Effects of blast exposure on central auditory processing

Abstract

Exposure to high-intensity blasts is the most common cause of injury in recent U.S. military conflicts. Prior work indicates that blast-exposed Veterans report significantly more hearing handicap than non-blast-exposed Veterans, often in spite of clinically normal hearing thresholds. Our research explores the auditory effects of blast exposure using a combination of self-report, behavioral, and electrophysiological measures of auditory processing. Results of these studies clearly indicate that blast-exposed individuals are significantly more likely to perform poorly on tests requiring the use of binaural information and tests of pitch sequencing and temporal acuity compared to non-blast-exposed control subjects. Behavioral measures are corroborated by numerous objective electrophysiological measures, and are not necessarily attributable to peripheral hearing loss or impaired cognition. Thus, evidence indicates that blast exposure can lead to acquired deficits in central auditory processing (CAP) which may persist for at least 10 years following blast exposure. Future studies of these deficits in this and other adult populations are needed to address important issues such as individual susceptibility, anatomical, and physiological changes in auditory pathways which contribute to symptoms of these types of deficits, and development of effective evidence-based methods of rehabilitation in adult patients. [Work supported by the VA Rehabilitation Research & Development Service and the VA Office of Academic Affiliations.]