Design and technical validation of a wearable biofeedback system for robotic gait rehabilitation

Abstract

Gait disabilities affect the human quality of life. Current directions for time-effective robotic gait rehabilitation require the inclusion of biofeedback systems (BSs) as a complementary robotic tool for efficient motor relearning. This work aims to present the user-centered design and validation of a wearable BS to foster users' active participation and enable therapists' effective participation during robotic gait rehabilitation driven by active orthoses. The multimodal BS comprises a development board to manage the activation of the stimuli (vibrotactile through the vibrotactile waist and shank bands, sonorous via single earphone, and visual using RGB LED) according to data tracked by orthosis embedded sensors. The BS's versatility allows its functioning as a modular and stand-alone system or integrated into the orthotic system. The system's operability was validated with four healthy subjects walking on a treadmill with the orthotic system and BS at 1 km/h. The results showed an operable system with good usability during robotic gait rehabilitation. This wearable BS has the potential to boost symmetric gait recovery and to effectively augment the user's active participation during robotic gait therapy; thus, contributing to accelerating the user's motor recovery.

Wearable Biofeedback Improves Human-Robot Compliance during Ankle-Foot Exoskeleton-Assisted Gait Training: A Pre-Post Controlled Study in Healthy Participants

“…The proposed human-robot interaction-based biofeedback strategies were implemented into a wearable, multimodal, and open-architecture BS ( Figure 2 ), as described in [ 12 ]. It can provide patient-oriented vibrotactile and auditory cues through Eccentric Rotating Mass motors placed on elastic waist and shank bands, and earphones, respectively.…”

“…Therefore, during this strategy, an auditory cue is enabled when the user is not compliant with the exoskeleton’s direction of movement. The auditory cue is a sinusoidal tone (200 Hz) provided through a single earphone included in the BS [ 12 ]. The volume was adjusted so that users can hear the physiotherapist’s verbal instructions for additional support.…”

“…The 1st, 5th, 24th, and 31st values correspond to the heel-strike, flat-foot, heel-off, and toe-off gait events according to Winter in [ 15 ]. The study by [ 12 ] shows the operability of this algorithm. Each pre-training trial involves a 1-min walk on a treadmill with the ankle-foot exoskeleton running the trajectory tracking control at the training gait speed.…”

“…During this strategy, a vibrotactile cue is enabled when the user interacts with the exoskeleton and the direction of interaction is following the exoskeleton’s direction of movement. The vibrotactile cue is provided at 200 Hz 1.8 G through a vibrotactile shank band included in the BS [ 12 ]. This frequency was successfully perceived by post-stroke patients in [ 18 ].…”

“…It includes visual cues from a Light-Emitting Diode oriented to the physiotherapists, and auditory and vibrotactile cues from an earphone and elastic vibrotactile shank bands, respectively, both oriented to the patients. Detailed information about the design of the used BS can be found in [ 12 ].…”