Objective Versus Subjective Measures of Executive Functions: Predictors of Participation and Quality of Life in Parkinson Disease?

Objectives: To determine whether objective (neuropsychological tests) and subjective measures (questionnaires) of executive functions (EFs) are associated in patients with Parkinson disease (PD), and to determine to what extent level of participation and quality of life (QoL) of patients with PD can be predicted by these measures of EFs. Design: Correlational research design (case-control and prediction design). Setting: Departments of neuropsychology of 3 medical centers. Participants: A sample (N=136) of patients with PD (n = 42) and their relatives, and controls without PD (n = 94). Interventions: Not applicable. Main Outcome Measures: A test battery measuring EFs. In addition, patients, their relatives, and controls completed the Dysexecutive Questionnaire, Brock Adaptive Functioning Questionnaire, and Barkley Deficits in Executive Functioning Scale - time management questionnaires measuring complaints about EFs. Participation and QoL were measured with the Impact on Participation and Autonomy scale and the Parkinson's Disease Questionnaire-39, respectively. Results: Patients with PD showed impairments in EFs on objective tests and reported significantly more complaints about EFs than did controls without PD. No associations were found between patients' performances on objective and subjective measures of EFs. However, both objective and subjective measures predicted patients' level of participation. In addition, subjective measures of EFs predicted QoL in patients with PD. Conclusions: These findings show that objective and subjective measures of EFs are not interchangeable and that both approaches predict level of participation and QoL in patients with PD. However, within this context, sex needs to be taken into account