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

Posttraumatic headache is a distinct headache type from migraine

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

The World Health Organization Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders and the headache revolution: from headache burden to a global action plan for headache disorders

The World Health Organization (WHO) Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders was developed by WHO to address the worldwide challenges and gaps in provision of care and services for people with epilepsy and other neurological disorders and to ensure a comprehensive, coordinated response across sectors to the burden of neurologic diseases and to promote brain health across life-course. Headache disorders constitute the second most burdensome of all neurological diseases after stroke, but the first if young and midlife adults are taken into account. Despite the availability of a range of treatments, disability associated with headache disorders, and with migraine, remains very high. In addition, there are inequalities between high-income and low and middle income countries in access to medical care. In line with several brain health initiatives following the WHOiGAP resolution, herein we tailor the main pillars of the action plan to headache disorders: (1) raising policy prioritization and strengthen governance; (2) providing effective, timely and responsive diagnosis, treatment and care; (3) implementing strategies for promotion and prevention; (4) fostering research and innovation and strengthen information systems. Specific targets for future policy actions are proposed. The Global Action Plan triggered a revolution in neurology, not only by increasing public awareness of brain disorders and brain health but also by boosting the number of neurologists in training, raising research funding and making neurology a public health priority for policy makers. Reducing the burden of headache disorders will not only improve the quality of life and wellbeing of people with headache but also reduce the burden of neurological disorders increasing global brain health and, thus, global population health.

Effects of Non-Invasive Neuromodulation of the Vagus Nerve for the Management of Cluster Headache: A Systematic Review

BACKGROUND

Cluster headache (CH) is a type of headache that has a global prevalence of 0.5-3/1000 people, provokes severe, strictly unilateral pain through the first branch of the trigeminal nerve, and is associated with observable autonomous responses. CH provokes intense pain and decreases quality of life.

OBJECTIVE

In this study, we aimed to carry out a systematic review of the effectiveness of non-invasive neuromodulation of the vagus nerve in patients with cluster headaches, which was registered on PROSPERO No. CRD42021265126.

METHODS

Six databases were used from their date of inception to February 2023 to obtain studies with the group intervention of non-invasive neuromodulation of the vagus nerve for cluster headache, with outcomes based on pain attacks, duration, and disabilities. Data on the subjects, group intervention, main outcomes, and results were collected by two authors.

RESULTS

The search provided 1003 articles, with three clinical trials being eligible for inclusion in the review. The methodological quality scores ranged from 6 to 8 points (mean: 7.3, SD: 0.8) out of a maximum of 10 points. The post-treatment results showed some positive effects using n-VNS as a treatment for cluster headache, more specifically regarding cervical neuromodulation of the vagus nerve.

CONCLUSIONS

The systematic review found moderate-to-high-quality evidence supporting that n-VNS and cervical n-VNS may have some positive effects at the end of the treatment being effective to relieve the frequency and intensity of cluster headaches. The poor quantity of studies available and the lack of homogeneity in the study protocols did not allow the pooling of data for a meta-analysis.

Calcitonin Gene-Related Peptide-Mediated Trigeminal Ganglionitis: The Biomolecular Link between Temporomandibular Disorders and Chronic Headaches

A bidirectional causal relationship has been established between temporomandibular disorders (TMDs) and chronic headaches. Recent advances in the neurobiology of chronic pain offer a framework for understanding the comorbidity between these two conditions that might reside in the shared biomolecular mechanisms of peripheral and central sensitization. The initiation of these processes is inflammatory in nature and is most likely mediated by key molecules, including calcitonin gene-related peptide (CGRP). This scoping review proposes that CGRP-mediated neuroinflammation in the trigeminal ganglion may partly explain the biomolecular bidirectional link between TMDs and chronic headaches. Finally, clinical implications of this neuropathologic process are briefly discussed.

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

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

Effects of Non-Invasive Neuromodulation of the Vagus Nerve for Management of Tinnitus: A Systematic Review with Meta-Analysis

BACKGROUND

Tinnitus is the perception of sound in the absence of actual external stimuli. Other associated symptoms include frustration, annoyance, anxiety, depression, stress, cognitive dysfunction, insomnia, or emotional exhaustion.

OBJECTIVE

In this study, we aimed to conduct a systematic review and meta-analysis on the effectiveness of the non-invasive neuromodulation of the vagus nerve in patients with tinnitus.

