Dementia in Parkinson's disease (PDD) is a frequent and distressing complication with major consequences. Clinical and pathological features closely link PDD and dementia with Lewy bodies (DLB), suggesting they represent part of the same disease spectrum. Although dopaminergic deficiency primarily determines the akinetic-rigid symptoms of PDD and DLB, there is overwhelming evidence that cholinergic dysfunction underpins many of the cognitive impairments and psychotic features. Open-label studies have suggested that cholinesterase inhibitor drugs may exert positive effects upon all aspects of the neuropsychiatric syndrome in PDD and DLB but particularly apathy, anxiety, impaired attention, hallucinations, delusions, sleep disturbance, and cognitive test performance. Worsening of extrapyramidal motor features is reported only rarely. Initial double-blind, placebo-controlled studies in PDD and DLB have so far confirmed these encouraging results. Early identification of PD patients at greatest risk of developing dementia would permit early use of disease modifying treatments which represent the "golden fleece" management approach to these groups.
Copyright 2002 Movement Disorder Society