Publications by authors named "Arun Jayaraman"

92 Publications

Utilization of Robotic Exoskeleton for Overground Walking in Acute and Chronic Stroke.

Front Neurorobot 2021 1;15:689363. Epub 2021 Sep 1.

University of Texas at Houston McGovern Medical School, Houston, TX, United States.

Stroke commonly results in gait deficits which impacts functional ambulation and quality of life. Robotic exoskeletons (RE) for overground walking are devices that are programmable to provide high dose and movement-impairment specific assistance thus offering new rehabilitation possibilities for recovery progression in individuals post stroke. The purpose of this investigation is to present preliminary utilization data in individuals with acute and chronic stroke after walking overground with an RE. Secondary analysis on a subset of individuals is presented to understand the mechanistic changes due to RE overground walking. Thirty-eight participants with hemiplegia secondary to stroke were enrolled in a clinical trial conducted at eight rehabilitation centers. Data is presented for four sessions of overground walking in the RE over the course of 2 weeks. Participants continued their standard of care if they had any ongoing therapy at the time of study enrollment. Gait speed during the 10 Meter Walk Test, Gait deviations and the Functional Ambulation Category (FAC) data were collected before (baseline) and after (follow-up) the RE walking sessions. Walking speed significantly increased between baseline and follow-up for participants in the chronic ( <0.01) and acute ( < 0.05) stage of stroke recovery. FAC level significantly improved ( < 0.05) and there were significantly fewer ( < 0.05) gait deviations observed for participants in the acute stages of stroke recovery between baseline and follow-up. Secondary analysis on a subset of eight participants indicated that after four sessions of overground walking with the RE, the participants significantly improved their spatial symmetry. The walk time, step count and ratio of walk time to up time increased from first session to the last session for participants in the chronic and acute stages of stroke. The RE was effectively utilized for overground walking for individuals with acute and chronic stroke with varying severity levels. The results demonstrated an increase in walking speed, improvement in FAC and a decrease in gait deviations (from baseline to follow-up) after four sessions of overground walking in the RE for participants. In addition, preliminary data indicated that spatial symmetry and step length also improved after utilization of an RE for overground walking.
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http://dx.doi.org/10.3389/fnbot.2021.689363DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8442911PMC
September 2021

Multiple myeloma and malignant lesions: a potential risk factor for local anesthetic systemic toxicity.

Reg Anesth Pain Med 2021 Sep 17. Epub 2021 Sep 17.

Department of Anesthesiology and Perioperative Medicine, Mayo Clinic Arizona, Scottsdale, Arizona, USA.

Background: Multiple myeloma is a cancer of plasma cells that often leads to complications including osteolytic bone lesions, nephropathy and neuropathy. Multiple myeloma is only one etiology of many cancer pain conditions that may necessitate interventional pain treatment when refractory to multimodal medications. Notably, local anesthetic systemic toxicity is a rare but life-threatening complication of local anesthetic administered for these interventions.

Case Presentation: A 50-60-year-old woman presented with multiple myeloma complicated by chronic bone pain and in an acute pain crisis. A fluoroscopic-guided L4-5 epidural catheter was placed with clinical doses of bupivacaine for comfort to undergo MRI of the spine. Soon after, she became tachycardic, tachypneic and hypoxic requiring non-invasive positive pressure airway support. As this respiratory distress was attributed to a large pleural effusion, a pigtail catheter was inserted in the intensive care unit with submaximally dosed lidocaine infiltration. She then developed a left bundle branch block followed by cardiovascular collapse minimally responsive to high-dose inotrope and vasopressor support. Lipid emulsion was started with dramatic therapeutic response and recovery to baseline. A CT of the thoracolumbar spine showed worsening extensive lytic lesions throughout all vertebral bodies and ribs from diffuse myeloma.

Conclusions: Patients with oncologic lesions focal to the thoracolumbar spine may be at higher risk for local anesthetic systemic toxicity from palliative epidurals due to increased cancer-related angiogenesis. Likewise, local anesthetic infiltration for procedures near any malignant sites could have a similar risk and may require lower initial fractionated dosages with increased vigilance.
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http://dx.doi.org/10.1136/rapm-2021-102845DOI Listing
September 2021

Usability, functionality, and efficacy of a custom myoelectric elbow-wrist-hand orthosis to assist elbow function in individuals with stroke.

J Rehabil Assist Technol Eng 2021 Jan-Dec;8:20556683211035057. Epub 2021 Aug 27.

Max Nader Center for Rehabilitation Technologies & Outcomes Research, Shirley Ryan AbilityLab, Chicago, USA.

Introduction: After stroke, upper limb impairment affects independent performance of activities of daily living. We evaluated the usability, functionality, and efficacy of a myoelectric elbow-wrist-hand orthosis to provide support, limit unsafe motion, and enhance the functional motion of paralyzed or weak upper limbs.

