title: Left-right asymmetries in hearing threshold levels in three age groups of a random population.
abstract: The average asymmetry between the hearing threshold levels in the left and right ears was analyzed in a random population (n = 3487) representing a normal population. Males and females of age groups 5-10 years, 15-50 years and over 50 years were analyzed separately. A significant average inferiority of the hearing in the left ear was found at high frequencies, especially at 3-6 kHz, among adult males and females but not among children. A slight but statistically significant average superiority of the left ear at low frequencies was noted in all age groups. At corresponding hearing threshold levels at 4 kHz, the average inferiority of the left ear in the male population was significantly greater among subjects aged 15-50 years than among older subjects. In conclusion, the inferiority of hearing in the left ear at 4 kHz seems to be associated more with noise damage than with presbyacusis. The average interaural difference at 4 kHz was significantly more marked among subjects aged 15-50 years than among older subjects when analyzed at the corresponding threshold levels. These findings indicate a pathophysiological difference between noise damage and presbyacusis.
authors.affiliation: Department of Otolaryngology, University of Oulu, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Pirilä
authors.forename: K
authors.initials: K
authors.lastname: Jounio-Ervasti
authors.forename: M
authors.initials: M
authors.lastname: Sorri
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001307:Auditory Perception / Q000502:physiology; D001309:Auditory Threshold / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D004423:Ear / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011304:Presbycusis / Q000175:diagnosis / Q000503:physiopathology; D012737:Sex Factors