Acute Concussion

Concussions are the most common type of traumatic brain injury. They result from external force to the head that causes a neuro-metabolic cascade to unfold. This can then lead to a variety of symptoms in the domains of physical, cognition, mood, and sleep. Concussions are a clinical diagnosis but it is important to rule out acute intracranial pathology through a detailed history and physical examination in addition to possible head imaging. Treatment should include an individualized approach that focuses on what domains are affected after concussion.

Treatment Options for Posttraumatic Headache: A Current Review of the Literature

PURPOSE OF REVIEW

We evaluate evidence-based treatments for posttraumatic headache (PTH), a secondary headache disorder resulting from traumatic brain injury (TBI), comprising nearly 4% of all symptomatic headache disorders. Utilizing recent publications, we aim to inform clinicians of current treatment methods.

RECENT FINDINGS

There is limited research on PTH treatment. A randomized controlled trial (RCT) of metoclopramide with diphenhydramine for acute PTH found that the treatment group (N = 81) experienced more significant pain improvement than placebo by 1.4 points. For persistent PTH, an open-label study of erenumab (N = 89) found that 28% of participants reported ≥ 50% reduction in moderate-to-severe headache days, but an RCT of fremanezumab showed a non-significant reduction in moderate-to-severe headache days. A randomized crossover study of 40 patients with persistent PTH found that onabotulinum toxin-A decreased cumulative number of headaches/week by 43.3% in the treatment group and increased by 35.1% among placebos. In a study of military veterans with severe posttraumatic stress disorder and persistent/delayed onset PTH (N = 193), patients who received Cognitive Behavioral Therapy reported significant improvements in headache-related disability compared to usual care (aggregate mean HIT-6, -3.4). A transcranial magnetic stimulation (N = 24) study found that 58% of participants with mild TBI-related headache experienced a 50% reduction in headache frequency. New studies indicate promise in improving clinically important outcomes of PTH. However, more research is necessary to determine the optimal treatment and whether combining pharmacologic and nonpharmacologic treatment versus a single modality is more effective.

A cross-sectional survey of non-specialist Australian audio-vestibular clinical practice for traumatic brain injury and rehabilitation

OBJECTIVE

This study explored non-specialist audiological clinical practice in the context of traumatic brain injury (TBI), and whether such practices incorporated considerations of TBI-related complexities pertaining to identification, diagnosis and management of associated auditory and vestibular disturbances.

DESIGN

A cross-sectional online survey exploring clinical practice, TBI-related training and information provision was distributed to audiologists across Australia via Audiology Australia and social media. Fifty audiologists, 80% female and 20% male, participated in this study. Years of professional practice ranged from new graduate to more than 20 years of experience.

RESULTS

Clear gaps of accuracy in knowledge and practice across all survey domains relating to the identification, diagnosis and management of patients with auditory and/or vestibular deficits following TBI were evident. Further, of the surveyed audiologists working in auditory and vestibular settings, 91% and 86%, respectively, reported not receiving professional development for the diagnosis and management of post-traumatic audio-vestibular deficits.

CONCLUSION

Inadequate resources, equipment availability and TBI-related training may have contributed to the gaps in service provision, influencing audiological management of patients with TBI. A tailored TBI approach to identification, diagnosis and management of post-traumatic auditory and vestibular disturbances is needed.

Long-term postural control in elite athletes following mild traumatic brain injury

Background

Traumas to the head and neck are common in sports and often affects otherwise healthy young individuals. Sports-related concussions (SRC), defined as a mild traumatic brain injury (mTBI), may inflict persistent neck and shoulder pain, and headache, but also more complex symptoms, such as imbalance, dizziness, and visual disturbances. These more complex symptoms are difficult to identify with standard health care diagnostic procedures.

Objective

To investigate postural control in a group of former elite athletes with persistent post-concussive symptoms (PPCS) at least 6 months after the incident.

Method

Postural control was examined using posturography during quiet stance and randomized balance perturbations with eyes open and eyes closed. Randomized balance perturbations were used to examine motor learning through sensorimotor adaptation. Force platform recordings were converted to reflect the energy used to maintain balance and spectrally categorized into total energy used, energy used for smooth corrective changes of posture (i.e., <0.1 Hz), and energy used for fast corrective movements to maintain balance (i.e., >0.1 Hz).

Results

The mTBI group included 20 (13 males, mean age 26.6 years) elite athletes with PPCS and the control group included 12 athletes (9 males, mean age 26.4 years) with no history of SRC. The mTBI group used significantly more energy during balance perturbations than controls: +143% total energy, p = 0.004; +122% low frequency energy, p = 0.007; and +162% high frequency energy, p = 0.004. The mTBI subjects also adapted less to the balance perturbations than controls in total (18% mTBI vs. 37% controls, p = 0.042), low frequency (24% mTBI vs. 42% controls, p = 0.046), and high frequency (6% mTBI vs. 28% controls, p = 0.040). The mTBI subjects used significantly more energy during quiet stance than controls: +128% total energy, p = 0.034; +136% low-frequency energy, p = 0.048; and +109% high-frequency energy, p = 0.015.

Conclusion

Athletes with previous mTBI and PPCS used more energy to stand compared to controls during balance perturbations and quiet stance and had diminished sensorimotor adaptation. Sports-related concussions are able to affect postural control and motor learning.

'I had nothing. It's just life experience that helped me through that situation': Australian audiologists' perspectives on audiological clinical practice for traumatic brain injury and rehabilitation

OBJECTIVE

Australian Audiologists' perspectives on standard non-specialized clinical practice in the context of Traumatic Brain Injury (TBI) were examined, including the perceived barriers to optimal service provision.

DESIGN

A qualitative research design utilizing semi-structured interviews was conducted using purposive sampling. Nine participants were interviewed about their understanding of the impact of TBI on hearing and balance; identification, diagnosis and management of auditory and vestibular dysfunction following TBI; barriers to service delivery; training relating to complex clients (i.e., TBI); and awareness of referral pathways.

RESULTS

Three major themes, each with subthemes, were evident in the data. The major themes reflected general considerations of audiological professional culture and specific issues related to knowledge of TBI and clinical practice with patients. Analysis revealed that professional culture seemed to act as a contextual barrier and interacted with the perceived lack of TBI related knowledge to hinder optimal clinical practice in this patient population.

CONCLUSION

Application of the biopsychosocial model, including interdisciplinary care in the management of patients with TBI, is needed. An improvement in theoretical and practical knowledge encompassing the wide-ranging effects of TBI is critical for the optimal audiological service delivery.

Eye Movements in Mild Traumatic Brain Injury: Ocular Biomarkers

Mild traumatic brain injury (mTBI, or concussion), results from direct and indirect trauma to the head (i.e. a closed injury of transmitted forces), with or without loss of consciousness. The current method of diagnosis is largely based on symptom assessment and clinical history. There is an urgent need to identify an objective biomarker which can not only detect injury, but inform prognosis and recovery. Ocular motor impairment is argued to be ubiquitous across mTBI subtypes and may serve as a valuable clinical biomarker with the recent advent of more affordable and portable eye tracking technology. Many groups have positively correlated the degree of ocular motor impairment to symptom severity with a minority attempting to validate these findings with diffusion tract imaging and functional MRI. However, numerous methodological issues limit the interpretation of results, preventing any singular ocular biomarker from prevailing. This review will comprehensively describe the anatomical susceptibility, clinical measurement, and current eye tracking literature surrounding saccades, smooth pursuit, vestibulo-ocular reflex, vergence, pupillary light reflex, and accommodation in mTBI.

