Concussion in the Military: an Evidence-Base Review of mTBI in US Military Personnel Focused on Posttraumatic Headache

Co-administration of Nanowired Oxiracetam and Neprilysin with Monoclonal Antibodies to Amyloid Beta Peptide and p-Tau Thwarted Exacerbation of Brain Pathology in Concussive Head Injury at Hot Environment

Environmental temperature adversely affects the outcome of concussive head injury (CHI)-induced brain pathology. Studies from our laboratory showed that animals reared at either cold environment or at hot environment exacerbate brain pathology following CHI. Our previous experiments showed that nanowired delivery of oxiracetam significantly attenuated CHI-induced brain pathology and associated neurovascular changes. Military personnel are the most susceptible to CHI caused by explosion, blasts, missile or blunt head trauma leading to lifetime functional and cognitive impairments affecting the quality of life. Severe CHI leads to instant death and/or lifetime paralysis. Military personnel engaged in combat operations are often subjected to extreme high or low environmental temperature zones across the globe. Thus, further exploration of novel therapeutic agents at cold or hot ambient temperatures following CHI are the need of the hour. CHI is also a major risk factor for developing Alzheimer's disease by enhancing amyloid beta peptide deposits in the brain. In this review, effect of hot environment on CHI-induced brain pathology is discussed. In addition, whether nanodelivery of oxiracetam together with neprilysin and monoclonal antibodies (mAb) to amyloid beta peptide and p-tau could lead to superior neuroprotection in CHI is explored. Our results show that co-administration of oxiracetam with neprilysin and mAb to AβP and p-tau significantly induced superior neuroprotection following CHI in hot environment, not reported earlier.

The Effect of Concussion History on Lower Extremity Injury Risk in College Athletes: A Systematic Review and Meta-Analysis

Introduction

Collegiate athletes who suffer a concussion may possess prolonged impairments even after clearance for return-to-participation, which may place them at an increased risk of lower extremity injury.

Objective

To conduct a systematic review and meta-analysis of studies examining risk of lower extremity musculoskeletal injury following a concussion in collegiate athletes.

Methods

A literature search was performed using the following databases: PubMed, CINAHL, SPORTDiscus. The following search terms were used to identify relevant articles, ["concussion" OR "brain injury" OR "mild traumatic brain injury" OR "mTBI"] AND ["lower extremity injury" OR "musculoskeletal injury"]. Articles were included if they were published between January 2000 and July 2021 and examined collegiate athletes' risk of sustaining a lower extremity musculoskeletal injury following a concussion. Methodological quality of included studies was performed with a modified Downs and Black Checklist. The primary outcome of interest was the risk of sustaining a lower extremity musculoskeletal injury following a concussion. A random effects meta-analysis was conducted in which a summative relative risk (RR) for sustaining a lower extremity injury in athletes with and without a history of concussion was calculated.

Results

Seven studies met the eligibility criteria to be included in the systematic review. There were 348 athletes in the concussion group and 482 control athletes in the included studies. Most of the studies were of good or excellent quality. Five of the seven studies were able to be included in the meta-analysis. College athletes who suffered a concussion possessed a 58% greater risk of sustaining a lower extremity musculoskeletal injury than those who did not have a history of a concussion (RR = 1.58[1.30, 1.93]).

Conclusions

Lower extremity injury risk is potentially increased in college athletes following a concussion compared to those without a history of a concussion. Further research is needed to investigate the mechanism behind this increased risk. Clinical assessments throughout the concussion return-to-play protocol may need to be improved in order to detect lingering impairments caused by concussions.

Level of Evidence

1.

Neuroimaging of Headache: Indications and Controversies

Headache is a common presenting symptom in the ambulatory setting that often prompts imaging. The increased use and associated health care money spent in the setting of headache have raised questions about the cost-effectiveness of neuroimaging in this setting. Neuroimaging for headache in most cases is unlikely to reveal significant abnormality or impact patient management. In this article, reasons behind an observed increase in neuroimaging and its impact on health care expenditures are discussed. The typical imaging modalities available and various imaging guidelines for common clinical headache scenarios are presented, including recommendations from the American College of Radiology.

