BackgroundThe quality-of-life (QoL) perception by Parkinson's disease (PD) patients and their caregivers (CG) has not been studied in depth. ObjectiveTo examine patient/proxy agreements on the PD QoL Questionnaire (PDQ-39), the Scale of Quality of Life of Care-Givers (SQLC) and the Multidimensional Caregiver Strain Index (MCSI). MethodsPatients with PD and their CG completed the above-mentioned questionnaires about themselves and each other. The intraclass correlations between their scores (paired t test) were compared. ResultsTwelve patient-CG pairs were studied. Agreements for QoL items were strong and comparable for the total scores of the PDQ-39, SQLC and MCSI questionnaires (75.4%14%; 78.1%+/- 14.1% and 78.2%+/- 14.3%, respectively). Agreements ranged from moderate to strong (0.57-0.88, P.05) for the patients' physical condition (PDQ-39 items 3, 5, 6, 8, 12-15, 23, 24, 35), mental concentration (item 31) and depression (item 17). Disagreements were apparent in 20%-25% of the pairs and were particularly significant for PDQ-39 items #33 and #25 (embarrassment of patients in public and distressing dreams or hallucinations), in which the CG gave higher scores than the patients. ConclusionsAgreements between patients with PD and CG were generally good for most, but not all, of the PDQ-39, SQLC and MCSI domains.