Vestibulo-ocular dysfunction in mTBI: Utility of the VOMS for evaluation and management – A review

BACKGROUND: Individuals who have suffered a concussion/mild traumatic brain injury (mTBI) frequently report symptoms associated with vestibular and/or oculomotor dysfunction (VOD) like dizziness, nausea, fatigue, brain fog, headache, gait and neurocognitive impairments which are associated with the development of chronic symptoms. The Vestibular/Ocular Motor Screening (VOMS) tool has been established as a reliable and clinically relevant complement to use alongside a battery of post-concussion tests to improve screening and referral for further evaluation and treatment of VOD. OBJECTIVES: This paper will review the pathoanatomy and symptomatology of common vestibular and oculomotor disorders after concussion, as well as the utility of the VOMS to assist in diagnosis, referral, and management. METHODS: Primary articles were identified using a search via PubMed, Google Scholar, OneSearch, and CINAHL. Search key terms were combinations of “mild traumatic brain injury” or “concussion” or “pursuit” or “accommodation” or “vergence” or “convergence insufficiency” or “saccades” or “vestibulo-ocular reflex” or “vestibular ocular motor screen” or “vestibular rehabilitation”, or “vision rehabilitation” including adult and pediatric populations that were published in print or electronically from 1989 to 2021 in English. Classic papers on anatomy of eye movements, vestibular system and pathological changes in mTBI were also included, regardless of publication date. RESULTS: Objective impairments are commonly found during testing of smooth pursuit, saccades, vergence, accommodation, vestibular ocular reflex, and visual motion sensitivity after mTBI. These deficits can be actively treated with vestibular physical therapy and oculomotor/neuro-optometric vision therapy. VOMS is an efficient and reliable tool that can be used by all healthcare and rehabilitation providers to aid in diagnosis of post-concussion VOD, to help facilitate the decision to refer for further evaluation and treatment to expedite symptomatic post-concussion recovery. CONCLUSIONS: VOD is common after concussion in acute, post-acute, and chronic phases. Once areas of impairments are identified through proper assessment, clinicians can maximize recovery by referring to vestibular physical therapy and/or neuro-optometry to design a targeted treatment program to address individual deficits.

Cognitive-Communication Complaints and Referrals for Speech-Language Pathology Services Following Concussion

PURPOSE

Speech-language pathologists are increasingly being recognized as key members of concussion management teams. This study investigates whether self-report of communication problems postconcussion may be useful in identifying clients who could benefit from speech-language pathology services.

METHOD

Participants included 41 adolescents and adults from an outpatient specialty concussion clinic. All completed the La Trobe Communication Questionnaire (LCQ) at admission, and 23 repeated this measure at discharge. Participants were prospectively enrolled, with chart reviews providing demographic, injury, and medical factors. The analysis considered (a) communication complaints and resolution over time, including comparison to two previously published LCQ studies of typical adults and adults with and without traumatic brain injury (TBI); (b) the relationship between communication complaints, participant factors, and common concussion assessments; and (c) factors related to speech-language pathology service referral for rehabilitation.

RESULTS

At first visit, 12 of 41 participants (29%) reported communication problems, although 19 (46%) reported difficulty with greater than half of LCQ items. At a group level, compared to published reference data of both people with chronic mixed severity TBI and controls, participants in this study reported more problems at first visit with communication overall, as well as greater difficulty with the LCQ Initiation/Conversation Flow subscale. Partner Sensitivity subscale scores at first visit were also greater than published control data. LCQ subscale scores of Initiation/Conversation Flow and Partner Sensitivity decreased from first visit to last visit, demonstrating resolution over time. Only concussion symptom scales and not demographic, injury, or cognitive screenings were related to LCQ scores. The same two LCQ subscales, Initiation/Conversation Flow and Partner Sensitivity, predicted referral for speech-language pathology services, along with symptom scales and being injured due to motor vehicle crash.

DISCUSSION

A subset of people recovering from concussion report experiencing communication problems. Reporting of particular communication problems was related to referral for speech-language pathology rehabilitation services and may be useful in directing care after concussion.

Post-Concussive Vestibular Dysfunction Is Related to Injury to the Inferior Vestibular Nerve

Symptoms of vestibular dysfunction such as dizziness and vertigo are common after sports-related concussions (SRC) and associated with a worse outcome and a prolonged recovery. Vestibular dysfunction after SRC can be because of an impairment of the peripheral or central neural parts of the vestibular system. The aim of the present study was to establish the cause of vestibular impairment in athletes with SRC who have persisting post-concussive symptoms (PPCS). We recruited 42 participants-21 athletes with previous SRCs and PPCS ≥6 months and 21 healthy athletic age- and sex-matched controls-who underwent symptom rating, a detailed test battery of vestibular function and 7T magnetic resonance imaging with diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) of cerebellar white matter tracts, and T1-weighted imaging for cerebellar volumetrics. Vestibular dysfunction was observed in 13 SRC athletes and three controls (p = 0.001). Athletes with vestibular dysfunction reported more pronounced symptoms on the Dizziness Handicap Inventory (DHI; p < 0.001) and the Hospital Anxiety and Depression Scale (HADS; p < 0.001). No significant differences in DTI metrics were found, while in DKI two metrics were observed in the superior and/or inferior cerebellar tracts. Cerebellar gray and white matter volumes were similar in athletes with SRC and controls. Compared with controls, pathological video head impulse test results (vHIT; p < 0.001) and cervical vestibular evoked myogenic potentials (cVEMP; p = 0.002) were observed in athletes with SRC, indicating peripheral vestibular dysfunction and specifically suggesting injury to the inferior vestibular nerve. In athletes with persisting symptoms after SRC, vestibular dysfunction is associated with injury to the inferior vestibular nerve.

Specialty-Specific Diagnoses in Pediatric Patients With Postconcussion Syndrome: Experience From a Multidisciplinary Concussion Clinic

OBJECTIVE

To describe the collaborative findings across a broad array of subspecialties in children and adolescents with postconcussion syndrome (PCS) in a pediatric multidisciplinary concussion clinic (MDCC) setting.

DESIGN

Retrospective analysis.

SETTING

Multidisciplinary concussion clinic at a pediatric tertiary-level hospital.

PATIENTS

Fifty-seven patients seen in MDCC for evaluation and management of PCS between June 2014 and January 2016.

INTERVENTIONS

Clinical evaluation by neurology, sports medicine, otolaryngology, optometry, ophthalmology, physical therapy, and psychology.

MAIN OUTCOME MEASURES

Specialty-specific clinical findings and specific, treatable diagnoses relevant to PCS symptoms.

RESULTS

A wide variety of treatable, specialty-specific diagnoses were identified as potential contributing factors to patients' postconcussion symptoms. The most common treatable diagnoses included binocular vision dysfunction (76%), anxiety, (57.7%), depression (44.2%), new or change in refractive error (21.7%), myofascial pain syndrome (19.2%), and benign paroxysmal positional vertigo (17.5%).

CONCLUSIONS

Patients seen in a MDCC setting receive a high number of treatable diagnoses that are potentially related to patients' PCS symptoms. The MDCC approach may (1) increase access to interventions for PCS-related impairments, such as visual rehabilitation, physical therapy, and psychological counseling; (2) provide patients with coordinated medical care across specialties; and (3) hasten recovery from PCS.

Relationship between Dizziness and the Core Vestibular Projection Injury in Patients with Mild Traumatic Brain Injury

Some studies have reported that a core vestibular projection (CVP) injury is associated with dizziness following a brain injury using diffusion tensor tractography (DTT). On the other hand, there has been no DTT study on dizziness caused by a CVP injury in patients with mild traumatic brain injury (TBI). In this study, DTT was used to examine the relationship between dizziness and CVP injury in patients with mild TBI. Forty-three patients with mild TBI and twenty-nine normal subjects were recruited. The patients were classified into two groups based on the dizziness score: group A, patients with a dizziness score less than 2 on the sub-item score for dizziness in the Rivermead Post-concussion Symptoms Questionnaire; group B, patients with a dizziness score above 2. The tract volume (TV) in group B was significantly lower than group A and the control group (p < 0.05). By contrast, the TV in group A was similar to the control group (p > 0.05). Regarding the correlation, the dizziness score of all patients showed a strong negative correlation with the TV of the CVP (r = −0.711, p < 0.05). DTT revealed the CVP injury in patients with dizziness after mild TBI. In addition, the severity of dizziness of these patients was closely related to the injury severity of the CVP.

