The Effects of Verbal Reaction Time in Alzheimer's Disease

Objectives/Hypothesis: Verbal fluency deteriorates with normal aging, but is much more severe in Alzheimer's Disease (AD). Verbal functions were analyzed to find differences between normal aging subjects in patients with mild cognitive impairment (MCI), and in patients with early and moderate stages of AD. This study measured the verbal response time in patients with AD, MCI, and in control subjects Study Design: This study measured the verbal response time in patients with AD, MCI, and in control subjects Methods: Fifteen patients with MCI, 15 patients with early AD, 8 patients with moderate AD, and 15 subjects for controls were included in the study. Word length in milliseconds, reaction time to a phoneme, word, or sentence and acoustic analysis of voice quality and speech diadochokinetic rate (DDK) were measured. Results: Reaction time for a phoneme, word, or sentence especially the initiation period for them were longer in patients with early AD compared to patients with MCI (P < .001). The mean DDK rate was lower with increased severity of the disease, and was much more severe in patients with moderate AD. Conclusions: Clinical discrimination of the early stages of AD and MCI is challenging. Unfortunately, there are no laboratory markers present for the diagnosis of preclinical cases of AD. With the results of this study, the assessments of verbal reaction time may helpful for diagnosis of early AD.