Italian validation of the functional difficulties questionnaire (FDQ-9) and its correlation with major determinants of quality of life in adults with hypermobile Ehlers-Danlos syndrome/hypermobility spectrum disorder

The 2017 nosology defines the new criteria for hypermobile Ehlers-Danlos syndrome (hEDS), which is now considered one end of a continuous spectrum encompassing isolated, nonsyndromic joint hypermobility (JH) and hypermobility spectrum disorders (HSDs). Preliminary data indicate a link between JH and neurodevelopmental disorders and, in particular, developmental coordination disorder (DCD) in children. Assessing DCD in adults is difficult and the recently described functional difficulties questionnaire 9 (FDQ-9) is one of the few available tools. The aims of this study are to (a) validate FDQ-9 written in Italian and present normal values in 230 Italian controls; (b) explore the relationship of FDQ-9 with the brief pain inventory, composite autonomic symptom score 31, multidimensional fatigue inventory, attention deficit/hyperactivity disorder self-report version 1.1, and the SF-36 for quality of life in 105 Italian adults with hEDS/HSD. Validation of the FDQ-9 in Italian was carried out by translation, cross-cultural adaptation and test/retest reliability analysis. A case-control study was performed comparing the FDQ-9 outcome between 105 patients and 105 sex- and age-matched controls. Fifty-nine percent of the patients resulted positive compared to the 3.8% of controls (p value < .00001). In patients, FDQ-9 positive result associated with positive attention deficit/hyperactivity disorder self-report version 1.1 (OR = 4.04). Multivariate regression analysis comparing FDQ-9 with the other questionnaires demonstrated a strong association between positive FDQ-9 and the number of painful joints. Our preliminary data open wider management and therapeutic perspectives for coordination difficulties in hypermobile individuals.