Description and psychometric properties of the CP QOL-Teen: a quality of life questionnaire for adolescents with cerebral palsy

To assess the measurement properties of a new QOL instrument, the Cerebral Palsy Quality of Life Questionnaire-Teen (CP QOL-Teen), in adolescents with cerebral palsy (CP) aged 13-18 years, examining domain structure, reliability, validity and adolescent-caregiver concordance. Based on age, 695 eligible families were invited to participate by mail. Questionnaires were returned by 112 primary caregivers (71.8% of questionnaires sent). 87 adolescents aged 12-18 years also completed the questionnaires. CP QOL-Teen, generic QOL instruments (KIDSCREEN, Pediatric Quality of Life Inventory), functioning (Gross Motor Function Classification System) and a condition-specific instrument (PedsQL-CP) were used. Principal components analysis produced seven scales: wellbeing and participation; communication and physical health; school wellbeing; social wellbeing; access to services; family health; feelings about functioning. Cronbach's alphas for the derived scales ranged from 0.81 to 0.96 (primary caregiver report) and 0.78 to 0.95 (adolescent report). Test-retest reliability (4 weeks) ranged from 0.57 to 0.88 for adolescent self-report and 0.29 to 0.83 for primary caregiver report. Moderate correlations were observed with other generic and condition specific measures of QOL, indicating adequate construct validity. Moderate correlations were observed between adolescent self-report and primary caregiver proxy report. This study demonstrates acceptable psychometric properties of both the adolescent self-report and the primary caregiver proxy report versions of the CP QOL-Teen.