Concurrent validity, test-retest reliability, and sensitivity of a PostureRite system measurement on dynamic postural sway and risk of fall in cerebral palsy

Abstract

BACKGROUND: Accurately diagnosing dynamic postural sway (DPS) is essential for effective and sustainable intervention in children with cerebral palsy (CP). We developed an accurate, inexpensive, and wearable DPS measurement system to measure DPS accurately and consistently during walking and functional activities of daily living. OBJECTIVE: We investigated the validity and reliability of this PostureRite system in children with CP, and the link between PostureRite and clinical measures including gross motor function measure (GMFM), pediatric balance scale (PBS), and fall efficacy scale (FES). METHODS: Twenty-one participants were categorized as follows: 11 healthy adults (3 females, mean age, 25.00±1.00 years) and 10 children with CP (mean age, 11.10±6.28 years). We determined the concurrent validity of PostureRite by comparing DPS data to the gold standard accelerometer measurement results. We determined test-retest reliability by measuring DPS data on three occasions at 2-h intervals. We assessed PostureRite measurement sensitivity to ascertain differences between healthy children and children with CP DPS measurements. RESULTS: Random and mixed intraclass correlation coefficients (ICC2,k and ICC3,k) were obtained; an independent T-test was performed (P < 0.05). Concurrent validity analysis showed a good relationship between the gold standard accelerometer and PostureRite (ICC2,k = 0.973, P < 0.05). Test-retest reliability demonstrated a good relationship across the three repeated measures of the DPS data (ICC3,k = 0.816–0.924, P < 0.05). Independent T-test revealed a significant difference in DPS data between healthy adults and children with CP (P < 0.05). CONCLUSIONS: We developed a portable, wireless, and affordable PostureRite system to measure DPS during gross motor function associated with daily activity and participation, and established the concurrent validity, test-retest reliability as sensitivity, and clinical relevance by comparing the DPS obtained from the participants with and without CP.