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

International audienceIntroduction: 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

Cross-cultural adaptation and psychometric evaluation of the French version of the Gilles de la Tourette Syndrome Quality of Life Scale (GTS-QOL)

International audienceIntroduction: The Gilles de la Tourette Syndrome-Quality of Life Scale (GTS-QOL) is a self-rated disease-specific questionnaire to assess health-related quality of life of subjects with GTS. Our aim was to perform the cross-cultural adaptation of the GTS-QOL into French and to assess its psychometric properties.Methods: The GTS-QOL was cross-culturally adapted by conducting forward and backward translations, following international guidelines. The psychometric properties of the GTS-QOL-French were assessed in 109 participants aged 16 years and above with regard to factor structure, internal consistency, reliability and convergent validity with the MOVES (Motor tic, Obsessions and compulsions, Vocal tic Evaluation Survey) and the WHOQOL-BREF (World Health Organization Quality of Life Brief).Results: Exploratory factor analysis of the GTS-QOL-French resulted in a 6-factor solution and did not replicate the original structure in four subscales. The results showed good acceptability (missing values per subscale ranging from 0% to 0.9%), good internal consistency (Cronbach's alpha ranging from 0.68 to 0.94) and good test-retest reliability (intraclass correlation coefficients ranging from 0.70 to 0.81). Convergent validity with the MOVES and WHOQOL-BREF scales showed high correlations.Discussion: Our study provides evidence of the good psychometric properties of the GTS-QOL-French. The cross-cultural adaptation and validation of this specific instrument will make it possible to assess health-related quality of life in French-speaking subjects with GTS. The GTS-QOL-French could be recommended for use in future research

The GTS-QOL-French-Ado.

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Path diagram of the factorial structure of the GTS-QOL-French-Ado from the exploratory factor analysis.

Factor latent variables are represented by ellipses. Measured variables (items of the GTS-QOL-French-Ado) are represented by rectangles. The curved double-headed links represent the correlations among factors. The directed links from factors to items represent the factor loadings estimates. The path diagram displays only the links that have loadings equal or greater than 0.32.</p

Corrected item-total correlations for the GTS-QOL-French-Ado subscales.

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Descriptive statistics and score distributions of the GTS-QOL-French-Ado subscales.

Descriptive statistics and score distributions of the GTS-QOL-French-Ado subscales.</p

Convergent validity for GTS-QOL-French-Ado.

Correlations represented on a HEATMAP: in red, positive correlations and in blue, negative correlations. Graduation in the colour indicates the strength of the correlation.</p

Factor loadings from the factor analysis of the GTS-QOL-French-Ado items.

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Effect size of sociodemographic and clinical factors on GTS-QOL-French-Ado subscales.

Effect sizes (ES) are presented as forest plot with 95% confidence interval [95% CI] for each GTS-QOL-French-Ado subscale. The ES are given for ‘Yes’ versus ‘No’ values of the sociodemographic and clinical factors. Positive ES indicates worse HRQoL and negative ES better HRQoL. Dotted lines represent the threshold for small (0.2), moderate (0.5) and large (0.8) ES.</p

Scree plot of the eigenvalues for the factor analysis of the GTS-QOL-French-Ado.

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