Concussion Management Guidelines Neglect Auditory Symptoms

Relationships between vestibular issues, noise sensitivity, anxiety and prolonged recovery from mild traumatic brain injury among adults: a scoping review

BACKGROUND

We investigated the extent of literature and findings on relationships between vestibular issues, noise sensitivity (NS), and anxiety. We were interested in how relationships among these factors impacted adults' recovery three months or more after mild traumatic brain injury (mTBI).

METHODS

We conducted a scoping review to evaluate the extent of evidence linking relationships between vestibular issues, NS and anxiety with recovery after mTBI. Data relating to study characteristics and key findings were extracted and used to inform a critical narrative synthesis of findings.

RESULTS

After screening and full-text review, we included two studies. Both studies considered the combination of vestibular issues, NS and anxiety and mTBI recovery. Vestibular issues, NS and anxiety were all significantly associated with one another and their presence was the strongest indicator that symptoms would extend beyond three-months after mTBI.

CONCLUSION

Few studies have focused on the relationships that vestibular issues, NS and anxiety have with one another and recovery after mTBI. Given the apparent strong relationships between these factors and prolonged recovery, we highlight this as an area warranting further investigation.

Counseling Protocol for a Transitional Intervention for Debilitating Hyperacusis

INTRODUCTION

This clinical focus article describes a structured counseling protocol for use with protected sound management and therapeutic sound in a transitional intervention for debilitating hyperacusis. The counseling protocol and its associated visual aids are crafted as a teaching tool to educate affected individuals about hyperacusis and encourage their acceptance of a transitional intervention.

DESCRIPTION OF COUNSELING COMPONENTS

The counseling protocol includes five components. First, the patient's audiometric results are reviewed with the patient, and the transitional intervention is introduced. An overview of peripheral auditory structures and central neural pathways and the concept of central gain are covered in the second and third components. Maladaptive hyper-gain processes within the auditory neural pathways, which underlie the hyperacusis condition, and associated connections with nonauditory processes responsible for negative reactions to hyperacusis are covered in the fourth component. Detrimental effects from misused hearing protection devices (HPDs) and the necessity to wean the patient from overuse of HPDs are also discussed. In the fifth component, the importance of therapeutic sound is introduced as a tool to downregulate hyper-gain activity within the auditory pathways; its implementation in uncontrolled and controlled sound environments is described. It is explained that, over the course of the transitional intervention, recalibration of the hyper-gain processes will be ongoing, leading to restoration of normal homeostasis within the auditory pathways. In turn, associated activation of reactive nonauditory processes, which contribute to hyperacusis-related distress, will be reduced or eliminated. As recalibration progresses, there will be less need for protected sound management and sound therapy. Sound tolerance will improve, hyperacusis will subside, and daily activities in typical healthy sound environments will again become routine.

RESULTS AND CONCLUSION

The combination of counseling with protected sound management and therapeutic sound is highlighted in companion reports, including a summary of the outcomes of a successful trial of the transitional intervention.

Exercise Intolerance After Mild Traumatic Brain Injury Occurs in All Subtypes in the Adult Population

Thematically grouped symptom clusters are present during the acute timeline of post-mild traumatic brain injuries (mTBI), representing clinical profiles called subtypes. Exercise intolerance has not been evaluated within the subtype classifications and, because guidelines support early submaximal aerobic exercise, further knowledge is required in regard to the exercise capabilities among the concussion subtypes. This cross-sectional study (n = 78) aimed to characterize the presence of exercise intolerance within the clinical subtypes and to explore performance on the Buffalo Concussion Treadmill Test (BCTT) in the adult subacute (2-12 weeks post-injury) mTBI population. All participants were evaluated using the BCTT to determine exercise tolerance. We first used the Neurobehavioral Symptom Inventory (NSI) questionnaire to assign each participant a primary subtype(s). To further explore all five subtypes (headache, cognitive, vestibular, ocular motor, and mood), participants were assessed using a multitude of thematically grouped assessments including self-reported questionnaires, clinical tests of vestibular and ocular motor function, balance function, and computerized cognitive testing. Thirty-seven (47%) subjects were exercise tolerant and 41 (53%) were exercise intolerant. There was no difference in the distribution of primary subtypes between the exercise tolerant and exercise intolerant groups. In addition, no significant differences were found between the exercise tolerant and exercise intolerant groups on other thematically grouped subtype assessments. The exercise intolerant group had a significantly higher resting heart rate (HR), lower percentage of age-predicted maximum HR achieved, lower Borg Rate of Perceived Exertion (RPE), and could walk on the treadmill for less time (lower duration) compared with the exercise tolerant group. The current findings suggest that exercise intolerance is common and pervasive across all five mTBI subtypes. A comprehensive mTBI assessment should include evaluation for exercise intolerance regardless of the primary clustering of symptoms and across patient populations. Therefore, early referral to physical therapists, athletic trainers, or medical clinics that can perform the BCTT may be helpful to initiate appropriate exercise prescriptions for patients with mTBI.

