Date Presented 04/06/19
Identifying subtle motor delays in early childhood is challenging. Accelerometry is a novel way to characterize upper-extremity motor patterns in typically developing children. Differences are identified between typical children and those with unilateral motor deficits.
Primary Author and Speaker: Catherine Hoyt
Contributing Authors: Andrew Van, Mario Ortega, Jon Koller, Elyse Everett, Annie Nguyen, Catherine Lang, Brad Schlaggar, Nico Dosenbach
PURPOSE: Developmental delays affect approximately one in six children in the United States and are a common medical problem seen by pediatric primary care providers (Boyle et al., 2011). Unfortunately, delays in the first years of life can be subtle, difficult to detect by parents, and not immediately obvious in brief clinical encounters. Wearable technology has opened the possibility to objectively measure real-world behavior outside of the clinical environment, which would be especially valuable for children, as they may behave differently in the clinical setting (Rand & Eng, 2012). Apart from general activity, bilaterally worn accelerometers can detect asymmetrical motor patterns. Cerebral palsy is the most common form of pediatric disability, with unilateral deficits being the most prevalent.A method for measuring real-world motor asymmetries could greatly improve diagnosis and treatment for this population.
DESIGN: A prospective, observational cohort design was used to measure bilateral upper limb activity in children 0–17.11 years that were typically developing or diagnosed with motor impairment.
METHOD: Approval was obtained from the institutional review board at Washington University School of Medicine. Parents completed the Movement Assessment Battery for Children-2 Checklist ( ≥5 years) or the motor subscales of the Ages and Stages Questionnaire ( ≤5 years). Scores from these measures were compared to published age norms. Real-world activity was sampled at 30 Hz using the Actigraph wGT3X-BT triaxial accelerometers. Children wore accelerometers bilaterally just above the ulnar styloid for 4x25 hours within a one-month period. Data from typical children were summarized using total daily activity and the use ratio between upper limbs. However, the use ratio excludes magnitude of movement and is less sensitive to identifying unilateral deficit. To solve this issue, we developed the mono-arm use index (MAUI) which uses magnitude of movement and we split the unilateral and bilateral contributions into separate metrics to provide a more realistic evaluation of the data.
RESULTS: A total of 214 children were enrolled and 181 (156 typical, 25 motor impairment) were included. The cohorts were demographically similar. In the typical cohort, activity was highest in middle childhood and the use ratio was 1 for the youngest children and declined sharply to reach adult norms by adolescence (t=-4.3, p<.001). Children with motor impairment had deficits impacting either one (80%) or both upper limbs (20%). Using a binary classification model we found that at a MAUI threshold of 0.54 (AUC=0.98) we could predict group assignment with 98% accuracy. With our cohort, MAUI had 87% sensitivity and a positive predictive value of 1.0 (F1=0.93). MAUI demonstrated that children with unilateral motor deficits use their dominant arm much more than their affected arm.
CONCLUSION: We report the first referent data set of bilateral upper limb real-world activity across childhood using wearable biosensors. Consistent with previous studies we identified a decline in adolescence, but report for the first time, an observable developmental curve of general upper limb activity. We report the first use of MAUI to discriminate between typically developing children and those with unilateral deficits with higher sensitivity and specificity than previousmethods.
IMPACT STATEMENT: Objective, non-invasive and affordable methods for early identification of motor deficits are desperately needed. These findings indicate that bilateral upper limb accelerometry can classify unilateral impairment in very young ages.
References
Boyle, C. A., Boulet, S., Schieve, L. A., Cohen, R. A., Blumberg, S. J., Yeargin-Allsopp, M., Kogan, M. D. (2011). Trends in the prevalence of developmental disabilities in US children, 1997-2008. Pediatrics, 127(6), 1034-1042. doi:10.1542/peds.2010-2989
Rand, D., & Eng, J. J. (2012). Disparity between functional recovery and daily use of the upper and lower extremities during subacute stroke rehabilitation. Neurorehabil Neural Repair, 26(1), 76-84. doi:10.1177/1545968311408918
