Comparison of subjective and objective measurements of balance disorders following traumatic brain injury

Psychometric Properties and Concurrent Validity of a 10-Item Questionnaire for Patients With Vestibular Disorders

OBJECTIVE

This study aimed to investigate the psychometric properties and concurrent validity of the Haukeland Dizziness Questionnaire (HDQ-10), a 10-item questionnaire designed for simplified assessment of symptom severity and emotional effects in patients with vestibular disorders.

STUDY DESIGN

Cross-sectional study.

SETTING

Secondary referral hospital.

METHODS

Out of 238 consecutive patients examined for suspected vestibular disease at an otolaryngology clinic, 201 completed the questionnaire. The psychometric properties of the HDQ-10 were examined by exploratory factor analysis and analysis of internal consistency. Concurrent validity was determined in comparison with the Dizziness Handicap Inventory (DHI), Vertigo Symptom Scale-Short Form (VSS-SF), and the Hospital Anxiety and Depression Scale.

RESULTS

The factor analysis revealed 3 subscales of the questionnaire covering "function," "unsteadiness," and "emotion." The examination of the total scale (α = .866) and its subscales indicated satisfactory psychometric properties. The HDQ-10 correlated highly with both DHI (r = .732. P < .001) and VSS-SF (r = .720. P < .001) indicating good concurrent validity.

CONCLUSION

The HDQ-10 is a 10-item questionnaire designed for simplified assessment of symptom severity and emotional effects in patients with vestibular disorders. It has satisfactory psychometric properties and good concurrent validity compared to existing dizziness questionnaires.

Lateral fluid percussion injury: A rat model of experimental traumatic brain injury

Traumatic brain injury (TBI) represents one of the leading causes of disability and death worldwide. The annual economic impact of TBI-including direct and indirect costs-is high, particularly impacting low- and middle-income countries. Despite extensive research, a comprehensive understanding of the primary and secondary TBI pathophysiology, followed by the development of promising therapeutic approaches, remains limited. These fundamental caveats in knowledge have motivated the development of various experimental models to explore the molecular mechanisms underpinning the pathogenesis of TBI. In this context, the Lateral Fluid Percussion Injury (LFPI) model produces a brain injury that mimics most of the neurological and systemic aspects observed in human TBI. Moreover, its high reproducibility makes the LFPI model one of the most widely used rodent-based TBI models. In this chapter, we provide a detailed surgical protocol of the LFPI model used to induce TBI in adult Wistar rats. We further highlight the neuroscore test as a valuable tool for the evaluation of TBI-induced sensorimotor consequences and their severity in rats. Lastly, we briefly summarize the current knowledge on the pathological aspects and functional outcomes observed in the LFPI-induced TBI model in rodents.

Exploring the relationship between sleep apnea and vestibular symptoms following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a complex health problem in military veterans and service members (V/SM) that often involves comorbid vestibular impairment. Sleep apnea is another comorbidity that may exacerbate, and/or be exacerbated by, vestibular dysfunction.

OBJECTIVE

To examine the relationship between sleep apnea and vestibular symptoms in V/SM diagnosed with TBI of any severity.

DESIGN

Multicenter cohort study; cross-sectional sample.

SETTING

In-patient TBI rehabilitation units within five Veterans Affairs (VA) Polytrauma Rehabilitation Centers.

PARTICIPANTS

V/SM with a diagnosis of TBI (N = 630) enrolled in the VA TBI Model Systems study.

INTERVENTION

Not applicable.

METHODS

A multivariable regression model was used to evaluate the association between sleep apnea and vestibular symptom severity while controlling for relevant covariates, for example, posttraumatic stress disorder (PTSD).

MAIN OUTCOME MEASURES

Lifetime history of sleep apnea was determined via best source reporting. Vestibular disturbances were measured with the 3-item Vestibular subscale of the Neurobehavioral Symptom Inventory (NSI).

RESULTS

One third (30.6%) of the sample had a self-reported sleep apnea diagnosis. Initial analysis showed that participants who had sleep apnea had more severe vestibular symptoms (M = 3.84, SD = 2.86) than those without sleep apnea (M = 2.88, SD = 2.67, p < .001). However, when the data was analyzed via a multiple regression model, sleep apnea no longer reached the threshold of significance as a factor associated with vestibular symptoms. PTSD severity was shown to be significantly associated with vestibular symptoms within this sample (p < .001).

CONCLUSION

Analysis of these data revealed a relationship between sleep apnea and vestibular symptoms in V/SM with TBI. The significance of this relationship was affected when PTSD symptoms were factored into a multivariable regression model. However, given that the mechanisms and directionality of these relationships are not yet well understood, we assert that in terms of clinical relevance, providers should emphasize screening for each of the three studied comorbidities (sleep apnea, vestibular symptoms, and PTSD).

Associations between white matter integrity and postural control in adults with traumatic brain injury

Abnormalities of postural sway have been extensively reported in traumatic brain injury (TBI). However, the underlying neural correlates of balance disturbances in TBI remain to be elucidated. Studies in children with TBI have reported associations between the Sensory Organization Test (SOT) and measures of white matter (WM) integrity with diffusion tensor imaging (DTI) in brain areas responsible for multisensory integration. This study seeks to replicate those associations in adults as well as explore relationships between DTI and the Limits of Stability (LOS) Test. Fifty-six participants (43±17 years old) with a history of TBI were tested 30 days to 5 years post-TBI. This study confirmed results in children for associations between the SOT and the medial lemniscus as well as middle cerebellar peduncle, and revealed additional associations with the posterior thalamic radiation. Additionally, this study found significant correlations between abnormal LOS scores and impaired WM integrity in the cingulum, corpus callosum, corticopontine and corticospinal tracts, fronto-occipital fasciculi, longitudinal fasciculi, medial lemniscus, optic tracts and thalamic radiations. Our findings indicate the involvement of a broad range of WM tracts in the control of posture, and demonstrate the impact of TBI on balance via disruptions to WM integrity.

Effect of Robotic-Assisted Gait at Different Levels of Guidance and Body Weight Support on Lower Limb Joint Kinematics and Coordination

The Lokomat provides task-oriented therapy for patients with gait disorders. This robotic technology drives the lower limbs in the sagittal plane. However, normative gait also involves motions in the coronal and transverse planes. This study aimed to compare the Lokomat with Treadmill gait through three-dimensional (3D)-joint kinematics and inter-joint coordination. Lower limb kinematics was recorded in 18 healthy participants who walked at 3 km/h on a Treadmill or in a Lokomat with nine combinations of Guidance (30%, 50%, 70%) and bodyweight support (30%, 50%, 70%). Compared to the Treadmill, the Lokomat altered pelvic rotation, decreased pelvis obliquity and hip adduction, and increased ankle rotation. Moreover, the Lokomat resulted in significantly slower velocity at the hip, knee, and ankle flexion compared to the treadmill condition. Moderate to strong correlations were observed between the Treadmill and Lokomat conditions in terms of inter-joint coordination between hip-knee (r = 0.67-0.91), hip-ankle (r = 0.66-0.85), and knee-ankle (r = 0.90-0.95). This study showed that some gait determinants, such as pelvis obliquity, rotation, and hip adduction, are altered when walking with Lokomat in comparison to a Treadmill. Kinematic deviations induced by the Lokomat were most prominent at high levels of bodyweight support. Interestingly, different levels of Guidance did not affect gait kinematics. The present results can help therapists to adequately select settings during Lokomat therapy.

The Dizziness Handicap Inventory and sickness absence: a cross-sectional study

PURPOSE

The aim of this study was to examine the association between the Dizziness Handicap Inventory (DHI) and sickness absence from work in patients with dizziness.

MATERIAL AND METHODS

This was a cross-sectional study conducted at an otolaryngology clinic with 238 patients referred for a suspected vestibular disorder during a 1-year period. The association between sickness absence over the last 30 days and DHI was examined with binary and ordinal logistic regression. The Hospital Anxiety and Depression scale (HADS), health-related quality of life (RAND-12), duration of dizziness, diagnosis, age and gender were used as adjustments variables.

RESULTS

The adjusted analysis showed that a 10-point increase on DHI was associated with an increased risk of sickness absence (yes/no) (OR: 1.50, 95% CI: 1.25-1.90, p < 0.001). In addition, a 10-point increase in DHI-score was associated with a higher degree of sickness absence (OR: 1.50, 95% CI: 1.25-1.80, p < 0.001).

