Shieh V1, Sansare A2, Jain M1, Collins J3, Bulea T1, Zampieri C1
1National Institutes of Health, Clinical Research Center/Rehab Med Dept, Bethesda, United States, 2University of Delaware, Newark, United States, 3George Mason University, Department of Rehabilitation Science, Fairfax, United States
Background: Currently the electronic walkway system GAITRiteTM is regarded as a gold standard for measuring spatiotemporal gait parameters. However, the GAITRiteTM confines walking to a restricted area and limits the number of gait cycles collected. Wearable inertial sensors are a potential alternative because they allow for a more natural walking behavior. Previous studies have validated gait measures obtained with APDM® Opal inertial sensors in young children (3-8 years old) and adults.
Purpose: The objective of this pilot study is to establish concurrent validity of APDM® Opal inertial sensors against GAITRiteTM in older children.
Methods: Twenty-one typically developing individuals (10 males) between the ages of 7-19 years participated in an IRB approved National Institutes of Health (NIH) Clinical Center study. All participants and parents provided informed consent. Participants completed 2-minute walk tests at a regular and fast pace on a 25-meter long hallway while wearing the sensors. Only the portions of the walk when subjects passed over the walkway were analyzed. A Bland-Altman analysis was completed per subject to determine agreement between systems for the following gait parameters: normalized velocity and stride length, gait cycle duration, cadence and double support time. Mixed effect models for the differences between GAITRite and Opal in each gait parameter were fit with fixed effects of gender, age, height, pace, and pass number. Random subject level and pass number effects were also considered.
Results: Age and height dropped from all models as not significant, and the random effect of pass number within individuals was retained only in the model for double support time. Mean difference and limits of agreement for each parameter during regular pace are presented as mean (lower LOA, upper LOA). Results are velocity 0.034 stature/sec (-0.042, 0.110), stride length 0.039 stature (-0.032, 0.110), gait cycle duration 0.005 sec (-0.080, 0.089), cadence -0.218 steps/min (-4.66, 4.23), and double support time 7.17 (-0.84, 15.18). The Bland-Altman plots displayed evidence of systematic disagreement in double support time with minimal bias for cadence and gait cycle duration.
Conclusion(s): Results of this pilot study support the validity of the APDM® Opal sensors in measuring gait velocity, stride length, gait cycle time and cadence in children during a 2-minute walking test. Drift in the accelerometers of the sensor over time may contribute to the discrepancy in double support time. Future studies are warranted with a larger sample size and broader age range to thoroughly represent the pediatric population.
Implications: If these findings are confirmed in a larger sample, then they potentially support the use of inertial sensors in a free environment as an alternative to foot-fall acquisition mats. It would make measurement of gait parameters in children with gait challenges easier and more accessible. In addition, the measures we obtained with the sensors can serve as normative data for other studies or clinical reference.
Keywords: Pediatrics, Inertial Sensors, Gait
Funding acknowledgements: This study was funded through the NIH intramural program.
Purpose: The objective of this pilot study is to establish concurrent validity of APDM® Opal inertial sensors against GAITRiteTM in older children.
Methods: Twenty-one typically developing individuals (10 males) between the ages of 7-19 years participated in an IRB approved National Institutes of Health (NIH) Clinical Center study. All participants and parents provided informed consent. Participants completed 2-minute walk tests at a regular and fast pace on a 25-meter long hallway while wearing the sensors. Only the portions of the walk when subjects passed over the walkway were analyzed. A Bland-Altman analysis was completed per subject to determine agreement between systems for the following gait parameters: normalized velocity and stride length, gait cycle duration, cadence and double support time. Mixed effect models for the differences between GAITRite and Opal in each gait parameter were fit with fixed effects of gender, age, height, pace, and pass number. Random subject level and pass number effects were also considered.
Results: Age and height dropped from all models as not significant, and the random effect of pass number within individuals was retained only in the model for double support time. Mean difference and limits of agreement for each parameter during regular pace are presented as mean (lower LOA, upper LOA). Results are velocity 0.034 stature/sec (-0.042, 0.110), stride length 0.039 stature (-0.032, 0.110), gait cycle duration 0.005 sec (-0.080, 0.089), cadence -0.218 steps/min (-4.66, 4.23), and double support time 7.17 (-0.84, 15.18). The Bland-Altman plots displayed evidence of systematic disagreement in double support time with minimal bias for cadence and gait cycle duration.
Conclusion(s): Results of this pilot study support the validity of the APDM® Opal sensors in measuring gait velocity, stride length, gait cycle time and cadence in children during a 2-minute walking test. Drift in the accelerometers of the sensor over time may contribute to the discrepancy in double support time. Future studies are warranted with a larger sample size and broader age range to thoroughly represent the pediatric population.
Implications: If these findings are confirmed in a larger sample, then they potentially support the use of inertial sensors in a free environment as an alternative to foot-fall acquisition mats. It would make measurement of gait parameters in children with gait challenges easier and more accessible. In addition, the measures we obtained with the sensors can serve as normative data for other studies or clinical reference.
Keywords: Pediatrics, Inertial Sensors, Gait
Funding acknowledgements: This study was funded through the NIH intramural program.
Topic: Paediatrics; Outcome measurement; Robotics & technology
Ethics approval required: Yes
Institution: National Institutes of Health
Ethics committee: Institutional Review Board
Ethics number: 90-CC-0168
All authors, affiliations and abstracts have been published as submitted.
