Motor Control Changes after Utilizing Upper Extremity Myoelectric Powered Wearable Orthotics in Persons with Acute SCI.

Following spinal cord injury (SCI), upper extremity (UE) weakness may impede one's ability to carry out activities of daily living (ADLs). Such a limitation drastically lowers a person's level of independence. Additionally, therapy and the field of assistive technology continue to place a strong premium on the restoration of UE motor function in patients with SCI. The main objective of this study was to assess the benefits of an UE myoelectric-powered wearable orthosis (MPWO) produced by MyoMo, Inc. (Boston, MA) on improving UE motor function in order to enhance ADLs and quality of life in individuals with subacute SCI. A 43-year-old man with subacute incomplete SCI (iSCI), American Spinal Injury Association (ASIA) Impairment Scale (AIS) C grade received 18 sessions (over a period of six weeks) of UE mobility therapy utilizing the MPWO. The MPWO was used to enhance active range of motion (AROM) of the hand and elbow, and associated muscle activations. After training with the MPWO, hand and elbow AROM and muscle activations were enhanced. These preliminary findings imply that UE-MPWO device-assisted rehabilitation may increase participants' UE activities, leading to improved function.Clinical Relevance- These preliminary findings from a person with iSCI in the subacute phase indicate that training with UE-MPWO assistive devices may enhance UE use during ADLs for people with muscle weakness but still having some residual voluntary muscle activation ability.

Upper Extremity Functional Improvements in Persons with SCI Resulted from Daily Utilization of Myoelectric Powered Wearable Orthotics.

Spinal cord injury (SCI) is a medically complex and life-disrupting condition. It is estimated that 17,700 new traumatic SCI cases are reported each year in the United States. Approximately half of those cases, involves paralysis, sensory loss, and impaired motor control in the upper extremity (UE) and lower extremities. Such impairments could affect the person's independence as well as their family members and caregiver. The limitation at the UE can significantly limit the general activities of daily living (ADL). The purpose of this paper is to determine the daily utilization effects on changing the handgrip AROM and handgrip forces before and after providing upper extremity in-clinic rehabilitation along with at-home utilization using an UE myoelectric powered wearable orthosis (UE-MPWO) in a person with incomplete spinal cord injury (iSCI). This device helps restore function to the weakened or paralyzed UE muscles. We demonstrate that the handgrip AROM and handgrip force improved after 6-weeks of training with the UE-MPWO. The overall goal of this study was to evaluate the effects of UE-MPWO (MyoPro) when utilized for in-clinic rehabilitation combined with at-home daily use in improving UE movement and function of people with iSCI.Clinical Relevance- The results of in-clinic rehabilitation combined with at-home daily utilization suggest that this UE-MPWO may improve UE function. The examined UE-MPWO could represent a relatively good example as a rehabilitation and assistive tool for persons with iSCI.

The Rehabilitation Effects of Myoelectric Powered Wearable Orthotics on Improving Upper Extremity Function in Persons with SCI.

Upper extremity (UE) weakness and/or paralysis following spinal cord injury (SCI) can lead to a limited capacity to perform activities of daily living (ADL). Such disability significantly reduces an individual's level of independence. Further, restoration of UE motor function in people with SCI remains a high priority in rehabilitation and the field of assistive technology. The overall goal of this study was to evaluate the effects of a myoelectric-powered wearable orthosis (MPWO) manufactured by MyoMo, Inc. (Boston, MA) for UE movement assistance on ameliorating UE motor function in order to improve ADL and quality of life in people with SCI. Two male participants with chronic incomplete SCI (iSCI), a 75- and a 31-year-old with AIS D and B, respectively, underwent 18 sessions (over 6 weeks) of UE movement rehabilitation using the MPWO. Handgrip strength, active range of motion (AROM) of the hand, response time to initiate a movement, and muscles activations were examined before and after the rehabilitation training using the MPWO. The response time to initiate UE movements decreased, and handgrip strength and AROM improved after training with the MPWO. These preliminary data suggest that rehabilitation with the use of the UE-MPWO device could enhance the participants' UE activities that led to improved function.Clinical Relevance- These preliminary results from two individuals with iSCI suggest that training with UE-MPWO assistive devices may improve UE utilization during ADL for individuals with muscle weakness or paralysis but still possessing residual voluntary muscle activation capabilities.

A pilot randomized controlled trial of robotic exoskeleton-assisted exercise rehabilitation in multiple sclerosis.