Potential Mechanisms of Acute Standing Balance Deficits After Concussions and Subconcussive Head Impacts: A Review

Standing balance deficits are prevalent after concussions and have also been reported after subconcussive head impacts. However, the mechanisms underlying such deficits are not fully understood. The objective of this review is to consolidate evidence linking head impact biomechanics to standing balance deficits. Mechanical energy transferred to the head during impacts may deform neural and sensory components involved in the control of standing balance. From our review of acute balance-related changes, concussions frequently resulted in increased magnitude but reduced complexity of postural sway, while subconcussive studies showed inconsistent outcomes. Although vestibular and visual symptoms are common, potential injury to these sensors and their neural pathways are often neglected in biomechanics analyses. While current evidence implies a link between tissue deformations in deep brain regions including the brainstem and common post-concussion balance-related deficits, this link has not been adequately investigated. Key limitations in current studies include inadequate balance sampling duration, varying test time points, and lack of head impact biomechanics measurements. Future investigations should also employ targeted quantitative methods to probe the sensorimotor and neural components underlying balance control. A deeper understanding of the specific injury mechanisms will inform diagnosis and management of balance deficits after concussions and subconcussive head impact exposure.

Altered Vestibular Balance Function in Combat Sport Athletes

Combat sports pose a risk for accumulative injuries to the nervous system, yet fighters have remained an understudied population. Here, our purpose was to determine whether repetitive blows to the head have an effect on vestibular balance reflexes in combat sports athletes. We compared lower-limb muscle responses evoked with electrical vestibular stimuluation (EVS) between fighters (boxing/muay thai) and non-fighter controls. Each participant received stochastic vestibular stimulation (0-25 Hz, ±3 mA) over their mastoid processes while they stood relaxed with their head to the left or right. Surface electromyography was recorded from the medial gastrocnemius and soleus muscles bilaterally. Short and medium latency response (SLR/MLR) peaks were significantly delayed in the fighter group compared to controls. SLR and MLR peak amplitudes were also significantly lower in fighters. Fighter-estimated cumulative repetitive head impact (RHI) events demonstrated strong positive correlations with the timing of SLR and MLR peaks. Cumulative RHI events also negatively correlated with peak MLR amplitude and response gain at frequencies above 5 Hz. Our results provide evidence of a progressive vestibular impairment in combat sports athletes, potentially resulting from blows to the head accumulated in sparring practice and competitive bouts throughout their careers. Taken together, EVS-based vestibular assessments may provide a valuable clinical diagnostic tool and help better inform "return-to-play" and career-length decisions for not only combat sports athletes, but potentially other populations at risk of RHIs.

Frequency of peripheral vestibular pathology following traumatic brain injury: a systematic review of literature

OBJECTIVE

To establish the frequency of occurrence of peripheral vestibular dysfunction in adults who have sustained non-blast-related traumatic brain injury (TBI) as measured through the standard audiological vestibular test battery.

DESIGN

A systematic search of English language literature using MEDLINE, EMBASE, PsycINFO, CINAHL, hand-searching of reference lists and SCOPUS author search was conducted from January 1, 1990 to May 14, 2019.

STUDY SAMPLES

Twenty-three out of 417 originally identified articles were retained. TBI and peripheral vestibular findings were extracted and synthesised.

RESULTS

Quality appraisal using the Oxford Centre for Evidence-Based Medicine (OCEBM) revealed Level 2b as the highest level of evidence. None of the primary studies explored vestibular deficits in acute settings, with data collected from tertiary institutions and in 20 of 23 studies retrospectively. Although retrospective studies provided important data, they fail to control for numerous threats to internal validity. BPPV was the most frequently identified peripheral vestibular deficit following TBI, diagnosed in 39.7% of 239 participants across six of 23 studies.

CONCLUSIONS

Further prospective longitudinal research into comparative recovery trajectories in patients across TBI severity levels would provide additional information to guide clinical diagnosis, prognosis and management of this patient population.

Altered Processing of Complex Visual Stimuli in Patients with Postconcussive Visual Motion Sensitivity

BACKGROUND AND PURPOSE

Vestibular symptoms are common after concussion. Vestibular Ocular Motor Screening identifies vestibular impairment, including postconcussive visual motion sensitivity, though the underlying functional brain alterations are not defined. We hypothesized that alterations in multisensory processing are responsible for postconcussive visual motion sensitivity, are detectable on fMRI, and correlate with symptom severity.

MATERIALS AND METHODS

Twelve patients with subacute postconcussive visual motion sensitivity and 10 healthy control subjects underwent vestibular testing and a novel fMRI visual-vestibular paradigm including 30-second "neutral" or "provocative" videos. The presence of symptoms/intensity was rated immediately after each video. fMRI group-level analysis was performed for a "provocative-neutral" condition. Z-statistic images were nonparametrically thresholded using clusters determined by Z > 2.3 and a corrected cluster significance threshold of P = .05. Symptoms assessed on Vestibular Ocular Motor Screening were correlated with fMRI mean parameter estimates using Pearson correlation coefficients.

RESULTS

Subjects with postconcussive visual motion sensitivity had significantly more Vestibular Ocular Motor Screening abnormalities and increased symptoms while viewing provocative videos. While robust mean activation in the primary and secondary visual areas, the parietal lobe, parietoinsular vestibular cortex, and cingulate gyrus was seen in both groups, selective increased activation was seen in subjects with postconcussive visual motion sensitivity in the primary vestibular/adjacent cortex and inferior frontal gyrus, which are putative multisensory visual-vestibular processing centers. Moderate-to-strong correlations were found between Vestibular Ocular Motor Screening scores and fMRI activation in the left frontal eye field, left middle temporal visual area, and right posterior hippocampus.

CONCLUSIONS

Increased fMRI brain activation in visual-vestibular multisensory processing regions is selectively seen in patients with postconcussive visual motion sensitivity and is correlated with Vestibular Ocular Motor Screening symptom severity, suggesting that increased visual input weighting into the vestibular network may underlie postconcussive visual motion sensitivity.

Acute cognitive impairment after traumatic brain injury predicts the occurrence of brain atrophy patterns similar to those observed in Alzheimer's disease

Traumatic brain injuries (TBIs) are often followed by persistent structural brain alterations and by cognitive sequalae, including memory deficits, reduced neural processing speed, impaired social function, and decision-making difficulties. Although mild TBI (mTBI) is a risk factor for Alzheimer's disease (AD), the extent to which these conditions share patterns of macroscale neurodegeneration has not been quantified. Comparing such patterns can not only reveal how the neurodegenerative trajectories of TBI and AD are similar, but may also identify brain atrophy features which can be leveraged to prognosticate AD risk after TBI. The primary aim of this study is to systematically map how TBI affects white matter (WM) and gray matter (GM) properties in AD-analogous patterns. Our findings identify substantial similarities in the regional macroscale neurodegeneration patterns associated with mTBI and AD. In cerebral GM, such similarities are most extensive in brain areas involved in memory and executive function, such as the temporal poles and orbitofrontal cortices, respectively. Our results indicate that the spatial pattern of cerebral WM degradation observed in AD is broadly similar to the pattern of diffuse axonal injury observed in TBI, which frequently affects WM structures like the fornix, corpus callosum, and corona radiata. Using machine learning, we find that the severity of AD-like brain changes observed during the chronic stage of mTBI can be accurately prognosticated based on acute assessments of post-traumatic mild cognitive impairment. These findings suggest that acute post-traumatic cognitive impairment predicts the magnitude of AD-like brain atrophy, which is itself associated with AD risk.

Traumatic Optic Neuropathy Is Associated with Visual Impairment, Neurodegeneration, and Endoplasmic Reticulum Stress in Adolescent Mice

Traumatic brain injury (TBI) results in a number of impairments, often including visual symptoms. In some cases, visual impairments after head trauma are mediated by traumatic injury to the optic nerve, termed traumatic optic neuropathy (TON), which has few effective options for treatment. Using a murine closed-head weight-drop model of head trauma, we previously reported in adult mice that there is relatively selective injury to the optic tract and thalamic/brainstem projections of the visual system. In the current study, we performed blunt head trauma on adolescent C57BL/6 mice and investigated visual impairment in the primary visual system, now including the retina and using behavioral and histologic methods at new time points. After injury, mice displayed evidence of decreased optomotor responses illustrated by decreased optokinetic nystagmus. There did not appear to be a significant change in circadian locomotor behavior patterns, although there was an overall decrease in locomotor behavior in mice with head injury. There was evidence of axonal degeneration of optic nerve fibers with associated retinal ganglion cell death. There was also evidence of astrogliosis and microgliosis in major central targets of optic nerve projections. Further, there was elevated expression of endoplasmic reticulum (ER) stress markers in retinas of injured mice. Visual impairment, histologic markers of gliosis and neurodegeneration, and elevated ER stress marker expression persisted for at least 30 days after injury. The current results extend our previous findings in adult mice into adolescent mice, provide direct evidence of retinal ganglion cell injury after head trauma and suggest that axonal degeneration is associated with elevated ER stress in this model of TON.

