title: Psychometric evaluation of the Persian version of the quality of life in epilepsy inventory-31.
abstract: BACKGROUND
  Health assessment in patients with epilepsy (PWE) should include both clinical outcomes and health related quality of life (HRQOL) measures. The quality of life (QoL) in epilepsy-31 inventory (QOLIE-31) is widely used for QOL studies in epilepsy. This study aims to evaluate psychometrics of the Persian version of the inventory (QOLIE-31-P).
  
  
  METHODS
  Following a standard forward-backward translation and cultural adaptation, the construct validity of the QOLIE-31-P was assessed by explanatory factor analysis, multi-trait scaling analysis, and known group comparison. The criterion validity was assessed by calculating the Pearson correlation to SF-36 (36-item short-form health survey). The reliability was assessed by calculating Cronbach's alpha and test-retest study.
  
  
  RESULTS
  The factor analysis extracted from 8 factors explaining 70.35% of the variations. Item-scale correlations revealed that individual items significantly had the strongest association with the domain they were loaded on. The Pearson coefficient of correlation between QOLIE-31-P and the overall scores of SF-36 was 0.876 (P < 0.0001). Patient with medically controlled seizures scored higher than those who experienced seizures during the previous year to study date (P < 0.0001). The Cronbach's α of overall QOLIE-31-P inventory was 0.9. The overall test-retest coefficient of correlation was 0.68 (P = 0.003).
  
  
  CONCLUSIONS
  QOLIE-31-P is a valid and reliable tool to be applied in health assessment of patients with epilepsy.
authors.affiliation: Associate Professor, Department of Community Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Navid
authors.initials: N
authors.lastname: Mohammadi
authors.forename: Shiva
authors.initials: S
authors.lastname: Kian
authors.forename: Farnoush
authors.initials: F
authors.lastname: Davoudi
authors.forename: Seyed Mohammad Ali Akbarian
authors.initials: SM
authors.lastname: Nia
authors.forename: Marzieh
authors.initials: M
authors.lastname: Nojomi
keywords: Epilepsy; Quality of Life; Quality of Life in Epilepsy