Relationship between poor decision-making process and fatigue perception in Parkinson's disease patients.

BACKGROUND: Fatigue is a common non-motor symptom in Parkinson's disease patients. The reasons for its perception are not completely understood. One suggested possibility might be that perceived fatigue is related with abnormal interpretation of somatic symptoms. It has been described that somatic markers misinterpretation leads to poor decision-making. We hypothesized that fatigued Parkinson's disease patients would show poorer performance than non-fatigued in a decision-making task. METHODS: To test our hypothesis, 89 Parkinson's disease patients were assessed for the presence of fatigue using the Parkinson Fatigue Scale. All patients were also administered scales evaluating psychopathology and neuropsychological tests, including the Iowa Gambling Task. RESULTS: 33 (37.1%) patients fulfilled the established criteria for fatigue. In the univariate analysis, fatigued patients showed higher levels of anxiety (state: p = 0.001, trait: p < 0.001), impulsivity (p = 0.051), and depression (p < 0.001) than non-fatigued patients. No statistically significant differences in other neuropsychological test results (Stroop, Trail Making Test, Tower of London) were found between fatigued and non-fatigued patients except for the Iowa Gambling Task, in which fatigued patients showed poorer performance (p = 0.001) after controlling for confounding factors. CONCLUSIONS: These results suggest that fatigued Parkinson's disease patients may present abnormal decision-making process, which may reflect abnormal processing of somatic markers when faced with an activity that requires effort.

The association of apathy with central fatigue perception in patients with Parkinson's disease.

This study was designed to evaluate the association of different apathy conceptual domains with central fatigue perception in Parkinson's disease (PD), taking into consideration other nonmotor symptoms. To this end, 90 consecutive PD patients (66.7% men, mean age 61.44 ± 13.2 years) underwent a comprehensive neurological and psychiatric examination, including the Structured Clinical Interview for DSM-IV, Parkinson Fatigue Scale, Lille Apathy Rating Scale, Hamilton Depression Scale, and State-Trait Anxiety Inventory. A linear regression model was applied to analyze the relationship between apathy and its different conceptual domains with fatigue severity. Thirty-seven (41.1%) patients presented fatigue. Its presence was associated with higher apathy total scores and with 2 of the 4 apathy conceptual domains (less intellectual curiosity and action initiation) with no associations in the emotion and self-awareness apathy domains. Patients with fatigue scored higher in depression (p < .001), anxiety trait (p < .001), and anxiety state (p = .006). Regression analysis identified that Lille Apathy Rating Scale total score (p = .008), intellectual curiosity and action initiation apathy subscores (p = .001 and p = .003) were associated with fatigue severity in patients with right predominant motor symptoms. Sex, age, disease duration, clinical stage, motor complications, prior psychiatric disorders, and treatment were not significantly associated with presence of fatigue. The findings suggest that some apathy-related domains are more frequent in fatigued PD and may be related with fatigue severity.