Cognitive effects of scopolamine in dementia.

Cholinergic deficiency was postulated to play an important role in the mental decline observed in Alzheimer's (AD), Parkinson's (PD) and multiinfarct (MID) dementia. In the present study, 11 AD, 8 MID and 7 PD patients (DSM III-R diagnostic criteria for dementia) and 9 healthy age-matched controls (CTRL) were given IV 0.5 mg scopolamine (SCO) or placebo (PLA) in random order (double blind) within one week. The Hebrew Short Mental Test (SMT) and Wechsler Memory Scale (WMS) were administered before and after SCO and PLA in each patient. A comparison of SCO vs. PLA utilizing MANCOVA (the covariate being the basal mental performance [BAS] with SMT or WMS) showed that SCO affected all the groups similarly, except for the Wechsler subtest of logic memory which showed larger deterioration in CTRL compared to demented patients. ANOVA and MANCOVA analyses did not distinguish between the three demented groups. SCO administration does not differentiate between demented patients and CTRL and does not enable discrimination between patients with AD, MID and PD. Moreover, some CTRL with still normal cognitive performance, but lower BAS may be more vulnerable to SCO than others. The integrity of the cholinergic system may be responsible for the different sensitivity to SCO challenge.

Effects of a single intravenous dose of scopolamine on the quantitative EEG in Alzheimer's disease patients and age-matched controls.

Quantitative EEG (qEEG) was evaluated in Alzheimer's disease (AD) patients and age-matched controls following the administration of a single acute intravenous dose of scopolamine. Eleven AD patients and 8 cognitively intact age-matched controls underwent qEEG in baseline conditions, following double-blind intravenous administration of 0.5 mg scopolamine or placebo. At baseline, AD patients had significantly decreased absolute and relative alpha and increased relative theta amplitudes. In both groups, scopolamine administration was followed by a decrease in absolute and relative alpha amplitude, and increase in the absolute and relative delta activity. The increase in the absolute and relative delta amplitude by scopolamine was significantly more prominent in the controls; the decrease of alpha activity, while larger in controls, was not statistically different from AD. We conclude that scopolamine affects the change in delta amplitude differently in AD patients and controls, probably reflecting the reduced cholinergic tone in AD.