Association Between Symptom Cluster Endorsement at Initiation of a Graduated Return-to-Activity Protocol and Time to Return to Unrestricted Activity After Concussion in United States Service Academy Cadets

BACKGROUND

The endorsement of symptoms upon initiation of a graduated return-to-activity (GRTA) protocol has been associated with prolonged protocols. It is unclear whether there are specific symptom clusters affecting protocol durations.

PURPOSE

To describe the endorsement of specific concussion symptom clusters at GRTA protocol initiation and examine the association between symptom cluster endorsement and GRTA protocol duration.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This study was conducted among cadets enrolled at 3 US service academies. Participants completed an evaluation upon GRTA protocol initiation. Participants endorsing symptoms were binarized based on 6 symptom clusters (cognitive, emotional, insomnia, physical, sensitivity, and ungrouped). The primary outcome of interest was GRTA protocol duration based on symptom cluster endorsement severity. Prevalence rates were calculated to describe symptom cluster endorsement. Kaplan-Meier survival estimates and univariate and multivariable Cox proportional hazards regression models were calculated for all 6 symptom clusters to estimate GRTA protocol duration while controlling for significant covariates.

RESULTS

Data from 961 concussed participants were analyzed. Of these, 636 participants were asymptomatic upon GRTA protocol initiation. Among the 325 symptomatic participants, the physical symptom cluster (80%) was most endorsed, followed by the cognitive (29%), insomnia (23%), ungrouped (19%), sensitivity (15%), and emotional (9%) clusters. Univariate results revealed a significant association between endorsing cognitive (hazard ratio [HR], 0.79; p = .001), physical (HR, 0.84; p < .001), insomnia (HR, 0.83; p = .013), sensitivity (HR, 0.70; p < .001), and ungrouped (HR, 0.75; p = .005) symptom clusters and GRTA protocol duration. Endorsing physical (HR, 0.84; p < .001) and sensitivity (HR, 0.81; p = .036) clusters maintained a significant association with GRTA protocol duration in the multivariable models.

CONCLUSION

Participants endorsing physical or sensitivity symptom clusters displayed GRTA protocols prolonged by 16% to 19% compared with participants not endorsing that respective cluster after controlling for significant covariates.

Subconcussion revealed by sound processing in the brain

Introduction/Purpose

We tested the hypothesis that an objective measure of auditory processing reveals a history of head trauma that does not meet the clinical definition of concussion.

Methods

Division I collegiate student-athletes (n = 709) across 19 sports were divided into groups, based on their sport, using prevailing classifications of "contact" (317 males, 212 females) and "noncontact" (58 males, 122 females). Participants were evaluated using the frequency-following response (FFR) to speech. The amplitude of FFR activity in a frequency band corresponding to the fundamental frequency (F0)-the voice pitch-of the speech stimulus, an outcome reduced in individuals with concussions, was critically examined.

Results

We found main effects of contact level and sex. The FFR-F0 was smaller in contact athletes than noncontact athletes and larger in females than males. There was a contact by sex interaction, with the FFR-F0 of males in the contact group being smaller than the three other groups. Secondary analyses found a correlation between FFR-F0 and length of participation in contact sports in male athletes.

Conclusion

These findings suggest that the disruption of sensory processing in the brain can be observed in individuals without a concussion but whose sport features regular physical contact. This evidence identifies sound processing in the brain as an objective marker of subconcussion in athletes.

Central Auditory Processing Dysfunction in Service Members and Veterans: Treatment Considerations and Strategies

PURPOSE

Military risk factors such as blast exposure, noise exposure, head trauma, and neurotoxin exposure place Service members and Veterans at risk for deficits associated with auditory processing dysfunction. However, there is no clinical guidance specific to the treatment of auditory processing deficits in this unique population. We provide an overview of available treatments and their limited supporting evidence for use in adults, emphasizing the need for multidisciplinary case management and interdisciplinary research to support evidence-based solutions.

METHOD

We explored relevant literature to inform the treatment of auditory processing dysfunction in adults, with emphasis on findings involving active or former military personnel. We were able to identify a limited number of studies, pertaining primarily to the treatment of auditory processing deficits through the use of assistive technologies and training strategies. We assessed the current state of the science for knowledge gaps that warrant additional study.

CONCLUSIONS

Auditory processing deficits often co-occur with other military injuries and may pose significant risk in military operational and occupational settings. Research is needed to advance clinical diagnostic and rehabilitative capabilities, guide treatment planning, support effective multidisciplinary management, and inform fitness-for-duty standards. We emphasize the need for an inclusive approach to the assessment and treatment of auditory processing concerns in Service members and Veterans and for evidence-based solutions to address complex military risk factors and injuries.

