Extraction of Habituation Correlates in Single-Sweep Sequences of Late Auditory Evoked Potentials using Time-Scale Coherence: Objective Detection of Uncomfortable Loudness Level

M. Mariam, W. Delb, F.I. Corona-Strauss, M. Bloching, and D.J. Strauss (Germany)


habituation, late auditory evoked potential, time-scale co herence, uncomfortable loudness level.


The fitting of cochlear implants as well as hearing aids re quires information on the hearing threshold as well as on the uncomfortable loudness level. Due to its very sub jective nature, the estimation of the uncomfortable loud ness level is particularly challenging and represents a clin ically unsolved problem. Using a computational monitor ing of the habituation processes in single sweeps record ings of late auditory evoked potentials (LAEP), we propose a method that might be able to objectively determine the uncomfortable loudness level in non–cooperative patients such as newborns. Here we presented preliminary results of an ongoing study. Single sweep recordings of LAEP were performed at 2 stimulation levels, 50dB and and 100dB hearing level (HL) with an interstimulus interval (ISI) of 1s. In a group of 10 voluntary adult subjects with nor mal hearing, our scheme based on the analysis of single sweeps recordings and the calculation of time-scale phase coherence, the 1.12% reduction of time-scale phase coher ence index for 50dB HL and 0.30% for 100dB HL were observed. Therefore, habituation of 50dB HL stimulus had successfully been detected and no significant difference in sweeps evolution for 100dB HL stimulus (Wilcoxon test, significance level p <0.05). It is concluded that the pro posed method possibly allows for the reliable detection of habituation and differentiation of comfortable from uncom fortable loudness levels in cochlear implants and hearing aids fitting.

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