MELODY RECOGNITION AND MUSICAL INTERVAL PERCEPTION BY DEAF SUBJECTS STIMULATED WITH ELECTRICAL PULSE TRAINS THROUGH SINGLE COCHLEAR IMPLANTELECTRODES

The perception of musical pitch was investigated in postlinguistically deaf subjects with cochlear implants. Stimuli consisted of sequences of biphasic electrical pulse trains at rates which represented the ton es of the equal-tempered musical scale, delivered at equalized comfort able loudness levels to selected single bipolar electrodes along the a rray of the Nucleus cochlear implant. Seventeen subjects correctly ide ntified a mean of 44% of rhythmically intact familiar tunes, presented in an open-set paradigm. Three subjects were tested with a closed set of melodies without rhythmic cues. The results showed relatively high er recognition scores at lower pulse rates, although melody recognitio n remained possible up to rates of approximately 600-800 pulses per se cond. Stimulation of apical electrodes yielded higher recognition scor es than of basal electrodes. The perception of musical intervals, defi ned as frequency ratios between two trains of stimulus pulse rates, wa s investigated in an interval intonation labeling experiment, for inte rvals ranging from a minor 3rd to a major 6th. Within a range of low p ulse rates, subjects defined the intervals mediated by electrical puls e rate by the same ratios which govern musical intervals of tonal freq uencies in normal-hearing listeners. It may be concluded that temporal cues are sufficient for the mediation of musical pitch, at least for the lower half of the range of fundamental frequencies commonly used i n music. (C) 1995 Acoustical Society of America.