Tone decay at threshold with auditory electrical stimulation in Digisonic cochlear implantees

The present study aims to evaluate tone decay (auditory adaptation) in Digi sonic cochlear implant patients, and to compare tone decay results with spe ech recognition performance. The following criteria are evaluated: tone dec ay occurrence, place effect, pulse rate effect, and correlation with speech recognition. A great variability in tone decay was found among the subject s. The amount of tone decay, measured as a percentage of the electrical dyn amic range, depends to some extent on electrode location, which may be link ed with the frequency dependence of acoustical tone decay. However, it is l ikely that acoustically and electrically evoked adaptation does not involve the same process. Also, an effect of pulse rate was found. However, no rel ationship between the amount of tone decay and speech recognition abilities was observed. Evaluation of tone decay in cochlear implant patients might not only allow further evaluation of the condition of their auditory system , but also provide a means to determine preoperatively the specific charact eristics of a subject's residual auditory capacities.