Journal of NeuroEngineering and Rehabilitation - Latest Articles

Sensory nerve action potentials and sensory perception in women with arthritis of the hand

Kristina Calder — 2012-05-10T00:00:00Z

Background: Arthritis of the hand can limit a person's ability to perform daily activities. Whether or not sensory deficits contribute to the disability in this population remains unknown. The primary purpose of this study was to determine if women with osteoarthritis (OA) or rheumatoid arthritis (RA) of the hand have sensory impairments. Methods: Sensory function in the dominant hand of women with hand OA or RA and healthy women was evaluated by measuring sensory nerve action potentials (SNAPs) from the median, ulnar and radial nerves, sensory mapping (SM), and vibratory and current perception thresholds (VPT and CPT, respectively) of the second and fifth fingers. Results: All SNAP amplitudes were significantly lower for the hand OA and hand RA groups compared with the healthy group (p < 0.05). No group differences were found for SNAP conduction velocities, SM, VPT, and CPT.DiscussionWe propose, based on these findings, that women with hand OA or RA may have axonal loss of sensory fibers in the median, ulnar and radial nerves. Less apparent were losses in conduction speed or sensory perception.

Clinical application of computerized evaluation and re-education biofeedback prototype for sensorimotor control of the hand in stroke patients

Hsiu-Yun Hsu — 2012-05-09T00:00:00Z

Background: Hemianaesthesia patients usually exhibit awkward and inefficient finger movements of theaffected hands. Conventionally, most interventions emphasize the improvement of motordeficits, but rarely address sensory capability and sensorimotor control following stroke.Thus it is critical for stroke patients with sensory problems to incorporate appropriatestrategies for dealing with sensory impairment, into traditional hand function rehabilitationprograms. In this study, we used a custom-designed computerized evaluation and reeducationbiofeedback (CERB) prototype to analyze hand grasp performances, and monitorthe training effects on hand coordination for stroke patients with sensory disturbance andwithout motor deficiency. Methods: The CERB prototype was constructed to detect momentary pinch force modulation for 14sub-acute and chronic stroke patients with sensory deficiency and 14 healthy controls. Theother ten chronic stroke patients (ranges of stroke period: 6-60 months) were recruited toinvestigate the effects of 4-weeks computerized biofeedback treatments on the hand controlability. The biofeedback procedures provide visual and auditory cues to the participants whenthe interactive force of hand-to-object exceeded the target latitude in a pinch-up-holding taskto trigger optimal motor strategy. Follow-up measurements were conducted one month aftertraining. The hand sensibility, grip forces and results of hand functional tests were recordedand analyzed. Results: The affected hands of the 14 predominant sensory stroke patients exhibited statisticallysignificant elevation in the magnitude of peak pinch force (p = 0.033) in pinching and liftinguptasks, and poor results for hand function tests (p = 0.005) than sound hands did. Inaddition, the sound hands of patients were less efficient in force modulation (p = 0.009) thanthe hands of healthy subjects were. Training with the biofeedback system producedsignificant improvements in grip force modulation (p = 0.020) and better performances in thesubtests of pin insertion (p = 0.019), and lifting of lightweight objects (p = 0.005). Conclusions: The CERB prototype can provide momentary and interactive information for quantitativeassessing and re-educating force modulation appropriately for stroke patients with sensorydeficits. Furthermore, the patients could transfer the learned strategy to improve handfunction.

Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation

Raviraj Nataraj — 2012-05-06T00:00:00Z

Background: The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). Methods: In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM acceleration data was analyzed. Results: Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, , performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Conclusions: Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.

A novel approach to surface electromyography: an exploratory study of electrode-pair selection based on signal characteristics

Cynthia Kendell — 2012-04-26T00:00:00Z

A 3 x 4 electrode array was placed over each of seven muscles and surface electromyography(sEMG) data were collected during isometric contractions. For each array, nine bipolarelectrode pairs were formed off-line and sEMG parameters were calculated and evaluatedbased on repeatability across trials and comparison to an anatomically placed electrode pair.The use of time-domain parameters for the selection of an electrode pair from within a gridlikearray may improve upon existing electrode placement methodologies.

European study of research and development in mobility technology for persons with disabilities

Brian Caulfield — 2012-04-20T00:00:00Z

In the fall of 2010, the National Science Foundation, the National Institutes of Health and the U.S. Veteran's Administration jointly supported a review of mobility technology in Europe. A delegation of American Scientists traveled to Europe to visit a number of research centers and engaged in a demonstration and dialogue related to the global state-of-the-art for mobility impairment rectification and augmentation. From the observations and exchanges between the U.S. delegation and host institutions, the researchers were able to derive a series of papers which are now published in this thematic series of Journal of NeuroEngineering and Rehabilitation. The papers describe the main themes of the European mobility technology research activities showing a healthy picture of research and innovation in the field.

