Psychophysical and speech perception studies: a case report on a binaural cochlear implant subject.

Further improvements in speech perception for cochlear implant patients in quiet and in noise should be possible with speech processing strategies using binaural implants. For this reason, presented here is a series of initial psychophysical and speech perception studies on the authors' first binaural cochlear implant patient. For an approximate matching of the places of stimulation on the two sides, the patient usually reported a single percept when the two sides were simultaneously stimulated. Lateralization was strongly influenced by amplitude differences between the electrical stimuli on the two sides, but only weakly by interaural time delays. Speech testing, comparing monaural with binaural electrical stimulation, showed a binaural advantage particularly in noise.