Benign Paroxysmal Positional Vertigo in Children and Adolescents With Concussion

Background:

Dizziness after concussion is primarily attributed to effects on the brain, but traumatic inner ear disorders can also contribute. Benign paroxysmal positional vertigo (BPPV) is a common vestibular disorder that can result from minor head trauma and can be easily diagnosed and rapidly treated in an office setting. The role of BPPV in pediatric postconcussive dizziness has not been well-studied.

Purpose:

To evaluate the prevalence and clinical features of BPPV in a group of pediatric patients with concussion and prolonged dizziness after concussion.

Study Design:

Case-control study.

Level of Evidence:

Level 3.

Methods:

Retrospective review of 102 patients seen within the past 3 years in a pediatric multidisciplinary concussion clinic for evaluation of postconcussive dizziness.

Results:

BPPV was diagnosed in 29.4% (30/102) of patients with postconcussion syndrome and dizziness. All patients with BPPV were treated with repositioning maneuvers, except for 5 patients who had spontaneous resolution of symptoms. Patients were evaluated at an average of 18.8 weeks (SD, 16.4 weeks) after the injury. BPPV was diagnosed at similar rates regardless of gender or age group (children vs adolescents). The mean Post-Concussion Symptom Scale (PCSS) score did not differ significantly between patients with (58.3 [SD, 22.5]) or without BPPV (55.8 [SD, 29.4]; P = 0.39). The PCSS “balance problems or dizziness” subscore also did not differ between patients with (3.3 [SD, 1.7]) or without BPPV (2.8 [SD, 1.6]; P = 0.13).

Conclusion:

BPPV is fairly common in pediatric concussion, occurring in one-third of the patients studied. BPPV is often not diagnosed and treated until many weeks after the injury. Increased awareness of the evaluation and management of BPPV among pediatric concussion providers may help expedite resolution of dizziness and hasten overall recovery in affected patients.

Clinical Relevance:

BPPV is a treatable cause of dizziness caused by minor head injuries and is more common than previously reported in pediatric patients with concussion. Improved awareness of BPPV by concussion providers may expedite recovery.

Dorsolateral prefrontal circuit effective connectivity mediates the relationship between white matter structure and PASAT-3 performance in multiple sclerosis

Three decades ago a series of parallel circuits were described involving the frontal cortex and deep grey matter structures, with putative roles in control of motor and oculomotor function, cognition, behaviour and emotion. The circuit comprising the dorsolateral prefrontal cortex, caudate, globus pallidus and thalamus has a putative role in regulating executive functions. The aim of this study is to investigate effective connectivity (EC) of the dorsolateral-prefrontal circuit and its association with PASAT-3 performance in people with multiple sclerosis(MS). We use Granger causality analysis of resting-state functional MRI from 52 people with MS and 36 healthy people to infer that reduced EC in the afferent limb of the dorsolateral prefrontal circuit occurs in the people with MS with cognitive dysfunction (left: p = .006; right: p = .029), with bilateral EC reductions in this circuit resulting in more severe cognitive dysfunction than unilateral reductions alone (p = .002). We show that reduced EC in the afferent limb of the dorsolateral prefrontal circuit mediates the relationship between cognitive performance and macrostrucutral and microstructural alterations of white matter tracts in components of the circuit. Specificity is shown by the absence of any relationship between cognition and EC in the analogous and anatomically proximal motor circuit. We demonstrate good stability of the EC measures in people with MS over an interval averaging 8-months. Key positive and negative results are replicated in an independent cohort of people with MS. Our findings identify the dorsolateral prefrontal circuit as a potential target for therapeutic strategies aimed at improving cognition in people with MS.

Symptoms upon postural change and orthostatic hypotension in adolescents with concussion

Objective: Concussion is associated with dysautonomia, altered blood pressure (BP) control, and may cause Orthostatic Hypotension (OH). We measured prevalence of OH using the 1-minute supine-to-standing OH Test in adolescents with concussion and controls.Participants: Adolescents within 10 days of injury (Concussion Group, n = 297, 15.0 ± 1.7 years, 59% male) were compared with controls (Control Group, n = 214, 15.0 ± 1.5 years, 58% male).Methods: BP, heart rate (HR), and complaints of lightheadedness/dizziness were measured after 2-minute supine and 1-minute standing. Control Group was assessed once. Concussion Group was assessed twice; (1) initial visit (mean 6.0 ± 3 days-since-injury) and (2) after clinical recovery (mean 46.3 ± 42 days-since-injury).Results: Initial visit; Concussion Group reported feeling lightheaded/dizzy on postural change more often than the Control Group (37% vs 4%, p < .001) but did not differ in meeting standard OH criteria (3% vs 5%, p = .32). Experiencing symptoms did not correlate with meeting OH criteria, but correlated with abnormal vestibulo-ocular reflex. After clinical recovery; Concussion Group did not differ in experiencing lightheaded/dizziness on postural change than controls (4%, p = .65).Conclusion: Adolescents commonly experience orthostatic intolerance after concussion without meeting the standard criteria for OH.

Assessing Physical Function and Mobility following Pediatric Traumatic Brain Injury with the NIH Toolbox Motor Battery: A Feasibility Study

AIMS

Traumatic brain injury (TBI) can impair physical function in children. The NIH Toolbox Motor Battery (NIHTB-M) was designed to be a brief assessment of physical function, but no studies have examined its use in children with TBI. This study aims to describe the feasibility of using the NIHTB-M to assess children with TBI.

METHODS

The NIHTB-M was administered to children with TBI 2 weeks (n = 22) and/or 6 months (n = 23) following injury. This descriptive study summarizes participant performance, administration challenges, and the association between NIHTB-M scores, participant characteristics, and subjective report of physical function.

RESULTS

Of the NIHTB-M domains, deficits in endurance and balance were most prevalent. Children aged 5 to 16 years could complete the assessment per administration guidelines, except for a few cases (n = 3) where orthopedic injuries limited participation. Younger children (aged 3 to 4) had difficulty following the NIHTB-M directions. Technological issues impacted balance assessment in several cases (n = 6).

CONCLUSION

The NIHTB-M is brief to administer, generally well tolerated by school-aged children and, despite occasional technological challenges, is a feasible performance-based battery for assessment of children with TBI for clinical and research purposes. Additional investigation of psychometric properties and ceiling and floor effects is needed.

Injury of the optic radiation in patients with mild TBI: A DTT study

Objectives

We investigated injuries of the optic radiations (ORs) in patients with mild traumatic brain injury (TBI) by using diffusion tensor tractography (DTT).

Methods

Fifty-two consecutive patients who complained of visual problems showed abnormal visual evoked potential (VEP) latency but no abnormality on conventional brain MRI after mild TBI, and fifty normal control subjects were recruited for this study. Subjects' ORs were reconstructed using DTT, and three DTT parameters (fractional anisotropy [FA], apparent diffusion coefficient [ADC], and tract volume) were measured for each OR.

Results

Mean FA value and tract volume of the OR were significantly lower in the patient group than in the control group (p < 0.05). However, there was no significant difference in the ADC values of the OR between the patient and control groups (p > 0.05). A weak negative correlation was detected between VEP latency and OR fiber number (r = 0.204, p < 0.05).

Conclusions

DTT revealed that OR injuries were not detected on the conventional brain MRI scans of patients who complained of visual problems and had abnormal VEP latency after mild TBI. Our results suggest that DTT would be a useful technique for detecting OR injury in patients with mild TBI.

