A Quick Test for Cognitive Speed: a measure of cognitive speed in dementia with Lewy bodies.

The purpose of this article is to investigate how patients with dementia with Lewy bodies (DLB) perform on A Quick Test for Cognitive Speed (AQT) compared with patients with Alzheimer's disease (AD) and age- and sex-matched controls and to see whether this test might be helpful in distinguishing DLB from AD at comparable cognitive levels. Twenty-three patients with DLB, 18 patients with AD, and 24 controls were included. The time in seconds to complete the AQT was recorded for the 3 independent study groups according to standard directives. The DLB patients had significantly longer reading times than the AD patients at equivalent and relatively high Mini-Mental State Examination levels. We suggest that slow performance on the AQT at relatively high Mini-Mental State Examination levels could be one way of distinguishing DLB from AD. This may have clinical implications for treatment as well as for understanding the neuropathological properties of the disease.