Objective measurements of auditory nerve recovery function in nucleus CI 24 implantees in relation to subjective preference of stimulation rate.
OBJECTIVE
Setting the optimal rate of stimulation for individual cochlear implant recipients is critical to the successful functional outcome of cochlear implantation. In the absence of an objective methodology, cochlear implants are currently fitted by means of a time-consuming (and therefore expensive) trial-and-error process of limited accuracy. The aim of this study was to evaluate a possible relationship between the patient's subjectively preferred stimulation rate and an objective measurement of auditory nerve recovery time.


METHODS
Eleven recipients of Nucleus CI 24 implants initially fitted with a speech processor using the advanced combination encoders speech-coding strategy at a rate of 900 Hz were introduced to 2 other stimulation rate options, 1200 and 1800 Hz, at 2 different fitting sessions and were asked to choose their preferred rate. Preferences were compared with objective measurements of auditory nerve recovery time obtained with the refractory recovery function of neural response telemetry.


RESULTS
The auditory nerve recovery time for individuals with a subjective preference for a slow stimulation rate was longer than that for individuals who preferred a fast stimulation rate, with significant differences between the 2 groups for 3 of the tested electrodes (Nos. 7, 11 and 15): p = 0.024, 0.009 and 0.03, respectively (Mann-Whitney test).


CONCLUSIONS
The association observed between subjective stimulation rate preference and measurements of auditory nerve recovery time indicates that the measured auditory nerve recovery time can be used as a reliable predictor for setting up a basic stimulation rate of a particular individual's map, thus reducing the cost of the technology and significantly increasing its effectiveness.
Shpak
Thalma
T
Department of Otolaryngology-Head and Neck Surgery, Bnai-Zion Medical Center, Bruce Rappaport Faculty of Medicine, Technion Israel School of Technology, Haifa, Israel.
Berlin
Mira
M
Luntz
Michal
M
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000502:physiology*; D003638:Deafness / Q000628:therapy; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D017755:Prosthesis Fitting; D011930:Reaction Time / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D012032:Refractory Period, Electrophysiological / Q000502:physiology*; D013686:Telemetry / Q000379:methods