Vestibular and Balance Dysfunction Following Sport-Related Concussion

Purpose

Sport-related concussion is a significant public health concern that requires a multidisciplinary team to appropriately manage. Athletes often report dizziness and imbalance following concussion, and these symptoms can predict increased time to recover. Vestibular diagnostic evaluations provide important information regarding the athlete's oculomotor, gaze stability, and balance function in order to identify deficits for rehabilitation. These measures also describe objective function helpful for determining when an athlete is ready to return to play. The purpose of this clinical focus article is to provide background on the current understanding of the effects of concussion on the peripheral and central vestibular system, as well as information on a protocol that can be used for acute concussion assessment. Case studies describing 3 common postconcussion presentations will highlight the usefulness of this protocol.

Conclusion

Sport-related concussion is a highly visible disorder with many symptoms that may be evaluated in the vestibular clinic. A thoughtful protocol evaluating the typical presentation of these patients may help guide the multidisciplinary team in determining appropriate management and clearance for return to sport.

History of High Motion Sickness Susceptibility Predicts Vestibular Dysfunction Following Sport/Recreation-Related Concussion

OBJECTIVE

To compare vestibular dysfunction at 1 to 10 and 11 to 20 days following sport/recreation-related concussion (SRC) in athletes with and without history of motion sickness susceptibility. Secondary aims of this study were to investigate differences in neurocognitive performance and affective symptoms in these groups.

DESIGN

Cross-sectional.

SETTING

Concussion Specialty Clinic.

PARTICIPANTS

One hundred twenty-four adolescents and adults (82 males, 42 females) aged 14 to 26 (16.36 ± 2.10) years, diagnosed with SRC in the past 10 (4.56 ± 2.54) days; 47 participants composed the sample for quartile analyses.

INDEPENDENT VARIABLE

Motion sickness susceptibility questionnaire short form score.

MAIN OUTCOME MEASURES

Computerized neurocognitive test scores, vestibular/oculomotor screening scores (VOMS), and symptom factor scores from a standardized concussion symptom inventory.

RESULTS

There was no association between history of motion sickness susceptibility and VOMS scores (above or below clinical cutoff) at 1 to 10 days after injury, although at 11 to 20 days after injury there was an association between high motion sickness susceptibility and symptoms above clinical cutoff on 5 of the 6 VOMS items (P values 0.01-0.04). The high motion sickness group had more affective symptoms on the symptom inventory than the no motion sickness group (P = 0.002) at 1 to 10 days after injury. Groups did not differ on computerized neurocognitive testing (P = 0.11).

CONCLUSION

Athletes with a preexisting history of motion sensitivity may exhibit more prolonged vestibular dysfunction following SRC, and may experience more affective symptoms early in recovery.

A Pilot Randomised Double-Blind Study of the Tolerability and efficacy of repetitive Transcranial Magnetic Stimulation on Persistent Post-Concussion Syndrome

This study investigates the effect of Repetitive Transcranial Magnetic Stimulation (rTMS) on persistent post-concussion syndrome (PCS). The study design was a randomized (coin toss), placebo controlled, and double-blind study. Thirty-seven participants with PCS were assessed for eligibility; 22 were randomised and 18 completed the study requirements. Half the participants with PCS were given an Active rTMS intervention and the other half given Sham rTMS over 3 weeks. Follow ups were at the end of treatment and at 30 and 60 days. The primary outcome measure was the Rivermead Post-Concussion Symptoms Questionnaire (RPQ3 & RPQ13). The results indicate participants with more recent injuries (<12 month), who received Active rTMS, showed significant improvements compared to those of: 1) the same subgroup who received Sham, and 2) those with a longer duration of injury (>14 months) who received Active rTMS. This improvement predominantly manifested in RPQ13 in the follow up periods 1 and 2 months after the intervention (RPQ13 change (mean ± SD): at 1 month, Active = −21.8 ± 6.6, Sham = −2.2 ± 9.8; at 2 months, Active = −21.2 ± 5.3, Sham = −5.4 ± 13.7). No improvement was found in the subgroup with longer duration injuries. The results support rTMS as a tolerable and potentially effective treatment option for individuals with a recent (<1 year) concussion.

Peripheral Vestibular System Histopathologic Changes following Head Injury without Temporal Bone Fracture

Objective

Vestibular symptoms such as dizziness and vertigo are common after head injury and may be due to trauma to the peripheral vestibular system. The pathophysiology of peripheral vestibular symptoms following head injury without temporal bone (TB) fracture, however, is not well understood. Herein, we investigate the histopathology of the peripheral vestibular system of patients who sustained head injury without a TB fracture.

Study Design

Otopathology study.

Setting

Otopathology laboratory.

Subjects and Methods

TB of subjects with a history of head injury without TB fractures were included and evaluated by light microscopy. Specimens were assessed for qualitative and quantitative characteristics, such as number of Scarpa’s ganglion cells in the superior and inferior vestibular nerves, vestibular hair cell and/or dendrite degeneration in vestibular end organs, presence of vestibular hydrops, and obstruction of the endolymphatic duct.

Results

Five cases (n = 5 TBs) had evidence of vestibular pathology. There was a decrease of 48.6% (range, 40%-59%) in the mean count of Scarpa’s ganglion cells as compared with that of normative historical age-matched controls. Moderate to severe degeneration of the vestibular membranous labyrinth was identified in the posterior, superior, and lateral canals in several cases (50%, n = 4 TBs). The maculae utriculi and sacculi showed mild to severe degeneration in 2 cases. Additional findings include vestibular hydrops (25%, n = 2 TBs) and blockage of the endolymphatic duct (n = 1 TB).

Conclusions

Otopathologic analysis of patients with a history of head injury without TB fracture demonstrated peripheral vestibular otopathology. Future studies are necessary to determine if otopathology findings are directly attributable to head injury.

Association of Visual Tracking Metrics With Post-concussion Symptomatology

Attention impairment may provide a cohesive neurobiological explanation for clusters of clinical symptoms that occur after a concussion; therefore, objective quantification of attention is needed. Visually tracking a moving target is an attention-dependent sensorimotor function, and eye movement can be recorded easily and objectively to quantify performance. Our previous work suggested the utility of gaze-target synchronization metrics of a predictive visual tracking task in concussion screening and recovery monitoring. Another objectively quantifiable performance measure frequently suggested for concussion screening is simple visuo-manual reaction time (simple reaction time, SRT). Here, we used visual tracking and SRT tasks to assess changes between pre- and within-2-week post-concussion performances and explore their relationships to post-concussion symptomatology. Athletes participating in organized competitive sports were recruited. Visual tracking and SRT records were collected from the recruited athlete pool as baseline measures over a 4-year period. When athletes experienced a concussion, they were re-assessed within 2 weeks of their injury. We present the data from a total of 29 concussed athletes. Post-concussion symptom burden was assessed with the Rivermead Post-Concussion Symptoms Questionnaire and subscales of the Brain Injury Screening Questionnaire. Post-concussion changes in visual tracking and SRT performance were examined using a paired t-test. Correlations of changes in visual tracking and SRT performance to symptom burden were examined using Pearson's coefficients. Post-concussion changes in visual tracking performance were not consistent among the athletes. However, changes in several visual tracking metrics had moderate to strong correlations to symptom scales (r up to 0.68). On the other hand, while post-concussion SRT performance was reduced (p < 0.01), the changes in the performance metrics were not meaningfully correlated to symptomatology (r ≤ 0.33). Results suggest that visual tracking performance metrics reflect clinical symptoms when assessed within 2 weeks of concussion. Evaluation of concussion requires assessments in multiple domains because the clinical profiles are heterogeneous. While most individuals show recovery within a week of injury, others experience prolonged recovery periods. Visual tracking performance metrics may serve as a biomarker of debilitating symptoms of concussion implicating attention as a root cause of such pathologies.