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

Detection of Chronic Blast-Related Mild Traumatic Brain Injury with Diffusion Tensor Imaging and Support Vector Machines

Blast-related mild traumatic brain injury (bmTBI) often leads to long-term sequalae, but diagnostic approaches are lacking due to insufficient knowledge about the predominant pathophysiology. This study aimed to build a diagnostic model for future verification by applying machine-learning based support vector machine (SVM) modeling to diffusion tensor imaging (DTI) datasets to elucidate white-matter features that distinguish bmTBI from healthy controls (HC). Twenty subacute/chronic bmTBI and 19 HC combat-deployed personnel underwent DTI. Clinically relevant features for modeling were selected using tract-based analyses that identified group differences throughout white-matter tracts in five DTI metrics to elucidate the pathogenesis of injury. These features were then analyzed using SVM modeling with cross validation. Tract-based analyses revealed abnormally decreased radial diffusivity (RD), increased fractional anisotropy (FA) and axial/radial diffusivity ratio (AD/RD) in the bmTBI group, mostly in anterior tracts (29 features). SVM models showed that FA of the anterior/superior corona radiata and AD/RD of the corpus callosum and anterior limbs of the internal capsule (5 features) best distinguished bmTBI from HCs with 89% accuracy. This is the first application of SVM to identify prominent features of bmTBI solely based on DTI metrics in well-defined tracts, which if successfully validated could promote targeted treatment interventions.

Prevalence of suicidal ideation and suicide attempt among patients with traumatic brain injury: A meta-analysis

BACKGROUND

Suicidality is common among patients with traumatic brain injury (TBI). This meta-analysis aimed to assess the prevalence of suicidal ideation (SI) and suicide attempt (SA) in TBI patients.

METHODS

Databases including PubMed, Cochrane Library, Embase, CINAHL, Web of Science, PsycINFO, China National Knowledge Infrastructure (CNKI), VIP, WanFang Data, and Chinese Biomedical Literature Database (CBM) were searched for relevant literature from inception to 9th January 2021. Random effects models were used to estimate the prevalence of SI and SA. The methodological quality of the included studies was assessed using the modified Newcastle-Ottawa Scale. Subgroup analysis was performed based on the geographical location of the institutions.

RESULTS

A total of 16 studies involving 1,146,271 patients with TBI were included in our meta-analysis. The prevalence of SI and SA were 19.1% (95% CI 13.6-24.6%) and 2.1% (95% CI 1.8-2.4%), respectively, while the prevalence of SA in Asian and non-Asian countries were 2.0% (95% CI 0.3-3.7%) and 2.0% (95% CI 1.6-2.3%). Meta-regression analyses revealed that the publication year and age were positively associated, while the geographical location of the institution and sample size were negatively associated with the pooled prevalence of SI. On the other hand, the geographical location of the institution, sample size and age were negatively associated with the pooled prevalence of SA.

LIMITATIONS

The overall heterogeneity between studies was high.

CONCLUSION

SI and SA are common among TBI patients. Therefore, targeted preventive measures are paramount to manage TBI-related suicide.

Prevalence of Comorbidities in Active and Reserve Service Members Pre and Post Traumatic Brain Injury, 2017-2019

OBJECTIVE

To understand the prevalence of comorbidities associated with traumatic brain injury (TBI) patients among active and reserve service members in the U.S. Military.

METHODS

Active and reserve SMs diagnosed with an incident TBI from January 2017 to October 2019 were selected. Nineteen comorbidities associated with TBI as identified in the literature and by clinical subject matter experts were described in this article. Each patient's medical encounters were evaluated from 6 months before to 2 years following the initial TBI diagnoses date in the Military Data Repository, if data were available. Time-to-event analyses were conducted to assess the cumulative prevalence over time of each comorbidity to the incident TBI diagnosis.

