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

Abstract

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

“…In parallel of our work (that began in 2012), two Italian and English versions of the GTS-QOL for children and adolescents, named the C&A-GTS-QOL, were developed and validated in 2013 and 2016 [ 45 , 46 ]. The five-factor structure of the GTS-QOL-French-Ado differs from the four-factor structure of the Italian version and the six-factor structure of the English-language version of the C&A-GTS-QOL [ 45 , 46 ] and from the six-factor structure of the GTS-QOL-French for adults [ 14 ]. Compared to the Italian version [ 45 ], the GTS-QOL-French-Ado has one additional subscale, the ‘Social’ subscale, and the other four subscales are not composed of exactly the same items.…”

“…Unlike in the Italian and English-language versions of the C&A-GTS-QOL [ 45 , 46 ], the ‘Psychological’ subscale of the GTS-QOL-French-Ado does not include items related to social domain grouped together in the ‘Social’ subscale. A ‘Social’ subscale also exists in the GTS-QOL-French for adults [ 14 ]. Several studies found impaired social functioning and peer relationship problems in youths with GTS [ 4 , 49 , 50 ].…”

“…The study was performed in two stages: adaptation of the French version of the GTS-QOL for adults [ 14 ] to adolescents (GTS-QOL-French-Ado), and assessment of the psychometric properties of the GTS-QOL-French-Ado.…”

“…Our team translated in French and cross-culturally adapted the GTS-QOL in adults (GTS-QOL-French). The French version had satisfactory acceptability, internal consistency, convergent validity and reliability [ 14 ]. It was immediately adapted for adolescents aged between 12 and 16 years by three clinicians with experience in the management of adolescents with GTS who suggested how to simplify or rephrase items that they thought could be confusing for subjects in this age group.…”

“…The use of the GTS-QOL is advocated in the European Clinical Guidelines for Tourette Syndrome and Other Tic Disorders [ 13 ]. Our team had validated a French version of the GTS-QOL for adults [ 14 ] that we decided to adapt for French speaking adolescents. Indeed, to our knowledge, there has been only one study in France that has assessed the HRQoL of adolescents with GTS, using the generic HRQoL instrument “Vécu et Santé Perçue de l’Adolescent” (VSP-A) [ 15 ].…”