抄録
Electrical stimulation of the cochlea with a transtympanic needle electrode is of clinical interest in patient selection before a Cochlear implant operation. This electrical promontory testing (PT) was used in 101 ears with profound deafness.
1) Auditory sensation was reported in 74 ears (73%) with profound deafness. Positive results of PT decreased with the duration of deafness.
2) A retrospective study of PT in 13 ears after cochlear implantation showed that electrical stimulation by 50 and 100Hz pulse bursts induced sound sensation in all ears. No positive correlation, however, was found between the threshold, the maximum acceptance level, and the dynamic range in PT and those obtained using the implanted electrode in the scala tympani.
3) PT at several points on the promontory produced different thresholds, and placement of the electrode within the round window niche showed the lowest current threshold among them.
It is concluded that PT is a qualitative test, and that electrical stimulation at the round window niche should be performed to avoid false negative responses and to get an accurate threshold level. In addtion, problems of PT in evaluating the candidates for a cochlear implant are discussed.