Traumatic Brain Injury-Related Symptoms Reported by Parents: Clinical, Imaging, and Host Predictors in Children with Impairments in Consciousness Less than 24 Hours

This study examined the relationship between acute neuroimaging, host and injury factors, and parent-reported traumatic brain injury (TBI)-related symptoms in children with noncritical head injury at two weeks and three months after injury. Data were collected prospectively on 45 subjects aged three to 16 years old enrolled in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) study. Subjects had rapid recovery of mental status (Glasgow Coma Score [GCS] = 15 within 24 h), and had no clinical need for neurosurgical intervention. Intra- or extra-axial magnetic resonance imaging (MRI) lesions were categorized using Common Data Elements (CDE) definitions. Host and acute injury factors including neurobehavioral history, race, extracranial injuries, loss of consciousness (LOC), and GCS were analyzed while controlling for pre-injury symptoms, age, sex, and socioeconomic status. Parent-reported cognitive and somatic symptoms were measured by the Health and Behavior Inventory (HBI). Forty-nine percent of children had MRI lesions, most of which were relatively small. LOC predicted increased cognitive and somatic symptoms at two weeks. At three months, pre-injury neurobehavioral history predicted increased cognitive and somatic symptoms. Neuroimaging findings did not predict parent-reported symptom severity, except at three months where extra-axial lesions were associated with less severe cognitive symptoms. While structural MRI lesions do not predict increased parent-reported symptoms in this population, age-specific child performance measures may be more sensitive outcome measures and require further study. Children with pre-injury neurobehavioral problems have more severe symptoms at three months and thus may benefit from longer follow-up and monitoring after traumatic brain injury.

Near Point of Convergence and Gait Deficits in Adolescents After Sport-Related Concussion

OBJECTIVE

To prospectively examine gait characteristics of participants acutely after concussion with and without receded near point of convergence (NPC), compared with healthy controls.

DESIGN

Cross-sectional study.

SETTING

Sports-medicine clinic.

PARTICIPANTS

Patients examined after concussion (n = 33; mean ± SD = 7.2 ± 3.1 days) and a group of uninjured athletes (n = 31) completed a Postconcussion Symptom Scale, underwent NPC testing, and single/dual-task gait assessments.

INDEPENDENT VARIABLES

Near point of convergence was defined as the patient-reported diplopia distance when a fixation target moved toward the nose. Receded NPC was defined as a distance >5 cm from the tip of the nose.

MAIN OUTCOME MEASURES

Spatiotemporal gait characteristics in single-task and dual-task conditions were evaluated with analysis of variance; correlations were calculated between NPC and gait measures.

RESULTS

Eighteen of 33 (55%) patients with concussion presented with receded NPC. Those with receded NPC exhibited slower gait speed (single-task = 1.06 ± 0.14 m/s vs 1.19 ± 0.15 m/s; dual-task = 0.80 ± 0.13 m/s vs 0.94 ± 0.13 m/s; P = 0.003) and shorter stride lengths (single-task = 1.11 ± 0.10 m vs 1.24 ± 0.11 m; dual-task = 0.97 ± 0.11 m vs 1.09 ± 0.11 m; P = 0.001) than healthy controls. Near point of convergence was moderately correlated with dual-task average walking speed for the normal NPC group (ρ = -0.56; P = 0.05). Postconcussion Symptom Scale scores did not significantly differ between groups (27 ± 18 vs 28 ± 16).

CONCLUSIONS

After concussion, adolescents with receded NPC exhibited significant gait-related deficits compared with healthy controls, whereas those with normal NPC did not. Vergence and gross motor system dysfunction may be associated after concussion. Gait and vergence measures may contribute useful information to postconcussion evaluations.

Peripheral Vestibular Disorders in Children and Adolescents with Concussion

Objective To review peripheral vestibular disorders in pediatric patients with dizziness following concussion. Study Design Case series with chart review. Setting Pediatric vestibular clinic and pediatric multidisciplinary concussion clinic at a tertiary level pediatric hospital. Subjects and Methods We retrospectively reviewed 109 patients seen for dizziness following a concussion between September 2012 and July 2015. Patients were ≤20 years of age at the time of concussion. Incidences of specific peripheral vestibular disorders were assessed along with timing of diagnosis relative to the date of injury, diagnostic test findings, and treatment interventions associated with those diagnoses. Results Twenty-eight patients (25.7%) were diagnosed with peripheral vestibular disorders. None of these disorders were diagnosed prior to evaluation in our pediatric vestibular clinic or our multidisciplinary concussion clinic, which occurred a mean of 133 days (95% confidence interval, 89.2-177.3) after injury. Benign paroxysmal positioning vertigo was diagnosed in 19 patients, all of whom underwent successful canalith repositioning maneuvers. Other diagnoses included temporal bone fracture (n = 3), labyrinthine concussion (n = 2), perilymphatic fistula (n = 2), and superior semicircular canal dehiscence (n = 2). Both patients with perilymphatic fistula and 1 patient with superior semicircular canal dehiscence underwent successful surgical management, while 1 patient with superior semicircular canal dehiscence was managed nonsurgically. Conclusion Peripheral vestibular disorders may occur in pediatric patients with dizziness following concussion, but these disorders may not be recognized until symptoms have persisted for several weeks. An algorithm is proposed to guide the diagnosis and management of peripheral vestibular disorders in pediatric patients with concussion.

Vestibular dysfunction and concussion

The assessment and treatment of sport-related concussion (SRC) often requires a multifaceted approach. Vestibular dysfunction represents an important profile of symptoms and pathology following SRC, with high prevalence and association with prolonged recovery. Signs and symptoms of vestibular dysfunction may include dizziness, vertigo, disequilibrium, nausea, and visual impairment. Identifying the central and peripheral vestibular mechanisms responsible for pathology can aid in management of SRC. The most common vestibular disturbances after SRC include benign paroxysmal positional vertigo, vestibulo-ocular reflex impairment, visual motion sensitivity, and balance impairment. A variety of evidence-based screening and assessment tools can help to identify the various types of vestibular pathology in SRC. When vestibular dysfunction is identified, there is emerging support for applying targeted vestibular rehabilitation to manage this condition.

Central vestibular disorder due to ischemic injury on the parieto-insular vestibular cortex in patients with middle cerebral artery territory infarction: Observational study

Central vestibular disorder is common after middle cerebral artery (MCA) territory infarction. The MCA supplies blood to the parieto-insular vestibular cortex (PIVC), a core region of central vestibular symptoms. We report on patients that sustained injuries of the core vestibular pathway to the PIVC with central vestibular disorder following MCA territory infarction, demonstrated on diffusion tensor imaging (DTI). Nineteen patients with MCA territory infarction and 12 control subjects were recruited. To reconstruct the core vestibular pathway to the PIVC, we defined seed region of interest (ROI) as vestibular nuclei of pons and target ROI as the PIVC. Fractional anisotropy (FA), mean diffusivity, and tract volume were measured. In the affected hemisphere, FA value of the core vestibular pathway to the PIVC revealed significant difference between all patient groups and the control group (P < .05). In contrast, patients with symptoms of ataxia only revealed significant decrement of tract volume compared with the control group (P < .05). Additionally, subgroup B revealed significant decrement of tract volume compared with that of subgroup A and the control group (P < .05). In the unaffected hemisphere, there was no significant difference in all DTI parameters between all patient groups and the control group (P < .05). Injury to the core vestibular pathway to the PIVC was demonstrated in patients that revealed typical central vestibular disorder following MCA territory infarction. Analysis of the core vestibular pathway to the PIVC using DTI would be beneficial in clinical evaluation and management of patients with MCA territory infarction.

An insight into the vision impairment following traumatic brain injury

Traumatic brain injury (TBI) is one of the major cause of morbidity and mortality and it affects more than 1.7 million Americans each year. Depending on its location and severity, TBI leads to structural and functional damage in several parts of the brain such as cranial nerves, optic nerve tract or other circuitry involved in vision, and occipital lobe. As a result, the function associated with vision processing and perception are significantly affected and cause blurred vision, double vision, decreased peripheral vision and blindness. In this mini-review, we will focus the recent progress made to understand the pathology and underlying cellular/molecular mechanisms involved in the impairment of the integrity of visual systems following TBI.

