Relationship between intraoperative eCAP thresholds and postoperative psychoacoustic levels as a prognostic tool in evaluating the rehabilitation of cochlear implantees.

A sufficient correlation between objective (e.g. eCAP of the auditory nerve) and psychoacoustic data has not yet been possible due to high interindividual variability in cochlear implantees. Therefore, the application of objective data in the evaluation of speech rehabilitation after cochlear implantation was investigated. eCaps of all electrodes were measured intraoperatively. The 'threshold' and 'comfort' levels, speech recognition and pure tone thresholds were determined at follow-up. The correlation coefficient was calculated between eCap thresholds and psychoacoustic levels. This correlation coefficient was ranked with other individual items in relation to their influence on the development of speech recognition. Only the duration of preimplant deafness, the pure tone hearing threshold and the correlation between eCAP and psychoacoustic levels have a significant influence on the rehabilitation within this selection of variables. Based on these results, an individualized mathematical modeling approach was introduced to predict the development of postoperative speech recognition by incorporating objective data. Copyright 2007 S. Karger AG, Basel.