Mukul Talaty

The ReWalk powered exoskeleton to restore ambulatory function to individuals with thoracic-level motor-complete spinal cord injury.

ObjectiveThe aim of this study was to assess the safety and performance of ReWalk in enabling people with paraplegia due to spinal cord injury to carry out routine ambulatory functions. DesignThis was an open, noncomparative, nonrandomized study of the safety and performance of the ReWalk powered exoskeleton. All 12 subjects have completed the active intervention; three remain in long-term follow-up. ResultsAfter training, all subjects were able to independently transfer and walk, without human assistance while using the ReWalk, for at least 50 to 100 m continuously, for a period of at least 5 to 10 mins continuously and with velocities ranging from 0.03 to 0.45 m/sec (mean, 0.25 m/sec). Excluding two subjects with considerably reduced walking abilities, average distances and velocities improved significantly. Some subjects reported improvements in pain, bowel and bladder function, and spasticity during the trial. All subjects had strong positive comments regarding the emotional/psychosocial benefits of the use of ReWalk. ConclusionsReWalk holds considerable potential as a safe ambulatory powered orthosis for motor-complete thoracic-level spinal cord injury patients. Most subjects achieved a level of walking proficiency close to that needed for limited community ambulation. A high degree of performance variability was observed across individuals. Some of this variability was explained by level of injury, but other factors have not been completely identified. Further development and application of this rehabilitation tool to other diagnoses are expected in the future.

Temporal-spatial feature of gait after traumatic brain injury.

The temporal-spatial characteristics of the gait of patients with traumatic brain injury (TBI) were investigated and compared with those of normal gait and the gait of stroke survivors. A slower walking velocity is evident in the TBI population when compared with normal. The average walking speed of TBI survivors is faster than that of stroke patients and is mainly related to a longer step length. TBI survivors produce a gait pattern with a prolonged stance period for the unaffected limb, without prolonged stance period for the affected limb, and a shorter step length for the unaffected limb.

Differentiating ability in users of the ReWalk TM powered exoskeleton: An analysis of walking kinematics

The ReWalkTM powered exoskeleton assists thoracic level motor complete spinal cord injury patients who are paralyzed to walk again with an independent, functional, upright, reciprocating gait. We completed an evaluation of twelve such individuals with promising results. All subjects met basic criteria to be able to use the ReWalkTM - including items such as sufficient bone mineral density, leg passive range of motion, strength, body size and weight limits. All subjects received approximately the same number of training sessions. However there was a wide distribution in walking ability. Walking velocities ranged from under 0.1m/s to approximately 0.5m/s. This variability was not completely explained by injury level The remaining sources of that variability are not clear at present. This paper reports our preliminary analysis into how the walking kinematics differed across the subjects - as a first step to understand the possible contribution to the velocity range and determine if the subjects who did not walk as well could be taught to improve by mimicking the better walkers.

Powered Exoskeletons for Walking Assistance in Persons with Central Nervous System Injuries: A Narrative Review

Individuals with central nervous system injuries are a large and apparently rapidly expanding population—as suggested by 2013 statistics from the American Heart Association. Increasing survival rates and lifespans emphasize the need to improve the quality of life for this population. In persons with central nervous system injuries, mobility limitations are among the most important factors contributing to reduced life satisfaction. Decreased mobility and subsequently reduced overall activity levels also contribute to lower levels of physical health. Braces to assist walking are options for greater‐functioning individuals but still limit overall mobility as the result of increased energy expenditure and difficulty of use. For individuals with greater levels of mobility impairment, wheelchairs remain the preferred mobility aid yet still fall considerably short compared with upright bipedal walking. Furthermore, the promise of functional electrical stimulation as a means to achieve walking has yet to materialize. None of these options allow individuals to achieve walking at speeds or levels comparable with those seen in individuals with unimpaired gait. Medical exoskeletons hold much promise to fulfill this unmet need and have advanced as a viable option in both therapeutic and personal mobility state, particularly during the past decade. The present review highlights the major developments in this technology, with a focus on exoskeletons for lower limb that may encompass the spine and that aim to allow independent upright walking for those who otherwise do not have this option. Specifically reviewed are powered exoskeletons that are either commercially available or have the potential to restore upright walking function. This paper includes a basic description of how each exoskeleton device works, a summation of key features, their known limitations, and a discussion of current and future clinical applicability.

Assessment of gait sensitivity norm as a predictor of risk of falling during walking in a neuromusculoskeletal model

Quantifying the risk of falling (falls risk) would be helpful in treating people with gait disorders. The gait sensitivity norm (GSN) is a stability measure that correlates well to risk of falling in passive dynamic walkers but has not been evaluated on humans or human-like walking models. We assessed the correlation of GSN to risk of falling in a neuromusculoskeletal (NMS) walking model. Specifically, we evaluated the correlation of GSN to the actual disturbance rejection (ADR) of the model and the sensitivity of this relationship to gait parameter, Poincaré section selection and steady state variability correction. Statistically significant results at p<0.05 were obtained for some of the gait indicators evaluated at the point in the gait cycle where they were most variable. The correlation between GSN and ADR was sensitive to gait indicator and Poincaré sections evaluated but not to steady state variability correction. The current work suggests some simple steps to reduce the sensitivity of GSN to arbitrary and subjective factors. Overall, the findings support the potential of GSN to be a clinically applicable measure of falls risk. Further study is required to identify methods to more definitively select the various factors within the GSN calculation and to confirm its ability to predict falls risk in human subjects.

