Evaluating central auditory processing in Veterans using population-appropriate norms

Abstract

Increasing numbers of military Veterans have reported substantive self-perceived hearing handicap despite normal/near normal hearing on standard audiometric testing. These hearing difficulties are especially true for Veterans with histories of blast exposure and presumed mild traumatic brain injury, with many of these Veterans also being comorbid for post-traumatic stress disorder (PTSD). Clinical tests of Central Auditory Processing Disorder (CAPD) commonly are used to investigate their hearing concerns, but performance on CAPD tests typically is compared to published norms established from non-Veteran populations. Since Veterans and non-Veterans differ significantly in many relevant domains, using non-Veteran norms is potentially problematic for the interpretation of CAPD test results. Veterans (n = 217; with and without histories of blast exposure and PTSD) completed a large CAPD test battery. An N = 1 approach was used to compare the performance of the blast-exposed Veterans and those with PTSD to published norms and data from the Veterans without histories of blast exposure and PTSD (control group). The number of abnormal cases identified based on the Veteran control group was lower than that found with the published norms for all tests. Therefore, establishing and using population-appropriate norms are critical for accurately diagnosing CAPD in Veterans.