Facial nerve stimulation in cochlear implant stimulation: effects of pulse polarity

摘要: MethodsWe used monopolar, pseudo-monophasic (psm) and biphasic CI-stimulation with charge-balanced pulses of alternating polarity. In electrically-evoked compound action potential (eCAP) recordings in 33 ears of 26 guinea pigs, we assessed the FNS thresholds, via custom-made Matlab routines. Additionally, wWe defined the offset to the eCAP-threshold in 254 cases. The 3 dimensional distance of each CI contact to the facial nerve was assessed using micro computer tomography images.ResultsFNS was detected in 67%(n= 192) of biphasic and 51%,(n= 81) of psm stimulations. The CI-contacts with lowest FNS thresholds had shortest distance to the facial nerve. The FNS was on average 6 dB above the eCAP threshold (max: 14 dB). In 83% of pairwise comparisons cathodic stimulation lead to lower FNS threshold than anodic stimulation. Correspondingly, the eCAP-to-FNS offset was significantly larger for …