Cortical Auditory Evoked Potentials to Complex Speech Stimuli in Auditory Neuropathy Spectrum Disorders

Abstract

The present study examined cortical auditory evoked potentials (CAEPs) for complex CV syllables in individuals with auditory neuropathy spectrum disorders (ANSD). CAEPs were recorded for /su/ and /chu/ (350ms and 180ms respectively) and their constituents (/s/, /us/, /ch/, /uch/) in 10 subjects with ANSD and 11 subjects with normal hearing. All normal subjects demonstrated an acoustic change complex (ACC) for both /su/ and /chu/. On the other hand, four out of 10 subjects with ANSD demonstrated an ACC for /su/ and one out of 10 subjects demonstrated an ACC for /chu/. In addition, those who had ACC absent demonstrated the CAEPs for individual constituents of the syllable but the whole stimulus elicited only a single response rather than a change complex probably indicating reduced temporal resolution and forward masking effects. Further, latencies and amplitudes were highly heterogeneous in the ANSD population and ranged from being within normal limits to being highly deviant. The study supports the feasibility of using the cortical potentials to study the cortical representation of complex speech stimuli in ANSD subjects.