Quantitative measurement of post-concussion syndrome Using Electrovestibulography

In this study, a noninvasive quantitative measure was used to identify short and long term post-concussion syndrome (PCS) both from each other and from healthy control populations. We used Electrovestibulography (EVestG) for detecting neurophysiological PCS consequent to a mild traumatic brain injury (mTBI) in both short-term (N = 8) and long-term (N = 30) (beyond the normal recovery period) symptomatic individuals. Peripheral, spontaneously evoked vestibuloacoustic signals incorporating - and modulated by - brainstem responses were recorded using EVestG, while individuals were stationary (no movement stimulus). Tested were 38 individuals with PCS in comparison to those of 33 age-and-gender-matched healthy controls. The extracted features were based on the shape of the averaged extracted field potentials (FPs) and their detected firing pattern. Linear discriminant analysis classification, incorporating a leave-one-out routine, resulted in (A) an unbiased 84% classification accuracy for separating healthy controls from a mix of long and short-term symptomatology PCS sufferers and (B) a 79% classification accuracy for separating between long and short-term symptomatology PCS sufferers. Comparatively, short-term symptomatology PCS was generally detected as more distal from controls. Based on the results, the EVestG recording shows promise as an assistive objective tool for detecting and monitoring individuals with PCS after normal recovery periods.

Disrupted Gamma Synchrony after Mild Traumatic Brain Injury and Its Correlation with White Matter Abnormality

Mild traumatic brain injury (mTBI) has been firmly associated with disrupted white matter integrity due to induced white matter damage and degeneration. However, comparatively less is known about the changes of the intrinsic functional connectivity mediated via neural synchronization in the brain after mTBI. Moreover, despite the presumed link between structural and functional connectivity, no existing studies in mTBI have demonstrated clear association between the structural abnormality of white matter axons and the disruption of neural synchronization. To investigate these questions, we recorded resting state EEG and diffusion tensor imaging (DTI) from a cohort of military service members. A newly developed synchronization measure, the weighted phase lag index was applied on the EEG data for estimating neural synchronization. Fractional anisotropy was computed from the DTI data for estimating white matter integrity. Fifteen service members with a history of mTBI within the past 3 years were compared to 22 demographically similar controls who reported no history of head injury. We observed that synchronization at low-gamma frequency band (25–40 Hz) across scalp regions was significantly decreased in mTBI cases compared with controls. The synchronization in theta (4–7 Hz), alpha (8–13 Hz), and beta (15–23 Hz) frequency bands were not significantly different between the two groups. In addition, we found that across mTBI cases, the disrupted synchronization at low-gamma frequency was significantly correlated with the white matter integrity of the inferior cerebellar peduncle, which was also significantly reduced in the mTBI group. These findings demonstrate an initial correlation between the impairment of white matter integrity and alterations in EEG synchronization in the brain after mTBI. The results also suggest that disruption of intrinsic neural synchronization at low-gamma frequency may be a characteristic functional pathology following mTBI and may prove useful for developing better methods of diagnosis and treatment.

Differences in Callosal and Forniceal Diffusion between Patients with and without Postconcussive Migraine

BACKGROUND AND PURPOSE

Posttraumatic migraines are common after mild traumatic brain injury. The purpose of this study was to determine if a specific axonal injury pattern underlies posttraumatic migraines after mild traumatic brain injury utilizing Tract-Based Spatial Statistics analysis of diffusion tensor imaging.

MATERIALS AND METHODS

DTI was performed in 58 patients with mild traumatic brain injury with posttraumatic migraines. Controls consisted of 17 patients with mild traumatic brain injury without posttraumatic migraines. Fractional anisotropy and diffusivity maps were generated to measure white matter integrity and were evaluated by using Tract-Based Spatial Statistics regression analysis with a general linear model. DTI findings were correlated with symptom severity, neurocognitive test scores, and time to recovery with the Pearson correlation coefficient.

RESULTS

Patients with mild traumatic brain injury with posttraumatic migraines were not significantly different from controls in terms of age, sex, type of injury, or neurocognitive test performance. Patients with posttraumatic migraines had higher initial symptom severity (P = .01) than controls. Compared with controls, patients with mild traumatic brain injury with posttraumatic migraines had decreased fractional anisotropy in the corpus callosum (P = .03) and fornix/septohippocampal circuit (P = .045). Injury to the fornix/septohippocampal circuit correlated with decreased visual memory (r = 0.325, P = .01). Injury to corpus callosum trended toward inverse correlation with recovery (r = -0.260, P = .05).

CONCLUSIONS

Injuries to the corpus callosum and fornix/septohippocampal circuit were seen in patients with mild traumatic brain injury with posttraumatic migraines, with injuries in the fornix/septohippocampal circuit correlating with decreased performance on neurocognitive testing.

Audiovestibular symptoms as predictors of prolonged sports-related concussion among NCAA athletes

OBJECTIVE

We looked to determine the rates of audiovestibular symptoms following sports-related concussions among collegiate athletes. Further, we assessed the correlation between these symptoms and the time to return to participation in athletic activity.

STUDY DESIGN

Retrospective analysis of the National Collegiate Athletic Association Injury Surveillance System (NCAA-ISS).

METHODS

The NCAA-ISS was queried from 2009 through 2014 for seven men's sports and eight women's sports across divisions 1, 2, and 3. Injuries resulting in concussions were analyzed for audiovestibular symptoms, duration of symptoms, and return to participation times.

RESULTS

From 2009 to 2014, there were 1,647 recorded sports-related concussions, with athletes reporting dizziness (68.2%), imbalance (35.8%), disorientation (31.4%), noise sensitivity (29.9%), and tinnitus (8.5%). Concussion symptoms resolved within 1 day (17.1%), within 2 to 7 days (50.0%), within 8 to 30 days (25.9%), or persisted over 1 month (7.0%). Return to participation occurred within 1 week (38.3%), within 1 month (53.0%), or over 1 month (8.7%). Using Mann-Whitney U testing, overall symptom duration and return to competition time were significantly increased when any of these symptoms were present (P < 0.05). Duration of concussion symptom correlated with dizziness (P = 0.043) and noise sensitivity (P = 0.000), whereas return to participation times correlated with imbalance (P = 0.011) and noise sensitivity (P = 0.000). Dizziness and imbalance (odds ratio: 4.15, confidence interval: 3.20-5.38, P < 0.001) were the two symptoms with the strongest association.

CONCLUSION

Audiovestibular symptoms are common complaints among collegiate athletes sustaining concussions. Dizziness and noise sensitivity correlated with the duration of concussive symptoms, whereas imbalance and noise sensitivity was correlated with prolonged return to competition time.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2850-2853, 2017.

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.

Vestibular disorders following different types of head and neck trauma

This review focuses on the published literature on vestibular disorders following different types of head and neck trauma. Current knowledge of the different causes and underlying mechanisms of vestibular disorders, as well as the sites of organic damage, is presented. Non-organic mechanisms are also surveyed. The frequency of occurrence of vestibular symptoms, and of other accompanying subjective complaints, associated with different types of trauma is presented and related to the specific causes. Hypotheses about the pathogenesis of traumatic vestibular disorders are presented, and the knowledge derived from animal experiments is also discussed. We believe this to be a very important topic, since vestibular complaints in traumatic patients often remain undiagnosed or underestimated in clinical practice. This review article aims to suggest directions for additional research and to provide guidance to both the scientific and clinical practice communities.

MR Imaging Applications in Mild Traumatic Brain Injury: An Imaging Update

Mild traumatic brain injury (mTBI), also commonly referred to as concussion, affects millions of Americans annually. Although computed tomography is the first-line imaging technique for all traumatic brain injury, it is incapable of providing long-term prognostic information in mTBI. In the past decade, the amount of research related to magnetic resonance (MR) imaging of mTBI has grown exponentially, partly due to development of novel analytical methods, which are applied to a variety of MR techniques. Here, evidence of subtle brain changes in mTBI as revealed by these techniques, which are not demonstrable by conventional imaging, will be reviewed. These changes can be considered in three main categories of brain structure, function, and metabolism. Macrostructural and microstructural changes have been revealed with three-dimensional MR imaging, susceptibility-weighted imaging, diffusion-weighted imaging, and higher order diffusion imaging. Functional abnormalities have been described with both task-mediated and resting-state blood oxygen level-dependent functional MR imaging. Metabolic changes suggesting neuronal injury have been demonstrated with MR spectroscopy. These findings improve understanding of the true impact of mTBI and its pathogenesis. Further investigation may eventually lead to improved diagnosis, prognosis, and management of this common and costly condition. (©) RSNA, 2016.

