A wearable pelvic sensor design for drop foot treatment in post-stroke patients

A novel wearable pelvic sensor design for gait analysis was developed and evaluated in both normal and pathological gait. The device is a hip worn fusion of gyroscopes and accelerometers which allows for monitoring of the periodic vertical rotation of the pelvis during the walking cycle and uses this information as a predictor of gait events such as Heel-Strike (HS) and Toe-Off (TO). The gait pattern of two age and gender-matched groups (40-65 years) of 10 healthy subjects (5 male, 5 female) and 10 subjects with hemiplegic drop foot were examined. The pelvic sensor method was correlated against an optical motion system and footswitches, to evaluate the technique's efficacy at detecting foot contact events in walking and hip pattern. Data analysis showed the device was able to predict foot contact events from recorded maximum and minimum pelvic angle (TO: Healthy - 130ms Hemiplegic - 95ms; HS: Healthy - 127ms, Hemiplegic- 96ms). This ability to detect gait events would allow this sensor design to be used in simplifying drop foot stimulation systems. The proposed method also records the relative range of motion of the pelvis from which useful information on gait symmetry can be obtained and used in ambulatory monitoring or treatment intervention analysis.