RESULTS

We identified 47,299 TBI patients, of which most were mild (88.8%), followed by moderate (10.5%), severe (0.5%), and of penetrating (0.2%) TBI severity. Two years from the initial TBI diagnoses, the top five comorbidities within our cohort were cognitive disorders (51.9%), sleep disorders (45.0%), post-traumatic stress disorder (PTSD; 36.0%), emotional disorders (22.7%), and anxiety disorders (22.6%) across severity groups. Cognitive, sleep, PTSD, and emotional disorders were the top comorbidities seen within each TBI severity group. Comorbidities increased pre-TBI to post-TBI; the more severe the TBI, the greater the prevalence of associated comorbidities.

CONCLUSION

A large proportion of our TBI patients are afflicted with comorbidities, particularly post-TBI, indicating many have a complex profile. The military health system should continue tracking comorbidities associated with TBI within the U.S. Military and devise clinical practices that acknowledge the complexity of the TBI patient.

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.

Incidence (2008-2015) of post-traumatic headaches in United States military personnel

Objective: To conduct a descriptive transversal study to evaluate the incidence and demographic characteristics of post-traumatic headache using data from the Defense Medical Epidemiology Database.Methods: A retrospective cohort study was conducted of data from 2008 to 2015 based on the International Classification of Diseases codes for both acute and chronic post-traumatic headache.Results: A total of 17,010 new cases of post-traumatic headaches were diagnosed among active duty military personnel. Reported incidence rates of post-traumatic headaches in the military increased 29-fold over the timeframe analyzed. Males enlisted in the Army were more likely to be diagnosed with post-traumatic headaches than females (O/E = 0.76), other branches, and officers.Conclusion: Findings of this study indicate that there is a significant incidence of post-traumatic headaches in the U.S. military. However, the incidence rates of post-traumatic headaches in the military are much lower than what was expected considering the number of traumatic brain injuries in the United States military reported by the Department of Defense for the same period. Additional research is needed to further evaluate these differences and the impact of PTHs on military personnel.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

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.

Impact of Pre-Existing Migraine and Other Co-Morbid or Co-Occurring Conditions on Presentation and Clinical Course Following Deployment-Related Concussion

OBJECTIVE

To describe the clinical presentation and early clinical course of a sample of deployed U.S. military service members following concussion, underscoring the impact of pre-existing migraine and other co-occurring conditions. It is important to obtain a comprehensive clinical history to identify evidence of underlying migraine and other health conditions which may contribute to an individual's presenting symptoms influencing early management and outcomes following concussion. Early outcome measures assessed include headache treatment response and fitness for return to duty.

BACKGROUND

Acute concussion is reported to result in an array of somatic, cognitive, and behavioral symptoms. It is well established that these symptoms are not specific for concussion and may result from exacerbation of pre-existing or underlying medical conditions and factors. Although most symptoms attributable to concussion resolve within days to weeks, there is evidence that persistent symptoms beyond that specific recovery time may be attributable to factors other than concussion. Military populations are at risk for a number of recognized co-morbid and co-occurring conditions, as well as special situational and psychosocial factors which may influence symptoms and clinical course following concussion. In addition, combat-related concussion frequently occurs in the setting of a blast or military vehicle accidents thus causing concurrent injuries where musculoskeletal injuries may contribute to the clinical presentation. The resultant acute stress reaction, secondary to the traumatic experience associated with concussion, may also cause or aggravate underlying psychological co-morbidities that may influence presenting symptoms. Prior studies identified co-morbidities associated with chronic post-concussive syndrome, which we find are also present during the early phase following deployment-related concussion, thereby influencing presentation and impacting recovery. This retrospective chart review was intended to demonstrate the presence and potential impact of co-morbid and co-occurring conditions contributing to symptoms following concussion, especially migraine due to its high prevalence among post-traumatic headaches.

