Persistent Post-Traumatic Headache and Migraine: Pre-Clinical Comparisons

A Scoping Review on the Use of Non-Invasive Brain Stimulation Techniques for Persistent Post-Concussive Symptoms

BACKGROUND

In the context of managing persistent post-concussive symptoms (PPCS), existing treatments like pharmacotherapy, cognitive behavioral therapy, and physical rehabilitation show only moderate effectiveness. The emergence of neuromodulation techniques in PPCS management has led to debates regarding optimal stimulation parameters and their overall efficacy.

METHODS

this scoping review involved a comprehensive search of PubMed and ScienceDirect databases, focusing on controlled studies examining the therapeutic potential of non-invasive brain stimulation (NIBS) techniques in adults with PPCS.

RESULTS

Among the 940 abstracts screened, only five studies, encompassing 103 patients (12 to 29 per study), met the inclusion criteria. These studies assessed the efficacy of transcranial direct current stimulation (tDCS), or repetitive transcranial magnetic stimulation (rTMS), applied to specific brain regions (i.e., the left dorsolateral pre-frontal cortex (DLPFC) or left motor cortex (M1)) for addressing cognitive and psychological symptoms, headaches, and general PPCSs. The results indicated improvements in cognitive functions with tDCS. In contrast, reductions in headache intensity and depression scores were observed with rTMS, while no significant findings were noted for general symptoms with rTMS.

CONCLUSION

although these pilot studies suggest promise for rTMS and tDCS in PPCS management, further research with larger-scale investigations and standardized protocols is imperative to enhance treatment outcomes for PPCS patients.

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.

Effectiveness of rTMS and tDCS treatment for chronic TBI symptoms: A systematic review and meta-analysis

INTRODUCTION

Traumatic brain injury (TBI) is a major cause of long-term disability with conventional treatments frequently falling short to restore a good quality-of-life. Non-invasive brain stimulation (NIBS) techniques have shown potential as therapeutic options for neuropsychiatric conditions, including TBI sequelae. This study aims at providing a systematic review and meta-analysis on the effectiveness of repetitive transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) on post-TBI symptoms.

METHODS

Fifteen randomized controlled trials (RCTs) on adult TBI patients that examined the effects of multiple treatment sessions of NIBS techniques were selected from five databases. Symptoms were clustered into four categories: depression, anxiety, headache and cognitive dysfunctions. Meta-analysis was performed using correlated and hierarchical effects models.

RESULTS

There were only few and heterogeneous studies with generally small sample sizes. Most studies targeted the dorsolateral prefrontal cortex (dlPFC). Overall, the effects of NIBS were small. However, there was a significant effect for overall symptoms (0.404, p = 0.031). Moreover, subgroup analyses revealed significant overall effects for anxiety (0.195, p = 0.020) and headache (0.354, p = 0.040).

CONCLUSIONS

To date, there is limited evidence supporting the effectiveness of NIBS concerning treatment for TBI sequelae. The observed effect sizes were modest, suggesting subtle improvements rather than drastic changes. While NIBS techniques remain promising for treating neuropsychiatric conditions, larger RCT studies with longer follow-ups, optimized stimulation parameters and standardized methodology are required to establish their efficacy in addressing TBI sequelae.

Risk of Migraine after Traumatic Brain Injury and Effects of Injury Management Levels and Treatment Modalities: A Nationwide Population-Based Cohort Study in Taiwan

Traumatic brain injury (TBI) causes several long-term disabilities, particularly headaches. An association between TBI and subsequent migraine has been reported. However, few longitudinal studies have explained the link between migraine and TBI. Moreover, the modifying effects of treatment remain unknown. This retrospective cohort study used records from Taiwan's Longitudinal Health Insurance Database 2005 to evaluate the risk of migraine among patients with TBI and to determine the effects of different treatment modalities. Initially, 187,906 patients, aged ≥ 18 years, who were diagnosed as TBI in 2000, were identified. In total, 151,098 patients with TBI and 604,394 patients without TBI were matched at a 1:4 ratio according to baseline variables during the same observation period. At the end of follow-up, 541 (0.36%) and 1491 (0.23%) patients in the TBI and non-TBI groups, respectively, developed migraine. The TBI group exhibited a higher risk of migraine than the non-TBI group (adjusted HR: 1.484). Major trauma (Injury Severity Score, ISS ≥ 16) was associated with a higher migraine risk than minor trauma (ISS < 16) (adjusted HR: 1.670). However, migraine risk did not differ significantly after surgery or occupational/physical therapy. These findings highlight the importance of long-term follow-up after TBI onset and the need to investigate the underlying pathophysiological link between TBI and subsequent migraine.

