Follow-Up of Auditory-Evoked Potentials and Temporary Threshold Shift in Subjects Developing Noise-Induced Permanent Hearing Loss¹

Abstract

The effects of auditory fatigue, using a temporary threshold shift (TTS) paradigm, on cochlear microphonics (CM) and on auditory brainstem-evoked potentials (ABEP), were studied in normal-hearing subjects during the development of permanent threshold shift (PTS). Behavioral threshold shifts were accompanied by different effects on CM and on ABEP, as PTS was gradually induced by occupational noise. Measures of the effect of increasing stimulus rate (ISR) on ABEP revealed decreased latency shifts during auditory fatigue. ABEP proved useful in early detection of changes in the auditory system, resulting from exposure to noise. In addition, this study further supports the suggestion that TTS acts as a peripheral attenuator of the effect of ISR on the central auditory pathway.

On a étudié les effets de la fatigue auditive sur le microphonique cochléaire (MC) et les réponses du tronc cérébral (RTC) en utilisant le déplacement temporaire du seuil (DTS), sur des sujets normo-entendants, pendant le développement du seuil de déplacement permanent. Les changements dans les seuils subjectifs sont accompagnés d'effets différents sur le MC et les RTC. L'accroissement du rythme de stimulation (ARS) réduit les changements de latence durant la fatigue auditive. Les RTC permettent de détecter précocement les changements auditifs dus au bruit. Cette étude suggère en outre que le DTS interviendrait comme un atténuateur périphérique des effets de l'ARS sur les voies auditives centrales.

Key Words:

• Cochlear microphonics
• Auditory brainstem-evoked potentials
• Temporary threshold shift
• Noise-induced hearing loss