CONCLUSION

A higher DHI-score was associated with sickness absence in addition to the duration of absence the previous month. These results indicate the relevance and clinical usefulness of the DHI as a possible indicator of sickness absence from work in patients with dizziness regardless of diagnosis.IMPLICATIONS FOR REHABILITATIONApproximately half of patients referred to a dizziness clinic have sickness absence.A higher score on The Dizziness Handicap Inventory is associated with longer duration of sickness absence.A vestibular diagnosis was not associated with sickness absence.The results indicate that the Dizziness Handicap Inventory may be a clinically useful tool for identifying patients with a high risk of sickness absence.

Lateral Centre of Mass Displacement can predict running in adults with traumatic brain injury

BACKGROUND

Running is an important skill that improves a person's ability to participate in community-based social, leisure and work activities, and therefore improve quality of life. Following traumatic brain injury, many ambulant people are unable to run. Whilst established for walking, the physical impairments that limit running following traumatic brain injury remain unknown. Therefore, the primary aim of this study was to identify which physical impairments contribute to a person's ability to run post traumatic brain injury.

METHODS

In this study, 88 adults with traumatic brain injury were included. Runners and non-runners were compared regarding their clinical assessment of physical impairments, including postural control, focal muscle spasticity, muscle strength, self-selected walking speed and ability to run. Participants also completed a three-dimensional quantitative gait analysis to assess motor skill using the Gait Profile Score. Logistic regression was applied to identify the most important predictors for the ability to run.

FINDINGS

Significant differences between runners and non-runners were found for postural control, motor control and strength. Dynamic postural control, measured by lateral center of mass displacement, was the best predictor of running, with every centimeter increase in lateral center of mass movement during walking associated with a 30% reduction in the chance of being able to run.

INTERPRETATION

Lateral center of mass displacement should be considered when selecting interventions for ambulant patients with the goal to run. Although postural control, motor control and muscle strength were all different between runners and non-runners, they did not contribute to a person's ability to run.

The Non-Concordance of Self-Reported and Performance-Based Measures of Vestibular Dysfunction in Military and Civilian Populations Following TBI

As a predominately young, physically active, and generally healthy population, service members (SMs) with vestibular dysfunction (VD) following a TBI may not be accurately represented by the current civilian reference ranges on assessments of VD. This study enrolled SMs who were referred for vestibular rehabilitation following a mild/moderate TBI. The participants self-reported VD using the Activities-specific Balance Confidence (ABC) scale and the Dizziness Handicap Inventory (DHI) followed by evaluation of vestibular performance using computerized dynamic posturography sensory organizational test (CDP−SOT). Retrospective analysis of these outcomes comparing the study sample of SMs to the reported civilian samples revealed SMs self-reported lower VD with significantly higher balance confidence (ABC: 77.11 ± 14.61, p < 0.05) and lower dizziness (DHI: 37.75 ± 11.74, p < 0.05) than civilians. However, the SMs underperformed in performance-based evaluations compared to civilians with significantly lower CDP−SOT composite and ratio scores (COMP: 68.46 ± 13.46, p < 0.05; VIS: 81.36 ± 14.03, p < 0.01; VEST: 55.63 ± 22.28, p < 0.05; SOM: 90.46 ± 10.17, p < 0.05). Correlational analyses identified significant relationships between the ABC and CDP−SOT composite (r = 0.380, p < 0.01) and ratio scores (VIS: r = 0.266, p < 0.05; VEST: r = 0.352, p < 0.01). These results highlight the importance of recognizing and understanding nuances in assessing VD in SMs to ensure they have access to adequate care and rehabilitation prior to returning to duty.

Skill-Related Adaptive Modifications of Gaze Stabilization in Elite and Non-Elite Athletes

The vestibular ocular reflex (VOR) provides gaze stability during head movements by driving eye movements in a direction opposing head motion. Although vestibular-based rehabilitation strategies are available, it is still unclear whether VOR can be modulated by training. By examining adaptations in gaze stabilization mechanisms in a population with distinct visuomotor requirements for task success (i.e., gymnasts), this study was designed to determine whether experience level (as a proxy of training potential) was associated with gaze stabilization modifications during fixed target (VOR promoting) and fixed-to-head-movement target (VOR suppressing) tasks. Thirteen gymnasts of different skill levels participated in VOR and VOR suppression tasks. The gain between head and eye movements was calculated and compared between skill levels using an analysis of covariance. Across experience levels, there was a similar degradation in VOR gain away from −1 at higher movement speeds. However, during the suppression tasks, more experienced participants were able to maintain VOR gain closer to 0 across movement speeds, whereas novice participants showed greater variability in task execution regardless of movement speed. Changes in adaptive modifications to gaze stability associated with experience level suggest that the mechanisms impacting gaze stabilization can be manipulated through training.

Individuals with Chronic Mild-to-Moderate Traumatic Brain Injury Exhibit Decreased Neuromuscular Complexity During Gait

BACKGROUND

Synergy analysis provides a means of quantifying the complexity of neuromuscular control during gait. Prior studies have shown evidence of reduced neuromuscular complexity during gait in individuals with neurological disorders associated with stroke, cerebral palsy, and Parkinson's disease.

OBJECTIVE

The purpose of this study was to investigate neuromuscular complexity during gait in individuals who experienced a prior traumatic brain injury (TBI) that resulted in chronic balance deficits.

METHODS

We measured and analyzed lower extremity electromyographic data during treadmill and overground walking for 44 individuals with residual balance deficits from a mild-to-moderate TBI at least 1 year prior. We also tested 20 unimpaired controls as a comparison. Muscle synergies were calculated for each limb using non-negative matrix factorization of the activation patterns for 6 leg muscles. We quantified neuromuscular complexity using Walk-DMC, a normalized metric of the total variance accounted for by a single synergy, in which a Walk-DMC score of 100 represents normal variance accounted for. We compared group average synergy structures and inter-limb similarity using cosine similarity. We also quantified each individual's gait and balance using the Sensory Organization Test, the Dynamic Gait Index, and the Six-Minute Walk Test.

RESULTS

Neuromuscular complexity was diminished for individuals with a prior TBI. Walk-DMC averaged 92.8 ± 12.3 for the TBI group during overground walking, which was significantly less than seen in controls (100.0 ± 10.0). Individuals with a prior TBI exhibited 13% slower overground walking speeds than controls and reduced performance on the Dynamic Gait Index (18.5 ± 4.7 out of 24). However, Walk-DMC measures were insufficient to stratify variations in assessments of gait and balance performance. Group average synergy structures were similar between groups, although there were considerable between-group differences in the inter-limb similarity of the synergy activation vectors.

CONCLUSIONS

Individuals with gait and balance deficits due to a prior TBI exhibit evidence of decreased neuromuscular complexity during gait. Our results suggest that individuals with TBI exhibit similar muscle synergy weightings as controls, but altered control of the temporal activation of these muscle weightings.

Relating Self-Reported Balance Problems to Sensory Organization and Dual-Tasking in Chronic Traumatic Brain Injury

BACKGROUND

Individuals who have experienced a traumatic brain injury (TBI) often have residual balance problems. It remains unclear whether these balance problems are driven by vestibular dysfunction or gait automaticity deficits, particularly in the chronic stages of TBI recovery, because most studies include only acute/subacute cases.

OBJECTIVES

Compare performance on the Sensory Organization Test vestibular score and Dual-Task test in individuals with and without subjective balance problems at least 1 year after a TBI. Investigate the ability of each test to predict perceived balance problems.

DESIGN

Prospective cohort study.

SETTING

Rehabilitation department within a single institution.

PARTICIPANTS

Fifty adults (21-71 years) with a history of mild, moderate, or severe TBI 1 to 5 years following nonpenetrating TBI.

INTERVENTIONS

N/A.

METHODS

Measures included the Dual-Task test, Sensory Organization Test, Neurobehavioral Symptom Inventory, Dizziness Handicap Inventory, and assessments of four cognitive domains and depression. Participants who endorsed "feeling dizzy" and "loss of balance" on the Neurobehavioral Symptom Inventory were classified as symptomatic (n = 26) and others as asymptomatic (n = 24). T-tests, chi-square, and regression analyses predicting the Dizziness Handicap Inventory total score were performed.

RESULTS

Dual-task gait cost was negatively associated with the Dizziness Handicap Inventory (P = .044), controlling for depression and gender, whereas vestibular scores failed to predict balance-related disability. Symptomatic individuals endorsed more balance problems (P < .001) and depression symptoms (P = .007), had poorer dual-task cognitive output (P = .036), and slower dual-task gait velocity (P = .036) than asymptomatic participants. Groups did not differ on Sensory Organization Test scores.

