Immittance and otoacoustic emissions in rhesus monkeys and humans

The purpose of this study was to compare multifrequency tympanometry and otoacoustic emissions (OAEs) in rhesus monkeys (Macaca mulatta) and humans. Tympanometry and OAEs can be recorded efficiently in Macaca mulatta to assess peripheral auditory function with results comparable to those in humans. Differences include (1) greater admittances and conductances in humans from 226 to 630 Hz, the frequency range validly assessed; (2) larger amplitude transient evoked OAEs (TEOAEs) and noise levels in humans; (3) larger amplitude monkey 2f(1)-f(2) distortion product OAEs (DPOAES) (f(2)s>2 kHz); (4) more prominent DPOAEs other than 2f(1)-f(2) in monkeys; (5) more narrowly tuned human f(2)/f(1) X 2f(1)-f(2) amplitude functions at the lower frequencies tested; and (6) lower 2f(1)-f(2) DPOAE thresholds at f(2)=0.5 kHz and > or = 8 kHz in monkeys.