Cholinesterases in cerebrospinal fluid. Correlations with clinical measures in Alzheimer's disease.

Acetylcholinesterase and butyrylcholinesterase activities in cerebrospinal fluid were measured in 17 patients with Alzheimer's disease and 6 control patients, as potential clinical measures of impaired cholinergic neurotransmission in Alzheimer's disease. The activity of butyrylcholinesterase was decreased in patients with Alzheimer's disease compared to that observed in control patients, but there was overlap between values in the 2 groups. Low butyrylcholinesterase activity was correlated with severity of dementia, memory impairment, and language disorder. Acetylcholinesterase activity was significantly correlated with visual contrast sensitivity, but not with dementia severity, and did not differentiate patients with Alzheimer's disease from control cases. These results suggest that cholinesterases in cerebrospinal fluid are related to brain cholinesterases, and indicate that the activities of acetylcholinesterase and butyrylcholinesterase should be distinguished in studies of cerebrospinal fluid.