Parkinson's disease and dementia

Parkinson's disease affects as many as 1 million Americans and with advanced age is complicated by dementia in a majority of cases. However, the recognition of cognitive impairment in Parkinson's disease is made complicated by the predominance of motor symptoms and a neuropsychiatric profile that differs from the more common dementia of the Alzheimer's type. Differentiating the decline in personal and social activities due to cognitive impairment rather than preexisting movement disorder is difficult. Several expert bodies have addressed the use of cholinesterase inhibitors for the dementia of Parkinson's disease, but the evidence base is far less substantial than that which exists for Alzheimer's disease. Although most patients with Parkinson's disease dementia should be offered a trial of anti-cholinesterase therapy, particularly those experiencing hallucinations, dramatic benefits are not common. Temporary symptomatic relief rather than disease modification is the most that can be expected. As a result, treatment should be presented as an option rather than an imperative.