Audiology concepts and clinical applications

Audiology

The hypothesis of this research project is that auditory difficulties create cognitive dysfunction. There are several reasons why cognitive functions are affected or deteriorate throughout the life of an individual. Whether this affect or deterioration is due to loss of hearing has yet to be determined. It is proposed that a test be developed to give to individuals with or without hearing impairment, that will determine the extent of loss of cognitive function. When this test is administered to those who have experienced loss of hearing, and the results are compared with a persons of the same age without auditory impairment, the comparable differences may determine whether the hearing loss is a factor in the test results. If the test is administered to groups of people of different ages, with and without hearing loss, the results may find a ratio of impairment of cognitive function to be evident in those with hearing loss. If the results show great differences in all ages, one may conclude that indeed the hearing loss has an effect. However, if the differences are greater in older persons than in younger subjects (both with and without hearing loss), then one may conclude that age indeed has some effect on cognitive function.

One study on whether developmental disorders of language and literacy is due to low-level auditory perceptual difficulties, inappropriate waveforms in the N1-P2-N2 region, suggests that specific language impairment (SLI) may be characterized by immature development of the auditory cortex, such that adult-level frequency discrimination performance is attained several years later than normal (McArthur, 2004).

In another study phonological processing was studied in a group of individuals with acquired severe hearing loss. They found specific aspects of the phonological system deteriorate in those who experience hearing loss as a function of auditory deprivation. The hearing loss affects their ability to rapidly perform analysis and compare phonological operations (Andersson, 2002).

A third study examines the relationship between hearing loss and dementia. It has been speculated that hearing loss and cognitive decline coexist coincidentally because of age (Weinstein, 2006, p. 77). But there is evidence that the auditory system is involved in Alzheimer's disease and several studies have demonstrated the positive relationship between hearing impairment and cognitive status (Gates, 1997).

In a separate study, researchers at Brandeis University concluded that aging adults with moderate hearing loss may spend cognitive energy on hearing accurately to the extent that their ability to remember spoken language suffers (Medical, 2005).

Although the studies above may have determined that age has some effect on loss of cognitive function, no definitive determination has been made as to whether hearing loss is the cause or simply a part of the reason for loss of cognitive function.