[Dementia in Parkinson's disease: risk factors, diagnosis and treatment].

Aside from limb tremor, bradykinesia, rigidity and gait disturbances, Parkinson's disease (PD) is also characterized by non-motor symptoms. A cognitive decline can occur early in the disease course and undoubtedly impact of the patient's quality of life. Dementia affects 80% of patients 20 years after disease onset but a small subgroup of patients remain free of dementia even after decades with PD. Risk factors and diagnosis of dementia can be easily assessed using bed-side clinical instruments. Advances in genetics and imagery will allow improving the diagnosis and therapeutic strategy dementia in Parkinson's disease.