The French version of the Gilles de la Tourette Syndrome Quality of Life Scale for adolescents (GTS-QOL-French-Ado): Adaptation and psychometric evaluation.

Introduction: The aim of this study was to create a new version of the French GTS-QOL adapted to adolescents with GTS aged 12-16 years (GTS-QOL-French-Ado) and to evaluate its psychometric properties.

Methods: We assessed the psychometric properties of the GTS-QOL-French-Ado in 84 adolescents (mean age 13.6 years, standard deviation 1.2) in terms of factor structure, internal consistency, reliability and convergent validity with the Child Depression Inventory (CDI), the Multidimensional Anxiety Scale for Children (MASC), the Motor tic, Obsessions and compulsions, Vocal tic Evaluation Survey (MOVES) and the French "Vécu et Santé Perçue de l'Adolescent" (VSP-A), a generic self-administered measure of health-related quality of life (HRQoL) in adolescents.

Results: Exploratory factor analysis of the GTS-QOL-French-Ado resulted in a 5-factor solution. The GTS-QOL-French-Ado demonstrated good acceptability with missing values per subscale ranging from 0% to 1.2%, good internal consistency for four of the five subscales with Cronbach's alpha ranging from 0.56 to 0.87 and good test-retest reliability with intraclass correlation coefficients ranging from 0.74 (95% CI: 0.52-0.86) to 0.82 (95% CI: 0.66-0.91). Convergent validity was supported by correlations with CDI, MASC, MOVES, VSP-A and clinical variables.

Discussion: The GTS-QOL-French-Ado is the first disease-specific HRQoL tool for French-speaking adolescents with GTS aged 12-16 years, and shows good psychometric properties. Further psychometric testing on responsiveness to change would be of great interest.