Haptic wearables as sensory replacement, sensory augmentation and trainer - a review

Sensory impairments decrease quality of life and can slow or hinder rehabilitation. Small, computationally powerful electronics have enabled the recent development of wearable systems aimed to improve function for individuals with sensory impairments. The purpose of this review is to synthesize current haptic wearable research for clinical applications involving sensory impairments. We define haptic wearables as untethered, ungrounded body worn devices that interact with skin directly or through clothing and can be used in natural environments outside a laboratory. Results of this review are categorized by degree of sensory impairment. Total impairment, such as in an amputee, blind, or deaf individual, involves haptics acting as sensory replacement; partial impairment, as is common in rehabilitation, involves haptics as sensory augmentation; and no impairment involves haptics as trainer. This review found that wearable haptic devices improved function for a variety of clinical applications including: rehabilitation, prosthetics, vestibular loss, osteoarthritis, vision loss and hearing loss. Future haptic wearables development should focus on clinical needs, intuitive and multimodal haptic displays, low energy demands, and biomechanical compliance for long-term usage

Design and Assessment of Vibrotactile Biofeedback and Instructional Systems for Balance Rehabilitation Applications.

Sensory augmentation, a type of biofeedback, is a technique for supplementing or reinforcing native sensory inputs. In the context of balance-related applications, it provides users with additional information about body motion, usually with respect to the gravito-inertial environment. Multiple studies have demonstrated that biofeedback, regardless of the feedback modality (i.e., vibrotactile, electrotactile, auditory), decreases body sway during real-time use within a laboratory setting. However, in their current laboratory-based form, existing vibrotactile biofeedback devices are not appropriate for use in clinical and/or home-based rehabilitation settings due to the expense, size, and operating complexity of the instrumentation required. This dissertation describes the design, development, and preliminary assessment of two technologies that support clinical and home-based balance rehabilitation training. The first system provides vibrotactile-based instructional motion cues to a trainee based on the measured difference between the expert’s and trainee’s motions. The design of the vibrotactile display is supported by a study that characterizes the non-volitional postural responses to vibrotactile stimulation applied to the torso. This study shows that vibration applied individually by tactors over the internal oblique and erector spinae muscles induces a postural shift of the order of one degree oriented in the direction of the stimulation. Furthermore, human performance is characterized both experimentally and theoretically when the expert–trainee error thresholds and nature of the control signal are varied. The results suggest that expert–subject cross-correlation values were maximized and position errors and time delays were minimized when the controller uses a 0.5 error threshold and proportional plus derivative feedback control signal, and that subject performance decreases as motion speed and complexity increase. The second system provides vibrotactile biofeedback about body motion using a cell phone. The system is capable of providing real-time vibrotactile cues that inform corrective trunk tilt responses. When feedback is available, both healthy subjects and those with vestibular involvement significantly reduce their anterior-posterior or medial-lateral root-mean-square body sway, have significantly smaller elliptical area fits to their sway trajectory, spend a significantly greater mean percentage time within the no feedback zone, and show a significantly greater A/P or M/L mean power frequency.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91546/1/channy_1.pd

Motion capture with actuated feedback for motor learning

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 65-67).Second Skin aims to combine three-dimensional (3D) motion tracking with tactile feedback for the purpose of improving users' motor-learning ability. Such a system would track a user's body and limb movements as he or she performs an action, and then give the user automatic, real-time tactile feedback to aid in the correction of movement and position errors. This thesis details the development of a robust and low-cost optical 3D motion capture system along with versatile and flexible tactile feedback hardware. The vision is that these technologies will facilitate further research and the future development of motor-learning platforms that fully integrate 3D motion tracking and tactile feedback.by Dennis Miaw.M.Eng

Accelerated and improved motor learning and rehabilitation using kinesthetic feedback

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.Includes bibliographical references (p. 69-71).About 21 million people in the United States [roughly 8%] have a basic motor skill inability [13], many stemming not from atrophy, but an improper mapping from the brain to the motor system. Devices exist today to aid people in rebuilding their motor system mappings, but do so in bulky, and inconvenient ways, since many of the users have adequate muscle strength, but the inability to control it properly. Hundreds of millions of people in the world participate in the arts, most of which involve motion of some sort. Typically, to become able to properly perform/paint/dance/etc, training is necessary. We learn from visual and auditory feedback, and sometimes, from the touch of a teacher. This research aims to improve the efficacy of such training with robotic touch, to enable people to become better, faster. This research proposes an augmented sensory feedback system - a lightweight comfortable wearable device that utilizes the communication channel of direct touch on the body, to give real-time feedback to the wearer about their performance in motor skill tasks. Using vibrotactile signals to indicate joint error in a user's motion, we enable a user to wear a full-body suit that provides subtle cues for the brain, as they perform a variety of motor skill tasks.(cont.) The hope is that utilizing tactile real-time feedback will act as a dance teacher or physical therapist does: by giving muscle aid through informational touch cues, not only through force or torque. This will enable people to undergo constant therapy/training, over all joints of the body simultaneously. with higher accuracy than a therapist/teacher provides. The device will enable more rapid motor rehabilitation and postural retraining to combat repetitive strain injuries (RSIs). It will also allow allow communication between a motion expert and a student in real-time [by comparing the student's performance to an expert's]. to aid in higher level motor learning skills such as sports and dance. It will function as a tool to accelerate and deepen peoples motor learning capabilities. This thesis focuses on actuator selection and feedback mechanisms for such a suit, in a low-joint-number test, comprising elements of the upper arm. Initial tests on a 5 degree-of-freedom suit show a decrease in motion errors of roughly 21% (p = 0.015), with 15% lower steady-state error (p = 0.007) and a 7% accelerated rate of learning (p = 0.007).by Jeff Lieberman.S.M

Paving the Way for Motor Imagery-Based Tele-Rehabilitation through a Fully Wearable BCI System

The present study introduces a brain–computer interface designed and prototyped to be wearable and usable in daily life. Eight dry electroencephalographic sensors were adopted to acquire the brain activity associated with motor imagery. Multimodal feedback in extended reality was exploited to improve the online detection of neurological phenomena. Twenty-seven healthy subjects used the proposed system in five sessions to investigate the effects of feedback on motor imagery. The sample was divided into two equal-sized groups: a “neurofeedback” group, which performed motor imagery while receiving feedback, and a “control” group, which performed motor imagery with no feedback. Questionnaires were administered to participants aiming to investigate the usability of the proposed system and an individual’s ability to imagine movements. The highest mean classification accuracy across the subjects of the control group was about 62% with 3% associated type A uncertainty, and it was 69% with 3% uncertainty for the neurofeedback group. Moreover, the results in some cases were significantly higher for the neurofeedback group. The perceived usability by all participants was high. Overall, the study aimed at highlighting the advantages and the pitfalls of using a wearable brain–computer interface with dry sensors. Notably, this technology can be adopted for safe and economically viable tele-rehabilitation

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications