AimTo investigate ataxia rating scales in children for reliability and the effect of age and sex. MethodThree independent neuropaediatric observers cross-sectionally scored a set of paediatric ataxia rating scales in a group of 52 healthy children (26 males, 26 females) aged 4 to 16years (mean age 10y 5mo SD 3y 11mo). The investigated scales involved the commonly applied International Cooperative Ataxia Rating Scale (ICARS), the Scale for Assessment and Rating of Ataxia (SARA), the Brief Ataxia Rating Scale (BARS), and PEG-board tests. We investigated the interrelatedness between individual ataxia scales, the influence of age and sex, inter- and intra-observer agreement, and test-retest reliability. ResultsSpearman's rank correlations revealed strong correlations between ICARS, SARA BARS, and PEG-board test (all p<0.001). ICARS, SARA, BARS and PEG-board test outcomes were age-dependent until 12.5, 10, 11, and 11.5years of age respectively. Intraclass correlation coefficients (ICCs) varied between moderate and almost perfect (interobserver agreement: 0.85, 0.72, and 0.69; intraobserver agreement: 0.92, 0.94, and 0.70; and test-retest reliability: 0.95, 0.50, and 0.71; for ICARS, SARA, and BARS respectively). Interobserver variability decreased after the sixth year of life. InterpretationIn healthy children, ataxia rating scales are reliable, but should include age-dependent interpretation in children up to 12years of age. To enable longitudinal interpretation of quantitative ataxia rating scales in children, European paediatric normative values are necessary. What this paper adds <list list-type="bulleted" id="dmcn12369-list-0001"> In children, ataxia rating scales can be reliably assessed. Ataxia rating scales are age-dependent until 12years of age. ICARS, SARA, BARS and the nine-hole PEG-board test are correlated. This article is commented on by Mink on pages of this issue.