Greek Translation and Preliminary Test–Retest Reliability of the AQUA CHILD Questionnaire in Children With Developmental Disabilities

Abstract

AQUA CHILD is a parent-proxy questionnaire for pre-aquatic assessment. This study describes its Greek translation and examines preliminary test–retest agreement, with explicit verification of response coding and the limits of score interpretation. Methods In a methodological repeated-measures study, 47 parents completed the questionnaire 7 days apart. The retained electronic paired files contained 99 of the 102 numbered items on the supplied forms. Swimming responses were analysed categorically; 20 non-swimming domain summaries were analysed as exploratory raw-code sums, excluding non-applicable responses and using complete domain pairs (n = 43–47). Intraclass correlation coefficients for absolute agreement, ICC(A, 1), and 95% confidence intervals (CIs), systematic differences, measurement-error estimates, and participant-level Bland–Altman analyses were calculated. No overall score was retained. Results Swimming-item exact agreement was 91.5%–97.9% (unweighted kappa, 0.899–0.974). Non-swimming ICCs ranged from 0.878 to 0.968, with lower 95% CI limits of 0.786–0.942. Only undertaking a single task retained a mean retest increase after Holm adjustment: 0.22 raw-code points (95% CI, 0.09–0.34; adjusted p = 0.019). Baseline domain alpha coefficients ranged from −0.375 to 0.329. At T2, 41 non-swimming responses from 24 of 47 participants were ‘not relevant’, all ‘not capable’ at T1; none were ‘not relevant’ at T1. Two domain analyses used incomplete item sets. Normal-theory limits of agreement were sensitive to the discrete, zero-heavy differences. Discussion These estimates describe the retained electronic records. The original paper questionnaires are no longer available, so the accuracy and origin of the 41 transitions could not be independently verified; this unresolved data-quality issue may bias reliability estimates. Unconfirmed clinical stability, incomplete adaptation records, and missing items further limit inference. The findings do not establish validated domain scales, diagnosis-specific reliability, or an overall score. Prospective validation with independent source-data verification remains necessary before individual treatment decisions.