Relation between electrical compound action potential measures and speech perception in cochlear implanted children: audiological and phonological outcomes

Purpose To study ECAP measures (threshold and amplitude growth function 'AGF') in children CI users and find the relation between these ECAP measures and speech outcomes using audiological and phonological assessment. Subjects and method Twenty-one children were unilaterally implanted with Medel CI, and all subjects were submitted to phonological assessment, basic audiological assessment, speech recognition tests (WRS and BKB-SIN) and Medel maestro software measures (IFT, AutoART and AGF measures "thresholds and slopes" across apical, middle and basal electrodes). Results This study demonstrated no statistically significant difference between AGF thresholds at apical, middle and basal electrodes and a statistically significant difference between AGF slopes at apical and both middle and basal electrodes. There was no statistically significant correlation between the ECAP threshold and speech perception tests. In contrast, a positive statistically significant correlation was found between the AGF slope of the apical electrode and word recognition score, and a negative statistically significant correlation between AGF slopes at apical, middle and basal electrodes and SNR loss of BKB-SIN. High sensitivity and specificity of AGF slope at apical electrode were found to differentiate between good and poor performers as regards SNR loss of BKB-SIN and language test. Conclusions The AGF slope reflects neural survival better than the ECAP threshold. AGF slope at apical electrodes correlated with better CI performance in both phoniatric and audiological measures of speech perception and can be used as an objective tool to predict CI outcome.