Affiliations: [a] Department of Neurology, Istanbul Faculty of Medicine, Istanbul, Turkey | [b] Department of Neurology and Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA | [c] Novartis Pharmaceuticals, East Hanover, NJ, USA
Correspondence:
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Corresponding author: Professor Murat Emre, Istanbul Tıp Fakültesi, Nöroloji Anabalim Dalı, 34390 Çapa, Istanbul, Turkey. Tel.: +90 212 533 8575; Fax: +90 212 533 8575; E-mail: muratemre@superonline.com
Abstract: Parkinson's disease dementia (PDD) and Alzheimer's disease (AD) are both characterized by cognitive abnormalities, neuropsychiatric symptoms, and cholinergic deficits. We reviewed data from large, placebo-controlled clinical trials conducted with rivastigmine in patients with PDD and AD to evaluate similarities and differences in response to treatment. In placebo groups, AD patients appeared to show more rapid cognitive decline than those with PDD. Treatment effects (rivastigmine versus placebo) on cognitive performance over 6 months were quantitatively similar in both populations, but qualitatively different: in AD, cognitive abilities were stabilized by rivastigmine compared to declines in placebo groups, whereas in PDD symptomatic improvements above baseline drove treatment effects while placebo patients had limited change. On activities of daily living, stabilization (rather than improvement) was observed in both dementia types. A more aggressive course of placebo decline, and greater treatment differences (rivastigmine versus placebo), were seen in sub-populations of both PDD and AD patients with hallucinations at baseline. The safety and adverse event profiles were comparable in the two populations. In conclusion, the magnitude of effect with rivastigmine versus placebo is quantitatively comparable in patients with AD and PD, but the treatment effect tended to be one of stabilization in AD, while in PDD improvements over baseline were seen. In both populations, hallucinations may identify patients who are likely to be more treatment-responsive.
