Validation and cross-cultural adjustment of PDQL-questionnaire, Spanish version (Ecuador) (PDQL-EV).

Objective: To validate the Ecuadorian Spanish-language version of the Parkinson's Disease Quality of Life Questionnaire (PDQL-EV).
Method: Cross-sectional study of patients with Parkinson's Disease attending a Movement Disorders Clinic. MEASURES APPLIED: Hoehn and Yahr (HY), Unified Parkinson's Disease Rating Scale (UPDRS-3.0), Schwab and England Scale (SES), Pfeiffer Questionnaire (SPMSQ), Hospital Anxiety and Depression Scale (HADS). PDQ-39 and PDQL-EV were applied, the latter after translation and back translation.
Results: The study included 137 patients with an age range of 69.43 +/- 10.18 years (mean +/- SD), duration of illness 5.87 +/- 2.58 years, and HY 2.28 +/- 0.77. The PDQL-EV internal consistency (Cronbach's alpha) yielded: Parkinson's symptoms (PS) 0.85; systemic symptoms (SS) 0.69; social function (SF) 0.81; and emotional function (EF) 0.78. The correlation between measurements varied from 0.68 (PS-SS) to 0.46 (SS-EF), and total measurement correlation from 0.58 (EF) to 0.74 (PS) (altogether, p < 0.0001). The correlation of PDQL with clinical variables was: HY -0.62; UPDRS (subscales 1, 2 and 3) -0.55, -0.76, and -0.48, respectively; SES 0.65; SPMSQ -0.35; HADS-anxiety -0.55; HADS-depression -0.67; and PDQ-39 -0.91 (altogether p < 0.0001). PDQL-EV scores were significantly different (p < 0.0001) between moderate and advanced stages, for all domains except for EF (p = 0.006).
Conclusion: The PDQ-EV has satisfactory internal consistency, and converging and discriminating validity.