Discerning the Utility of Cognitive and Behavioural Measures for the Early Detection of Alzheimer's and Parkinson's Disease

Communication difficulties are common in Alzheimer's dementia (AD) and in mild cognitive impairment (MCI; an early mental decline stage prior to dementia). These communication difficulties are due to dementia decline's negative effect on working memory, which is our mind's ability to integrate information and perform tasks. Working memory capacity declines in dementia and with this lack of mental resources comes difficulty in perceiving and comprehending speech. A proposed solution to this difficulty is audiovisual (AV) communication: the presentation of facial communication alongside audio. AV communication has been reliably shown to decrease the degree of mental resources required to perceive and comprehend speech, a phenomena known as the AV enhancement effect. Older adults, due to experiencing hearing decline as part of normal aging, become particularly skilled in using visual information to assist in otherwise challenging communication. The proposed study will utilize the AV enhancement effect with MCI and AD populations to determine how much of an improvement in speech perception and recognition is afforded by AV communication. To measure this, participants will be shown sentences that either have grammatical errors or content errors. These sentences are known to tax working memory significantly due to the effort required to perceive and determine the error. These sentences for MCI and AD populations during normal conditions would be highly challenging, but AV enhancement will ideally overcome this difficulty and facilitate communication. The success of this project will lead to a new understanding of how best to facilitate speech perception and recognition in minds with deteriorating mental resources. This information will be used to inform caregivers and other parties on the most effective means to communicate with dementia patients, overall assisting in alleviating the debilitating consequences of mental decline.