Prognostic value of round-window psychophysical testing with cochlear-implant candidates.

The preimplant, psychophysical-test results obtained with a single-ball, round-window electrode for 32 peri- or postlingually deafened, adult, Nucleus 22-channel cochlear-implant users were analyzed and correlated with their postimplant, open-set, speech recognition performance. The results revealed that some preimplant measures do have value as predictors of speech recognition abilities in this group of subjects. All subjects used the MPEAK speech-coding strategy and had been using their device for at least 6 months. The psychophysical measures that were found to correlate most highly with postimplant performance included the detection threshold at 400 Hz and the threshold slope function from 50 to 400 Hz, with lower values associated with higher speech recognition. To a lesser extent, detection thresholds at 100 and 200 Hz, the dynamic range at 200 and 400 Hz, and the gap detection threshold at 100 Hz correlated with speech performance. As well, duration-of-deafness variables were found to correlate significantly with postimplant performance.