Otoacoustic emission, evoked potential, and behavioral auditory thresholdsin the rhesus monkey (Macaca mulatta)

Distortion product otoacoustic emission (DPOAE), auditory brainstem evoked response (ABR), and behavioral thresholds were recorded in a group of 15 ad ult rhesus monkeys with normal auditory function. DPOAE thresholds were rec orded with stimulus parameters selected to maximize signal-to-noise ratio. Additional averaging at the lowest frequencies ensured comparable noise lev els across frequencies. DPOAE thresholds decreased with increasing frequenc y (f(2) = 0.5-16 kHz) and at 16 kHz were close to 0 dB SPL. ABR thresholds were best from 1 through 16 kHz (32-38 dB peSPL); higher at 0.5 (45 dB peSP L), 24 (39 dB peSPL), and 30 kHz (49 dB peSPL). At all levels including thr eshold, the early ABR waves (II and I) were more prominent at the high freq uencies while the later waves (IV and V) were more prominent at the low fre quencies. The behavioral thresholds recorded were similar to those reported by other researchers although elevated by about 10 dB presumably because o f the complexity of the threshold task. DPOAE and ABR thresholds can be rel iably and efficiently recorded in the rhesus monkey and provide information concerning site of processing in the auditory pathway not directly availab le from behavioral data. (C) 1999 Elsevier Science B.V. All rights reserved .