Development and validation of a measure of the impact of epilepsy on a young person’s quality of life: Glasgow epilepsy outcome scale for young persons (GEOS-YP)

Abstract

Objective The goal of the work described here was to develop and validate a measure of the impact of epilepsy on an adolescent’s quality of life that is based on direct exploration of the adolescent’s views. Methods Initial scale development was based on data generated through qualitative methods (focus groups) in a previous study [McEwan MJ, Espie CA, Metcalfe J, Brodie MJ, Wilson MT. Seizure 2004;13:15–31]. A draft measure was piloted ( n = 30) and refined using correlational methods. Psychometric properties were established by means of a preliminary field trial ( n = 78). Results An initial item pool of 76 was refined to 50. The structure of the measure mirrored the conceptual model derived from focus group study; Part 1 covered issues relating to adolescent development (identity formation) with five subscales, and Part 2 covered epilepsy-related issues with four subscales. The final GEOS-YP had good internal consistency ( α = 0.91) and test–retest reliability ( ρ = 0.75). Concurrent and construct validity was acceptable, and the GEOS-YP discriminated on dimensions of clinical importance. Participant feedback suggested the measure has excellent face validity and potential clinical utility. Conclusions The GEOS-YP is a direct measure of how adolescents perceive epilepsy impacts their quality of life. The GEOS-YP has sound psychometric properties and provides a relatively brief and potentially useful clinical outcome tool.