BACKGROUND: Co-occurring mobility and cognitive impairments are common, debilitating, and poorly-managed with pharmacological therapies in persons with multiple sclerosis (MS). Exercise rehabilitation (ER), particularly walking ER, has been suggested as one of the best approaches for managing these manifestations of MS. However, there is a focal lack of efficacy of ER on mobility and cognitive outcomes in persons with MS who present with substantial neurological disability. Such severe neurological disability oftentimes precludes the ability for participation in highly-intensive and repetitive ER that is necessary for eliciting adaptations in mobility and cognition. To address such a concern, robotic exoskeleton-assisted ER (REAER) might represent a promising intervention approach for managing co-occurring mobility and cognitive impairments in those with substantial MS disability who might not benefit from traditional ER. METHODS: The current pilot single-blind, randomized controlled trial (RCT) compared the effects of 4-weeks of REAER with 4-weeks of conventional gait training (CGT) as a standard-of-care control condition on functional mobility (timed up-and-go; TUG), walking endurance (six-minute walk test; 6MWT), cognitive processing speed (CPS; Symbol Digit Modalities Test; SDMT), and brain connectivity (thalamocortical resting-state functional connectivity (RSFC) based on fMRI) outcomes in 10 persons with substantial MS-related neurological disability. RESULTS: Overall, compared with CGT, 4-weeks of REAER was associated with large improvements in functional mobility (ηp2=.38), CPS (ηp2=.53), and RSFC between the thalamus and ventromedial prefrontal cortex (ηp2=.72), but not walking endurance (ηp2=.01). Further, changes in RSFC were moderately associated with changes in TUG, 6MWT, and SDMT performance, respectively, whereby increased thalamocortical RSFC was associated with improved functional mobility, walking endurance, and CPS (|ρ|>.36). CONCLUSION: The current pilot RCT provides initial support for REAER as an approach for improving functional mobility and CPS, perhaps based on adaptive and integrative central nervous system plasticity, namely increases in RSFC between the thalamus and ventromedial prefrontal cortex, in a small sample of persons with substantial MS disability. Such a pilot trial provides proof-of-concept data for the design and implementation of an appropriately-powered RCT of REAER in a larger sample of persons with MS who present with co-occurring impairments in both mobility and cognitive functioning.

Mobility and Cognitive Improvements Resulted from Overground Robotic Exoskeleton Gait-Training in Persons with MS.

Multiple sclerosis (MS) is a non-traumatic, immune-mediated neurodegenerative disease of the central nervous system (CNS), affecting more than 2 million individuals globally and approximately one million in the United States [1], [2]. This autoimmune inflammatory disease of the CNS featuring both neuroinflammatory and neurodegenerative aspects [3], often results in mobility and cognitive impairment. Rehabilitation has been suggested as the best [4], and perhaps, one of few methods for restoring function in MS [5]. The goal of the present investigation is to examine the effects of 4 weeks of supervised, over-ground gait training using a robotic exoskeleton (RE) compared with a control condition (conventional gait therapy, CGT) in persons with MS with ambulatory and cognition disabilities. Four subjects (mean age=50 years, three females) with relapsing-remitting MS (RRMS) participated in this study and completed a total of eight sessions (1-hour/session) gait training in a standard therapy gym either using a RE supervised by an RE training physical therapist (PT) or with the CGT supervised by a PT. Outcome measures (walking speed and temporal-spatial parameters) were measured on a level surface without RE using an instrumented walkway, for both groups, pre- and post-intervention. The two participants in the RE group were also tested in the same testing environment, while wearing a RE pre- and post-intervention. Cognitive processing speed was assessed using the Symbol Digit Modalities Test (SDMT) pre- and post-intervention. Subjects in the RE group tested without a RE increased average walking speed, stride length, and step length with decreased stride width and step time bilaterally after the 8-session of RE training. The two participants in the CGT group only had modest improvements in walking performance. Furthermore, while the CGT group had no improvements in the processing speed (SDMT scores), an average of 80% improvement in the processing speed was noted in the RE group.

Design of a low-cost MRI compatible plantarflexion force measurement device.

Investigating the neural correlates of ankles' joint rotation is critical to better understand the underlying deficit in balance or posture control in the clinical population. This work describes the design and characteristics of a low-cost MRI compatible isometric plantarflexion force measurement device. The device is fully adjustable to the particular height and shoe size of participants. Each individual force sensor has an operational linear range up to 80-100kg amounting to a force range up to 180kg when combining the two sensors, which is well above the maximal force for the majority of the population. Preliminary neuroimaging tests suggest that performing submaximal ankle plantar flexions on the device induce minimal motion artifacts on fMRI signal that are within an acceptable range.

