The impact of hearing aids on the cognitive functions of postlingually hearing impaired older adults

Kok, Danelia (2015) The impact of hearing aids on the cognitive functions of postlingually hearing impaired older adults. Honours thesis, Murdoch University.

Abstract

Background: The World Health Organisation estimates that 360 million people worldwide suffer from a disabling hearing loss (WHO, 2012). In Australia alone, one in six suffer from hearing impairment, with the incidence increasing to three out of four by the time an individual reaches 70 years of age (Wilson et al., 1999). Age Related Hearing Loss or presbycusis is a common type of hearing impairment in older adults. Hearing loss is known to affect speech perception (Moore, 1996) but is also associated with a higher risk of loneliness (Pronk et al., 2013). The effect of untreated hearing loss on cognitive functions has also been investigated. Reports by Lin et al. (2011 & 2013) indicate that untreated hearing loss is independently associated with accelerated cognitive decline, cognitive impairments in executive function and memory, and an increased risk of incident dementia. Aims: This study had two objectives; 1) determine if a significant difference exists between Normal Hearing (NH) and Hearing Aid Candidates (HAC) in mental health scores and cognitive tests of executive function and memory, and 2) investigate whether the use of hearing aids improves these mental health scores and cognitive functions in HAC.

Methods: Testing was conducted at baseline before hearing aid use and three months after fitting of hearing aids. Participants completed a questionnaire on anxiety, stress, and depression as a means to obtain and control for mental state. A battery of computerised tests was used to assess cognitive functions.

Results: A significant difference was found in the test of delayed visual recognition memory matching (DMS) and attention switching (AST) between NH and HAC groups. It appears that a task mediated through the temporal lobe (DMS) is impaired in HAC whereas tasks mediated through the frontal lobe (AST) showed a compensatory mechanism and therefore performance was better in the HAC. Hearing aid use did not affect these scores at three months, perhaps because three months is not long enough for acclimatisation to occur in the brain. Presbycusis sufferers displayed a higher risk for depression and stress. Hearing aids did not significantly improve this.

Conclusion: More research is needed to specifically identify which cognitive functions are affected by hearing loss to target specific treatments to these areas.

Item Type:	Thesis (Honours)
Murdoch Affiliation(s):	School of Veterinary and Life Sciences
Supervisor(s):	Jayakody, D.M.P. and Mead, Robert
URI:	http://researchrepository.murdoch.edu.au/id/eprint/38308

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