METHODS

Retrospective chart review was performed by the treating neurologist of 40 service members following concussion in the deployed environment. Clinical symptoms and co-morbid and co-occurring conditions including evidence of pre-existing migraine identified during comprehensive neurologic evaluations were collected. Both pre-deployment/pre-traumatic and post-traumatic headache features supporting migraine and early instituted headache management and treatment response are described. Rates of return to duty in this sample were also tabulated.

RESULTS

Headaches were the most frequently reported acute symptom following concussion in this deployed service member population (38/40 patients [98%]), followed by insomnia, tinnitus, impaired concentration, nausea, dizziness, anxiety, impaired balance, depression, and hearing loss. Co-occurring acute injuries, acute stress reaction, and recent onset medication overuse were the most frequent co-occurring conditions identified by the treating neurologist as potentially contributing to the service member's presentation. Chronic co-morbidities identified included chronic headache, anxiety/depression, insomnia, and post-traumatic stress disorder. Service members with 3 or more identified co-morbidities or co-occurring conditions were more likely to require evacuation from theater. Pre-deployment headaches were reported by 25/40 [63%] service members, with 5/40 [12.5%] reporting known prior personal history of migraine. Of those reporting pre-deployment headaches, 21/25 [84%] described migraine features and/or triggers, though most [(15/25) 60%] reported as infrequent. Daily post-traumatic headaches were frequent (26/38 [68%]) and associated with typical migraine features and/or triggers. Of those treated with triptans (16/40 patient [42%]), most (12/16 patient [75%]) showed positive treatment response.

CONCLUSIONS

Concussion in the deployed settings does not occur in isolation, with co-morbid and co-occurring conditions being common. Presence of multiple co-morbidities appears to influence clinical course and overall recovery. Post-traumatic headaches are often phenotypically fully consistent with migraine, and appear related to pre-existing migraine if supported by detailed pre-deployment headache history suggesting same. Careful and comprehensive history taking and evaluation is invaluable in identifying associated conditions including migraine, potentially helping clinicians with more accurate symptom attribution, diagnoses, and improved clinical management following acute concussion.

Management of Chronic Migraine and Occipital Neuralgia in Post 9/11 Combat Veterans

Introduction

The rate of chronic migraine (CM) has been shown to be 20% or greater in the post 9/11 combat veteran population with a history of traumatic brain injury, while the rate is much lower at 3–5% in the general population. Studies have shown that medications such as oral topiramate or intramuscular injections of onabotulinum toxin A (Botox) have been used for CM prevention, and occipital blocks have been shown to be helpful in treating occipital neuralgia and short-term relief of CM. However, there are no known studies that have specifically evaluated the use of Botox and occipital blocks for reducing headache frequency in the US veteran population. The purpose of this study was to evaluate the effectiveness of using occipital blocks and Botox as dual therapy for reducing headache frequency in post 9/11 combat veterans with CM, occipital neuralgia, and a history of TBI or neck trauma.

Materials and Methods

Following Institutional Review Board approval, a retrospective chart review was completed on post 9/11 combat veterans treated in a headache clinic located at the Central Texas Veteran Health Care System. The electronic medical record was used to retrieve the charts of post 9/11 combat veterans who (1) had a confirmed deployment-related history of TBI or neck trauma; (2) were diagnosed with CM and occipital neuralgia; and (3) were treated in the headache clinic between January 1, 2014 and December 31, 2015 with the administration of occipital blocks and Botox within the first six months. Of 282 charts that were reviewed, a total of 30 (N = 30) veterans fit the criteria. The mean number of self-reported headache days per month (28 days) for the month prior to starting treatment was compared to the number of headache days per month (28 days) 6 months after initiation of therapy.

Results

Results revealed that the mean number of headache days in the month prior to treatment was 24.1 (22.0, 25.7). The mean number of headache days in the month post-treatment (6 months after the initiation of dual therapy with occipital blocks and Botox) was 12.9 (9.7, 16.4). The mean difference in the number of headache days from pre- to post-treatment (pre-treatment minus post-treatment) was 11.2 (8.2, 14.2).

