Stacy J. Morris Bamberg

A feasibility study of an upper limb rehabilitation system using kinect and computer games

A new low-cost system for rehabilitation of the impaired upper limb for stroke survivors is presented. A computer game was developed specifically for this purpose and the users impaired upper extremity is tracked using a downward-pointed Kinect, an inexpensive motion capture system commercially available from Microsoft. A Kalman filter was implemented to reduce data jittering. Patients are required to move their impaired arm, sliding it on top of a transparent support, in order to play the game. The game is personalized to the patient through specific settings that adapt to the patients range of motion and motor control at the start of the game as well as performance during the game. The final score is proportional to the arms movement speed. A feasibility study was carried out with one stroke survivor. The game was played for ten days and usability surveys were answered before and after the study. The patient was engaged with the game, found it easy to understand and reported willingness to use it in the home environment and enjoyment of the use in the clinic.

Kinetic Gait Analysis Using a Low-Cost Insole

Abnormal gait caused by stroke or other pathological reasons can greatly impact the life of an individual. Being able to measure and analyze that gait is often critical for rehabilitation. Motion analysis labs and many current methods of gait analysis are expensive and inaccessible to most individuals. The low-cost, wearable, and wireless insole-based gait analysis system in this study provides kinetic measurements of gait by using low-cost force sensitive resistors. This paper describes the design and fabrication of the insole and its evaluation in six control subjects and four hemiplegic stroke subjects. Subject-specific linear regression models were used to determine ground reaction force plus moments corresponding to ankle dorsiflexion/plantarflexion, knee flexion/extension, and knee abduction/adduction. Comparison with data simultaneously collected from a clinical motion analysis laboratory demonstrated that the insole results for ground reaction force and ankle moment were highly correlated (all >0.95) for all subjects, while the two knee moments were less strongly correlated (generally >0.80). This provides a means of cost-effective and efficient healthcare delivery of mobile gait analysis that can be used anywhere from large clinics to an individuals home.

A Wireless Sensory Feedback Device for Real-Time Gait Feedback and Training

This paper presents a new sensing and feedback system for a personal gait rehabilitation device based on wireless transmission of ambulation data for real-time sensory feedback for assistive healthcare. An integrated force-sensing insole was designed, using embedded force sensitive resistors that were sampled using a microprocessor, which then transmitted the data to an Android smartphone for presentation to the user. Experiments were performed to verify that the device captured accurate gait data, and was able to influence the gait of the subject. In addition, different sensory methods of feedback were tested to determine their individual efficacy at modulating the gait of study subject. The results show that the feedback system is capable of influencing the gait of the user, without the need for direct supervision by a rehabilitation specialist. In addition, a statistical analysis was performed to establish the reliability and repeatability of the system. From these results, this feedback system is established as a novel, inexpensive, and effective candidate for use in clinical rehabilitation of persons with gait abnormalities.

Utilization of a lower extremity ambulatory feedback system to reduce gait asymmetry in transtibial amputation gait

The goal of our research is to augment gait rehabilitation for persons with gait asymmetry through a real-time feedback system that can be used independently by patients in the community. Our wireless, wearable, real-time gait asymmetry detection system called the lower extremity ambulatory feedback system (LEAFS) is a low-cost, in-shoe gait detection device that provides real-time auditory feedback based on the stance time symmetry ratio between the right and left limbs. This study evaluated the performance of the LEAFS in three study subjects with gait asymmetry secondary to unilateral transtibial amputation. Study subjects used the LEAFS for six 30-min training sessions under the supervision of a physical therapist. Two subjects demonstrated improved gait symmetry, with one subject reducing trunk sway by 85.5%, and the other subject reducing trunk sway by 16.0% and increasing symmetry ratio toward unity by 26.5%, as measured by a clinical motion analysis lab. The third subject did not demonstrate any objective improvements in gait symmetry or trunk sway. While testing with a larger number of subjects is necessary, this initial study using LEAFS with persons with transtibial amputations suggests that it can assist in improving gait symmetry in this population.