Methods: Individuals with stroke participated in a single-session study to evaluate the device. Ability to activate the device was tested in supported and unsupported shoulder position, as well as the elbow range of motion, ability to maintain elbow position, and ability to lift and hold a range of weights while using the device.

Results: No adverse events were reported. 71% of users were able to operate the device in all three active myoelectric activation modes (Biceps, Triceps, Dual) during testing. Users were able to hold a range of wrist weights (0.5-2 lbs) for 10-120 seconds, with the largest percentage of participants able to hold weights with the device in Biceps Mode.

Conclusions: The myoelectric elbow-wrist-hand orthosis improved range of motion during use and was efficacious at remediating upper extremity impairment after stroke. All users could operate the device in at least one mode, and most could lift and hold weights representative of some everyday objects using the device.
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http://dx.doi.org/10.1177/20556683211035057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8404626PMC
August 2021

A smartphone-based online system for fall detection with alert notifications and contextual information of real-life falls.

J Neuroeng Rehabil 2021 08 10;18(1):124. Epub 2021 Aug 10.

Max Nader Rehabilitation Technologies and Outcomes Lab, Shirley Ryan Ability Lab, IL, Chicago, USA.

Background: Falls are a leading cause of accidental deaths and injuries worldwide. The risk of falling is especially high for individuals suffering from balance impairments. Retrospective surveys and studies of simulated falling in lab conditions are frequently used and are informative, but prospective information about real-life falls remains sparse. Such data are essential to address fall risks and develop fall detection and alert systems. Here we present the results of a prospective study investigating a proof-of-concept, smartphone-based, online system for fall detection and notification.

Methods: The system uses the smartphone's accelerometer and gyroscope to monitor the participants' motion, and falls are detected using a regularized logistic regression. Data on falls and near-fall events (i.e., stumbles) is stored in a cloud server and fall-related variables are logged onto a web portal developed for data exploration, including the event time and weather, fall probability, and the faller's location and activity before the fall.

Results: In total, 23 individuals with an elevated risk of falling carried the phones for 2070 days in which the model classified 14,904,000 events. The system detected 27 of the 37 falls that occurred (sensitivity = 73.0 %) and resulted in one false alarm every 46 days (specificity > 99.9 %, precision = 37.5 %). 42.2 % of the events falsely classified as falls were validated as stumbles.

Conclusions: The system's performance shows the potential of using smartphones for fall detection and notification in real-life. Apart from functioning as a practical fall monitoring instrument, this system may serve as a valuable research tool, enable future studies to scale their ability to capture fall-related data, and help researchers and clinicians to investigate real-falls.
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http://dx.doi.org/10.1186/s12984-021-00918-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8353784PMC
August 2021

Telerehabilitation in neurorehabilitation: has it passed the COVID test?

Expert Rev Neurother 2021 Aug 4;21(8):833-836. Epub 2021 Aug 4.

Departments of Physical Medicine and Rehabilitation; Medical Social Sciences; and Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, USA.

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http://dx.doi.org/10.1080/14737175.2021.1958676DOI Listing
August 2021

Combining Accelerometer and GPS Features to Evaluate Community Mobility in Knee Ankle Foot Orthoses (KAFO) Users.

IEEE Trans Neural Syst Rehabil Eng 2021 26;29:1386-1393. Epub 2021 Jul 26.

Orthotic and assistive devices such as knee ankle foot orthoses (KAFO), come in a variety of forms and fits, with several levels of available features that could help users perform daily activities more naturally. However, objective data on the actual use of these devices outside of the research lab is usually not obtained. Such data could enhance traditional lab-based outcome measures and inform clinical decision-making when prescribing new orthotic and assistive technology. Here, we link data from a GPS unit and an accelerometer mounted on the orthotic device to quantify its usage in the community and examine the correlations with clinical metrics. We collected data from 14 individuals over a period of 2 months as they used their personal KAFO first, and then a novel research KAFO; for each device we quantified number of steps, cadence, time spent at community locations and time wearing the KAFO at those locations. Sensor-derived metrics showed that mobility patterns differed widely between participants (mean steps: 591.3, SD =704.2). The novel KAFO generally enabled participants to walk faster during clinical tests ( ∆6 Minute-Walk-Test=71.5m, p=0.006). However, some participants wore the novel device less often despite improved performance on these clinical measures, leading to poor correlation between changes in clinical outcome measures and changes in community mobility ( ∆6 Minute-Walk-Test - ∆ Community Steps: r=0.09, p=0.76). Our results suggest that some traditional clinical outcome measures may not be associated with the actual wear time of an assistive device in the community, and obtaining personalized data from real-world use through wearable technology is valuable.
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http://dx.doi.org/10.1109/TNSRE.2021.3096434DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8363134PMC
August 2021

A Novel Technique to Reject Artifact Components for Surface EMG Signals Recorded During Walking With Transcutaneous Spinal Cord Stimulation: A Pilot Study.

