Evidence of cochlear neural degeneration in normal-hearing subjects with tinnitus

• Published in: Scientific reports Vol. 13; no. 1; p. 19870
• Main Authors: Vasilkov, Viacheslav, Caswell-Midwinter, Benjamin, Zhao, Yan, de Gruttola, Victor, Jung, David H., Liberman, M. Charles, Maison, Stéphane F.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30-11-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/378/2619; 631/378/2619/1387; 631/378/2619/1592; Adult; Auditory nerve; Auditory pathways; Auditory Perception; Auditory Threshold - physiology; Brain stem; Central nervous system; Cochlea; Cochlea - innervation; Electrodes; Hearing - physiology; Hearing loss; Humanities and Social Sciences; Humans; Hyperactivity; Information processing; multidisciplinary; Nervous system; Neurodegeneration; Population studies; Reflexes; Science; Science (multidisciplinary); Sound; Tinnitus; Vestibulocochlear Nerve Diseases
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-46741-5

Tinnitus, reduced sound-level tolerance, and difficulties hearing in noisy environments are the most common complaints associated with sensorineural hearing loss in adult populations. This study aims to clarify if cochlear neural degeneration estimated in a large pool of participants with normal audiograms is associated with self-report of tinnitus using a test battery probing the different stages of the auditory processing from hair cell responses to the auditory reflexes of the brainstem. Self-report of chronic tinnitus was significantly associated with (1) reduced cochlear nerve responses, (2) weaker middle-ear muscle reflexes, (3) stronger medial olivocochlear efferent reflexes and (4) hyperactivity in the central auditory pathways. These results support the model of tinnitus generation whereby decreased neural activity from a damaged cochlea can elicit hyperactivity from decreased inhibition in the central nervous system.