The Spanish version of the quality-of-life in epilepsy inventory (QOLIE-31): Translation, validity, and reliability

Purpose: Spanish adaptation of the Quality of Life in Epilepsy Inventory (Q OLIE-31). Methods: Internal consistency and construct validity of the Spanish transla tion of the QOLIE-31 were tested in 252 patients with epilepsy. Patients al so were administered the General Health Questionnaire (GHQ-28), and the Not tingham Health Profile (NHP). Two weeks after the first test, a subgroup of randomly selected patients were readministered the QOLIE-31 along with a n ew five-option question about change in health status. Patients reporting n o change in health status were included in the study of temporal stability. Sensitivity to clinical change was assessed in 31 additional patients who had successfully undergone epilepsy surgery. Results: The QOLIE-31 was highly correlated with the GHQ-28 (r = -0.63) and the NHP (r = -0.69), demonstrating construct validity. Cronbach's alpha co efficient was 0.92, showing the items of the QOLIE-31 to be interdependent and homogeneous. For a 2-week lest retest, both Pearson product-moment corr elation and intraclass correlation coefficients were 0.90, indicating tempo ral stability. Sensitivity to clinical change was suggested by a significan t mean difference between the global scores both before and after epilepsy surgery (-21.87, p < 0.0001; 95% CI, -28.08 to -15.66). The standardized re sponse mean of the global score was 1.67, and the effect size was 1.35, bot h indicating large clinical change as a result of seizure relief. Conclusions: The similarity of psychometric properties between the English and the Spanish versions of the QOLIE-31 supports their conceptual equivale nce. The questionnaire's responsiveness to clinical change suggests its uti lity in outcome assessment of drug trials and epilepsy surgery.