CONCLUSIONS

The nature of balance problems in chronic TBI may be related to automaticity of gait. These findings suggest that patients in the chronic stages of TBI may benefit from dual-task assessments and interventions. Balance rehabilitation should be tailored to patient needs and assess cognition and affect.

Graph-theoretical analysis of EEG functional connectivity during balance perturbation in traumatic brain injury: A pilot study

Traumatic brain injury (TBI) often results in balance impairment, increasing the risk of falls, and the chances of further injuries. However, the underlying neural mechanisms of postural control after TBI are not well understood. To this end, we conducted a pilot study to explore the neural mechanisms of unpredictable balance perturbations in 17 chronic TBI participants and 15 matched healthy controls (HC) using the EEG, MRI, and diffusion tensor imaging (DTI) data. As quantitative measures of the functional integration and segregation of the brain networks during the postural task, we computed the global graph-theoretic network measures (global efficiency and modularity) of brain functional connectivity derived from source-space EEG in different frequency bands. We observed that the TBI group showed a lower balance performance as measured by the center of pressure displacement during the task, and the Berg Balance Scale (BBS). They also showed reduced brain activation and connectivity during the balance task. Furthermore, the decrease in brain network segregation in alpha-band from baseline to task was smaller in TBI than HC. The DTI findings revealed widespread structural damage. In terms of the neural correlates, we observed a distinct role played by different frequency bands: theta-band modularity during the task was negatively correlated with the BBS in the TBI group; lower beta-band network connectivity was associated with the reduction in white matter structural integrity. Our future studies will focus on how postural training will modulate the functional brain networks in TBI.

Effects of Proprioceptive and Craniocervical Flexor Training on Static Balance in University Student Smartphone Users with Balance Impairment: A Randomized Controlled Trial

Purpose

University student smartphone users adopt flexed neck postures during smartphone use, creating an increased compressive load on their neck structures. This study was conducted to compare the effects of proprioceptive and craniocervical flexor training with a control group on static balance in a group of university student smartphone users with balance impairment.

Methods

A double-blinded, randomized controlled trial was conducted involving 42 university students (19.67±1.68 years old) with balance impairment. Participants were randomized into a proprioceptive training (ProT) group (n=14), a craniocervical flexor training (CCFT) group (n=14), and a control group (CG; n=14) for a 6-week intervention. The balance error scoring system (BESS), cervical joint position sense (CJPS), craniocervical flexion (CCF) test, and visual analog scale (VAS) for neck pain were evaluated using univariate analysis of covariance (ANCOVA).

Results

After 6 weeks of intervention, the ProT group showed significantly greater improvement of CJPS than the CG (p=0.000) and the CCFT group significantly improved of CCF test than CG (p=0.002). Findings, at 4 weeks after intervention, were (i) the ProT group had significantly more improvement in BESS than the CCFT group (p=0.014) and CG (p=0.003), (ii) the ProT group had significantly more improvement of CJPS than the CG (right and left rotate) (p=0.001, p=0.016, respectively) and CCFT group (right rotate) (p=0.004), (iii) the CCFT group had significantly more improvement of craniocervical flexor strength than CG (p=0.004), and (iv) the ProT group and CCFT group had significantly more decreased pain than CG (p=0.015, p=0.033, respectively). No adverse effects occurred during or after training in any group.

Conclusion

ProT is important for regaining static balance and CJPS, while CCFT improved craniocervical flexor strength. Moreover, both ProT and CCFT can reduce neck pain. We recommend performing ProT to improve static balance, CJPS and to reduce neck pain in smartphone users with static balance impairment.

Clinical Trail Registration Number

TCTR20190909003.

Worsening of Dizziness Impairment Is Associated with Bone Marrow Kinase on Chromosome X Level in Patients after Mild Traumatic Brain Injury

Over 2 million people suffer from mild traumatic brain injury (mTBI) each year. Predicting symptoms of mTBI and the characterization of those symptoms has been challenging. Biomarkers that correlate clinical symptoms to disease outcome are desired to improve understanding of the disease and optimize patient care. Bone marrow kinase on chromosome X (BMX), a member of the TEC family of nonreceptor tyrosine kinases, is up-regulated after traumatic neural injury in a rat model of mTBI. The aim of this investigation was to determine whether BMX serum concentrations can effectively be used to predict outcomes after mTBI in a clinical setting. A total of 63 patients with mTBI (Glasgow Coma Score [GCS] between 13 and 15) were included. Blood samples taken at the time of hospital admission were analyzed for BMX. Data collected included demographic and clinical variables. Outcomes were assessed using the Dizziness Handicap Inventory (DHI) questionnaire at baseline and 6 weeks postinjury. The participant was asssigned to the case group if the subject's complaints of dizziness became worse at the sixth week assessment; otherwise, the participant was assigned to the control group. A receiver operating characteristic curve was constructed to explore BMX level. Significant associations were found between serum levels of BMX and dizziness. Areas under the curve for prediction of change in DHI postinjury were 0.76 for total score, 0.69 for physical score, 0.65 for emotional score, and 0.66 for functional score. Specificities were between 0.69 and 0.77 for total score and emotional score, respectively. Therefore, BMX demonstrates potential as a candidate serum biomarker of exacerbating dizziness post-mTBI.

Ankle Power Generation Has a Greater Influence on Walking Speed Reserve Than Balance Following Traumatic Brain Injury

OBJECTIVE

Reduced walking speed is common following traumatic brain injury (TBI). Walking speed reserve (WSR) refers to the ability to increase walking speed on demand and is calculated as the difference between self-selected and fast walking speeds. Walking speed reserve is important for adaptive functional mobility in the community. Predictors of WSR following TBI are yet to be determined. The aim of the study was to identify whether static balance or ankle power generation (APG) was a stronger predictor of WSR following TBI.

SETTING

A major metropolitan rehabilitation hospital.

PARTICIPANTS

A total of 92 individuals receiving inpatient physiotherapy for mobility limitations following TBI were recruited.

DESIGN

A cross-sectional study.

METHODS

Walking speed (self-selected and fast), APG, and a summed single-leg stance scores were measured. The ability to increase walking speed on demand by 0.20 m/s or more defined WSR. Correlations, logistic regression, and receiver operating characteristic (ROC) curve analyses were performed to investigate independent relationships between WSR, APG, and static balance.

RESULTS

Fifty participants (54.3%) had a WSR of 0.20 m/s or more. The strongest predictor of WSR was APG (odds ratio [OR] = 3.34; 95% CI, 1.50-7.43) when compared with static balance (OR = 1.03; 95% CI, 1.01-1.06). The ROC curve demonstrated that APG could accurately discriminate between individuals with a WSR from those without (AUC [area under the ROC curve] = 0.79; 95% CI, 0.70-0.88). The APG cutoff score identified on the curve that maximized combined sensitivity (92.0%) and specificity (54.8%) was 0.75 W/kg.

CONCLUSION

Following TBI, APG was a stronger predictor of WSR than static balance. Clinicians should consider interventions that preferentially target APG in order to increase WSR for community mobility.

Normative values for the Sensory Organization Test in an active duty military cohort

BACKGROUND

Computerized dynamic posturography is commonly used to assess balance in service members, but normative values for the military population have not been established.

RESEARCH QUESTION

What are the normative values for the Motor Control Test (MCT), Sensory Organization Test (SOT) and the enhanced SOT (eSOT) within the military population and at which point do they differ?

METHODS

Cross-sectional study. 237 active duty service members (78 % male) completed the MCT, SOT and the eSOT with the sway manipulated at a gain of 1.2, 1.4, 1.6, 1.8, or 2.0. A Mann-Whitney U test was used to compare the means of men and women for the SOT and MCT composite scores. A Kruskal-Wallis H test was used to compare the means of age groups for the SOT composite score. An independent t-test was used to compare the SOT composite scores from our military population to the manufacturer's normative (civilian) data. The means and standard deviations for the eSOT scores were reported for each gain. Paired-samples t-tests were performed to compare the SOT composite score with the eSOT composite score for each level of gain.

RESULTS

There was no difference between SOT composite scores for men and women (Mann-Whitney U = 4363.50, p = 0.19) or among age groups (Kruskal-Wallis = 2.77, p = 0.25). The mean SOT composite scores were not different from the manufacturer's normative values (p = 0.155). SOT composite scores were significantly higher than eSOT composite scores for gains of 1.4 (t = 3.16, p = 0.003), 1.6 (t = 5.73, p < 0.001), 1.8 (t = 5.26, p < 0.001) and 2.0 (t = 5.89, p < 0.001). MCT composite scores were lower in the 18-26 year old than the 36-45 year old age group (p = 0.013).

