Investigating perceptual features of electrode stimulation via a multidimensional scaling paradigm

To achieve the most effective speech processing for individuals with cochle ar implants, it is important to understand the perceptual features associat ed with the stimulation parameters. In general, when electrodes are stimula ted in order from apex to base, the pitch of the perceived sound changes in an orderly fashion from low to high. Some deviations from this assumed ord er have been documented. Also, pitch is the dominant perceptual attribute o f a sound when the stimuli associated with different electrodes have been a ccurately loudness balanced. In this study, the results of a multidimension al scaling (MDS) paradigm were compared to the results of a pitch-ranking p rocedure for six subjects implanted with multichannel cochlear prostheses. Results indicate that there may be multiple percepts that change with elect rode location. Not surprisingly, the dominant percept is strongly correlate d with pitch. The results also indicate that the structure of the second pe rcept is consistent across subjects, although not interpretable using the d ata measured in this study. Furthermore, results indicate that MDS data can be used to pinpoint indiscriminable electrodes more accurately than pitch data. The results of this study may have importance for the design of the n ext generation of speech processors. (C) 2000 Acoustical Society of America . [S0001-4966(00)02511-X].