Inter-rater reliability and validity of two ataxia rating scales in children with brain tumours

This study aimed to investigate the inter-rater reliability and construct validity of the Scale for the Assessment and Rating of Ataxia (SARA) and Brief Ataxia Rating Scale (BARS) in children with posterior fossa tumours. These scales have been developed for adults with genetic ataxias, and the performance of these scales in children with brain tumours has not previously been described. The participants, who had undergone surgical resection for a posterior fossa tumour (inclusion criteria age 4-18 years), were recruited from the neuro-oncology service at a tertiary children's hospital. Children were assessed using the SARA, BARS and Paediatric Evaluation of Disability Index (PEDI) mobility domain, a measure of function. Children were independently rated by two therapists to determine the inter-rater reliability of the SARA and BARS. The construct validity was determined by assessing the correlation between the two scales with the PEDI. Forty-four children were recruited. Inter-rater reliability was good for both scales, demonstrating the strong correlations (SARA, r = 0.94; BARS, r = 0.91) and the good consistency (93 % of SARA and 90 % of BARS paired scores differing by less than 2 points) between two raters. Both ataxia scales demonstrated a strong negative correlation with the mobility domain of the PEDI (SARA, r = -0.77; BARS, r = -0.76), indicating that more severe ataxia was associated with worse mobility. The mean time for completion of the SARA was 4.5 and 2.7 min for the BARS. The SARA and BARS are reliable and valid measures and appear to be of equal value in determining the severity of ataxia in children with posterior fossa tumours.