SIGNIFICANCE

This study establishes normative values for the MCT, SOT and eSOT in active duty military service members. The results suggest that the manufacturer's normal values are appropriate for making judgments about the postural stability of service members.

Case Report: Auditory Neuropathy and Central Auditory Processing Deficits in a Neuro-Otological Case-Study of Infratentorial Superficial Siderosis

Hearing and balance impairment are the most frequently reported features of infratentorial (classical) superficial siderosis (iSS). There are few comprehensive descriptions of audiovestibular function in iSS and therefore limited understanding of the affected segment(s) of the audiovestibular pathway. In addition, monitoring disease progression and response to treatment is challenging and currently mainly guided by subjective patient reports and magnetic resonance imaging. To the best of our knowledge, there have been no previous reports assessing central auditory function in iSS. We describe such findings in a patient with iSS in an attempt to precisely localize the site of the audiovestibular dysfunction, determine its severity and functional impact. We confirm the presence of (asymmetrical) auditory neuropathy and identify central auditory processing deficits, suggesting involvement of the central auditory pathway beyond the brainstem. We correlate the audiological and vestibular findings with self-report measures and the siderosis appearances on brain magnetic resonance images.

Vestibular Assessment in Patients with Persistent Symptoms of Mild Traumatic Brain Injury

Aim

The estimated worldwide incidence of TBI is 10 million cases per year. Dizziness and imbalance are two common symptoms in mild TBI (mTBI). In about 10-15% of TBI patients, these symptoms remain for a long time and may show no recovery. These persistent symptoms may relate to different factors including vestibular abnormalities. The aim of this study is a vestibular assessment of patients with persistent symptoms of mTBI by different tests including computerized dynamic posturography.

Materials and Methods

21 patients with mTBI evaluated in this study. Patients were civilians with persistent symptoms. TBI did cause by blunt force trauma (mainly from falling) in the past 6 months. They had normal neurologic and musculoskeletal assessments and no temporal bone fracture. Several auditory and vestibular evaluations were performed for each patient. They included: case history, otoscopy, pure tone and speech audiometry, tympanometry, vestibular bedside examination (spontaneous nystagmus, gaze, saccade, pursuit, Dix-Hallpike maneuver, side-lying maneuver, roll, and Romberg test), cervical Vestibular Myogenic Evoked Potential (c-VEMP), Computerized Dynamic Posturography (CDP) and Dizziness Handicap Inventory (DHI).

Results

Patients showed hearing loss in 10 (47.6%) and tinnitus in 4 (19.0%) cases. In ocular motor tests, patients had the most abnormal results in the pursuit test. 6 patients also had Benign Paroxysmal Positional Vertigo (BPPV) in the posterior canal. c-VEMP showed abnormal saccular function in 14 patients. In CDP, the composite scores were decreased relative to normal populations.

Conclusion

vestibular tests showed abnormal results in most patients. Vestibular abnormality could relate to persisting symptoms of mTBI patients.

Evaluating Sensory Acuity as a Marker of Balance Dysfunction After a Traumatic Brain Injury: A Psychophysical Approach

There is limited research on sensory acuity i.e., ability to perceive external perturbations via body-sway during standing in individuals with a traumatic brain injury (TBI). It is unclear whether sensory acuity diminishes after a TBI and if it is a contributing factor to balance dysfunction. The objective of this investigation is to first objectively quantify the sensory acuity in terms of perturbation perception threshold (PPT) and determine if it is related to functional outcomes of static and dynamic balance. Ten individuals with chronic TBI and 11 age-matched healthy controls (HC) performed PPT assessments at 0.33, 0.5, and 1 Hz horizontal perturbations to the base of support in the anterior-posterior direction, and a battery of functional assessments of static and dynamic balance and mobility [Berg balance scale (BBS), timed-up and go (TUG) and 5-m (5MWT) and 10-m walk test (10MWT)]. A psychophysical approach based on Single Interval Adjustment Matrix Protocol (SIAM), i.e., a yes-no task, was used to quantify the multi-sensory thresholds of perceived external perturbations to calculate PPT. A mixed-design analysis of variance (ANOVA) and post-hoc analyses were performed using independent and paired t-tests to evaluate within and between-group differences. Pearson correlation was computed to determine the relationship between the PPT and functional measures. The PPT values were significantly higher for the TBI group (0.33 Hz: 2.97 ± 1.0, 0.5 Hz: 2.39 ± 0.7, 1 Hz: 1.22 ± 0.4) compared to the HC group (0.33 Hz: 1.03 ± 0.6, 0.5 Hz: 0.89 ± 0.4, 1 Hz: 0.42 ± 0.2) for all three perturbation frequencies (p < 0.006 post Bonferroni correction). For the TBI group, the PPT for 1 Hz perturbations showed significant correlation with the functional measures of balance (BBS: r = −0.66, p = 0.037; TUG: r = 0.78, p = 0.008; 5MWT: r = 0.67, p = 0.034, 10MWT: r = 0.76, p = 0.012). These findings demonstrate that individuals with TBI have diminished sensory acuity during standing which may be linked to impaired balance function after TBI.

Balance Tests in Pre-Adolescent Children: Retest Reliability, Construct Validity, and Relative Ability

Balance is an essential prerequisite for the normal physical development of a child. It consists of the ability to maintain the body’s centre of mass over its base of support, which is enabled by automatic postural adjustments, and maintain posture and stability in various conditions and activities. The present study aimed to determine the measurement characteristics (reliability and concurrent validity) and the relative ability of balance tests and different motor tests in healthy 11-year-olds. We also evaluated the impact of vision on balance ability. Our results showed high interrater reliability (from 0.810 to 0.910) and confirmed the construct validity of the included balance tests. Girls performed significantly better than boys in laboratory tandem stance in following balance components: total sway path with eyes open (BSEO) (t = 2.68, p = 0.01, effect size (ES) = 0.81), total body sway with eyes closed of centre of pressure (CoP) displacement in the a-p direction (BSEC) (t = 1.86, p = 0.07, ES = 0.57), mean velocity of CoP displacements (VEO) (t = 2.67, p = 0.01, ES = 0.83), mean amplitude of CoP displacements in the a-p direction (AapEO) (t = 3.38. p = 0.00, ES = 1.01) and in mean amplitude of CoP displacements in the m-l direction (AmlEO) (t = 3.68, p = 0.00, ES = 1.19). With eyes closed, girls performed significantly better (t = 2.28, p = 0.03, ES = 0.70) than boys did in the mean amplitude of COP displacements in the a-p direction (AapEO) and significantly better (t = 2.37, p = 0.03, ES = 0.71) in the mean amplitude of COP displacements in the m-l direction (AmlEC). Insignificant correlations between different balance tests, except for a correlation between the flamingo test and one-leg stance on a low beam (r = 0.558, p < 0.01), show that each test assesses different aspects of balance ability; therefore, balance cannot be assessed with a single test.

Altered Cortical and Postural Response to Balance Perturbation in Traumatic Brain Injury - An EEG Pilot Study

30-60% of traumatic brain injury (TBI) patients suffer from long-term balance deficit. Even though motor preparation and execution are altered and slowed in TBI, their relative contribution and importance to posture instability remain poorly understood. This study investigates the impaired cortical dynamics and neuromuscular response in TBI in response to balance perturbation and its relation to balance deficit. 12 TBI and 6 healthy control (HC) participants took the Berg Balance Scale (BBS) test and participated in a balance perturbation task where they were subjected to random anterior/posterior translation, while brain (EEG), muscle (EMG) activities, and center of pressure (COP) were continuously recorded. Using independent component analysis (ICA), the component most responsible for the N1 component of the perturbation evoked potential (PEP) was selected and its amplitude and latency were extracted. Balance task performance was measured by computing the COP displacement during the task. TBI had a significantly lower BBS, larger COP displacement and lower N1 amplitude compared to the HC group. No group differences was found for N1 latency and muscle activity onset delay to the perturbation. BBS was correlated with the COP displacement and N1 amplitude, and COP displacement was correlated with N1 latency. TBI balance deficit may be associated with more impaired than delayed cortical response to balance perturbation.

