Co-occurrence of parkinsonism and dementia in clinical practice: relevant differential diagnoses.

Co-occurrence of parkinsonism and dementia is commonly observed in the aging population. This narrative review gives an overview of disorders regularly presenting with these symptoms, e.g., idiopathic Parkinson disease with dementia, dementia with Lewy bodies, progressive supranuclear palsy, corticobasal degeneration syndrome, vascular cognitive impairment, drug-induced parkinsonism, and normal-pressure hydrocephalus. Both a thoroughly performed medical history and a comprehensive clinical examination can narrow down relevant differential diagnoses. Characteristic clinical and neuropsychological features are highlighted, including cognitive screening strategies. Neurophysiological and neuropathological aspects of the disorders are briefly discussed to give a better understanding of treatment options.