Apathy is one of the least investigated symptom of Parkinson disease (PD). In the article there are data of frequency, diagnostic features, pathophysiology and treatment of apathy in PD. The aim of the investigation was to evaluate the frequency of apathy in PD without dementia, evaluate the relationship with other neuropsychiatric and motor disorders, influence on the life quality. 115 patients (age-63.84±0.6 years, stage-2.6±0.3) with PD without dementia were included in the investigation. There were used the following scales: scale of evaluation stages of PD by Hoehn-Yahr, UPDRS (part ?activity of daily living?, ?motor functions ?); Beck Depression Inventory, Spielberger State Trait Anxiety Inventory, Parkinson Disease Sleep Scale- PDSS, Epworth Sleepiness Scale, Parkinson Fatigue Scale-PFS-16, SCOPA-Cog, Lilli Apathy Rating Scale LARS and Apathy Scale AS.

Apathy was found in 25% of patients. The frequency and severity of apathy does not depend on stage and duration of PD. It was found positive correlation of apathy and hypokinesia. In different stages of PD there was variability of relationships of apathy with depression, executive functions and sleep disorders. We suppose the heterogeneity of apathy in PD because of the variability of the association with other neuropsychiatric (affective, cognitive, sleep) disorders. It was found the negative influence of apathy on daily activity, emotional and social aspects of life quality.