Rhythmic Haptic Cueing for Gait Rehabilitation of Hemiparetic Stroke and Brain Injury Survivors

This thesis explores the gait rehabilitation of hemiparetic stroke and brain injury survivors by a process of haptic entrainment to rhythmic cues. Entrainment to auditory metronomes is known to improve gait; this thesis presents the first systematic study of entrainment for gait rehabilitation via the haptic modality. To investigate this approach, a multi-limb metronome capable of delivering a steady, isochronous haptic rhythm to alternating legs was developed, purpose-built for gait rehabilitation, together with appropriate software for monitoring and assessing gait. A formative observational study, carried out at a specialised neurological centre, supplemented by discussions with physiotherapists and neuropsychologists, was used to focus the scope on hemiparetic stroke and brain injury. A second formative study used a technology probe approach to explore the behaviour of hemiparetic participants under haptic cueing using a pre-existing prototype. Qualitative data was collected by observation of, and discussion with, participants and health professionals. In preparation for a quantitative gait study, a formal experiment was carried out to identify a workable range for haptic entrainment. This led to the creation of a procedure to screen out those with cognitive difficulties entraining to a rhythm, regardless of their walking ability. The final study was a quantitative gait study combining temporal and spatial data on haptically cued participants with hemiparetic stroke and brain injury. Gait characteristics were measured before, during and after cueing. All successfully screened participants were able to synchronise their steps to a haptically presented rhythm. For a substantial proportion of participants, an immediate (though not necessarily lasting) improvement of temporal gait characteristics was found during cueing. Some improvements over baseline occurred immediately afterwards, rather than during, haptic cueing. Design issues and trade-offs are identified, and interactions between perception, sensory deficit, attention, memory, cognitive load and haptic entrainment are noted

The Haptic Bracelets: Gait rehabilitation after Stroke

Restoring mobility and rehabilitation of gait are high priorities for rehabilitation of neurological conditions. Cueing using metronomic rhythmic sensory stimulation has been shown to improve gait, but most versions of this approach have used auditory and visual cues. In contrast, we propose the development of a prototype wearable system for rhythmic cueing based on haptics. The main aim of this research is to investigate how real-time gait monitoring and rhythmic haptic cueing can assist with gait rehabilitation for neurological conditions

An Investigation of the Interrelationship between Physical Stiffness and Perceived Roughness

Research in the area of haptics and how we perceive the sensations that come from haptic interaction started almost a century ago, yet there is little fundamental knowledge as to how and whether a change in the physical values of one characteristic can alter the perception of another. The increasing availability of haptic interaction through the development of force-feedback devices opened new possibilities in interaction. It allowed for accurate real time change of physical attributes on virtual objects in order to test the haptic perception changes to the human user. An experiment was carried out to ascertain whether a change in the stiffness value would have a noticeable effect on the perceived roughness of a virtual object. Participants were presented with a textured surface and were asked to estimate how rough it felt compared to a standard. What the participants did not know was that the simulated texture on both surfaces remained constant and the only physical attribute changing in every trial was the comparison object’s surface stiffness. The results showed that there is a strong relationship between physical stiffness and perceived roughness that can be accurately described by a power function. Furthermore, the roughness magnitude estimations showed an increase with increasing stiffness values. The conclusion is that there are relationships between these parameters, but that further work is required to validate those relationships

Wearables for Long Term Gait Rehabilitation of Neurological Conditions

Many people with long-term neurological and neurodegenerative conditions such as stroke, brain injury, multiple sclerosis or Parkinson’s disease suffer from an impaired walking gait pattern. Gait improvement can lead to better fluidity in walking, improved health outcomes, greater independence, and enhanced quality of life. Existing lab-based studies with wearable devices have shown that rhythmic haptic cueing can cause immediate improvements to gait features such as temporal symmetry, stride length and walking speed. However, current wearable systems are unsuitable for self-managed use, and to move this approach from out of the lab into long-term sustained usage, numerous design challenges need to be addressed. We are designing, developing, and testing a closed-loop system to provide adaptive haptic rhythmic cues for sustainable self-managed long-term use outside the lab by survivors of stroke, and other neurological conditions, in their everyday lives

Wearable Haptic Devices for Long-Term Gait Re-education for Neurological Conditions

Many people with long-term neurological and neurodegenerative conditions such as stroke, brain injury, multiple sclerosis or Parkinson’s disease suffer from an impaired walking gait pattern. Gait improvement can lead to better fluidity in walking, improved health outcomes, greater independence, and enhanced quality of life. Existing lab-based studies with wearable haptic devices have shown that rhythmic haptic cueing can cause immediate improvements to gait features such as temporal symmetry, stride length and walking speed. However, such wearable haptic devices are unsuitable for self-managed use, and to move this approach from out of the lab into long-term sustained usage, numerous design challenges need to be addressed. We are designing, developing, and testing a closed-loop system to provide adaptive haptic rhythmic cues for sustainable self-managed long-term use outside the lab by survivors of stroke, and other neurological conditions, in their everyday lives