Balance Assessment in Traumatic Brain Injury: A Comparison of the Sensory Organization and Limits of Stability Tests

Balance problems are common after a traumatic brain injury (TBI). Symptoms of dizziness, unsteadiness, or imbalance have been most frequently attributed to sensory organization problems involving the use of visual, proprioceptive, and/or vestibular information for postural control. These problems can be assessed with the Sensory Organization Test (SOT). However, as head trauma can affect any brain region, areas responsible for voluntary control of movements involved in dynamic balance tasks, such as the motor cortex and its projections, could also be compromised, which would likely affect one's limits of stability. The Limits of Stability (LOS) balance test has received little attention in TBI. In the present study, we compared the prevalence of SOT versus LOS abnormalities in a cohort of 48 patients, the majority classified as having mild or moderate chronic TBI. Compared with a normative database provided by the balance testing manufacturer, a larger portion of our cohort presented abnormalities in the LOS test. Dizziness Handicap Inventory (DHI) results indicated mild disability, with the five activities most frequently endorsed as problematic being: looking up, performing quick head movements, performing ambitious such as sports or dancing activities, feeling frustrated, and performing strenuous house/yard work. Although regression analysis revealed that both tests significantly predicted subjective scores on the DHI, more LOS than SOT testing variables were important predictors of DHI results indicating disability. These results suggest that the LOS test is an informative tool that should be included in any objective balance evaluations that screen TBI patients with balance complaints.

The investigation of four technologies to assist in detecting mild to moderate traumatic brain injury of U.S. Military service members

BACKGROUND

A standard, reliable, objective measure is needed for identifying individuals with mild to moderate traumatic brain injury (TBI).

OBJECTIVE

The purpose of this study was to examine balance using an AMTI OR6-7 force platform (FP), neurocognition and mood using the Automated Neuropsychological Assessment Metric4 (ANAM4), blood flow comparisons using a Brain Acoustic Monitor (BAM), and voice using Voice Analysis software (VA) for screening service members for a mild to moderate TBI.

METHODS

Active duty and retired service member volunteers (n = 88, 35 with a diagnosis of mild to moderate TBI and 53 who never had a TBI) completed an informed consent document, and evaluations using the four technologies.

RESULTS

Development of a clinical prediction rule yielded two FP variables and one ANAM4 Mood Scale variable (vigor) as helpful in predicting the presence of a TBI. Assuming a 15% pre-test probability, these predictors yield a post-test probability of 75.7% for a positive result with any two or more measures being positive, and a post-test probability of 2.3% for a negative result with zero measures being positive.

CONCLUSIONS

This study demonstrated the usefulness of a force platform and a self-reported mood scale for predicting presence of mild to moderate TBI.

Combined use of cervical headache snag and cervical snag half rotation techniques in the treatment of cervicogenic headache

[Purpose] Cervicogenic headache is a major problem in patients with upper cervical dysfunction. However, its physical therapy management is a topic of debate. This study aims to determine the effect of C1-C2 Mulligan sustained natural apophyseal glide mobilizations on cervicogenic headache and associated dizziness. [Participants and Methods] This study included 48 patients with cervicogenic headache, who were randomly assigned to three equal groups: Group A (Headache SNAG), group B (C1-C2 SNAG rotation), and group C (combined). Neck Disability Index was used to examine neck pain intensity and cervicogenic headache symptoms. The 6-item Headache Impact Test scale was used to examine headache severity and its adverse effects on social life and functions. Flexion-Rotation Test was used to assess rotation range of motion at the level of C1-C2 and confirmed by a cervical range of motion device. Dizziness Handicap Inventory scale was used to evaluate dizziness. The evaluation was done pre- and post-treatment and compared between the groups. [Results] Group C showed significant improvement in all variables compared with groups A and B. [Conclusion] Sustained natural apophyseal glide mobilizations used in the study were effective in reducing cervicogenic headache and dizziness in all groups with a greater improvement in the combined group. The use of cervical SNAG mobilizations is encouraged as a noninvasive intervention depending on the therapist's assessment, findings, and clinical reasoning.

Dizziness Handicap and Its Contributing Factors in Patients With Migraine

OBJECTIVE

Dizziness is frequently reported in patients with migraine. However, its assessment is often neglected in clinical practice. We investigated the dizziness handicap experienced by patients with migraine and its contributing factors.

METHODS

A total of 361 migraine outpatients (270 women, 91 men; mean age 39.01 ± 11.2 years) were given the Korean Dizziness Handicap Inventory (KDHI) questionnaire (total score: 100 points; cutoff: 29). The Headache Impact Test, Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, and Pittsburgh Sleep Quality Index were also administered. Clinical data such as age, sex, number of headache attacks per month, pain intensity on the visual analog scale, and average sleep hours were collected to find contributing factors. Comparisons were made between chronic and episodic migraine.

RESULTS

A total of 153 patients were classified as having dizziness handicap (M+DH) and 208 had migraine without dizziness handicap (M-DH). Patients with M+DH experienced more headache attacks per month than patients with M-DH (P = 0.010). The proportion of patients with chronic migraine was larger in the M+DH group (29.4% vs. 17.3%, P = 0.006). Patients with M+DH showed higher scores than patients with M-DH in all the KDHI subscales. Multivariable logistic regression showed headache impact, pain intensity, anxiety, and depression to be significantly associated with dizziness handicap.

CONCLUSION

The data suggest that patients with migraine, especially those with chronic-type migraine, experience physical, emotional, and functional handicaps due to dizziness. Dizziness handicap is related to headache impact, anxiety, and depression. Targeted management of such factors is required to reduce the severity of subjective discomfort.

Association Between Acid-Sensing Ion Channel 3 Gene Variants and Balance Impairment in People With Mild Traumatic Brain Injury

Introduction: Dizziness and balance impairment are common symptoms of mild traumatic brain injury (mTBI). Acid-sensing ion channel 3 (ASIC3) is expressed in the vestibular and proprioceptive systems and associated with balance functions. However, whether the genetic variants of ASIC3 are associated with people who suffer dizziness and balance impairment after mTBI remained unknown. Materials and methods: A total of 200 people with mTBI and 109 non-mTBI controls were recruited. Dizziness, balance functions, and the ability to perform daily activities were assessed by Dizziness Handicap Inventory (DHI), and objective balance functions were investigated by the postural stability test. Three diseases-related genetic variants of ASIC3 were determined through polymerase chain reaction and followed by restriction fragment length polymorphism. The Student's t-test and Mann-Whitney U-test were used for normal and abnormal distributed data, respectively. The regression was applied to adjust gender and age. The normality of continuous data was evaluated by Shapiro-Wilk test. Results: In the mTBI people, the rs2288645-A allele carriers exhibited a significantly worse physical domain DHI score (A-allele carriers: 11.39 ± 8.42, non-A carriers: 8.76 ± 7.87, p = 0.03). The rs4148855-GTC deletion carriers an exhibited significantly worse overall postural stability (GTC deletion carriers: 0.53 ± 0.33, non-carriers: 0.46 ± 0.20, p = 0.03). In the controls, rs2288646-A allele carriers were significant worse in the medial-to-lateral postural stability (A-allele carriers: 0.31 ± 0.17, non-A carriers: 0.21 ± 0.10, p = 0.01). Conclusion: The present study demonstrated that ASIC3 genetic variants were associated with certain aspects of balance functions and dizziness questionnaires in people of mTBI and non-mTBI. It provides a possible evidence that ASIC3 could be a new target for the management of the balancing disorders. However, further investigations are warranted to elucidate the underlying mechanisms and clinical significance.

Sensorimotor and Physiological Indicators of Impairment in Mild Traumatic Brain Injury: A Meta-Analysis

OBJECTIVE

To systematically review the literature with meta-analysis to determine whether persistence of sensorimotor or physiological impairment exists between 4 weeks to 6 months post mild traumatic brain injury (mTBI), and assign level of evidence to findings.

METHOD

The databases PubMed, pscyINFO, SPORTdiscus, Medline, CINAHL and Embase were searched from inception to November 2016 using a priori inclusion criteria. Critical appraisal was performed, and an evidence matrix established level of evidence. Meta-analysis of pooled results identified standardized mean difference (SMD) and 95% confidence intervals (95% CI) between mTBI and healthy controls for a variety of physiological and sensorimotor indicators.

RESULTS

Eighteen eligible articles, with a mean quality score of 15.67 (SD = 2.33) were included in the final review. Meta-analysis of center of motion variable; maximal mediolateral center of motion/center of pressure separation distance SMD [95% CI] approached significance at (-0.42 [-0.84, -0.00], I² = 0%) for dual task, level walking indicating a potential reduction in maximal mediolateral excursion during gait in the mTBI group compared to healthy controls. Significantly reduced variability in the standard deviation of heart beat intervals was observed in the mTBI group (-0.51 [-0.74, -0.28], I² = 0%). Overall, significant group differences in 36 sensorimotor and physiological variables (eg, balance, gait velocity and motion analysis outcomes, various oculomotor tasks, as well as heart rate variability frequency domains) were identified.

