Effects of hearing aid amplification and stimulus intensity on cortical auditory evoked potentials.
Hearing aid amplification can be used as a model for studying the effects of auditory stimulation on the central auditory system (CAS). We examined the effects of stimulus presentation level on the physiological detection of sound in unaided and aided conditions. P1, N1, P2, and N2 cortical evoked potentials were recorded in sound field from 13 normal-hearing young adults in response to a 1000-Hz tone presented at seven stimulus intensity levels. As expected, peak amplitudes increased and peak latencies decreased with increasing intensity for unaided and aided conditions. However, there was no significant effect of amplification on latencies or amplitudes. Taken together, these results demonstrate that 20 dB of hearing aid gain affects neural responses differently than 20 dB of stimulus intensity change. Hearing aid signal processing is discussed as a possible contributor to these results. This study demonstrates (1) the importance of controlling for stimulus intensity when evoking responses in aided conditions, and (2) the need to better understand the interaction between the hearing aid and the CAS.
Billings
Curtis J
CJ
Department of Speech and Hearing Sciences, University of Washington, Seattle, WA 98105, USA. curtisjb@u.washington.edu
Tremblay
Kelly L
KL
Souza
Pamela E
PE
Binns
Malcolm A
MA
D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D004424:Ear Canal; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006310:Hearing Aids; D006801:Humans; D008144:Loudness Perception / Q000502:physiology; D008297:Male; D011930:Reaction Time / Q000502:physiology