METHODS

Six databases were searched from their date of inception to 15 June 2022 to identify clinical trials in which at least one group received any form of non-invasive neuromodulation of the vagus nerve for tinnitus management, with outcomes based on annoyance and related disability. Data on participants, interventions, blinding strategies, assessment outcomes, and results were extracted by two reviewers.

RESULTS

The search identified 183 articles with five clinical trials eligible for inclusion in the review and four for the meta-analysis. The methodological quality scores ranged from 6 to 8 (mean: 7.3, SD: 0.8) points. The meta-analysis identified a significant positive effect on THI post-treatment for unilateral auricular stimulation (hg = 0.69, 95% CI 0.06, 1.32) or transcutaneous nerve stimulation (hg = 0.51, 95% CI 0.1, 0.9) compared with a comparative group. No effect on loudness intensity was observed.

CONCLUSION

The results of the meta-analysis suggest that the application of the non-invasive neuromodulation of the vagus nerve has a positive effect post-treatment in terms of related disability in patients with tinnitus, although its clinical relevance is low. No firm conclusions about the effect of the non-invasive neuromodulation of the vagus nerve on tinnitus are available based on the current literature.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Post-traumatic headaches and vision: A review

BACKGROUND: Post-traumatic headache is the most common sequela of brain injury and can last months or years after the damaging event. Many headache types are associated with visual concerns also known to stem from concussion. OBJECTIVES: To describe the various headache types seen after head injury and demonstrate how they impact or are impacted by the visual system. METHODS: We will mirror the International Classification of Headache Disorders (ICHD) format to demonstrate the variety of headaches following brain injury and relate correlates to the visual pathways. The PubMed database was searched using terms such as headache, head pain, vision, concussion, traumatic brain injury, glare, visuomotor pathways. RESULTS: Every type of headache described in the International Classification of Headache Disorders Edition III can be initiated or worsened after head trauma. Furthermore, there is very often a direct or indirect impact upon the visual system for each of these headaches. CONCLUSION: Headaches of every described type in the ICHD can be caused by brain injury and all are related in some way to the afferent, efferent or association areas of the visual system.

Effect of Collaborative Care for Persistent Postconcussive Symptoms on Academic Function: A Randomized Clinical Trial

BACKGROUND

There is limited long-term data on the course of school-related problems and academic needs for youth with persistent post-concussive symptoms (PPCS).

METHODS

This was a randomized trial comparing collaborative care to usual care for 200 youth 11-18 years of age with PPCS. In this report, the main outcomes were academic functioning, GPA, school absences, date of return to school, and school days missed.

RESULTS

Youth were mean age of 14.7 (SD = 1.7), 62.0% female. New or worsening academic problems occurred in half of participants in both groups at 12 months after injury. Students were most concerned about grades and falling behind. There were no significant differences by study group on school problems or GPA, but number of days missed was lower in the collaborative care group compared at 3 months (12.5 [SD = 14.5] vs 16.1 days [20.4] adjusted relative risk [aRR] 0.67 [95% CI: 0.61, 0.74; p < .001]), 6 months (14.5 [22.1] vs 19.3 [26.6] aRR 0.77 [95% CI: 0.71, 0.84; p < .001]), and 12 months (16.9 [25.4] vs 19.6 [27.7], aRR 0.68 [95% CI: 0.62, 0.74; p < .001]).

CONCLUSIONS

Youth with PPCS are at high risk of school problems in the year after injury.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Models for Treating Post-traumatic Headache

PURPOSE OF REVIEW

To discuss the treatment of post-traumatic headache (PTH) and how to choose pharmacotherapy based upon known pathophysiology.

RECENT FINDINGS

Preclinical models of traumatic brain injury are finally revealing some of the mechanisms of PTH, including the significant role that inflammatory neuropeptides like calcitonin gene-related peptide (CGRP) play in the initiation and persistence of symptoms. To effectively treat post-traumatic headache (PTH), one needs to understand the pathophysiology behind the initiation and persistence of symptoms. Recent animal models are starting to elucidate these mechanisms, but effective treatment will also likely rely on the identification of patients who are most at risk for persistent PTH. Trials of early, targeted therapy for at-risk patients will be needed to validate these hypotheses. Additionally, high powered clinical trials are lacking in the field of persistent PTH for medications that are known to be effective in primary headache disorders. Effective treatment for persistent PTH also requires understanding how headache interacts with the complex nature of persistent post-concussion symptoms, as this disease often necessitates a multi-disciplinary approach. Regardless, with the knowledge gained by new PTH models cited in this paper, and an increasing availability of novel headache medications, more effective treatment models are on the horizon.

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.

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'.