Date of Paper/Work


Type of Paper/Work

Research Project

Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

First Advisor

David D. Chapman


BACKGROUND AND PURPOSE: Video-based behavior coding is the ‘gold-standard’ for identifying leg movements (LMs) and kicks in pre-walking infants. 3-D motion sensors have been successfully used to assess the frequency and quality of LMs in adults. Little research has been conducted to determine if 3-D motion sensors can accurately detect LMs and kicks produced by young infants. Therefore, the purpose of this pilot study was to compare the accuracy of wireless 3-D sensors to the current gold standard of behavior coded video-taped data to identify the LMs and kicks produced by pre-walking infants.

METHODS: The spontaneous LMs and kicks of 4 typically developing infants who entered the study at 1 month of age were video-taped when they were supine with and without the wireless sensors attached to their thighs and shanks. The video-taped data was behavior coded via frame by frame analysis to identify each infant’s LMs and kicks in each condition. Custom Matlab programs, based on the mean peak acceleration and velocity of the infants’ LMs in each cardinal plane, were written to identify the LMs detected by the 3-D wireless sensors.

RESULTS: Wearing the 3-D wireless sensors did not result in a significant change in the number of LMs and kicks generated by this small group of infants (p < .05). Two sets of algorithms that relied on the peak acceleration and velocity of the infants’ LMs were written into the custom Matlab programs. These calculations revealed that the 3-D wireless sensors detected, on average, 89 to 93% of the LMs identified through the frame by frame behavior coding of the video-taped data. The wireless sensors placed on the distal thigh were slightly more accurate than the sensors placed on the distal shank

DISCUSSION: These preliminary results are consistent with the literature regarding the use of 3- D wireless sensors to detect infant LMs. Although promising, these initial results need to be viewed cautiously given the small number of babies included in this pilot study. With additional data, we hope to make a recommendation regarding the clinical use of 3-D wireless sensors to monitor the LMs and kicks of young infants with and without disabilities in the near future.