Final answer:
Lewy body dementia (LBD) is the type of dementia most commonly misdiagnosed as Parkinson's disease due to shared symptoms, including motor and cognitive impairments caused by the presence of Lewy bodies in neurons.
Step-by-step explanation:
The type of dementia most commonly misdiagnosed as Parkinson's disease is Lewy body dementia (LBD). Parkinson's disease and Lewy body dementia share many symptoms due to the presence of Lewy bodies, which are abnormal protein clumps in dopaminergic neurons in both conditions. Some of these overlapping symptoms include movement issues such as tremor and rigidity as well as cognitive impairment that can progress to dementia.
Unlike Parkinson's disease, which is primarily characterized by motor symptoms and is more common after the age of 50, Lewy body dementia typically presents earlier with symptoms such as visual hallucinations, cognitive fluctuations, and sleep disturbances in addition to motor symptoms.