Front Hum Neurosci 2021 3;15:660583. Epub 2021 Jun 3.

Shirley Ryan AbilityLab, Chicago, IL, United States.

Transcutaneous spinal cord electrical stimulation (tSCS) is an emerging technology that targets to restore functionally integrated neuromuscular control of gait. The purpose of this study was to demonstrate a novel filtering method, Artifact Component Specific Rejection (ACSR), for removing artifacts induced by tSCS from surface electromyogram (sEMG) data for investigation of muscle response during walking when applying spinal stimulation. Both simulated and real tSCS contaminated sEMG data from six stroke survivors were processed using ACSR and notch filtering, respectively. The performance of the filters was evaluated with data collected in various conditions (e.g., simulated artifacts contaminating sEMG in multiple degrees, various tSCS intensities in five lower-limb muscles of six participants). In the simulation test, after applying the ACSR filter, the contaminated-signal was well matched with the original signal, showing a high correlation ( = 0.959) and low amplitude difference (normalized root means square error = 0.266) between them. In the real tSCS contaminated data, the ACSR filter showed superior performance on reducing the artifacts (96% decrease) over the notch filter (25% decrease). These results indicate that ACSR filtering is capable of eliminating artifacts from sEMG collected during tSCS application, improving the precision of quantitative analysis of muscle activity.
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http://dx.doi.org/10.3389/fnhum.2021.660583DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8209256PMC
June 2021

Using a microprocessor knee (C-Leg) with appropriate foot transitioned individuals with dysvascular transfemoral amputations to higher performance levels: a longitudinal randomized clinical trial.

J Neuroeng Rehabil 2021 05 25;18(1):88. Epub 2021 May 25.

Max Näder Lab for Rehabilitation Technologies and Outcomes Research, Shirley Ryan AbilityLab, Chicago, USA.

Background: Individuals with transfemoral amputations who are considered to be limited community ambulators are classified as Medicare functional classification (MFCL) level K2. These individuals are usually prescribed a non-microprocessor controlled knee (NMPK) with an appropriate foot for simple walking functions. However, existing research suggests that these individuals can benefit from using a microprocessor controlled knee (MPK) and appropriate foot for their ambulation, but cannot obtain one due to insurance policy restrictions. With a steady increase in older adults with amputations due to vascular conditions, it is critical to evaluate whether advanced prostheses can provide better safety and performance capabilities to maintain and improve quality of life in individuals who are predominantly designated MFCL level K2. To decipher this we conducted a 13 month longitudinal clinical trial to determine the benefits of using a C-Leg and 1M10 foot in individuals at K2 level with transfemoral amputation due to vascular disease. This longitudinal clinical trial incorporated recommendations prescribed by the lower limb prosthesis workgroup to design a study that can add evidence to improve reimbursement policy through clinical outcomes using an MPK in K2 level individuals with transfemoral amputation who were using an NMPK for everyday use.

Methods: Ten individuals (mean age: 63 ± 9 years) with unilateral transfemoral amputation due to vascular conditions designated as MFCL K2 participated in this longitudinal crossover randomized clinical trial. Baseline outcomes were collected with their current prosthesis. Participants were then randomized to one of two groups, either an intervention with the MPK with a standardized 1M10 foot or their predicate NMPK with a standardized 1M10 foot. On completion of the first intervention, participants crossed over to the next group to complete the study. Each intervention lasted for 6 months (3 months of acclimation and 3 months of take-home trial to monitor home use). At the end of each intervention, clinical outcomes and self-reported outcomes were collected to compare with their baseline performance. A generalized linear model ANOVA was used to compare the performance of each intervention with respect to their own baseline.

Results: Statistically significant and clinically meaningful improvements were observed in gait performance, safety, and participant-reported measures when using the MPK C-Leg + 1M10 foot. Most participants were able to achieve higher clinical scores in gait speed, balance, self-reported mobility, and fall safety, while using the MPK + 1M10 combination. The improvement in scores were within range of scores achieved by individuals with K3 functional level as reported in previous studies.

Conclusions: Individuals with transfemoral amputation from dysvascular conditions designated MFCL level K2 benefited from using an MPK + appropriate foot. The inference and evidence from this longitudinal clinical trial will add to the knowledgebase related to reimbursement policy-making. Trial registration This study is registered on clinical trials.gov with the study title "Functional outcomes in dysvascular transfemoral amputees" and the associated ClinicalTrials.gov Identifier: NCT01537211. The trial was retroactively registered on February 7, 2012 after the first participant was enrolled.
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http://dx.doi.org/10.1186/s12984-021-00879-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146219PMC
May 2021

Rational design of Shewanella sp. l-arabinose isomerase for d-galactose isomerase activity under mesophilic conditions.

