Abstracts

Rationale: There are no validated tools to assess satisfaction with epilepsy surgery and its outcomes. This study aims to develop and assess the psychometric properties of a new measure of patients’ satisfaction with epilepsy surgery, the Epilepsy Surgery Satisfaction Questionnaire (ESSQ). Methods: Questionnaire derivation: literature review, thematic analysis using focus groups of epilepsy surgery patients (n = 9), epilepsy surgery expert consensus (Delphi technique, n = 13), and member-checking with participants to ensure item relevance and clarity. This yielded a 31-item questionnaire with 7- or 8-point Likert-type response options. The ESSQ underwent rigorous translation and back translation into French and Swedish. For scoring, answers of 30 items were converted to 0-100 point scores, (0= worst, 100=best level of satisfaction). Item #31 is a global satisfaction item, not included in summary scoring. The ESSQ was administered twice, 6 weeks apart, to adults (>18 years) who underwent epilepsy surgery >1 year earlier, at 4 different centres. Patients also completed 7 questionnaires to assess convergent validity: quality of life: EuroQOL (EQ-5D-5L) and Quality of Life in Epilepsy (QOLIE-31-P), Depression: Patient Health Questionnaire (PHQ-9), Global Assessment of Severity of Epilepsy (GASE), Global Assessment of Disability for Seizure Disorders (GADS); and two for divergent validity: Social desirability: Marlowe-Crowne Social Desirability Scale (MCSD) and Treatment Satisfaction Questionnaire for Medication (TSQM-II). Clinical-demographic data were obtained. Exploratory factor analyses (EFA) assessed the subscale structure of the questionnaire. Item elimination used standard psychometric criteria. Cronbach's alpha coefficient assessed internal consistency reliability, and intra-class correlation coefficient (ICC) evaluated test-retest reliability. Spearman and polyserial correlations were used to assess construct validity by comparing ESSQ with the scales above. Results: 112 patients completed all questionnaires. Mean age = 41.7 years (SD=13.6), 53% female, mean time since surgery 6.5 years, 54% were seizure free, 71% had temporal lobe surgery, 12.5% had adverse effects. EFA yielded 21 items plus one global item (ESSQ-22), and a four-factor solution: satisfaction with overall quality of life, satisfaction with mood related outcomes, satisfaction with surgical complications, and satisfaction with surgical recovery, based on the magnitude of each item’s factor loadings. The domain and summary scores of the ESSQ-22 demonstrated good to excellent internal reliability (Cronbach’s a range = 0.82 to 0.94). Test-retest reliability for ESSQ domains and summary score ranged from 0.61-0.81. ESSQ summary score showed high to moderate correlations in the expected direction with EQ-5D-5L (0.59; p<0.01), QOLIE-31-P (0.71; p<0.01), PHQ-9 (-0.49; p<0.01), GASE (0.48; p<0.01), GADS scores (0.55; p<0.01), and as expected, lower correlation with MCSD (0.43; p<0.01), and TSQM-II (0.31 to 0.42; p<0.01). Conclusions: The ESSQ-22 measures epilepsy surgery satisfaction, its primary underlying construct. Preliminary results support the reliability and validity of the ESSQ. Confirmatory Factor Analyses will further assess the structure of ESSQ-22 domains. Funding: Not applicable