this comprehensive review article, the author reveals the prevalence of MTBI-HA and its clinical manifestation, discusses existing clinical and mechanistic evidence supporting the classification of chronic persistent MTBI-HA as a neuropathic pain state, and explores current available treatment options and future directions of therapeutic research related to MTBI-HA.

New insights in post-traumatic headache with cluster headache phenotype: a cohort study

OBJECTIVES

To define the characteristics of post-traumatic headache with cluster headache phenotype (PTH-CH) and to compare these characteristics with primary CH.

METHODS

A retrospective study was conducted of patients seen between 2007 and 2017 in a headache centre and diagnosed with PTH-CH that developed within 7 days of head trauma. A control cohort included 553 patients with primary CH without any history of trauma who attended the headache clinic during the same period. Data including demographics, attack characteristics and response to treatments were recorded.

RESULTS

Twenty-six patients with PTH-CH were identified. Multivariate analysis revealed significant associations between PTH-CH and family history of CH (OR 3.32, 95% CI 1.31 to 8.63), chronic form (OR 3.29, 95% CI 1.70 to 6.49), parietal (OR 14.82, 95% CI 6.32 to 37.39) or temporal (OR 2.04, 95% CI 1.10 to 3.84) location of pain, and presence of prominent cranial autonomic features during attacks (miosis OR 11.24, 95% CI 3.21 to 41.34; eyelid oedema OR 5.79, 95% CI 2.57 to 13.82; rhinorrhoea OR 2.65, 95% CI 1.26 to 5.86; facial sweating OR 2.53, 95% CI 1.33 to 4.93). Patients with PTH-CH were at a higher risk of being intractable to acute (OR 12.34, 95% CI 2.51 to 64.73) and preventive (OR 16.98, 95% CI 6.88 to 45.52) treatments and of suffering from associated chronic migraine (OR 10.35, 95% CI 3.96 to 28.82).

CONCLUSION

This largest series of PTH-CH defines it as a unique entity with specific evolutive profile. Patients with PTH-CH are more likely to suffer from the chronic variant, have marked autonomic features, be intractable to treatment and have associated chronic migraine compared with primary CH.

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

BACKGROUND

Headache is a common complication of traumatic brain injury. The International Headache Society defines post-traumatic headache as a secondary headache attributed to trauma or injury to the head that develops within seven days following trauma. Acute post-traumatic headache resolves after 3 months, but persistent post-traumatic headache usually lasts much longer and accounts for 4% of all secondary headache disorders.

MAIN BODY

The clinical features of post-traumatic headache after traumatic brain injury resemble various types of primary headaches and the most frequent are migraine-like or tension-type-like phenotypes. The neuroimaging studies that have compared persistent post-traumatic headache and migraine found different structural and functional brain changes, although migraine and post-traumatic headache may be clinically similar. Therapy of various clinical phenotypes of post-traumatic headache almost entirely mirrors the therapy of the corresponding primary headache and are currently based on expert opinion rather than scientific evidence. Pharmacologic therapies include both abortive and prophylactic agents with prophylaxis targeting comorbidities, especially impaired sleep and post-traumatic disorder. There are also effective options for non-pharmacologic therapy of post-traumatic headache, including cognitive-behavioral approaches, onabotulinum toxin injections, life-style considerations, etc. CONCLUSION: Notwithstanding some phenotypic similarities, persistent post-traumatic headache after traumatic brain injury, is considered a separate phenomenon from migraine but available data is inconclusive. High-quality studies are further required to investigate the pathophysiological mechanisms of this secondary headache, in order to identify new targets for treatment and to prevent disability.

Walking the Tightrope: A Proposed Model of Chronic Pain and Stress

Pain and stress are both phenomena that challenge an individual’s homeostasis and have significant overlap in conceptual and physiological processes. Allostasis is the ability to adapt to pain and stress and maintain homeostasis; however, if either process becomes chronic, it may result in negative long-term outcomes. The negative effects of stress on health outcomes on physiology and behavior, including pain, have been well documented; however, the specific mechanisms of how stress and what quantity of stress contributes to the maintenance and exacerbation of pain have not been identified, and thus pharmacological interventions are lacking. The objective of this brief review is to: 1. identify the gaps in the literature on the impact of acute and chronic stress on chronic pain, 2. highlight future directions for stress and chronic pain research; and 3. introduce the Pain-Stress Model in the context of the current literature on stress and chronic pain. A better understanding of the connection between stress and chronic pain could provide greater insight into the neurobiology of these processes and contribute to individualized treatment for pain rehabilitation and drug development for these often comorbid conditions.

