Optimization of TEOAE recording protocols - A linear protocol derived fromparameters of a time- frequency analysis: a pilot study on neonatal subjects

Linear and non-linear TEOAE protocols were compared in terms of nine parame ters in order to define the protocol producing recordings with the highest signal quality (lowest noise and highest signal-to-noise ratio). The pilot project acquired data using ILO-92 apparatus from 220 neonates (397 ears) a t the second/third day after birth in three European laboratories. A Gabor spectrogram time-frequency representation of the recordings showed consider able frequency dispersion in TEOAE latencies >4.0 ms. The data, analysed wi th a Wilcoxon test, indicated that a linear TEOAE protocol: (i) generates r ecordings of a lower noise and a higher signal-to-noise (S/N) ratio in the 2.0, 3.0, 4.0 kHz TEOAE bands; (ii) the increase in the S/N ratio can resul t in a decrement of the required number of TEOAE sweeps; (iii) the higher v alues of S/N can be used in the estimation of more robust pass-fail criteri a, minimizing the percentage of false positives and negatives.