CONCLUSION

Findings demonstrate that persistence of sensorimotor and physiological changes beyond expected recovery times following subacute mTBI in an adult population is possible. These findings have implications for post-injury assessment and management.

Physical Performance and Fall Risk in Persons With Traumatic Brain Injury

Injuries sustained from traumatic brain injury (TBI) culminate in both cognitive and neuromuscular deficits. Patients often progress to higher functioning on the Rancho continuum even while mobility deficits persist. Although prior studies have examined physical performance among persons with chronic symptoms of TBI, less is known about the relatively acute phase of TBI as patients prepare for rehabilitation discharge. The aims of this cross-sectional study were to (a) compare balance and gait performance in 20 ambulant persons with moderate to severe TBI who were nearing rehabilitation discharge with their age-matched controls and (b) describe performance with thresholds for fall risk and community navigation. During a designed task circuit, 40 participants (20 persons with TBI and 20 controls) performed the Timed Up and Go (TUG), gait velocity, and Walking and Remembering tests. Balance testing included the Fullerton Advanced Balance Scale (FABS) and instrumented Modified Clinical Test for Sensory Interaction in Balance (MCTSIB). Statistical analyses included analysis of covariance for group comparisons and a multivariate analysis of covariance for MCTSIB sway velocities with anthropometric controls. The TBI group (mean [ M] age = 42, standard deviation [ SD] =19.5 years; 70% males) performed significantly more poorly on all mobility tests ( p < .05) and their scores reflected a potential fall risk. Gait velocity was significantly slower for the TBI versus control group ( M = .96, SD = 2.6 vs. M = 1.5, SD = 2.2 m/s; p < .001), including TUG times ( M = 13.5, SD = 4.9 vs. M = 7.7, SD = 1.4; p < .001). TBI participants also demonstrated significantly greater sway velocity on all MCTSIB conditions ( p < .01) and lower performance on the FABS ( p < .001). Performance indices indicate potential fall risk and community navigation compromise for individuals with moderate to severe TBI. Physical performance scores support the need for continued interventions to optimize functional mobility upon discharge.

Design of a low-cost MRI compatible plantarflexion force measurement device

Investigating the neural correlates of ankles' joint rotation is critical to better understand the underlying deficit in balance or posture control in the clinical population. This work describes the design and characteristics of a low-cost MRI compatible isometric plantarflexion force measurement device. The device is fully adjustable to the particular height and shoe size of participants. Each individual force sensor has an operational linear range up to 80-100kg amounting to a force range up to 180kg when combining the two sensors, which is well above the maximal force for the majority of the population. Preliminary neuroimaging tests suggest that performing submaximal ankle plantar flexions on the device induce minimal motion artifacts on fMRI signal that are within an acceptable range.

Is balance performance reduced after mild traumatic brain injury?: Interim analysis from chronic effects of neurotrauma consortium (CENC) multi-centre study

OBJECTIVES

Determine if mild traumatic brain injury (mTBI) history is associated with balance disturbances.

SETTING

Chronic Effects of Neurotrauma Consortium (CENC) centres.

PARTICIPANTS

The CENC multi-centre study enrols post-9/11 era Service Members and Veterans with combat exposure. This sample (n = 322) consisted of enrolees completing initial evaluation by September 2016 at the three sites conducting computerized dynamic post-urography (CDP) testing.

DESIGN

Observational study with cross-sectional analyses using structural equation modelling.

MAIN MEASURES

Comprehensive structured interviews were used to diagnose all lifetime mild traumatic brain injuries (mTBIs). The outcome, Sensory Organization Test (SOT), was measured on CDP dual-plate force platform. Other studied variables were measured by structured interviews, record review and questionnaires.

RESULTS

The overall positive/negative mTBI classification did not have a significant effect on the composite equilibrium score. However, the repetitive mTBI classification showed lower scores for participants with ≥ 3 mTBI versus 1-2 lifetime mTBIs. For repetitive mTBI, pain interference acted as a mediator for the indirect effect, and a direct effect was evident on some sensory condition equilibrium scores.

CONCLUSION

These findings show that repeated mTBI, partially mediated by pain, may lead to later balance disturbances among military combatants. Further study of CDP outcomes within this accruing cohort is warranted.

Abnormal muscle activation patterns are associated with chronic gait deficits following traumatic brain injury

BACKGROUND

Gait and balance disorders are common among individuals who have experienced a mild to moderate traumatic brain injury (TBI). However, little is known about how the neuromuscular control of gait is altered following a TBI.

RESEARCH QUESTION

Investigate the relationship between lower limb muscle activation patterns and chronic gait deficits in individuals who previously experienced a mild to moderate TBI.

METHODS

Lower extremity electromyographic (EMG) signals were collected bilaterally during treadmill and overground walking in 44 ambulatory individuals with a TBI >1 year prior and 20 unimpaired controls. Activation patterns of TBI muscles were cross-correlated with normative data from control subjects to assess temporal phasing of muscle recruitment. Clinical assessments of gait and balance were performed using dynamic posturography, the dynamic gait index, six-minute walk test, and preferred walking speed.

RESULTS

TBI subjects exhibited abnormal activation patterns in the tibialis anterior, medial gastrocnemius, and rectus femoris muscles during both overground and treadmill walking. Activation patterns of the vastus lateralis and soleus muscles did not differ from normal. There was considerable heterogeneity in performance on clinical balance and gait assessments. Abnormal muscle activation patterns were significantly correlated with variations in the dynamic gait index among the TBI subjects.

SIGNIFICANCE

Individuals who have experienced a prior TBI do exhibit characteristic changes in the temporal coordination of select lower extremity muscles, which may contribute to impairments during challenging walking tasks.

A Longitudinal Examination of Postural Impairments in Children With Mild Traumatic Brain Injury: Implications for Acute Testing

OBJECTIVE

To examine how postural control changes following pediatric mild traumatic brain injury.

SETTING

Urban pediatric emergency department.

PARTICIPANTS

Children 11 to 16 years old who presented within 6 hours of sustaining mild traumatic brain injury.

DESIGN

Prospective observational cohort followed for 1 month.

MAIN MEASURES

Total center of pressure path velocity and path velocity within distinct frequency bands, ranging from moderate to ultralow, were recorded by the Nintendo Wii Balance Board during a 2-legged stance. Measurements were recorded in 2 separate tests with eyes open and closed. The scores of the 2 tests were compared, and a Romberg quotient was computed.

RESULTS

Eleven children were followed for 1 month postinjury. The ultralow frequency, which reflects slow postural movements associated with exploring stability boundaries, was lower (p = .02) during the eyes closed stance acutely following injury. The Romberg quotient for this frequency was also significantly lower acutely following injury (p = .007) than at 1 month.

CONCLUSION

Following mild traumatic brain injury, children acutely demonstrate significantly more rigid sway patterns with eyes closed than with eyes open, which were highlighted by the Romberg quotient. The Romberg quotient could allow for accurate identification and tracking of postural instability without requiring knowledge of preinjury balance ability.

Postural Instability in Patients With Injury of Corticoreticular Pathway Following Mild Traumatic Brain Injury

OBJECTIVE

We attempted to investigate postural instability in patients with injury of the corticoreticular pathway (CRP) after mild traumatic brain injury.

METHODS

The CRP was reconstructed, and the fractional anisotropy value, apparent diffusion coefficient value, and fiber volume of the CRP were measured. For evaluation of postural instability, both the Balance Error Scoring System score and the displacement of center of pressure were measured.

RESULT

Significantly lower tract volume of the CRP was observed in the patient group than in the control group with no significant difference in fractional anisotropy and apparent diffusion coefficient values(P > 0.05). The results of the Balance Error Scoring System shown on a firm and foam surface were significantly higher in the patient group than in the control group (P < 0.05). Significant increments in displacement of center of pressure for 3 stances of double-leg, single-leg, and tandem stances in distance, maximum distance, and path length were observed in the patient group compared with the control group (P < 0.05). By contrast, no significant difference in the double stance on the x axis of the distance was observed between the patient and control groups (P > 0.05).

CONCLUSION

We demonstrated postural instability in patients with injury of the CRP following mild traumatic brain injury.

Diagnostic accuracy of tablet-based software for the detection of concussion

Despite the high prevalence of traumatic brain injuries (TBI), there are few rapid and straightforward tests to improve its assessment. To this end, we developed a tablet-based software battery ("BrainCheck") for concussion detection that is well suited to sports, emergency department, and clinical settings. This article is a study of the diagnostic accuracy of BrainCheck. We administered BrainCheck to 30 TBI patients and 30 pain-matched controls at a hospital Emergency Department (ED), and 538 healthy individuals at 10 control test sites. We compared the results of the tablet-based assessment against physician diagnoses derived from brain scans, clinical examination, and the SCAT3 test, a traditional measure of TBI. We found consistent distributions of normative data and high test-retest reliability. Based on these assessments, we defined a composite score that distinguishes TBI from non-TBI individuals with high sensitivity (83%) and specificity (87%). We conclude that our testing application provides a rapid, portable testing method for TBI.

Rapid sideline performance meets outpatient clinic: Results from a multidisciplinary concussion center registry

OBJECTIVE

This study investigated the utility of sideline concussion tests, including components of the Sports Concussion Assessment Tool, 3rd Edition (SCAT3) and the King-Devick (K-D), a vision-based test of rapid number naming, in an outpatient, multidisciplinary concussion center treating patients with both sports-related and non-sports related concussions. The ability of these tests to predict clinical outcomes based on the scores at the initial visit was evaluated.

METHODS

Scores for components of the SCAT3 and the K-D were fit into regression models accounting for age, gender, and sport/non-sport etiology in order to predict clinical outcome measures including total number of visits to the concussion center, whether the patient reached a SCAT3 symptom severity score≤7, and the total types of referrals each patient received over their course. Patient characteristics, differences between those with sport and non-sport etiologies, and correlations between the tests were also analyzed.

RESULTS

Among 426 patients with concussion, SCAT3 total symptom score and symptom severity score at the initial visit predicted each of the clinical outcome variables. K-D score at the initial visit predicted the total number of visits and the total number of referrals. Those with sports-related concussions were younger, had less severely-affected test scores, had fewer visits and types of referrals, and were more likely to have clinical resolution of their concussion and to reach a symptom severity score≤7.

CONCLUSIONS

This large-scale study of concussion patients supports the use of sideline concussion tests as part of outpatient concussion assessment, especially the total symptom and symptom severity score portions of the SCAT3 and the K-D. Women in this cohort had higher total symptom and symptom severity scores compared to men. Our data also suggest that those with non-sports-related concussions have longer lasting symptoms than those with sports-related concussions, and that these two groups should perhaps be regarded separately when assessing outcomes and needs in a multidisciplinary setting.

Targeted rehabilitation reduces visual dependency and improves balance in severe traumatic brain injury: a case study

PURPOSE

To further understand the mechanisms underlying gait impairment following traumatic brain injury.

CASE REPORT

A 58-year-old man presented with marked unsteadiness and motion sensitivity following a severe traumatic brain injury. He underwent a 6-week inpatient rehabilitation program focused on re-weighting and subsequently re-integrating ascending interoceptive information, by gradual reduction of maladaptive visual fixation techniques. We report clinical neurological outcomes and measures of functional outcome, as well as an objective assessment of visual dependency (the rod and disk test) at baseline and after the rehabilitation.

RESULTS

Clinically, the patient had gait unsteadiness exacerbated by visual motion. A significant reduction in visual dependency occurred with tailored multi-disciplinary rehabilitation via gradual removal of visual fixation strategies that the patient had developed to maintain balance (t-test; p < 0.01), as well as clinical improvements in gait, balance, and functional outcome.

CONCLUSIONS

We highlight the importance of visual dependency in the generation of maladaptive gait strategies following brain injury. Our data suggest assessing and treating visual dependency to be an important component of gait rehabilitation after traumatic brain injury. Implications for rehabilitation Whilst gait disturbance in TBI is multifactorial, abnormal visual dependency may be important but under-recognised component of the disorder. Visual dependency can be easily and objectively assessed by the bedside in patients using a dynamic rod and disc test. Tailored rehabilitation with gradual reduction of maladaptive visual fixation can reduce visual dependency and contribute to improved gait and balance following TBI.

Postural stability in patients with different types of head and neck trauma in comparison to healthy subjects

OBJECTIVE

Dizziness is a common complaint in patients following mild head or neck trauma, but neurological signs are usually rare or absent. The aim of the study was to compare postural control in patients with different types of head and neck trauma to healthy subjects.

METHODS

Balance function was evaluated by computerized dynamic platform posturography (CDPP) in 57 dizzy patients with whiplash injury (n = 11), mild head trauma without loss of consciousness (HTNLC) (n = 23), whiplash injury and mild head trauma without loss of consciousness (WHTNLC) (n = 12) and mild head trauma with loss of consciousness (n = 11) and in 14 healthy subjects.

RESULTS

Compared to healthy subjects and after adjustment for inter-group age differences, sway index (SI) was significantly higher in patients with WHTNLC in three of the tests. There were no significant differences within the patient group according to type of injury. When time following the injury was considered, the SI was non-significantly higher within the first week after trauma compared to other time intervals.

CONCLUSION

The severity of the postural abnormality in patients with head and/or neck trauma is not uniform and is influenced by the type of trauma.

Effects of a rapid-resisted elliptical training program on motor, cognitive and neurobehavioral functioning in adults with chronic traumatic brain injury

This small clinical trial utilized a novel rehabilitation strategy, rapid-resisted elliptical training, in an effort to increase motor, and thereby cognitive, processing speed in ambulatory individuals with traumatic brain injury (TBI). As an initial step, multimodal functional abilities were quantified and compared in 12 ambulatory adults with and 12 without TBI. After the baseline assessment, the group with TBI participated in an intensive 8-week daily exercise program using an elliptical trainer and was reassessed after completion and at an 8-week follow-up. The focus of training was on achieving a fast movement speed, and once the target was reached, resistance to motion was increased in small increments to increase intensity of muscle activation. Primary outcomes were: High-Level Mobility Assessment Tool (HiMAT), instrumented balance tests, dual-task (DT) performance and neurobehavioral questionnaires. The group with TBI had poorer movement excursion during balance tests and poorer dual-task (DT) performance. After training, balance reaction times improved and were correlated with gains in the HiMAT and DT. Sleep quality also improved and was correlated with improved depression and learning. This study illustrates how brain injury can affect multiple linked aspects of functioning and provides preliminary evidence that intensive rapid-resisted training has specific positive effects on dynamic balance and more generalized effects on sleep quality in TBI.

Balance function and sensory integration after mild traumatic brain injury

OBJECTIVE

This study examined the disparities in balance functions and sensory integration in patients with mild traumatic brain injuries (mTBIs) and healthy controls.

PARTICIPANTS

One hundred and seven patients with mTBI and 107 age- and sex-matched controls were recruaited for this study.

PRIMARY MEASURES

Symptoms of dizziness, balance functions and the ability to perform daily activities were assessed using the dizziness handicap inventory (DHI). This study also performed the postural-stability test and a modified clinical test of sensory integration by using the Biodex Stability System (BBS).

RESULTS

DHI scores (functional, emotional, physical and total self-reported scores) were substantially increased in patients following an mTBI compared with the scores of the controls (p < 0.000). The postural-stability test indices (anterior-posterior) (p = 0.045) and the sensory-integration test index (eyes-open-firm-surface index) (p = 0.006) were substantially lower in patients with mTBI than in the controls. However, indices of two other postural-stability test indices (overall and medial-lateral) and three other sensory-integration tests indices (eyes-closed-firm-surface, eyes-open-foam-surface and eyes-closed-foam-surface) measured for the mTBI group did not differ from those of the control group.

CONCLUSION

Activities of daily living, balance in postural stability and sensory integration were strongly impaired in patients with mTBI.

Investigating the Feasibility and Utility of Bedside Balance Technology Acutely After Pediatric Concussion: A Pilot Study

OBJECTIVE

To examine postural instability in children acutely after concussion, using the Wii Balance Board (WBB). We hypothesized that children with traumatic brain injury would have significantly worse balance relative to children without brain injury.

DESIGN

Prospective case-control pilot study.

SETTING

Emergency department of a tertiary urban pediatric hospital.

PARTICIPANTS

Cases were a convenience sample 11-16 years old who presented within 6 hours of sustaining concussion. Two controls, matched on gender, height, and age, were enrolled for each case that completed study procedures. Controls were children who presented for a minor complaint that was unlikely to affect balance.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The participant's postural sway expressed as the displacement in centimeters of the center of pressure during a timed balance task. Balance testing was performed using 4 stances (single or double limb, eyes open or closed).

RESULTS

Three of the 17 (17.6%) cases were too dizzy to complete testing. One stance, double limbs eyes open, was significantly higher in cases versus controls (85.6 vs 64.3 cm, P = 0.04).