Conclusion

This study evaluated the effectiveness of using occipital blocks and Botox as dual therapy for reducing headache frequency for post 9/11 combat veterans with CM, occipital neuralgia, and a history of TBI or neck trauma. Results revealed a statistically significant reduction in the number of headache days per month after the dual therapy. There were multiple limitations to the study to include a small sample size, lack of a control group, self-reported headaches for only 1 month pre-and post-treatment, and no control for other interventions or events which may have influenced the outcome. There is a strong need for randomized, double blinded, placebo- controlled studies involving dual therapy in this population. This study, though small, may be helpful in stimulating additional studies and treatments in this veteran population.

Rehabilitation Assessment and Management of Neurosensory Deficits After Traumatic Brain Injury in the Polytrauma Veteran

Neurosensory deficits after traumatic brain injury can frequently lead to disability; therefore, diagnosis and treatment are important. Posttraumatic headaches typically resemble migraines and are managed similarly, but adjuvant physical therapy may be beneficial. Sleep-related issues are treated pharmacologically based on the specific sleep-related complaint. Fatigue is difficult to treat; cognitive behavioral therapy and aquatic therapy can be beneficial. Additionally, methylphenidate and modafinil have been used. Peripheral and central vestibular dysfunction causes dizziness and balance dysfunction, and the mainstay of treatment is vestibular physical therapy. Visual dysfunction incorporates numerous different diagnoses, which are frequently treated with specific rehabilitation programs.

Imaging Post-Traumatic Headache

PURPOSE OF REVIEW

Headache is a frequent and debilitating symptom after mild traumatic brain injury, yet little is known about its pathophysiology and most effective treatments. The goal of this review is to summarize findings from imaging studies used during the clinical evaluation and research investigation of post-traumatic headache (PTH).

RECENT FINDINGS

There are no published recommendations or guidelines for when to acquire imaging studies of the head or neck in patients with PTH. Clinical acumen is required to determine if imaging is needed to assess for a secondary cause of headache which may have been precipitated or unmasked by the trauma. Several guidelines for when to image the patient with mild traumatic brain injury (mTBI) in the emergency setting consider headache among the deciding factors. In the research arena, imaging techniques including proton spectroscopy magnetic resonance imaging, diffusion tensor imaging, magnetic resonance morphometry, and functional neck x-rays have been employed with the goal of identifying diagnostic and prognostic factors for PTH and to help understand its underlying pathophysiologic mechanisms. Results indicate that changes in regional cortical thickness and damage to specific white matter tracts warrant further research. Future research should interrogate whether these imaging findings contribute to the classification and prognosis of PTH. Current research provides evidence that imaging findings associated with PTH may be distinct from those attributable to mTBI. A variety of imaging techniques have potential to further our understanding of the pathophysiologic processes underlying PTH as well as to provide diagnostic and prognostic indicators. However, considerable work must be undertaken for this to be realized.

Preclinical modelling of militarily relevant traumatic brain injuries: Challenges and recommendations for future directions

As a follow-up to the 2008 state-of-the-art (SOTA) conference on traumatic brain injuries (TBIs), the 2015 event organized by the United States Department of Veterans Affairs (VA) Office of Research and Development (ORD) analysed the knowledge gained over the last 7 years as it relates to basic scientific methods, experimental findings, diagnosis, therapy, and rehabilitation of TBIs and blast-induced neurotraumas (BINTs). The current article summarizes the discussions and recommendations of the scientific panel attending the Preclinical Modeling and Therapeutic Development Workshop of the conference, with special emphasis on factors slowing research progress and recommendations for ways of addressing the most significant pitfalls.

Associations Between Traumatic Brain Injury History and Future Headache Severity in Veterans: A Longitudinal Study

OBJECTIVE

To determine whether traumatic brain injury (TBI) history is associated with worse headache severity outcomes.

