Customizable Wearable Vibrotactile Display for Gait Biofeedback Research

ME450 Capstone Design and Manufacturing Experience: Winter 2021Approximately a third of American adults experience balance problems throughout their lifetime which can lead to a fear of falling, activity avoidance, and an increasingly sedentary lifestyle. While gait and balance training regimens are the most common therapeutic solution for adults with increased risk for falling, interventions that involve personalized biofeedback have been successfully shown to improve standing balance in research studies; however, it is still unclear how best to provide meaningful biofeedback during gait-related activities. Current gait correction systems are limited to providing feedback on a single gait parameter which cannot capture the full complexity of gait, and commonly use only one feedback scheme/modality. Additionally, many devices cannot provide the device wearer with immediate feedback. Therefore, there is a need to develop a customizable/reconfigurable wearable device to be used in a research setting, which will explore the effects of vibrotactile feedback on individuals with vestibular disorders. This device must be able to gather information on multiple kinematic parameters related to gait and provide vibrotactile feedback for the device wearer to interpret and correct their balance irregularities within each testing trial. Ultimately, this research platform will inform the development of a clinic-based and home-based biofeedback system.Christopher DiCesare, Safa Jabri, Kathleen Sienko: Sienko Research Labhttp://deepblue.lib.umich.edu/bitstream/2027.42/167651/1/Team_7-Customizable_Wearable_Vibrotactile_Display_for_Gait_Biofeedback_Research.pd

A Haptic Feedback System for Lower Limb Amputees Based on Gait Event Detection

Lower limb amputation has significant effects on a person’s quality of life and ability to perform activities of daily living. Prescription of prosthetic device post amputation aims to help restore some degrees of mobility function, however studies have shown evidence of low balance confidence and higher risk of falling among amputee community, especially those suffering from above knee amputation. While advanced prostheses offer better control, they often lack a form of feedback that delivers the awareness of the limb position to the prosthetic user while walking. This research presents the development and evaluation of a wearable skinstretch haptic feedback system intended to deliver cues of two crucial gait events, namely the Initial Contact (IC) and Toe-off (TO) to its wearer. The system comprises a haptic module that applies lateral skin-stretch on the upper leg or the trunk, corresponding to the gait event detection module based on Inertial Measurement Unit (IMU) attached at the shank. The design and development iterations of the haptic module is presented, and characterization of the feedback parameters is discussed. The validation of the gait event detection module is carried out and finally the integration of the haptic feedback system is described. Experimental work with healthy subjects and an amputee indicated good perceptibility of the feedback during static and dynamic (walking) condition, although higher magnitude of stretch was required to perceive the feedback during dynamic condition. User response time during dynamic activity showed that the haptic feedback system is suitable for delivering cues of IC and TO within the duration of the stance phase. In addition, feedback delivered in discernible patterns can be learned and adapted by the subjects. Finally, a case study was carried out with an above-knee amputee to assess the effects of the haptic feedback on spatio-temporal gait parameters and on the vertical ground reaction force during treadmill and overground walking. The research presented in this report introduces a novel design of a haptic feedback device. As such, the outcome includes a well-controlled skin-stretch effect which contributes to the research by investigating skin-stretch feedback for conveying discrete event information rather than conveying direction information as presented in other studies. In addition, it is found that stretch magnitude as small as 3 mm could be perceived in short duration of 150 ms during dynamic condition, making it a suitable alternative to other widely investigated haptic modality such as vibration for ambulatory feedback application. With continuous training, the haptic feedback system could possibly benefit lower limb amputees by creating awareness of the limb placement during ambulation, potentially reducing visual dependency and increasing walking confidence