Detection of Anticipatory Postural Adjustments Prior to Gait Initiation Using Inertial Wearable Sensors
By Martinez-Mendez, Rigoberto; Sekine, Masaki; Tamura, Toshiyo; Journal of NeuroEngineering and Rehabilitation, Vol. 8, No. 17Publication Date: April 6, 2011
Study evaluated the potential of accelerometers and angular velocity sensors to detect and assess anticipatory postural adjustments (APAs) generated by the first step at the beginning of the gait. Participants were 7 men and 3 women without disabilities and with an average age of 26 years. Each participant wore an inertial unit containing a triaxial accelerometer and a triaxial angular velocity sensor attached to the lower back and one footswitch on the dominant leg to detect the beginning of the step. Participants were standing upright on a stabilometer to detect the center of pressure displacement (CoP) generated by the anticipatory adjustments. They were then asked to take a step forward at their own speed and stride length. The duration and amplitude of the APAs detected by the accelerometer and angular velocity sensors were measured and compared with the results obtained from the stabilometer. The different phases of gait initiation were identified and compared using inertial sensors. The APAs were detected by all sensors. Angular velocity sensors proved to be adequate to detect the beginning of the step in a manner similar to the footswitch by using a simple algorithm which is easy to implement in low computational power devices. The amplitude and duration of APAs detected using only inertial sensors were similar to those detected by the stabilometer. An automatic algorithm to detect APA duration using triaxial inertial sensors was proposed. The results presented can be used to develop portable sensors that may be useful for monitoring patients in the home environment.
Published by: BioMed Central Ltd (Website:http://www.biomedcentral.com)
Link to text: http://www.jneuroengrehab.com/content/8/1/17