Athleticism and sex impact neural processing of sound

Biology and experience both influence the auditory brain. Sex is one biological factor with pervasive effects on auditory processing. Females process sounds faster and more robustly than males. These differences are linked to hormone differences between the sexes. Athleticism is an experiential factor known to reduce ongoing neural noise, but whether it influences how sounds are processed by the brain is unknown. Furthermore, it is unknown whether sports participation influences auditory processing differently in males and females, given the well-documented sex differences in auditory processing seen in the general population. We hypothesized that athleticism enhances auditory processing and that these enhancements are greater in females. To test these hypotheses, we measured auditory processing in collegiate Division I male and female student-athletes and their non-athlete peers (total n = 1012) using the frequency-following response (FFR). The FFR is a neurophysiological response to sound that reflects the processing of discrete sound features. We measured across-trial consistency of the response in addition to fundamental frequency (F0) and harmonic encoding. We found that athletes had enhanced encoding of the harmonics, which was greatest in the female athletes, and that athletes had more consistent responses than non-athletes. In contrast, F0 encoding was reduced in athletes. The harmonic-encoding advantage in female athletes aligns with previous work linking harmonic encoding strength to female hormone levels and studies showing estrogen as mediating athlete sex differences in other sensory domains. Lastly, persistent deficits in auditory processing from previous concussive and repetitive subconcussive head trauma may underlie the reduced F0 encoding in athletes, as poor F0 encoding is a hallmark of concussion injury.

Psychological and Social Needs: Athletes’ and Mental Performance Consultants’ Perspectives on a Gap in Concussion Protocols

While research advancements have substantially improved concussion management efforts, consideration for the psychological and social aspects of concussive injuries have remained largely absent from concussion protocols. The present study was undertaken to identify elite athletes’ psychological and social needs during the recovery process. Elite athletes with a history of concussion and mental performance consultants who work with concussed elite athletes participated in focus group interviews to shed light on these needs. A thematic analysis of these focus groups revealed six psychological and social needs: acceptance, normality, confidence, self-efficacy, trust in relationships, and social support. These themes are framed within concussion literature to help initiate a conversation on how psychological and social needs should be addressed as part of multifaceted efforts to improve concussion recovery.

Clinical Importance of Binaural Information: Extending Auditory Assessment in Clinical Populations Using a Portable Testing Platform

Purpose The purpose of this study is to use variability on tests of basic auditory processing to allow identification of those tests that could be used clinically to describe functional hearing ability beyond the pure-tone audiogram and clinical speech-in-noise tests. Method Psychoacoustic tests implemented using the Portable Automated Rapid Testing system on a calibrated iPad were evaluated for nine young normal-hearing participants (M _age = 21.3, SD = 2.5) and seven hearing-impaired participants (M _age = 64.9, SD = 13.5). Participants completed 10 psychoacoustic subtests in a quiet room. Correlational analyses were used to compare performance on the psychoacoustic test battery with performance on a clinical speech-in-noise test and with the 4-frequency pure-tone average (4FreqPTA). Results Spectral processing ability was highly correlated with 4FreqPTA, and temporal processing ability showed minimal variability across the hearing-impaired group. Tests involving binaural processing captured variability across hearing-impaired listeners not associated with 4FreqPTA or speech-in-noise performance. Conclusions Tests that capture the ability to use binaural cues may add information to what current clinical protocols reveal about patients with auditory complaints. Further testing with a larger sample size is needed to confirm the need for binaural measurements and to develop normative data for clinical settings.

Baseline, retest, and post-injury profiles of auditory neural function in collegiate football players

OBJECTIVES

Recent retrospective studies report differences in auditory neurophysiology between concussed athletes and uninjured controls using the frequency-following response (FFR). Adopting a prospective design in college football players, we compared FFRs before and after a concussion and evaluated test-retest reliability in non-concussed teammates.

DESIGN

Testing took place in a locker room. We analysed the FFR to the fundamental frequency (F0) (FFR-F0) of a speech stimulus, previously identified as a potential concussion biomarker. Baseline FFRs were obtained during the football pre-season. In athletes diagnosed with concussions during the season, FFRs were measured days after injury and compared to pre-season baseline. In uninjured controls, comparisons were made between pre- and post-season.

STUDY SAMPLE

Participants were Tulane University football athletes (n = 65).

RESULTS

In concussed athletes, there was a significant group-level decrease in FFR-F0 from baseline (26% decrease on average). By contrast, the control group's change from baseline was not statistically significant, and comparisons of pre- and post-season had good repeatability (intraclass correlation coefficient = 0.75).

CONCLUSIONS

Results converge with previous work to evince suppressed neural function to the FFR-F0 following concussion. This preliminary study paves the way for larger-scale clinical evaluation of the specificity and reliability of the FFR as a concussion diagnostic.HighlightsThis prospective study reveals suppressed neural responses to sound in concussed athletes compared to baseline.Neural responses to sound show good repeatability in uninjured athletes tested in a locker-room setting.Results support the feasibility of recording frequency-following responses in non-laboratory conditions.