Development of a Quantitative In-Shoe Measurement System for Assessing Balance: Sixteen-Sensor Insoles

This work presents the first phase in the development of an in-shoe sensor system designed to evaluate balance. Sixteen force-sensitive resistors were strategically mounted to a removable insole, and the bilateral outputs were recorded. The initial results indicate that these sensors are capable of detecting subtle changes in weight distribution, corresponding to the subjects ability to balance. Preliminary analysis of this data found a clear correlation between the ability to balance and the state of health of the subject

Instrumented insole vs. force plate: A comparison of center of plantar pressure

Instrumented insoles allow analysis of gait outside of the confines of a motion analysis lab and capture motion data on every step. This study assesses the concurrent validity of center of plantar pressure (COPP) measurements during walking, and shows that our custom instrumented insoles compare favorably to an Advanced Mechanical Technology Inc. (AMTI) force plate in a clinical motion laboratory, particularly when the large difference in price is considered (an insole is nearly two orders of magnitude less expensive than a force plate). Deploying inexpensive insoles such as ours for ubiquitous health monitoring allows measurement of gait in more typical environments. This affords the opportunity to evaluate the gait of older adults in the home environment, and a future opportunity of providing real-time feedback corresponding to changes in gait.

A wireless sensory feedback system for real-time gait modification

Current rehabilitation technology and techniques have proven effective at modifying and correcting gait abnormalities. They are however limited to laboratory and clinical settings, under the supervision of a specialist. Conventional techniques for quantifying gait asymmetries can be combined with sensory feedback methods to provide an intuitive and inexpensive feedback system for extra-clinical rehabilitation. A wireless feedback system has been designed to collect gait information, process it in real-time, and provide corrective feedback to the user. The corrective feedback can be presented through visual, audible, or vibrotactile methods, or a combination thereof. Initial results have led to improvement in the sensory interface of the device to maximize the corrective influence on inexperienced subjects. These preliminary findings suggest that the wireless feedback device can influence the gait of the user, and effectively adapt to their personal feedback preferences.

Progress in Vibrotactile Threshold Evaluation Techniques: A Review

Vibrotactile threshold (VT) testing has been used for nearly a century to investigate activation of human somatosensory pathways. This use of vibrotactile stimuli provides a versatile tool for detecting peripheral neuropathies, and has been broadly used for investigation of carpal tunnel syndrome. New applications include investigation of drug-induced neuropathies and diabetes-related neuropathies. As a feedback device, the vibrotactile stimuli could be used as an information delivery system for rehabilitative feedback devices for upper limb musculoskeletal disorders or as information channels for the visually impaired. This review provides a comprehensive review of the advancement in VT measurement techniques over time and a comparison of these techniques in terms of various hardware features used and the testing protocols implemented. The advantages and limitations of these methods have been discussed along with specific recommendations for their implementation and suggestions for incorporation into clinical practice.

The Lower Extremity Ambulation Feedback System for Analysis of Gait Asymmetries: Preliminary Design and Validation Results

Asymmetric gait, commonly referred to as “limping,” is frequently seen in individuals with a variety of musculoskeletal and neurologic conditions. Asymmetric gait impacts the metabolic cost of ambulation and the development of osteoarthritis and also affects the cosmetic appearance of gait. This is especially true for individuals with lower limb amputations who ambulate with prosthetic limbs. The Lower Extremity Ambulation Feedback System (LEAFS) is a shoe-insert device that uses force sensors to evaluate asymmetries in gait and provide auditory feedback when an asymmetric gait threshold is reached. The aim of this study was to validate the ability of the LEAFS to accurately measure stance time and detect asymmetries in stance time. A prospective, consecutive case series study design was used. The study population consisted of individuals with lower limb amputations at the transtibial level. Data were collected simultaneously using both the LEAFS and a force plate and markers on the foot in a clinical motion analysis laboratory as subjects ambulated at their self-selected walking speed. The methods comparison approach of Bland and Altman was used to validate the measurement of stance time, and two-sample t-tests were used to validate the detection of asymmetry. The LEAFS determined the stance time with a bias error of −10.4 ± 37.2 ms, when compared with the clinical motion laboratory, and detected the same asymmetries in stance time for subjects with unilateral amputation (a shorter stance time on the limb with the prosthetic, when compared with the intact limb) as the clinical motion laboratory.

A laboratory insole for analysis of sensor placement to determine ground reaction force and ankle moment in patients with stroke

An insole system was constructed with 32 sensors inside a size 10 mens shoe. This system allows evaluation of the contributions of individual sensors spread throughout the surface area of the insole. The kinetic variables of interest in this initial study are ground reaction force and anterior-posterior ankle moment. Use of all 32 sensors are able to replicate the shape of the ground reaction force and ankle moment in a stroke patient who has regained a more normal gait, but less so in a stroke patient with impaired gait. Subsets of sensors can now be evaluated in order to ultimately identify an optimum set of sensors for determining kinetic variables necessary to classify presence or absence of a particular gait abnormality or other pathology.