Quality of life in Parkinson's disease: Greek translation and validation of the Parkinson's disease questionnaire (PDQ-39)

The Parkinson's disease questionnaire (PDQ-39) is a well-validated British scale for the assessment of health-related quality of life (HQoL) in Parkinson's disease (PD). The PDQ-39 has been translated into Greek and it was applied to 119 Greek PD patients. These patients were classified in stages according to the Hoehn and Yahr (HY) scale and their motor disability was assessed by means of the Unified Parkinson's disease rating scale (UPDRS) as well as the Schwab and England activities of daily living scale (ADL). The Beck depression inventory (BDI) was applied for the evaluation of depression. The translated version of PDQ-39, designated PDQ-39GrV, was validated as follows: (1) Cronbach's alpha coefficient and item-total Spearman's rank-order correlations were calculated in order to estimate the internal consistency of PDQ-39GrV scales. (2) Validity of the PDQ-39GrV was examined in terms of agreement with the clinical assessment parameters (stage, UPDRS. ADL and BDI scores). (3) Sixty one PD patients were re-evaluated 3-7 days later in order to check test-retest reliability. The results showed the following: (1) The PDQ-39GrV demonstrated very good internal consistency (alpha 0.71-0.94). Item-total correlations were statistically significant (r: 0.52-0.93). Test-retest measurements correlated significantly (p = 0.001). (2) Clinically obtained motor parameters correlated well with PDQ-39GrV scales influenced by physical aspects of the disease, while emotionally and socially influenced ones correlated with depression. Our findings indicate that PDQ-39 GrV is a reliable, easy to administer scale for the assessment of HQoL in Greek PD patients.