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

OBJECTIVE/ BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

Background

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

Methods

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

Results

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

Conclusion

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

Migraine: interactions between brain's trait and state

It is well established that migraine is a multifactorial disorder. A deep understanding of migraine should be based upon both the underlying traits and the current states affected by different physiological, psychological, and environmental factors. At this point, there is no framework fully meeting these criteria. Here, we describe a broader view of the migraine disorder defined as a dysfunctional brain state and trait interaction. In this model, we consider events that may enhance or diminish migraine responsivity based on an individual's trait and state. This could provide an expanded view for considering how migraine attacks are sometimes precipitated by "triggers" and sometimes not, how these factors only lead to migraine attacks in migraine patients, or how individuals with an increased risk for migraine do not show any symptoms at all. Summarizing recent studies and evidence that support the concept of migraine as a brain state-trait interaction can also contribute to improving patient care by highlighting the importance of precision medicine and applying measures that are able to capture how different traits and states work together to determine migraine.

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.

Total tenderness score and pressure pain thresholds in persistent post-traumatic headache attributed to mild traumatic brain injury

Objective

To investigate whether persistent post-traumatic headache attributed to mild traumatic brain injury (TBI) is associated with more pronounced pericranial tenderness and lower pressure pain thresholds (PPTs) in the head and neck region, compared with healthy controls.

Methods

Patients with persistent post-traumatic headache (n = 100) and age- and gender-matched healthy controls (n = 100) were included between July 2018 and June 2019. Total tenderness score (TTS) was used to assess pericranial tenderness by bilateral manual palpation in eight muscles or tendon insertions. Summation was then used to calculate a TTS from 0 to 48 based on individual right- and left-sided scores; higher TTS score indicated more pronounced pericranial tenderness. PPTs were examined in m. temporalis and m. trapezius (upper and middle part) using an electronic pressure algometer that applies increasing blunt pressure at a constant rate.

Results

The TTS score was higher in patients with persistent post-traumatic headache (median, 21; IQR, 12–31), compared with healthy controls (median, 10; IQR, 6–17; P < .001). PPTs were lower in patients with persistent post-traumatic headache than in controls in both the left-sided m. temporalis (mean ± SD, 157.5 ± 59.9 vs. 201.1 ± 65.2; P < .001) and right-sided m. temporalis (mean ± SD, 159.5 ± 63.8 vs. 212.3 ± 61.9; P < .001). Furthermore, patients with persistent post-traumatic headache also had lower left- and right-sided PPTs in the upper as well as middle part of m. trapezius, compared with healthy controls; all P values were .05 or less.

Conclusions

Among patients with persistent post-traumatic headache, pericranial tenderness was more pronounced and PPTs in the head and neck region were lower than in healthy controls free of headache and mild TBI. Further research is needed to better understand the involvement of pericranial myofascial nociceptors in the disease mechanisms underlying post-traumatic headache.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01457-1.

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.

Characterization of persistent post-traumatic headache and management strategies in adolescents and young adults following mild traumatic brain injury

Characteristics of persistent post-traumatic headache (PTH) in young individuals are poorly known leading to diagnostic problems and diverse management. We aimed to describe headache phenotypes and self-reported management strategies in young individuals with PTH following mild traumatic brain injury (mTBI). A comprehensive structured questionnaire was used to evaluate headache phenotypes/characteristics and management strategies to relieve headache in 107, 15–30-year-old individuals with PTH. Around 4 months post-injury, migraine-like headache in combination with tension-type like headache (40%) was the most commonly encountered headache phenotype followed by migraine-like headache (36%). Around 50% reported aura-like symptoms before/during the headache attack. Medication-overuse headache was diagnosed in 10%. Stress, sleep disturbances, and bright lights were the most common trigger factors. More than 80% reported that their headache was worsened by work-related activity and alleviated by rest/lying down. Simple analgesics were commonly used (88%) whereas prophylactic drugs were rarely used (5%). Bedrest and physiotherapy were also commonly used as management strategies by 56% and 34% of the participants, respectively. In conclusion, most young individuals with PTH after mTBI presented with combined migraine-like and tension-type-like headache followed by migraine-like headache, only. Preventive headache medication was rarely used, while simple analgesics and bedrest were commonly used for short-term headache relief.

Altered speech patterns in subjects with post-traumatic headache due to mild traumatic brain injury

Background/objective

Changes in speech can be detected objectively before and during migraine attacks. The goal of this study was to interrogate whether speech changes can be detected in subjects with post-traumatic headache (PTH) attributed to mild traumatic brain injury (mTBI) and whether there are within-subject changes in speech during headaches compared to the headache-free state.

Methods

Using a series of speech elicitation tasks uploaded via a mobile application, PTH subjects and healthy controls (HC) provided speech samples once every 3 days, over a period of 12 weeks. The following speech parameters were assessed: vowel space area, vowel articulation precision, consonant articulation precision, average pitch, pitch variance, speaking rate and pause rate. Speech samples of subjects with PTH were compared to HC. To assess speech changes associated with PTH, speech samples of subjects during headache were compared to speech samples when subjects were headache-free. All analyses were conducted using a mixed-effect model design.

Results

Longitudinal speech samples were collected from nineteen subjects with PTH (mean age = 42.5, SD = 13.7) who were an average of 14 days (SD = 32.2) from their mTBI at the time of enrollment and thirty-one HC (mean age = 38.7, SD = 12.5). Regardless of headache presence or absence, PTH subjects had longer pause rates and reductions in vowel and consonant articulation precision relative to HC. On days when speech was collected during a headache, there were longer pause rates, slower sentence speaking rates and less precise consonant articulation compared to the speech production of HC. During headache, PTH subjects had slower speaking rates yet more precise vowel articulation compared to when they were headache-free.

Conclusions

Compared to HC, subjects with acute PTH demonstrate altered speech as measured by objective features of speech production. For individuals with PTH, speech production may have been more effortful resulting in slower speaking rates and more precise vowel articulation during headache vs. when they were headache-free, suggesting that speech alterations were related to PTH and not solely due to the underlying mTBI.

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

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

Distinguishing persistent post-traumatic headache from migraine: Classification based on clinical symptoms and brain structural MRI data

BACKGROUND

Persistent post-traumatic headache most commonly has symptoms that overlap those of migraine. In some cases, it can be clinically difficult to differentiate persistent post-traumatic headache with a migraine phenotype from migraine. The objective of this study was to develop a classification model based on questionnaire data and structural neuroimaging data that distinguishes individuals with migraine from those with persistent post-traumatic headache.

METHODS

Questionnaires assessing headache characteristics, sensory hypersensitivities, cognitive functioning, and mood, as well as T1-weighted magnetic resonance imaging and diffusion tensor data from 34 patients with migraine and 48 patients with persistent post-traumatic headache attributed to mild traumatic brain injury were included for analysis. The majority of patients with persistent post-traumatic headache had a migraine/probable migraine phenotype (77%). A machine-learning leave-one-out cross-validation algorithm determined the average accuracy for distinguishing individual migraine patients from individual patients with persistent post-traumatic headache.

RESULTS

Based on questionnaire data alone, the average classification accuracy for determining whether an individual person had migraine or persistent post-traumatic headache was 71.9%. Adding imaging data features to the model improved the classification accuracy to 78%, including an average accuracy of 97.1% for identifying individual migraine patients and an average accuracy of 64.6% for identifying individual patients with persistent post-traumatic headache. The most important clinical features that contributed to the classification accuracy included questions related to anxiety and decision making. Cortical brain features and fibertract data from the following regions or tracts most contributed to the classification accuracy: Bilateral superior temporal, inferior parietal and posterior cingulate; right lateral occipital, uncinate, and superior longitudinal fasciculus. A post-hoc analysis showed that compared to incorrectly classified persistent post-traumatic headache patients, those who were correctly classified as having persistent post-traumatic headache had more severe physical, autonomic, anxiety and depression symptoms, were more likely to have post-traumatic stress disorder, and were more likely to have had mild traumatic brain injury attributed to blasts.

