The contribution of speech motor function to the cognitive testing

Abstract

This pilot study was to explore speech function as a possible confounding factor in the assessment of persons with Mild Cognitive Impairment (MCI) due to Alzheimer’s disease (AD). In the United States, over 30 million people are 65 and older with 10 to 20% of them suffering from MCI due to AD. Episodic memory is tested in diagnosis of MCI due to AD using recall of a story or a list of words. Such tasks involve both speech and hearing. Normal aging also impacts one’s speech and hearing. In this study, we designed a test battery to investigate the contribution of speech and hearing on testing of episodic memory. Sixty community-dwelling Black and 60 demographically matched White, all over 74 years, non-demented persons participated in the study. They each produced a story-retell and named animals in one minute. All subjects were tested with hearing and speech measures (maximum-sustained vowel phonation and diadochokinetic rates). Preliminary results showed that small but consistent differences were seen between the two racial groups in the diadochokinetic rates (p < 0.05). There were negative correlations between the Story-retell and diadochokinetic rates, which may suggest that speech motor control may indeed be a confounding factor in episodic memory testing.