A preliminary examination of aging and sex on dichotic listening performance
Degree GrantorUniversity of Canterbury
Degree NameMaster of Audiology
Dichotic listening of auditory stimuli is a method of assessing brain lateralisation. Different stimuli are presented simultaneously to the left and right ears, with the listener reporting which stimulus is perceived most clearly. To date, several studies that have examined the effects of aging on dichotic listening performance have indicated a pronounced right ear advantage (REA) with increasing age, but few studies have considered the effects of sex, and findings to date have been inconclusive. The aim of this research was to investigate whether the effects of age and sex resulted in a difference in the magnitude of the REA in both undirected and directed attentional tasks. Forty sex-matched, right-handed subjects with normal hearing or symmetrical bilateral sensorineural hearing loss participated in a series of directed and undirected dichotic listening tasks using consonant-vowel (CV) stimuli. The interaural intensity difference (IID) was modulated randomly during the undirected attention task. Results indicated that all groups (age & sex) showed a REA for both undirected and directed dichotic listening tasks. No age or sex-related differences were found. The findings were suggestive of a task-linked effect for dichotic listening performance. The use of CV stimuli, in combination with detailed testing via manipulation of the IID, appeared to minimize any possible age or sex-related differences. These findings have implications for theories on laterality and hemispheric asymmetry for older adults.