Auditory Nerve and Brain Stem Responses to Sound Stimuli at Various Frequencies

Abstract

The responses of the auditory nerve and brain stem auditory nuclei have been recorded with ear lobe and scalp electrodes in response to unfiltered click stimuli which excite mainly high-frequency nerve fibers. In order to overcome this limitation, normal subjects and patients with hearing loss were stimulated with third-octave filtered clicks with center frequencies of 250, 500 and 1 000 Hz. Analysis of the responses suggests that these lower-frequency stimuli excite lower-frequency cochlear nerve fibers. It is concluded that low-frequency filtered clicks can be used to complement unfiltered clicks in order to obtain a more complete objective audiogram.

Key Words:

• Filtered clicks
• Electric response audiometry
• Surface electrodes
• Cochlear action potential
• Brain stem response