Major trends in mobility technology research and development: Overview of the results of the NSF-WTEC European study

David Reinkensmeyer — 2012-04-20T00:00:00Z

Mobility technologies, including wheelchairs, prostheses, joint replacements, assistive devices, and therapeutic exercise equipment help millions of people participate in desired life activities. Yet, these technologies are not yet fully transformative because many desired activities cannot be pursued or are difficult to pursue for the millions of individuals with mobility related impairments. This WTEC study, initiated and funded by the National Science Foundation, was designed to gather information on European innovations and trends in technology that might lead to greater mobility for a wider range of people. What might these transformative technologies be and how might they arise? Based on visits to leading mobility technology research labs in western Europe, the WTEC panel identified eight major trends in mobility technology research. This commentary summarizes these trends, which are then described in detail in companion papers appearing in this special issue.

A review of wearable sensors and systems with application in rehabilitation

Shyamal Patel — 2012-04-20T00:00:00Z

The aim of this review paper is to summarize recent developments in the field of wearable sensors and systems that are relevant to the field of rehabilitation. The growing body of work focused on the application of wearable technology to monitor older adults and subjects with chronic conditions in the home and community settings justifies the emphasis of this review paper on summarizing clinical applications of wearable technology currently undergoing assessment rather than describing the development of new wearable sensors and systems. A short description of key enabling technologies (i.e. sensor technology, communication technology, and data analysis techniques) that have allowed researchers to implement wearable systems is followed by a detailed description of major areas of application of wearable technology. Applications described in this review paper include those that focus on health and wellness, safety, home rehabilitation, assessment of treatment efficacy, and early detection of disorders. The integration of wearable and ambient sensors is discussed in the context of achieving home monitoring of older adults and subjects with chronic conditions. Future work required to advance the field toward clinical deployment of wearable sensors and systems is discussed.

Recent trends in assistive technology for mobility

Rachel Cowan — 2012-04-20T00:00:00Z

Loss of physical mobility makes maximal participation in desired activities more difficult and in the worst case fully prevents participation. This paper surveys recent work in assistive technology to improve mobility for persons with a disability, drawing on examples observed during a tour of academic and industrial research sites in Europe. The underlying theme of this recent work is a more seamless integration of the capabilities of the user and the assistive technology. This improved integration spans diverse technologies, including powered wheelchairs, prosthetic limbs, functional electrical stimulation, and wearable exoskeletons. Improved integration is being accomplished in three ways: 1) improving the assistive technology mechanics; 2) improving the user-technology physical interface; and 3) sharing of control between the user and the technology. We provide an overview of these improvements in user-technology integration and discuss whether such improvements have the potential to be transformative for people with mobility impairments.

Personalized neuromusculoskeletal modeling to improve treatment of mobility impairments: a perspective from European research sites

Benjamin Fregly — 2012-03-30T00:00:00Z

Mobility impairments due to injury or disease have a significant impact on quality of life. Consequently, development of effective treatments to restore or replace lost function is an important societal challenge. In current clinical practice, a treatment plan is often selected from a standard menu of options rather than customized to the unique characteristics of the patient. Furthermore, the treatment selection process is normally based on subjective clinical experience rather than objective prediction of post-treatment function. The net result is treatment methods that are less effective than desired at restoring lost function. This paper discusses the possible use of personalized neuromusculoskeletal computer models to improve customization, objectivity, and ultimately effectiveness of treatments for mobility impairments. The discussion is based on information gathered from academic and industrial research sites throughout Europe, and both clinical and technical aspects of personalized neuromusculoskeletal modeling are explored. On the clinical front, we discuss the purpose and process of personalized neuromusculoskeletal modeling, the application of personalized models to clinical problems, and gaps in clinical application. On the technical front, we discuss current capabilities of personalized neuromusculoskeletal models along with technical gaps that limit future clinical application. We conclude by summarizing recommendations for future research efforts that would allow personalized neuromusculoskeletal models to make the greatest impact possible on treatment design for mobility impairments.

Technologies and combination therapies for enhancing movement training for people with a disability

David Reinkensmeyer — 2012-03-30T00:00:00Z

There has been a dramatic increase over the last decade in research on technologies for enhancing movement training and exercise for people with a disability. This paper reviews some of the recent developments in this area, using examples from a National Science Foundation initiated study of mobility research projects in Europe to illustrate important themes and key directions for future research. This paper also reviews several recent studies aimed at combining movement training with plasticity or regeneration therapies, again drawing in part from European research examples. Such combination therapies will likely involve complex interactions with motor training that must be understood in order to achieve the goal of eliminating severe motor impairment.