Pulse timing dominates binaural hearing with cochlear implants

• 成果类型: Article
• 署名作者: Schnupp, Jan W. H.; Buchholz, Sarah; Buck, Alexa N.; Budig, Henrike; Khurana, Lakshay; Rosskothen-Kuhl, Nicole
• 署名单位: City University of Hong Kong; Chinese University of Hong Kong; Chinese University of Hong Kong; University of Freiburg; University of Freiburg; University of Freiburg
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11269
• DOI: 10.1073/pnas.2416697122
• 发表日期: 2025-04-22
• 关键词: interaural time differences; inferior colliculus neurons; fine-structure; difference sensitivity; enhancing sensitivity; delay sensitivity; spatial hearing; c-fos; envelope; lateralization

摘要

Although cochlear implants (CIs) provide valuable auditory information to more than one million profoundly deaf patients, these devices remain inadequate in conveying fine timing cues. Early deaf patients in particular struggle to use interaural time differences (ITDs) for spatial hearing and auditory scene analysis. Why CI patients experience these limitations remains controversial. One possible explanation, which we investigate here, is that the stimulation by clinical CIs is inappropriate, as it encodes temporal features of sounds only in the envelope of electrical pulse trains, not the pulse timing. We have recently demonstrated that early deaf, adult implanted rats fitted with bilateral CIs that deliver carefully timed pulses routinely develop sensitivity to very small ITDs. Here we show that, while the early deafened mammalian auditory pathway can innately easily resolve pulse timing ITDs as small as 80 mu s, it is many times less sensitive to the ITDs of pulse train envelopes. Our results indicate that the stimulation strategies in current clinical use do not present ITD cues in a manner that the inexperienced auditory pathway is highly sensitive to. This may deprive early deaf CI patients of the opportunity to hone their submillisecond temporal processing skills as they learn to hear through their prosthetic devices.