Validation of the side effect and life satisfaction (SEALS) inventory

Diminished quality of life (QOL) is a common feature of epilepsy. It is generally more severe among patients with poor seizure control but prevalent, to a clinically significant degree, even among those whose seizures are well controlled. People with epilepsy frequently report diminished socialization, negative self image, feelings of stigmatization, reduced earnings potential, and diminished hope and ambition. Problems with antiepileptic drug (AED) therapy are common, and AED therapy is recognized as an important determinant of health-related quality of life (HRQOL). A clinically efficient psychometric instrument is needed to measure its impact. The Side Effect and Life Satisfaction (SEALS) inventory is a 38-item, patient-completed questionnaire designed to measure satisfaction with AED therapy. We tested its construct validity in comparison with three widely used psychometric instruments of similar design, the Profile of Mood States (POMS), the Hospital Anxiety and Depression (HAD) scale, and the Medical Outcomes Study-Cognitive Functioning (MOS-COG) scale. All four instruments were completed by 307 epilepsy patients. A matrix of Pearson's correlations was produced for the SEALS inventory and the comparative instruments. A statistically significant correlation was found for each planned comparison. We conclude that the SEALS inventory is a valid psychometric instrument, well suited for use in clinical investigations of AED therapy and in the practical, long-term management of epilepsy.