Free-Living Motor Activity Monitoring in Ataxia-Telangiectasia

With disease-modifying approaches under evaluation in ataxia-telangiectasia and other ataxias, there is a need for objective and reliable biomarkers of free-living motor function. In this study, we test the hypothesis that metrics derived from a single wrist sensor worn at home provide accurate, reliable, and interpretable information about neurological disease severity in children with A-T. A total of 15 children with A-T and 15 age- and sex-matched controls wore a sensor with a triaxial accelerometer on their dominant wrist for 1 week at home. Activity intensity measures, derived from the sensor data, were compared with in-person neurological evaluation on the Brief Ataxia Rating Scale (BARS) and performance on a validated computer mouse task.Children with A-T were inactive the same proportion of each day as controls but produced more low intensity movements (p<0.01; Cohen's d=1.48) and fewer high intensity movements (p<0.001; Cohen's d=1.71). The range of activity intensities was markedly reduced in A-T compared to controls (p<0.0001; Cohen's d=2.72). The activity metrics correlated strongly with arm, gait, and total clinical severity (r: 0.71-0.87; p<0.0001), correlated with specific computer task motor features (r: 0.67-0.92; p<0.01), demonstrated high reliability (r: 0.86-0.93; p<0.00001), and were not significantly influenced by age in the healthy control group. Motor activity metrics from a single, inexpensive wrist sensor during free-living behavior provide accurate and reliable information about diagnosis, neurological disease severity, and motor performance. These low-burden measurements are applicable independent of ambulatory status and are potential digital behavioral biomarkers in A-T.

Automated summary

This study found that children with A-T were less active in terms of high intensity movements and had a narrower range of activity intensities compared to controls. Activity metrics derived from a wrist sensor were strongly correlated with clinical severity and specific motor features, demonstrating high reliability. These findings suggest that wrist sensors can provide accurate and reliable information about motor performance in A-T children.