Measuring distance walked and step count in children with cerebral palsy: an evaluation of two portable activity monitors.

Assessing clinical outcomes in the context of activity and participation is essential to reflect functional changes in the home and community for children with cerebral palsy (CP). However, no activity monitor has been investigated for measurement of the distance walked and step count in children with CP who have atypical gait. Twenty typically developing children and twenty children with CP, aged 4-16 years, were recruited to evaluate two portable activity monitors, AMP 331 (AMP) and Dynaport Minimod (Minimod), under three walking conditions (continuous walking, structured activity lap walking and stair climbing). Measurements of the activity monitors were compared to known walking distances and video recordings for step count. The devices performed differently under different walking conditions. The Minimod gave more accurate measurement of continuous walking over level ground. On the other hand, the AMP performed better in detecting the walks in a structured activity lap and during stair ascent and descent. Researchers and clinicians need to consider different characteristics of the monitoring devices and walking conditions, and choose an appropriate device that is most reflective of what they want to measure.