Electromyography Assessment During Gait in a Robotic Exoskeleton for Acute Stroke.

Background: Robotic exoskeleton (RE) based gait training involves repetitive task-oriented movements and weight shifts to promote functional recovery. To effectively understand the neuromuscular alterations occurring due to hemiplegia as well as due to the utilization of RE in acute stroke, there is a need for electromyography (EMG) techniques that not only quantify the intensity of muscle activations but also quantify and compare activation timings in different gait training environments. Purpose: To examine the applicability of a novel EMG analysis technique, Burst Duration Similarity Index (BDSI) during a single session of inpatient gait training in RE and during traditional overground gait training for individuals with acute stroke. Methods: Surface EMG was collected bilaterally with and without the RE device for five participants with acute stroke during the normalized gait cycle to measure lower limb muscle activations. EMG outcomes included integrated EMG (iEMG) calculated from the root-mean-square profiles, and a novel measure, BDSI derived from activation timing comparisons. Results: EMG data demonstrated volitional although varied levels of muscle activations on the affected and unaffected limbs, during gait with and without the RE. During the stance phase mean iEMG of the soleus (p = 0.019) and rectus femoris (RF) (p = 0.017) on the affected side significantly decreased with RE, as compared to without the RE. The differences in mean BDSI scores on the affected side with RE were significantly higher than without RE for the vastus lateralis (VL) (p = 0.010) and RF (p = 0.019). Conclusions: A traditional amplitude analysis (iEMG) and a novel timing analysis (BDSI) techniques were presented to assess the neuromuscular adaptations resulting in lower extremities muscles during RE assisted hemiplegic gait post acute stroke. The RE gait training environment allowed participants with hemiplegia post acute stroke to preserve their volitional neuromuscular activations during gait iEMG and BDSI analyses showed that the neuromuscular changes occurring in the RE environment were characterized by correctly timed amplitude and temporal adaptations. As a result of these adaptations, VL and RF on the affected side closely matched the activation patterns of healthy gait. Preliminary EMG data suggests that the RE provides an effective gait training environment for in acute stroke rehabilitation.

Motor control investigation of dystonic cerebral palsy: A pilot study of passive knee trajectory.

The purpose of this study is to better understand dystonia in CP and be able to objectively distinguish between individuals who experience spasticity, dystonia, or a combination of these conditions while evaluating the effect of 2Hz vestibular stimulation. Selected outcome measures included knee ROM, angular velocity and acceleration and all measures increased post vestibular stimulation; these results are indications of a possible reduction in the level of disability. The current investigation also identified an unexpected and unique behavior of the knee in children with dystonic cerebral palsy (CP) that was noticed while administering the Pendulum Knee Drop test (PKD) at approximately 0.4 rad (a mid-angle between full extension and zero vertical). There was a catch-like phenomenon at the described mid-angle in dystonic individuals. These results may suggest that dystonia is not a velocity dependent hypersensitivity of reflexes, but may include position dependent muscle reflexes and co-contractions. This reinforces the need for a more precise objective measure or perhaps a modified measure such as a mid-angle PKD test. Furthermore, based on the results obtained through the modified technique, beneficial alterations can be made to the form of treatment such as: robotic therapy or physical therapy that specifically accommodates the unique motor control disorder in individuals with dystonic CP.

Estimation of intrinsic joint impedance using quasi-static passive and dynamic methods in individuals with and without Cerebral Palsy.

Modeling the passive behavior of the knee in subjects with spasticity involves the applied external torques (e.g. gravitational torque), the intrinsic moments due to tissue properties, as well as active, neurally defined moments resulting from the hypersensitivity of reflexes introduced by disability. In order to provide estimates of the necessary intrinsic terms in the equation of motion, the push-pull and Wartenberg Pendulum Knee Drop (PKD) tests were administered. Four subjects without disability and two subjects with Cerebral Palsy (CP) were evaluated for their active and intrinsic knee stiffness parameters. Separation of these two terms requires an additional stiffness term be added to the traditional equation of motion. This holds true for subjects with and without neurological disability. Very interestingly, the optimized non-disabled PKD produced lumped stiffness (K) that is similar to the push-pull passive stiffness (KI) for both populations. On the other hand the optimized K value in the PKD test for subjects with disability was approximately 19 times larger than the KI value found graphically from the push-pull test. This leads us to the conclusion that we can partition our lumped K as the sum of a neurally generated stiffness (Ka) and KI to complete the trajectory model. Therefore, this study shows that spasticity is a velocity dependent, that would not appear in disabled individuals unless the examined limb has a non-zero velocity.