Functional hearing impairments in normal-hearing listeners with a history of deployment-related blast exposure

Over the past decade, DoD and VA audiologists have reported large numbers of relatively young adult patients who have normal-audiometric thresholds but who report greater than expected difficulty understanding speech in noisy environments. One common theme in the history of these patients is that they self-report having experienced exposure to explosive blast as part of their military service. Recent studies in our laboratory suggest that some blast-exposed patients with normal-hearing thresholds have greater than expected difficulty in tasks that require spatial sound perception (auditory localization and N0Sπ tone detection) or those that involve the perception of time-compressed speech in reverberant environments. They also tend to report more hearing difficulties compared to non-blast exposed patients on a questionnaire that evaluates spatial perception, speech perception, and perceived sound quality. These laboratory results appear to be confirmed by preliminary results from roughly 2000 active-duty ...