Etude psychoacoustique de la fatigue auditive a court terme
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Paris 5Disciplines:
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Abstract EN:
Auditory fatigue refers to the temporary loss of auditory sensitivity that takes place after exposing the ear to an intense sound. The psychoacoustic characteristics of temporary loudness shift (tls) are different from those of temporary threshold shift (tts). The only existing model is not able to explain these differences in a consistent way. The present study compares tts and tls systematically by varying the parameters of exposure (level, duration and frequency) and testing (level) and frequency). Recovery was measured for a period warying between three and five and half minutes. The results show an important short-term tls (recovery time : five minutes) after a moderate or high-level exposure. This kind of tls is also present at test frequencies at which the auditory threshold is unchanged or only slightly elevated. By increasing the level of exposure the tls spreads to frequencies situated more and more above the test frequency. We suggest-in contrast to the previous model explaining auditory fatigue by a single mechanism (progressive deterioration of the most sensible elements of the auditory function) - the existence of a second mechanism short-term fatigue which is similar to a sensory adaptation regulation under the effects of stimulation.
Abstract FR:
La fatigue auditive est une diminution temporaire de la sensibilite de l'oreille apres une exposition sonore. Les caracteristiques de la fatigue aux niveaux d'audition supraliminaires different de celles au seuil d'audition. L'unique modele existant explique mal ces differences. L'etude presente compare systematiquement la fatigue au seuil a la fatigue supraliminaire en faisant varier les parametres d'exposition (niveau, duree et frequence) et de test (niveau et frequence) ; la recuperation a ete mesuree pendant une duree variant entre trois et cinq minutes et demie. Les resultats revelent l'existence d'une fatigue supraliminaire importante de courte duree (5 minutes) se manifestant apres des expositions moderees ou intenses et egalement a des frequences tests auxquelles le seuil est inchange ou seulement legerement eleve. En augmentant le niveau d'exposition la fatigue s'etend sur une zone de frequence de plus en plus large situee au-dessus de la frequence d'exposition. Nous suggerons- au contraire des modeles expliquant la fatigue auditive par un mecanisme unique (deterioriation progressive des elements les plus sensibles de la fonction auditive) - l'existence d'un deuxieme mecanisme induisant une fatigue de courte duree semblable a une adaptation regulation sensorielle sous l'effet d'une stimulation.