A longitudinal rehabilitation case study for hemiparetic gait using outdoor rhythmic haptic cueing via a wearable device

Introduction Improvement of gait is a high priority for hemiparetic stroke survivors. Auditory rhythmic cueing is a proven method for improving gait via entrainment but use is limited outside the lab. The lack of use in outdoor settings seems to reflect the problem that auditory cueing can be distracting and isolating out of doors, where survivors typically need to remain safe, aware of the environment. In such settings, haptic cueing offers an unobtrusive, invisible, sociable, safe alternative. Research Question Existing studies have demonstrated improvements in temporal symmetry, increase in stride length and walking speed by means of post-stroke gait rehabilitation using wearable haptic devices in the lab. However, previous studies have been limited to laboratory settings and have focused on short-term improvements. By contrast, we present the first case study on the self-managed use of wearable haptics for gait rehabilitation via entrainment in outdoor settings, and the first findings from applying this technique over a number of days. Methods A longitudinal pilot study was conducted with a single hemiparetic participant providing rhythmic haptic cueing using a wearable haptic device for a two-week period. The participant was asked to walk in synchrony to the haptic rhythm at a suitable outdoor setting for a minimum of 10 minutes each day. Gait data was measured before and after the two-week intervention using lab-based IMU sensors. Results On comparing before and after gait characteristics, preliminary results showed substantial improvement in temporal symmetry and walking speed. Conclusions There is implications for potential long-term benefits for stroke survivors in gait rehabilitation using rhythmic haptic cueing. Improvements in temporal symmetry, increase in stride length and walking speed could improve confidence, independence and overall quality of life for stroke survivors, with implications for reduction of costs associated with care and rehabilitation

Human haptic perception in virtual environments: An investigation of the interrelationship between physical stiffness and perceived roughness.

Research in the area of haptics and how we perceive the sensations that come from haptic interaction started almost a century ago, yet there is little fundamental knowledge as to how and whether a change in the physical values of one characteristic can alter the perception of another. The increasing availability of haptic interaction through the development of force-feedback devices opens new possibilities in interaction, allowing for accurate real time change of physical attributes on virtual objects in order to test the haptic perception changes to the human user. An experiment was carried out to ascertain whether a change in the stiffness value would have a noticeable effect on the perceived roughness of a virtual object. Participants were presented with a textured surface and were asked to estimate how rough it felt compared to a standard. What the participants did not know was that the simulated texture on both surfaces remained constant and the only physical attribute changing in every trial was the comparison object’s surface stiffness. The results showed that there is a strong relationship between physical stiffness and perceived roughness that can be accurately described by a power function, and the roughness magnitude estimations of roughness showed an increase with increasing stiffness values. The conclusion is that there are relationships between these parameters, where changes in the physical stiffness of a virtual object can change how rough it is perceived to be in a very clear and predictable way. Extending this study can lead to an investigation on how other physical attributes affects one or more perceived haptic dimensions and subsequently insights can be used for constructing something like a haptic pallet for a haptic display designer, where altering one physical attribute can in turn change a whole array of perceived haptic dimensions in a clear and predictable way

A Comparison of CNN and Classic Features for Image Retrieval

Feature detectors and descriptors have been successfully used for various computer vision tasks, such as video object tracking and content-based image retrieval. Many methods use image gradients in different stages of the detection-description pipeline to describe local image structures. Recently, some, or all, of these stages have been replaced by convolutional neural networks (CNNs), in order to increase their performance. A detector is defined as a selection problem, which makes it more challenging to implement as a CNN. They are therefore generally defined as regressors, converting input images to score maps and keypoints can be selected with non-maximum suppression. This paper discusses and compares several recent methods that use CNNs for keypoint detection. Experiments are performed both on the CNN based approaches, as well as a selection of conventional methods. In addition to qualitative measures defined on keypoints and descriptors, the bag-of-words (BoW) model is used to implement an image retrieval application, in order to determine how the methods perform in practice. The results show that each type of features are best in different contexts.Comment: 5 pages, 3 figures, 3 tables, CBMI 201

Wearable Haptic Devices For Post- Stroke Gait Rehabilitation

Wearable technologies, in the form of small, light and inconspicuous devices, can be designed to help individuals suffering from neurological conditions carry out regular rehabilitation exercises. Current research has shown that walking to a rhythm can lead to significant improvements in various aspects of gait. Our primary aim is to provide a suitable, technology based intervention to enhance gait rehabilitation of people with chronic and degenerative neurological health conditions (such as stroke). This intervention will be in the form of small, lightweight, wireless, wearable devices the user can take out of the clinic, extending their rehabilitation to their own home setting. The devices can deliver a series of vibrations at a steady rhythm giving the patient a more stable and symmetric pace of walking. The simplest version of this approach typically comprise of a very small network of just two nodes and a central controller. The existing prototypes (called the Haptic Bracelets) capture and analyse motion data in real time to provide adaptive haptic (through vibrations) cueing. In the future and after more refinement, the system could allow a single therapist to monitor and advise groups of stroke survivors undergoing therapy sessions