Objective and Subjective Auditory Effects of Traumatic Brain Injury and Blast Exposure in Service Members and Veterans.

Stefanie E Kuchinsky,Rael T Lange,Douglas S Brungart,Megan M Eitel,Louis M French,Sara M Lippa,Tracey A Brickell

doi:10.3389/fneur.2020.00613

Abstract

Service members and veterans (SMVs) with a history of traumatic brain injury (TBI) or blast-related injury often report difficulties understanding speech in complex environments that are not captured by clinical tests of auditory function. Little is currently known about the relative contribution of other auditory, cognitive, and symptomological factors to these communication challenges. This study evaluated the influence of these factors on subjective and objective measures of hearing difficulties in SMVs with and without a history of TBI or blast exposure. Analyses included 212 U.S. SMVs who completed auditory and cognitive batteries and surveys of hearing and other symptoms as part of a larger longitudinal study of TBI. Objective speech recognition performance was predicted by TBI status, while subjective hearing complaints were predicted by blast exposure. Bothersome tinnitus was associated with a history of more severe TBI. Speech recognition performance deficits and tinnitus complaints were also associated with poorer cognitive function. Hearing complaints were predicted by high frequency hearing loss and reports of more severe PTSD symptoms. These results suggest that SMVs with a history of blast exposure and/or TBI experience communication deficits that go beyond what would be expected based on standard audiometric assessments of their injuries.

Highlights

Traumatic brain injury (TBI) is a common injury among military service members and veterans (SMVs) [1]
Of the remaining 212 participants, 40% had a history of an uncomplicated mild TBI, 29% had greater than an uncomplicated mTBI (i.e., n = 16 complicated mTBI, n = moderate TBI, n = severe TBI, n = penetrating TBI), and 31% of had no history of TBI. 40% of all participants responded on a screening question as having been close enough to an explosive blast to self-report symptoms of a “possible” alteration of consciousness (Blast Exposure question described below)
Factors associated with worse speech recognition performance were decreasing age, a history of TBI, slower Modified rhyme test (MRT) RT, poorer hearing thresholds for the better and worse ears in the lower frequencies and for the better ear in the high frequencies, and worse executive function

Summary

Introduction

Traumatic brain injury (TBI) is a common injury among military service members and veterans (SMVs) [1]. Critical for improving patient care is our ability to comprehensively assess the range of problems that individuals with a TBI or blast exposure experience. This goal is complicated by variability in the causes and symptoms associated with these deficits. Hearing loss and tinnitus are among the most prevalent service-connected disabilities for veterans [4] and the incidence of hearing difficulties in service members, those deployed [5], exceeds that of the U.S working population [6]. Bothersome tinnitus is often experienced in people with trauma-related injuries, exposure to high levels of occupational noise, and hearing loss; all of which are common in the military population. 20% of people with chronic tinnitus have bothersome tinnitus that can promote cognitive difficulties, mental health disorders, insomnia, and decreased psychosocial functioning [10,11,12]

Methods

Results

Conclusion