Diagnosing Contributions of Sensory and Cognitive Deficits to Hearing Dysfunction in Blast-Exposed/TBI Service Members
Abstract
Blast-induced traumatic brain injury (TBI) and hearing loss are two of the most common injuries sustained as a result of the U.S. Global War on Terror. Recently, audiology clinics at DoD and VA healthcare centers have been reporting an increasing number of blast-exposed Service Members (SMs) complaining of having complications with speech comprehension in everyday social situations with competing talkers and interfering sounds despite having normal to near-normal audiometric thresholds. We hypothesized these speech comprehension problems might be the result of two possible mechanisms of injury: 1) damage to the auditory sensory periphery resulting in either cochlear dysfunction or the loss of auditory nerve fibers responsible for the encoding of suprathreshold sounds ("hidden hearing loss") or 2) blast-induced traumatic brain injury (TBI) to cortical networks associated with the processing of attention, working memory, speed of processing, and other executive functions related to speech and language processing. Results from a comprehensive battery of audiological, electrophysiological, and neuro-cognitive tests performed on blast-exposed SMs showed evidence of subclinical levels of sensory damage compared to SMs who had not been exposed to blast. These losses, however, are still within the range of what is typically considered "clinically" normal hearing. Different from what we observed in a earlier study of blast-exposed Veteran Administration (VA) SMs seeking treatment for post-traumatic stress disorder (PTSD) (Bressler, Goldberg, and Shinn-Cunningham, 2016), we found no evidence of cognitive deficits in attention or executive control in either the auditory or visual domains. However, neuro-cognitive outcomes for measures administered in the visual domain (thereby bypassing any peripheral auditory-system weakness) showed evidence that exposure to blast may have affected neural processing speed for language comprehension.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2020
- Accession Number
- AD1139892
Entities
People
- Barbara Shinn-Cunningham
- Kenneth Grant
- Scott Bressler
Organizations
- Boston University