Brain choline acetyltransferase and mental function in Alzheimer disease

Objective: To determine whether higher brain levels of choline acetyltransferase (ChAT) are associated with improved neuropsychological function in patients with Alzheimer disease (AD). Design: Case series with single-blind post hoc analysis of biopsy specimens. Setting: Urban hospital and medical school. Patients: A consecutive sample of 8 patients with AD undergoing brain biopsy and surgical implantation of intraventricular pumps for administration of potential chemotherapeutic agents. Interventions: Brain biopsy, surgical implantation of intraventricular pumps, and, in 1 patient, ventriculo-peritoneal shunt placement. Main Outcome Measures: All patients underwent neuropsychological testing no more than 2 weeks before surgical biopsy. Levels of ChAT were determined in fresh brain tissue from biopsy samples. Results: Significant positive correlations were found between ChAT levels and 2 neuropsychological test scores, Mini-Mental State Examination and the Logical Memory subtest of the Wechsler Memory Scale. Conclusion: Degeneration of the cholinergic system in vivo correlates with decreasing cognitive function in patients with AD.