Bidirectional Changes in Anisotropy Are Associated with Outcomes in Mild Traumatic Brain Injury

BACKGROUND AND PURPOSE

Mild traumatic brain injury results in a heterogeneous constellation of deficits and symptoms that persist in a subset of patients. This prospective longitudinal study identifies early diffusion tensor imaging biomarkers of mild traumatic brain injury that significantly relate to outcomes at 1 year following injury.

MATERIALS AND METHODS

DTI was performed on 39 subjects with mild traumatic brain injury within 16 days of injury and 40 controls; 26 subjects with mild traumatic brain injury returned for follow-up at 1 year. We identified subject-specific regions of abnormally high and low fractional anisotropy and calculated mean fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity across all white matter voxels brain-wide and each of several white matter regions. Assessment of cognitive performance and symptom burden was performed at 1 year.

RESULTS

Significant associations of brain-wide DTI measures and outcomes included the following: mean radial diffusivity and mean diffusivity with memory; and mean fractional anisotropy, radial diffusivity, and mean diffusivity with health-related quality of life. Significant differences in outcomes were found between subjects with and without abnormally high fractional anisotropy for the following white matter regions and outcome measures: left frontal lobe and left temporal lobe with attention at 1 year, left and right cerebelli with somatic postconcussion symptoms at 1 year, and right thalamus with emotional postconcussion symptoms at 1 year.

CONCLUSIONS

Individualized assessment of DTI abnormalities significantly relates to long-term outcomes in mild traumatic brain injury. Abnormally high fractional anisotropy is significantly associated with better outcomes and might represent an imaging correlate of postinjury compensatory processes.

Clinical Intravoxel Incoherent Motion and Diffusion MR Imaging: Past, Present, and Future

The concept of diffusion magnetic resonance (MR) imaging emerged in the mid-1980s, together with the first images of water diffusion in the human brain, as a way to probe tissue structure at a microscopic scale, although the images were acquired at a millimetric scale. Since then, diffusion MR imaging has become a pillar of modern clinical imaging. Diffusion MR imaging has mainly been used to investigate neurologic disorders. A dramatic application of diffusion MR imaging has been acute brain ischemia, providing patients with the opportunity to receive suitable treatment at a stage when brain tissue might still be salvageable, thus avoiding terrible handicaps. On the other hand, it was found that water diffusion is anisotropic in white matter, because axon membranes limit molecular movement perpendicularly to the nerve fibers. This feature can be exploited to produce stunning maps of the orientation in space of the white matter tracts and brain connections in just a few minutes. Diffusion MR imaging is now also rapidly expanding in oncology, for the detection of malignant lesions and metastases, as well as monitoring. Water diffusion is usually largely decreased in malignant tissues, and body diffusion MR imaging, which does not require any tracer injection, is rapidly becoming a modality of choice to detect, characterize, or even stage malignant lesions, especially for breast or prostate cancer. After a brief summary of the key methodological concepts beyond diffusion MR imaging, this article will give a review of the clinical literature, mainly focusing on current outstanding issues, followed by some innovative proposals for future improvements.

Altered Cerebellar White Matter Integrity in Patients with Mild Traumatic Brain Injury in the Acute Stage

Background and Purpose

Imaging studies of traumatic brain injury demonstrate that the cerebellum is often affected. We aim to examine fractional anisotropy alteration in acute-phase mild traumatic brain injury patients in cerebellum-related white matter tracts.

Materials and Methods

This prospective study included 47 mild traumatic brain injury patients in the acute stage and 37 controls. MR imaging and neurocognitive tests were performed in patients within 7 days of injury. White matter integrity was examined by using diffusion tensor imaging. We used three approaches, tract-based spatial statistics, graphical-model-based multivariate analysis, and region-of-interest analysis, to detect altered cerebellar white matter integrity in mild traumatic brain injury patients.

Results

Results from three analysis methods were in accordance with each other, and suggested fractional anisotropy in the middle cerebellar peduncle and the pontine crossing tract was changed in the acute-phase mild traumatic brain injury patients, relative to controls (adjusted p-value < 0.05). Higher fractional anisotropy in the middle cerebellar peduncle was associated with worse performance in the fluid cognition composite (r = -0.289, p-value = 0.037).

Conclusion

Altered cerebellar fractional anisotropy in acute-phase mild traumatic brain injury patients is localized in specific regions and statistically associated with cognitive deficits detectable on neurocognitive testing.

Principal Component Analysis of Diffusion Tensor Images to Determine White Matter Injury Patterns Underlying Postconcussive Headache

BACKGROUND AND PURPOSE

Principal component analysis, a data-reduction algorithm, generates a set of principal components that are independent, linear combinations of the original dataset. Our study sought to use principal component analysis of fractional anisotropy maps to identify white matter injury patterns that correlate with posttraumatic headache after mild traumatic brain injury.

MATERIALS AND METHODS

Diffusion tensor imaging and neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Test were performed in 40 patients with mild traumatic brain injury and 24 without posttraumatic headache. Principal component analysis of coregistered fractional anisotropy maps was performed. Regression analysis of the major principal components was used to identify those correlated with posttraumatic headache. Finally, each principal component that correlated with posttraumatic headache was screened against other postconcussive symptoms and demographic factors.

RESULTS

Principal component 4 (mean, 7.1 ± 10.3) correlated with the presence of posttraumatic headache in mild traumatic brain injury (odds ratio per SD, 2.32; 95% CI, 1.29-4.67; P = .01). Decreasing principal component 4 corresponded with decreased fractional anisotropy in the midsplenium and increased fractional anisotropy in the genu of the corpus callosum. Principal component 4 identified patients with posttraumatic headache with an area under the receiver operating characteristic curve of 0.73 and uniquely correlated with posttraumatic headache and no other postconcussive symptom or demographic factors.

CONCLUSIONS

Principal component analysis can be an effective data-mining method to identify white matter injury patterns on DTI that correlate with clinically relevant symptoms in mild traumatic brain injury. A pattern of reduced fractional anisotropy in the splenium and increased fractional anisotropy in the genu of the corpus callosum identified by principal component analysis can help identify patients at risk for posttraumatic headache after mild traumatic brain injury.

Evaluation of White Matter Injury Patterns Underlying Neuropsychiatric Symptoms after Mild Traumatic Brain Injury

PURPOSE

To determine if a central axonal injury underlies neuropsychiatric symptoms after mild traumatic brain injury (mTBI) by using tract-based spatial statistics analysis of diffusion-tensor images.

MATERIALS AND METHODS

The institutional review board approved this study, with waiver of informed consent. Diffusion-tensor imaging and serial neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Testing evaluation were performed in 45 patients with mTBI (38 with irritability, 32 with depression, and 18 with anxiety). Control subjects consisted of 29 patients with mTBI without neuropsychiatric symptoms. Fractional anisotropy and diffusivity maps were analyzed by using tract-based spatial statistics with a multivariate general linear model. Diffusion-tensor imaging findings were correlated with symptom severity, neurocognitive test scores, and time to recovery with the Pearson correlation coefficient.

RESULTS

Compared with control subjects, patients with mTBI and depression had decreased fractional anisotropy in the superior longitudinal fasciculus (P = .006), white matter around the nucleus accumbens (P = .03), and anterior limb of the internal capsule (P = .02). Patients with anxiety had diminished fractional anisotropy in the vermis (P = .04). No regions of significantly decreased fractional anisotropy were seen in patients with irritability relative to control subjects. Injury in the region of the nucleus accumbens inversely correlated with recovery time in patients with depression (r = -0.480, P = .005).

CONCLUSION

Unique white matter injury patterns were seen for two major posttraumatic neuropsychiatric symptoms. Injury to the cerebellar vermis in patients with mTBI and anxiety may indicate underlying dysfunction in primitive fear conditioning circuits in the cerebellum. Involvement of the nucleus accumbens in depression after mTBI may suggest an underlying dysfunctional reward circuit that affects the prognosis in these patients.