Role of Cochlear Microphonics in Newborn Hearing Screening

Abstract

Objectives:

Investigate the role of cochlear microphonics (CM) that could be simultaneously acquired in auditory brain stem response (ABR) test in neonatal hearing screening.

Methods:

From April 2013 to January 2014, hearing screening tests were performed on 51 newborns treated in neonate intensive care unit. The subjects underwent transient evoked otoacoustic emission (TEOAE) and auditory brain stem response (ABR). The amplitude of CM was acquired by applying 90 dB-click sound of condensating and rarefacting polarity.

Results:

There were 68 ears with normal results in ABR, CM and OAE. Auditory neuropathy was suspected in 2 ears that had presence of CM and OAE with abnormal ABR waveform. Amplitude of CM correlated with reproducibility of OAE (p<.01) inversely correlated with latencies of wave I and III (P = .016, P = .010). The subjects with presence of OAE showed higher amplitude of CM than those with absent OAE (P < .01). Mean CM amplitude of subjects with normal ABR threshold was higher than those with abnormal ABR, but there was no statistical significance. Five subjects who had normal ABR threshold showed no OAE response but CM was measured.

Conclusions:

Amplitude of CM had correlation with results of OAE and ABR test. CM might provide more stable information about cochlear hair cell than OAE test which could be easily influenced by condition of middle ear or external ear. We suggest CM as a useful supplementary tool for OAE test.