Determination of Dynamic Prosthetic Alignment Using Forceline Visualization

ABSTRACT Objective techniques for determining proper configuration (alignment) of lower limb prostheses can help standardize and improve the functional outcomes for amputees. We propose that a dynamic forceline visualization system can assist in the development of such techniques. The forceline is a tool that allows the visualization of the ground reaction force in real time and in a spatially accurate manner relative to the image of the person as he/she walks. We evaluated a simplified version of an alignment protocol based on the forceline and using three novice clinicians and four amputee test subjects. The goal was to determine how easily the novice clinicians could learn the technique and how well they could apply it. All three clinicians were given a group training lasting about 1.5 hrs in which they were familiarized with the forceline visualization tool and were shown how to use it for determining prosthetic alignment on subjects with lower limb amputation. Then, each clinician evaluated the same four amputees both with and without the use of the forceline. The clinicians were able to learn and incorporate the simple alignment methodology using the forceline easily—each demonstrating basic understanding and skill in applying the method on the first amputee that each one evaluated. In 36% of the cases, using the line helped to standardize the clinicians’ alignments to the target alignment (the laboratory “nominal”). In 14% of the cases, using the forceline actually moved the clinicians away from the laboratory nominal. The alignment technique presented can assist clinical thinking by removing some of the guesswork and uncertainty involved during the alignment process. No objective or widely accepted standard exists for the definition of an optimal prosthetic alignment. A technique, such as that presented here, may help in defining and also subsequently in obtaining an optimal alignment.

Poster 359: Safety and Performance Evaluation of ReWalk Reciprocating Gait Orthosis

cadence, stride length, gait cycle duration, double support, single support, stance duration, step duration prosthesis, step duration normal, swing duration prosthesis, swing duration normal, symmetry stance, symmetry step duration, symmetry double support, symmetry swing), out of which significant differences were found in velocity, step duration, and cadence. The velocity with unweighted prosthesis is 74.4 m/min, with 0.30 kg is 61.38 m/min and with 0.5 kg is 57.66 m/min. PCI increased with increase in weight of prosthesis. When comparing prosthetic limb with normal limb, there was no significant difference in other kinematic gait parameters. Conclusions: The study is ongoing, and initial data show that a small increase in prosthetic weight does not alter kinematic parameters, but PCI and velocity showed significant difference. The recent trend to provide light weight prosthesis for transtibial amputee may not be the optimum weight to get the best possible performance. Hence, instead of light-weight prosthesis, an optimal weight one would be more suitable for Indian population given the cost constraint.

A Randomized Comparison of the Biomechanical Effect of Two Commercially Available Rocker Bottom Shoes to a Conventional Athletic Shoe During Walking in Healthy Individuals

Rocker bottom shoes have recently gained considerable popularity, likely in part because of the many purported benefits, including reducing joint loading and toning muscles. Scientific inquiry about these benefits has not kept pace with the increased usage of this shoe type. A fundamental premise of rocker bottom shoes is that they transform hard, flat, level surfaces into more uneven ones. Published studies have described a variety of such shoes-all having a somewhat rounded bottom and a cut heel region or a cut forefoot region, or both (double rocker). Despite the fundamentally similar shoe geometries, the reported effects of rocker bottom shoes on gait biomechanics have varied considerably. Ten healthy subjects agreed to participate in the present study and were given appropriately sized Masai Barefoot Technology (St. Louis, MO), Skechers(™) (Manhattan Beach, CA), and New Balance (Boston, MA) conventional walking shoes. After a 12-day accommodation period, the subjects walked wearing each shoe while 3-dimensional motion and force data were collected in the gait laboratory. The key findings included (1) increased trunk flexion, decreased ankle plantarflexion range, and reduced plantarflexion moment in the early stance; (2) increased ankle dorsiflexion and knee flexor moment in the midstance; (3) decreased peak ankle plantarflexion in the late stance; and (4) decreased ankle plantarflexion and decreased hip flexor and knee extensor moments in the pre-swing and into swing phase. The walking speed was unconstrained and was maintained across all shoe types. A biomechanical explanation is suggested for the observed changes. Suggestions for cautions are provided for using rocker bottom shoes in patients with neuromuscular insufficiency.

**Poster 133 Impact of Two Types of Commercially Available “Unstable” Shoes on Gait. A 3D Kinetic, Kinematic and Electromyographic Evaluation

CRDs is of uncertain significance. Also unclear is the significance of dementia in this case. The association of ALS and dementia is well documented in the literature (e.g., ALS with frontotemporal dementia and Western Pacific ALS-parkinsonism-dementia complex). Current understanding of the pathophysiology implicate ubiquitinpositive inclusions, which are found in motor neurons as well as the frontal and temporal lobes in patients with both ALS and dementia. Conclusions: This case describes a unique presentation of widespread CRDs on electromyography in a patient presenting with both dementia and slowly progressive motor neuron disease.