CONCLUSIONS

A simple test on the WBB consisting of a 2-legged standing balance task with eyes open discriminated children with concussion from non-head-injured controls. The low cost and feasibility of this device make it a potentially viable tool for assessing postural stability in children with concussion for both longitudinal research studies and clinical care.

CLINICAL RELEVANCE

These pilot data suggest that the WBB is an inexpensive tool that can be used on the sideline or in the outpatient setting to objectively identify and quantify postural instability.

A computer vision based candidate for functional balance test

Balance in humans is a motor skill based on complex multimodal sensing, processing and control. Ability to maintain balance in activities of daily living (ADL) is compromised due to aging, diseases, injuries and environmental factors. Center for Disease Control and Prevention (CDC) estimate of the costs of falls among older adults was $34 billion in 2013 and is expected to reach $54.9 billion in 2020. In this paper, we present a brief review of balance impairments followed by subjective and objective tools currently used in clinical settings for human balance assessment. We propose a novel computer vision (CV) based approach as a candidate for functional balance test. The test will take less than a minute to administer and expected to be objective, repeatable and highly discriminative in quantifying ability to maintain posture and balance. We present an informal study with preliminary data from 10 healthy volunteers, and compare performance with a balance assessment system called BTrackS Balance Assessment Board. Our results show high degree of correlation with BTrackS. The proposed system promises to be a good candidate for objective functional balance tests and warrants further investigations to assess validity in clinical settings, including acute care, long term care and assisted living care facilities. Our long term goals include non-intrusive approaches to assess balance competence during ADL in independent living environments.

The distribution of positive work and power generation amongst the lower-limb joints during walking normalises following recovery from traumatic brain injury

OBJECTIVE

To determine whether better walking performance following recovery from traumatic brain injury (TBI) is attributable to an accentuation of compensatory strategies or an improvement in the way positive work is done and power is generated by the lower-limb joints.

SETTING

A large metropolitan rehabilitation hospital.

PARTICIPANTS

Thirty-five ambulant people with extremely-severe TBI who were attending physiotherapy for mobility limitations, and a comparative sample of 25 healthy controls (HC).

DESIGN

Cross-sectional cohort study with six month follow-up.

MAIN MEASURES

Positive work done and average power (i.e. over time) generation by the hip, knee and ankle during stance as well as self-selected gait velocity.

RESULTS

In comparison to HCs, TBI participants walked at baseline with a significantly (p<.01) reduced contribution from the ankle to total lower-limb average power generation (and positive work done) during stance, and a significantly (p=.03) greater contribution from the hip. However, this compensatory strategy resolved over time such that at six month follow-up no significant differences in the relative contributions from the ankle and hip were identified for the TBI participants when compared to HCs.

CONCLUSION

Better walking performance following recovery from TBI is attributable to an improvement in the way positive work is done and power is generated by the lower-limb joints rather than an accentuation of compensatory strategies.

Measuring postural stability with an inertial sensor: validity and sensitivity

Introduction/purpose

To examine the concurrent validity, and sensitivity, of an inertial sensor for use in the assessment of postural sway.

Methods

This was a laboratory-based, repeated-measures design with ten healthy participants. Concurrent validity was tested between an inertial sensor, forceplate, and rigid-body kinematics across three commonly used balance tests. Further, the inertial sensor measures were compared across eight commonly used tests of balance. Variables manipulated include stance position, surface condition, and eyes-open versus eyes-closed.

Results

The inertial sensor was correlated to both the forceplate-derived measures (r=0.793) and rigid-body kinematics (r=0.887). Significant differences between the balance tests were observed when tested with the inertial sensor. In general, there was a three-way interactions between the three balance factors (surface, stance, and vision) leading to pairwise comparisons between each balance test. The root-mean-square showed an increase across tasks of greater difficulty ranging from an average of 0.0368 with two legs, eyes-open to 0.911 when tested during tandem stance, eyes-closed tested on a foam pad.

Conclusion

The new inertial sensor shows promise for use in the assessment of postural sway. Additionally, the inertial sensor appears sensitive to differences in balance tasks of varying degrees of difficulty when tested in a healthy sample of young adults. This inertial sensor may provide new opportunities for further research in the assessment of balance changes in the mild traumatic brain injury population.

Glucocorticoids improve acute dizziness symptoms following acute unilateral vestibulopathy

Acute unilateral vestibulopathy (AUV) is characterized by acute vertigo, nausea, and imbalance without neurological deficits or auditory symptomatology. Here, we explore the effect of glucocorticoid treatment on the degree of canal paresis in patients with AUV, and critically, establish its relationship with dizziness symptom recovery. We recruited consecutive patients who were retrospectively assigned to one of the two groups according to whether they received glucocorticoid treatment (n = 32) or not (n = 44). All patients underwent pure-tone audiometry, bithermal caloric testing, MRI brain imaging, and were asked to complete a dizziness handicap inventory on admission to hospital and just prior to hospital discharge. In the treatment group, the canal paresis at discharge was significantly lower than in the control group (mean ± SD % 38.04 ± 21.57 versus 82.79 ± 21.51, p < 0.001). We also observed a significant reduction in the intensity of nystagmus in patients receiving glucocorticoid treatment compared to the non-treatment group (p = 0.03). DHI test score was significantly lower at discharge in the treatment group (mean ± SD % 23.15 ± 12.40 versus 64.07 ± 12.87, p < 0.001), as was the length of hospital stay (2.18 ± 1.5 days versus 3.6 ± 1.7 days, p = 0.002). Glucocorticoid treatment leads to acute symptomatic improvement, with a reduced hospital stay and reduction in the intensity of acute nystagmus. Our findings suggest that glucocorticoids may accelerate vestibular compensation via a restoration of peripheral vestibular function, and therefore has important clinical implications for the treatment of AUV.

Regional volumes in brain stem and cerebellum are associated with postural impairments in young brain-injured patients

Many patients with traumatic brain injury (TBI) suffer from postural control impairments that can profoundly affect daily life. The cerebellum and brain stem are crucial for the neural control of posture and have been shown to be vulnerable to primary and secondary structural consequences of TBI. The aim of this study was to investigate whether morphometric differences in the brain stem and cerebellum can account for impairments in static and dynamic postural control in TBI. TBI patients (n = 18) and healthy controls (n = 30) completed three challenging postural control tasks on the EquiTest® system (Neurocom). Infratentorial grey matter (GM) and white matter (WM) volumes were analyzed with cerebellum-optimized voxel-based morphometry using the spatially unbiased infratentorial toolbox. Volume loss in TBI patients was revealed in global cerebellar GM, global infratentorial WM, middle cerebellar peduncles, pons and midbrain. In the TBI group and across both groups, lower postural control performance was associated with reduced GM volume in the vermal/paravermal regions of lobules I-IV, V and VI. Moreover, across all participants, worse postural control performance was associated with lower WM volume in the pons, medulla, midbrain, superior and middle cerebellar peduncles and cerebellum. This is the first study in TBI patients to demonstrate an association between postural impairments and reduced volume in specific infratentorial brain areas. Volumetric measures of the brain stem and cerebellum may be valuable prognostic markers of the chronic neural pathology, which complicates rehabilitation of postural control in TBI.

Static and dynamic postural stability in veterans with combat-related mild traumatic brain injury

Persistent post-concussive symptoms are reported by 10-15% of individuals who suffer mild traumatic brain injury (mTBI), but their basis is often uncertain. One such symptom is disequilibrium, a sensation of impaired balance during standing and walking. The hypothesis for this study was that this subjective symptom is associated with objective and measurable deficits in static and dynamic postural stability. An infrared motion tracking system was used to record body motion during quiet standing and in response to waist perturbations in fourteen veterans (age 22-40 years, 13 male) of the Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF), who had a history of mTBI that occurred 7 months to 7 years prior to testing. We compared body sway between veterans with mTBI reporting persistent disequilibrium (TD, n=8) and those with no vestibular symptoms (n=6), as well as to a group of non-veterans with no balance symptoms (n=10). Static postural stability was reduced in TD veterans in comparison to each of the other two groups (p<0.0002), most notably on a compliant surface with eyes closed. The TD group also had decreased dynamic stability of the upper trunk (p<0.05) and enhanced postural oscillations (p<0.02) following waist perturbations. Our findings support a physiological basis for persistent disequilibrium after mTBI and are consistent with impaired vestibular processing. Disruption of semicircular canal inputs is unlikely to be the cause, as head impulse responses were normal in all groups. The unexpected finding of dynamic postural oscillations requires further study but may indicate enhanced instability in sensorimotor networks responsible for postural control.