Objective: To develop a French language instrument whose primary aim is the description of oral health status in Down syndrome (DS) individuals.
Method: Due to the reduced intellectual capacity in DS individuals, the instrument was designed to be completed by their parents. Items were generated through a literature review plus interviews with relevant professionals and DS parents. Following pilot testing, the 31-item questionnaire was divided into seven domains (access, function, development, signs, pain, disability and a global evaluation of oral health status), and subjected to a psychometric evaluation of internal reliability, test-retest reliability and discriminant validity. Internal reliability was assessed through evaluation of Cronbach's alpha or the Kuder-Richardson-20 value where appropriate. Test-retest reliability was assessed through the evaluation of the intra-class correlation coefficient (ICC) for each domain. Discriminant validity was assessed through evaluations of hypothesised differences in domain scores between different groups of DS individuals by age and between DS and non-DS individuals. The theoretical domain categorisation was empirically evaluated through the generation of inter-item correlation coefficients.
Results: Internal reliability coefficients ranged from 0.43 for the disability domain to 0.83 for the function domain, while the domain ICCs ranged from 0.56 to 0.77 for the signs and function domains respectively. For discriminant validity, the domains largely performed as hypothesised. Finally, inter-item correlation coefficients largely supported the proposed domain structure of the questionnaire.
Conclusion: This investigation of the psychometric properties of a proxy. French language, assessment of oral health problems in the DS population has demonstrated an instrument with good preliminary indicators of reliability and validity.