Wearable vibrotactile stimulation for upper extremity rehabilitation in chronic stroke: clinical feasibility trial using the VTS Glove

Objective: Evaluate the feasibility and potential impacts on hand function using a wearable stimulation device (the VTS Glove) which provides mechanical, vibratory input to the affected limb of chronic stroke survivors. Methods: A double-blind, randomized, controlled feasibility study including sixteen chronic stroke survivors (mean age: 54; 1-13 years post-stroke) with diminished movement and tactile perception in their affected hand. Participants were given a wearable device to take home and asked to wear it for three hours daily over eight weeks. The device intervention was either (1) the VTS Glove, which provided vibrotactile stimulation to the hand, or (2) an identical glove with vibration disabled. Participants were equally randomly assigned to each condition. Hand and arm function were measured weekly at home and in local physical therapy clinics. Results: Participants using the VTS Glove showed significantly improved Semmes-Weinstein monofilament exam, reduction in Modified Ashworth measures in the fingers, and some increased voluntary finger flexion, elbow and shoulder range of motion. Conclusions: Vibrotactile stimulation applied to the disabled limb may impact tactile perception, tone and spasticity, and voluntary range of motion. Wearable devices allow extended application and study of stimulation methods outside of a clinical setting

Isometric force pillow: using air pressure to quantify involuntary finger flexion in the presence of hypertonia

Survivors of central nervous system injury commonly present with spastic hypertonia. The affected muscles are hyperexcitable and can display involuntary static muscle tone and an exaggerated stretch reflex. These symptoms affect posture and disrupt activities of daily living. Symptoms are typically measured using subjective manual tests such as the Modified Ashworth Scale; however, more quantitative measures are necessary to evaluate potential treatments. The hands are one of the most common targets for intervention, but few investigators attempt to quantify symptoms of spastic hypertonia affecting the fingers. We present the isometric force pillow (IFP) to quantify involuntary grip force. This lightweight, computerized tool provides a holistic measure of finger flexion force and can be used in various orientations for clinical testing and to measure the impact of assistive devices

Next steps for Human-Computer Integration

Human-Computer Integration (HInt) is an emerging paradigm in which computational and human systems are closely interwoven. Integrating computers with the human body is not new. However, we believe that with rapid technological advancements, increasing real-world deployments, and growing ethical and societal implications, it is critical to identify an agenda for future research. We present a set of challenges for HInt research, formulated over the course of a five-day workshop consisting of 29 experts who have designed, deployed, and studied HInt systems. This agenda aims to guide researchers in a structured way towards a more coordinated and conscientious future of human-computer integration

Wearable vibrotactile stimulation: How passive stimulation can train and rehabilitate

Haptic feedback from wearable devices is primarily used for alerts and virtual reality; however, wearable computing provides unique advantages in haptic interaction. Wearable devices can now provide tactile stimulation for extended periods of time and in the background of other tasks. Since repetition is key to practice, learning, and rehabilitation, stimulation for extended periods of time may enable intensive haptic training or mobile stimulation therapy. Training and rehabilitation require time, dedication and sometimes exertion. Stimulation in the background of other tasks can allow passive training and therapy, without requiring movement or attentional focus from the user. My work takes advantage of these unique considerations to develop wearable computing solutions to help address real-world applications, while informing what is possible using passive tactile stimulation and enabling others to apply these methods in the future. Ambient stimuli can enable passive learning: training while users are focused on other tasks. Most research on this topic has used audio or visual stimuli, and few have explored the use of haptic stimuli for passive learning. In this dissertation, I present evidence that wearable vibrotactile stimulation can help train a variety of skills including those involving rhythm, simultaneous actions, and various body parts. This work also provides essential guidelines on how to construct wearable computing systems that apply this technique to practical problems. Results suggest that this passive training method may allow users to recall dozens of motor actions with little practice and learn challenging skills with less difficulty. Wearable vibrotactile stimulation may also help re-train sensorimotor functions, for example, diminished arm function after a stroke. Stroke can lead to chronic physical disability in the limbs. In fact, stroke is the leading cause of adult disability in the US. Preliminary evidence suggests that peripheral tactile stimulation may facilitate limb rehabilitation, but current methods for applying this technique are limited to laboratory settings. Currently, there is no device available to administer and study therapeutic tactile stimulation for extended periods of time or outside the clinic environment. I present a low-cost, wireless wearable device to provide tactile stimulation therapy and an initial randomized controlled trial in stroke survivors over 8 weeks. Results suggest that wearable vibrotactile stimulation may also be a powerful tool to reduce disability after a stroke.Ph.D

Passive Haptic Learning for Vibrotactile Skin-Reading: Comparison of Teaching Structures

This paper investigates the effects of using passive haptic learning to train the skill of reading text from vibrotactile patterns. The vibrotactile method of transmitting messages, skin-reading, is effective at conveying rich information but its active training method requires full user attention, is demanding, time-consuming, and tedious. Passive haptic learning offers the possibility to learn in the background while performing another primary task. We present a study investigating the use of passive haptic learning to train for skin-reading. Additionally, a word-based learning structure is typically used for this passive learning method. We expose trends that suggest this word-based incrimental teaching may not be optimal

Perception in Hand-Worn Haptics: Placement, Simultaneous Stimuli, and Vibration Motor Comparisons

Glove-based tactile interfaces are used for augmented reality, rehabilitation, teaching, and consumer electronics control. Yet questions remain regarding perception of tactile stimuli on the hands. In an effort to inform the design of such tactile interfaces, we investigate participants' abilities to sense vibration on the hands. First, we examine the effect of stimulus location on recognition accuracy. Ventral (palm-side) placement on the fingers is critical: accuracy increases with proximity to the palm, linearly, on all fingers. Second, we study perception of multiple simultaneous vibrations on the fingers. Recognition degrades with increasing number of simultaneous tactile stimuli and no subitizing is found. Error is >60-80\% for more than two simultaneous stimuli points. Our third study compares the perception of Eccentric Rotating Mass (ERM) and Linear Resonant Actuator (LRA) vibration motors. Recognition accuracy was less using LRA motors, especially in placements on the palm side of the fingers (-20.3% versus -10.1% for ERM). Correct recognition of chords was also less or comparable using LRA motors, suggesting that the ERM motor is preferable