DISCUSSION

A classification model that included a combination of questionnaire data and structural imaging parameters classified individual patients as having migraine versus persistent post-traumatic headache with good accuracy. The most important clinical measures that contributed to the classification accuracy included questions on mood. Regional brain structures and fibertracts that play roles in pain processing and pain integration were important brain features that contributed to the classification accuracy. The lower classification accuracy for patients with persistent post-traumatic headache compared to migraine may be related to greater heterogeneity of patients in the persistent post-traumatic headache cohort regarding their traumatic brain injury mechanisms, and physical, emotional, and cognitive symptoms.

Greater Severity and Functional Impact of Post-traumatic Headache in Veterans With Comorbid Neck Pain Following Traumatic Brain Injury

BACKGROUND

Post-traumatic headache (PTH) is a commonly experienced symptom after mild traumatic brain injury (mTBI). Blast injury- or blunt injury-related mechanisms for mTBI in veterans can also affect musculoskeletal structures in the neck, resulting in comorbid neck pain (NP). However, it is unknown whether the presence of comorbid NP may be associated with a different pattern of headache symptoms, physical functioning, or emotional functioning compared to those without comorbid NP. The purpose of this study is to examine the role of comorbid NP in veterans with mTBI and PTH.

DESIGN AND METHODS

This was a cross-sectional investigation of an existing dataset that included 33 veterans who met inclusion criteria for PTH after mTBI. Standardized measures of headache severity and frequency, insomnia, fatigue, mood disorders, and physical and emotional role function were compared between groups with and without comorbid NP.

RESULTS

The majority of participants with PTH reported comorbid NP (n = 22/33, 67%). Those with comorbid NP experienced more headache symptoms that were severe or incapacitating, as compared to mild or moderate for those without NP (φ = 0.343, P = .049); however, no differences in headache frequency (φ = 0.231, P = .231) or duration (φ = 0.129, P = .712) were observed. Participants with comorbid NP also reported greater insomnia (d = 1.16, P = .003) and fatigue (d = 0.868, P = .040) as well as lower physical functioning (d = 0.802, P = .036) and greater bodily pain (d = 0.762, P = .012). There were no differences in anxiety, depression, mental health, emotional role limitations, vitality, or social functioning between those with and without comorbid NP (d ≤ 0.656, P ≥ .079).

CONCLUSIONS

A majority of veterans with mTBI and PTH in our sample reported comorbid NP that was associated with greater headache symptom severity and physical limitations, but not with mood or emotional limitations. Preliminary findings from this small convenience sample indicate that routine assessment of comorbid NP and associated physical limitations should be considered in veterans with mTBI and PTH.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Altered hypothalamic functional connectivity in post-traumatic headache after mild traumatic brain injury

Background

Post-traumatic headache (PTH) is one of the most frequent symptoms following mild traumatic brain injury (mTBI). Neuroimaging studies implicate hypothalamic function connectivity (FC) disruption as an important factor in pain disorders. However, it is unknown whether there are alterations in the hypothalamus-based resting state FC within PTH following mTBI at the acute stage and its relationship with headache symptom measurement.

Methods

Forty-four mTBI patients with PTH, 27 mTBI patients without PTH and 43 healthy controls who were well matched for age, gender, and years of education were enrolled in this study. All participants underwent resting-state functional magnetic resonance imaging (fMRI) scanning as well as headache symptom measurement and cognitive assessment. Hypothalamic resting state networks were characterized by using a standard seed-based whole-brain correlation method. The bilateral hypothalamic FC was compared among the three groups. Furthermore, the correlations between hypothalamic resting state networks and headache frequency, headache intensity and MoCA scores was investigated in mTBI patients with PTH using Pearson rank correlation.

Results

Compared with mTBI patients without PTH, mTBI patients with PTH at the acute stage presented significantly decreased left hypothalamus-based FC with the right middle frontal gyrus (MFG) and right medial superior frontal gyrus (mSFG), and significantly decreased right hypothalamus-based FC with the right MFG. Decreased FC of the right MFG was significantly positively associated with headache frequency and headache intensity (r = 0.339, p = 0.024; r = 0.408, p = 0.006, respectively). Decreased FC of the right mSFG was significantly positively associated with headache frequency and headache intensity (r = 0.740, p < 0.0001; r = 0.655, p < 0.0001, respectively).

Conclusion

Our data provided evidence of disrupted hypothalamic FC in patients with acute mTBI with PTH, while abnormal FC significantly correlated with headache symptom measurement. Taken together, these changes may play an essential role in the neuropathological mechanism of mTBI patients with PTH.

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

Background

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

Main body

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

Conclusion

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

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.

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

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