Reliability and Validity of the Japanese Versions of SEALS and QOLIE‐31

Abstract

Purpose: The growing evidence that factors other than epileptic seizures affect the quality of life (QOL) of people with epilepsy has led to the development of a number of tools for assessing QOL. These tools were originally published in English. It has been considered that a patient's perception of QOL may be influenced significantly by cultural differences. Many cultural differences exist between the West and Japan, and one of the major problems is linguistic differences. The translation process for creating valid Japanese versions of tests made in foreign languages must involve many problems that would affect the reliability and validity of the test results. In this study, we investigated the reliability and validity of the Japanese versions of Side Effects and Life Satisfaction (SEALS) and 31–Items Quality of Life in Epilepsy (QOLIE‐31). The results highlight psychosocial difficulties for Japanese people with epilepsy and demonstrate some of the cultural problems encountered when translating QOL questionnaires. Methods: SEALS is a self‐rating questionnaire that was developed in the United Kingdom to assess the effects of antiepileptic drugs (AEDs) on psychosocial functioning. Gillham and her colleagues recently developed a revised version which comprises 38 items with five subscales (Cognition, Dysphoria, Tiredness, Temper, and Worry). QOLIE is a novel QOL instrument that was developed in the United States. This test consists of seven subscales (Seizure Worry, Overall Quality of Life, Emotional Well‐Being, Energy/Fatigue, Cognitive Functioning, Medication Effects, and Social Functioning). Eighty‐five adults with epilepsy (43 women and 42 men with a mean age of 33 years), who were leading an ordinary social life, provided valid data for analysis. All of them completed QOLIE‐31, SEALS, and the Washington Psychosocial Seizure Inventory (WPSI) at the same time. The severity of their epileptic seizures was assessed by using the VA Severity Scale and the Revised Chalfont Scale. Results: The reliability of the Japanese versions of SEALS and QOLIE‐31 was estimated by using Cronbach's alpha value. These values for the SEALS total score and QOLIE‐3I overall score were 0.89 and 0.91, respectively. The correlation coefficients between the QOLIE‐3I overall score and the SEALS total score with the WPS1 Overall psychosocial functioning score were highly significant. These results indicate that SEALS and QOLIE‐31 exhibit good reliability and validity in a Japanese population of persons with epilepsy. We analyzed the correlation between these indexes and clinical features multidimensionally. Factors that influenced the test results were gender, VA Severity Scale score, seizures frequency, type of epilepsy, AEDs, and social adaptation. No significant differences were observed between these two tests. Conclusions: We introduced SEALS and QOLIE‐31 to Japan with the permission of the original investigators and created Japanese versions of these questionnaires. In this study, we investigated the validity and reliability of these Japanese versions. These tests showed good reliability and validity as to the measurement of psychosocial problems in Japanese people with epilepsy. The studies described confirmed that SEALS and QOLIE‐31 are promising self‐rating tools for use in assessing QOL issues in Japanese persons with epilepsy.