Colloquium du DEC

"Pitch perception in acoustic and electric hearing: Hunting down the missing fundamentals"

Par Bob Carlyon (MRC Cognition & Brain Sciences Unit, Cambridge, England)

Résumé :
Pitch perception is important not only for the enjoyment of music and for the perception of prosody in speech, but also for our ability to process one sound, such as a voice, in the presence of competing sounds. Poor pitch perception, and the resulting difficulties when listening in noisy situations, are a common source of disability in deaf patients whose hearing has been restored by a cochlear implant (CI). I will summarise some experiments that address the following questions; (i) What aspects of the auditory-nerve response to sound are crucial for good pitch perception by normal hearing (NH) listeners? (ii) What is the biological basis for the severe limitations in pitch perception experienced by CI users? (iii) Are these limits fixed, or can they be partially overcome by the chronic electrical stimulation that occurs in the months following activation of a patient’s CI?, (iv) can pitch perception by CI users be improved by a drug that modulated fast-acting potassium channels? The experiments involve a combination of NH psychoacoustics, investigation of an illusory percept, CI psychophysics, electrophysiological recordings, and the results of a double-blind placebo-controlled drug trial. I will also briefly describe other experiments from our lab that aim to improve hearing by CI listeners.