A validation study of a modified Bouchard activity record that extends the concept of 'uptime' to Rett syndrome

Aim - The aim of this study was to investigate the validity of using a Bouchard activity record (BAR) in individuals with Rett syndrome to measure physical activity, as compared with pragmatic criterion standard measures of walking status and step counts recorded using the StepWatch activity monitor (SAM). Method - During the waking hours of 1 day, 43 females (mean age 21y, SD 9y) wore a SAM whilst a proxy completed a modified BAR. Responses to the BAR were compared among participants, who were grouped according to walking status, using the Mann–Whitney two-sample rank-sum test. Relationships were sought between BAR responses and step counts using linear regression. Results - According to the proxy-reported BAR responses, those who needed assistance with walking spent more time sitting (median [interquartile range] 9h 15min [8h 8min–10h 30min] vs 6h 15min [4h 15min–8h 30min]; p<0.001) and less time standing (1h [38min–1h 30min] vs 2h 15min [45min–3h 45min]; p=0.04) than those who could walk independently. In those who could walk independently, time classified as ‘uptime’ (standing and walking) using the BAR was associated with increased step count (r2=0.58; p