Delayed blink reflex in dementia with Lewy bodies is sensitive to cholinergic modulation

To assess the possible responsiveness of blink reflex alterations present in dementia with Lewy bodies (DLB) to treatment with cholinesterase inhibitors.

Twenty-six patients with DLB and 20 patients with Alzheimer disease underwent clinical, neuropsychological (including assessment of cognitive fluctuations, with the Cognitive Assessment of Fluctuations and the One-Day Fluctuation Assessment questionnaires), and the blink reflex evaluation at baseline, 1 week after vitamin E administration (to assess test-retest reliability), and 1 and 2 weeks after donepezil administration at the dose of 10 mg/d. Results were compared with data obtained from 30 healthy controls treated with vitamin E capsules for 2 weeks.

Treatment with donepezil did not cause modifications of cognitive or motor performances in both groups of patients. In DLB patients, One-Day Fluctuation Assessment scores were modified by donepezil treatment with a mean reduction of 2.8 +/- 1.8 compared with baseline (P < 0.05). After 2 weeks of treatment with donepezil, R2 latency was significantly decreased in DLB patients. The mean R2 latency reduction was by 3.0 +/- 3.2 milliseconds (P < 0.0001 compared with baseline). R2 mean latency reduction was significantly correlated with R2 mean latency delay at baseline (Spearman rho = 0.8).

Short-term donepezil administration can correct the alterations of the blink response together with the daily occurrence of cognitive fluctuations present in DLB patients.