Dementia with Parkinsonism

Kim, Ho Chan; Kim, Seong Hwan

Abstract

Parkinson's disease (PD) is a extrapyramidal movement disorder characterized by rigidity and bradykinesia. PD is one of the most common neurodegenerative disorders, affecting 1% of the population over the age of 60. Dementia is common and affects 40% of patients with PD during the course of the disease, the risk for the development of dementia being 6 times higher than in age-matched general population. In addition to motor abnormalities, there are several non-motor signs and symptoms that may create a considerable burden for patients and caregivers. Parkinsonism is a major feature of several dementing diseases. The parkinsonian disorders with dementia are Parkinson's disease dementia (PDD), parkinsonian-plus syndromes, sepcific heredodegenerative diseases, and secondary parkinsonisms. The parkinsonian-plus syndromes are neurodegenerative disorders charaterized by parkinsonism and at least one other nonparkinsonian neurological manfestation. This brief review concentrates on those disorders in which cognitive impairment/dementia and parkinsonism coexist: Parkinson's disease dementia, progressive supranuclear palsy, and corticobasal degeneration. The clinical and neuropsychological similarities and differences in these disorders are compared and contrasted along with Alzheimer's disease, Parkinson's disease, and dementia of Lewy bodies, highlighting the features critical for identifying the correct diagnosis.