Delayed blink reflex in dementia with Lewy bodies

Blink reflexes ( BR) to electric stimuli of the supraorbital nerve were recorded in 26 patients with dementia with Lewy bodies ( DLB), 26 patients with multiple system atrophy, 26 patients with Parkinson's disease, with or without REM sleep behaviour disorder ( RBD), and in 20 patients with Alzheimer's disease and 20 with progressive supranuclear palsy without RBD, and compared with recordings in 30 healthy controls. BR were significantly delayed ( p< 0.001) only in DLB patients in comparison with controls and with the other groups of patients; 14 ( 53.8%) patients had BR latency above 2 SD of the control mean, ranging from 36.1 to 46.3 ms. BR latency was not related to the presence of RBD, while a Spearman correlation rho of 0.68 was found for scores assessing the presence of cognitive fluctuations. R2 delay was prominently ( 71.5%) bilateral.