Exploring naturally occurring clinical subgroups of post-traumatic headache

Objective

To explore naturally occurring clinical subgroups of post-traumatic headache.

Background

Persistent post-traumatic headache (PTH) is defined as a headache developing within 7 days of an injury that lasts for greater than 3 months. However, there is no evidence available from the International Classification of Headache Disorders (ICHD) based classification between persistent and acute PTH based on clinical phenotypes.

Methods

We conducted a retrospective study using the Stanford Research Repository Cohort Discovery Tool. We reviewed 500 electronic patient charts between January 2015 to September 2019 using inclusion criteria of adults older than 18 years with a diagnosis of PTH. The following variables were extracted from each patient’s chart: diagnosis of PTH as dependent variable, and predictor variables as age, sex, history of migraine, loss of consciousness during head injury, pre-existing psychological history, duration of PTH and new PTH-associated comorbidities (e.g. new onset vertigo, post-traumatic stress disorder). Logistic regression was employed to identify clinical phenotypes predicting persistent PTH. All predictor variables were tested in one block to determine their predictive capacity while controlling for other predictors in the model. Two-step cluster analysis was conducted to identify naturally occurring PTH subgroups.

Results

A total of 300 patients were included (150 acute, 150 persistent PTH) with a median age of 47 years (IQR 31, 59) and female: male ratio of 2.7:1. Two hundred patients were excluded due to misdiagnoses. Pre-existing psychological history (standardized beta 0.16), history of migraine (0.20), new PTH-associated comorbidities (0.23) and medication overuse (0.37) statistically significantly predicted the presence of persistent PTH (p <  0.0001). Clustering analysis revealed PTH subgrouping comparable to ICHD-based classification: 140 patients in Cluster 1 (76% persistent PTH) and 160 patients in Cluster 2 (83% acute PTH). Four distinct clusters were found within persistent PTH.

Conclusion

Pre-existing psychological history, history of migraine, new PTH-associated comorbidities and medication overuse predicted the occurrence of persistent PTH as well as two naturally occurring PTH clusters correlating to acute and persistent PTH. Management emphasis should focus on these phenotypes.

Update on the prevalence of persistent post-traumatic headache in adult civilian traumatic brain injury: protocol for a systematic review and meta-analysis

INTRODUCTION

Traumatic brain injury (TBI) is a major public health concern. Persistent post-traumatic headache (PTH) is a common consequence of TBI affecting productivity and quality of life. The only review providing information about headache prevalence after TBI was published in 2008, combined data from civilian and military TBI, and was strictly derived from Medline database. Due to recent changes in TBI diagnosis and trauma epidemiology, the aim of the current study is to perform a systematic review and meta-analysis to derive updated prevalence estimates of persistent PTH in adult civilian TBI.

METHODS AND ANALYSIS

The methods have been defined following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies published from 2008 to 2019 will be identified searching the electronic databases Medline, Embase, Cochrane, Google Scholar, Directory of Open Access Journals and Web of Science. Retrieved records will be independently screened by two authors and relevant data will be extracted from studies reporting data on persistent PTH prevalence among civilian TBI individuals (≥16 years). The pooled prevalence estimates of any form of headache will be computed applying random-effects meta-analysis. Heterogeneity will be assessed using the I2 statistic and explored through subgroup analyses considering TBI severity (mild vs moderate/severe). Estimations of risk of bias will be performed using the Risk of Bias Tool for Prevalence Studies.

ETHICS AND DISSEMINATION

The result of this systematic review will be published in a peer-reviewed journal and disseminated at relevant conferences presentations. Formal ethical approval is not required because we will search and evaluate only existing sources of literature. By focusing on studies conducted in the last decade, this review will provide the most up-to-date information about the global prevalence of persistent PTH after TBI. Considering the economical and social burden of persistent PTH after TBI, accurate estimates of this problematic disorder is of utmost importance for planning, implementing and evaluating prevention interventions.

PROSPERO REGISTRATION NUMBER

CRD42018094138.