Intracranial electrophysiology of spectrally degraded speech in the human cortex.

Autor:	Nourski KV; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States.; Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, United States., Steinschneider M; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States.; Departments of Neurology and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States., Rhone AE; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States., Berger JI; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States., Dappen ER; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States.; Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, United States., Kawasaki H; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States., Howard Iii MA; Department of Neurosurgery, The University of Iowa, Iowa City, IA, United States.; Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, United States.; Pappajohn Biomedical Institute, The University of Iowa, Iowa City, IA, United States.
Jazyk:	angličtina
Zdroj:	Frontiers in human neuroscience [Front Hum Neurosci] 2024 Jan 22; Vol. 17, pp. 1334742. Date of Electronic Publication: 2024 Jan 22 (Print Publication: 2023).
DOI:	10.3389/fnhum.2023.1334742
Abstrakt:	Introduction: Cochlear implants (CIs) are the treatment of choice for severe to profound hearing loss. Variability in CI outcomes remains despite advances in technology and is attributed in part to differences in cortical processing. Studying these differences in CI users is technically challenging. Spectrally degraded stimuli presented to normal-hearing individuals approximate input to the central auditory system in CI users. This study used intracranial electroencephalography (iEEG) to investigate cortical processing of spectrally degraded speech. Methods: Participants were adult neurosurgical epilepsy patients. Stimuli were utterances /aba/ and /ada/, spectrally degraded using a noise vocoder (1-4 bands) or presented without vocoding. The stimuli were presented in a two-alternative forced choice task. Cortical activity was recorded using depth and subdural iEEG electrodes. Electrode coverage included auditory core in posteromedial Heschl's gyrus (HGPM), superior temporal gyrus (STG), ventral and dorsal auditory-related areas, and prefrontal and sensorimotor cortex. Analysis focused on high gamma (70-150 Hz) power augmentation and alpha (8-14 Hz) suppression. Results: Chance task performance occurred with 1-2 spectral bands and was near-ceiling for clear stimuli. Performance was variable with 3-4 bands, permitting identification of good and poor performers. There was no relationship between task performance and participants demographic, audiometric, neuropsychological, or clinical profiles. Several response patterns were identified based on magnitude and differences between stimulus conditions. HGPM responded strongly to all stimuli. A preference for clear speech emerged within non-core auditory cortex. Good performers typically had strong responses to all stimuli along the dorsal stream, including posterior STG, supramarginal, and precentral gyrus; a minority of sites in STG and supramarginal gyrus had a preference for vocoded stimuli. In poor performers, responses were typically restricted to clear speech. Alpha suppression was more pronounced in good performers. In contrast, poor performers exhibited a greater involvement of posterior middle temporal gyrus when listening to clear speech. Discussion: Responses to noise-vocoded speech provide insights into potential factors underlying CI outcome variability. The results emphasize differences in the balance of neural processing along the dorsal and ventral stream between good and poor performers, identify specific cortical regions that may have diagnostic and prognostic utility, and suggest potential targets for neuromodulation-based CI rehabilitation strategies. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2024 Nourski, Steinschneider, Rhone, Berger, Dappen, Kawasaki and Howard.)
Databáze:	MEDLINE
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