Psychophysical studies on prelingual patients using a multiple electrode cochlear implant

Abstract

Psychophysical studies were conducted on three prelingual patients during the first year of usage of a multiple electrode cochlear implant. The results were compared with those obtained from postlingual patients. For the identification of two electrode positions (6 mm apart), the d′ sensitivity index for prelinguals was <0.75 and for postlinguals > 3.0. For the identification of two electric repetition rates (an octave apart), d′ for prelinguals was <0.6 and >3.0 for postlinguals. Temporal resolution discrimination was also poorer for prelinguals, gap detection >64 ms and duration difference limens >38 ms from a fixed standard duration of 30 ms, while for postlinguals, <3 ms and <38 ms, respectively. The ability to count a variable number of short electrical stimuli deteriorated at high rates (>5/s) of presentation for prelinguals but not for postlinguals, while for visual and tactile stimuli performance was similar across all patients. However, improvements in one prelingual patient after one year of usage were recorded for electrode place and rate identification (d′ > 1.5).