DESIGN

Prospective cohort study.

SETTING

Department of Veterans Affairs (VA) outpatient clinics.

PARTICIPANTS

Veterans (N=2566) who completed a mail follow-up survey an average of 3 years after a comprehensive TBI evaluation (CTBIE).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The presence or absence of TBI, and TBI severity were evaluated by a trained clinician and classified according to VA/Department of Defense clinical practice guidelines. Headache severity was evaluated at both the baseline CTBIE assessment and 3-year follow-up using a 5-level headache score ranging from 0 ("none") to 4 ("very severe") based on headache-associated activity interference in the past 30 days. We examined associations of mild and moderate/severe TBI history, as compared to no TBI history, with headache severity in cross-sectional and longitudinal analyses, with and without adjustment for potential confounders.

RESULTS

Mean headache severity scores were 2.4 at baseline and 2.3 at 3-year follow-up. Mild TBI was associated with greater headache severity in multivariate-adjusted cross-sectional analyses (β [SE]=.61 [.07], P<.001), as compared with no TBI, but not in longitudinal analyses (β [SE]=.09 [.07], P=.20). Moderate/severe TBI was significantly associated with greater headache severity in both cross-sectional (β [SE]=.66 [.09], P<.001) and longitudinal analyses (β [SE]=.18 [.09], P=.04).

CONCLUSIONS

Headache outcomes are poor in veterans who receive VA TBI evaluations, irrespective of past TBI exposure, but significantly worse in those with a history of moderate/severe TBI. No association was found between mild TBI and future headache severity in veterans. Veterans with headache presenting for TBI evaluations, and particularly those with moderate/severe TBI, may benefit from further evaluation and treatment of headache.

White matter changes in patients with mild traumatic brain injury: MRI perspective

This review focuses on white matter (WM) changes in mild traumatic brain injury (mTBI) as assessed by multimodal MRI. All the peer reviewed publications on WM changes in mTBI from January 2011 through September 2016 are included in this review. This review is organized as follows: introduction to mTBI, the basics of multimodal MRI techniques that are potentially useful for probing the WM integrity, summary and critical evaluation of the published literature on the application of multimodal MRI techniques to assess the changes of WM in mTBI, and correlation of MRI measures with behavioral deficits. The MRI–pathology correlation studies based on preclinical models of mTBI are also reviewed. Finally, the author's perspective of future research directions is described.

Concussion/mild traumatic brain injury-related chronic pain in males and females: A diagnostic modelling study

Pain is an unpleasant, complex, and perceived experience that places a significant burden on patients and clinicians. Its severity may be mediated by emotion, attitude, and environmental influences, and pain may be expressed differently in males and females. Traumatic brain injury (TBI) is frequently associated with chronic pain. This diagnostic modeling study examined sex differences in the construct of chronic pain in patients with delayed recovery from concussion/mild traumatic brain injury (mTBI).Data were collected from standardized questionnaires, neuroimaging records, and comprehensive clinical assessments. Bivariate associations were calculated using the Spearman correlation coefficient or analysis of variance. We established sex-specific stepwise multivariate linear regression models of factors associated with pain.Of the 94 participants diagnosed with mTBI (the mean age was 45.20 ± 9.94 years; 61.2% were males; the median time since injury was 197 days [interquartile range 139-416]), head/neck, and bodily pain were reported by 93% and 64%, respectively. No sex differences were identified in pain frequencies or severity. Pain was significantly associated with certain socio-demographic, injury-related, behavioral, and clinical variables. In the multivariable regression analysis, several determinants explained 60% of the pain variance in males and 46% in females.Pain is common in patients with delayed recovery from mTBI and is significantly associated with potentially modifiable clinical and nonclinical variables. Examining the multidimensional construct of pain in concussion/mTBI through a sex lens garners new directions for future longitudinal research on the pain mechanisms involved in postconcussion syndrome.