Vestibular stimulation by multichannel cochlear implants

The recipient of a Nucleus 22 multichannel cochlear implant began to experience severe vestibular stimulation related to the implant, This patient's experience initiated a study with the objective of determining the frequency of implant-related vestibuloocular stimulation, Subjects consisted of 17 randomly selected patients who use cochlear implants, Included in the study were 14 Nucleus 22 and three Med-El Combi 40-devices. Stimulation of the implants was performed both by individual channel and with sound field broad-band 80-dB noise using the users' normal device settings, Eye movements were monitored with infrared videonystagmography. Only one subject, who used a Med-El Combi 40, showed a consistent and strong ocular response to cochlear stimulation but had no subjective symptoms, The authors conclude that vestibulo ocular activation is possible with multichannel cochlear implants but is infrequent and may not be clinically significant.