Enzyme Microb Technol 2021 Jun 31;147:109796. Epub 2021 Mar 31.

Centre for Biotechnology, Anna University, Chennai, 600025, India. Electronic address:

d-Tagatose, a potential low calorific substitute for sucrose, can be produced by bioconversion of d-galactose catalysed by l-arabinose isomerase. l-Arabinose isomerase from Shewanella sp. ANA-3 is unique for its ability to catalyse bioconversion reactions under mesophilic conditions. However, d-galactose not being a natural substrate for l-arabinose isomerase is catalysed at a slower rate. We attempted to increase the biocatalytic efficiency of Shewanella sp. l-arabinose isomerase by rational design to enhance galactose isomerisation activity. In silico molecular docking, analysis has revealed that F279 is sterically hindering the binding of d-galactose at the C6 position. Substitution of bulky Phe residue with smaller hydrophilic residues such as Asn and Thr increased the galactose isomerase activity by 86 % and 12 % respectively. At mesophilic conditions, F279N mutant catalysed the bioconversion of d-galactose more efficiently than l-arabinose, indicating a shift in substrate preference.
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http://dx.doi.org/10.1016/j.enzmictec.2021.109796DOI Listing
June 2021

Differential cardiopulmonary monitoring system for artifact-canceled physiological tracking of athletes, workers, and COVID-19 patients.

Sci Adv 2021 05 12;7(20). Epub 2021 May 12.

Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA.

Soft, skin-integrated electronic sensors can provide continuous measurements of diverse physiological parameters, with broad relevance to the future of human health care. Motion artifacts can, however, corrupt the recorded signals, particularly those associated with mechanical signatures of cardiopulmonary processes. Design strategies introduced here address this limitation through differential operation of a matched, time-synchronized pair of high-bandwidth accelerometers located on parts of the anatomy that exhibit strong spatial gradients in motion characteristics. When mounted at a location that spans the suprasternal notch and the sternal manubrium, these dual-sensing devices allow measurements of heart rate and sounds, respiratory activities, body temperature, body orientation, and activity level, along with swallowing, coughing, talking, and related processes, without sensitivity to ambient conditions during routine daily activities, vigorous exercises, intense manual labor, and even swimming. Deployments on patients with COVID-19 allow clinical-grade ambulatory monitoring of the key symptoms of the disease even during rehabilitation protocols.
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http://dx.doi.org/10.1126/sciadv.abg3092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8115927PMC
May 2021

Automated, multiparametric monitoring of respiratory biomarkers and vital signs in clinical and home settings for COVID-19 patients.

Proc Natl Acad Sci U S A 2021 05;118(19)

Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208;

Capabilities in continuous monitoring of key physiological parameters of disease have never been more important than in the context of the global COVID-19 pandemic. Soft, skin-mounted electronics that incorporate high-bandwidth, miniaturized motion sensors enable digital, wireless measurements of mechanoacoustic (MA) signatures of both core vital signs (heart rate, respiratory rate, and temperature) and underexplored biomarkers (coughing count) with high fidelity and immunity to ambient noises. This paper summarizes an effort that integrates such MA sensors with a cloud data infrastructure and a set of analytics approaches based on digital filtering and convolutional neural networks for monitoring of COVID-19 infections in sick and healthy individuals in the hospital and the home. Unique features are in quantitative measurements of coughing and other vocal events, as indicators of both disease and infectiousness. Systematic imaging studies demonstrate correlations between the time and intensity of coughing, speaking, and laughing and the total droplet production, as an approximate indicator of the probability for disease spread. The sensors, deployed on COVID-19 patients along with healthy controls in both inpatient and home settings, record coughing frequency and intensity continuously, along with a collection of other biometrics. The results indicate a decaying trend of coughing frequency and intensity through the course of disease recovery, but with wide variations across patient populations. The methodology creates opportunities to study patterns in biometrics across individuals and among different demographic groups.
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http://dx.doi.org/10.1073/pnas.2026610118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8126790PMC
May 2021

Relationship between gait quality measures and modular neuromuscular control parameters in chronic post-stroke individuals.

J Neuroeng Rehabil 2021 04 7;18(1):58. Epub 2021 Apr 7.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daehak-ro 291, Yuseong-gu, Daejeon, 34141, Republic of Korea.

Background: Recent evidence suggests that disinhibition and/or hyperexcitation of the brainstem descending pathways and intraspinal motor network diffuse spastic synergistic activation patterns after stroke. This results in simplified or merged muscle sets (i.e., muscle modules or synergies) compared to non-impaired individuals and this leads to poor walking performance. However, the relations of how these neuromuscular deficits influence gait quality (e.g., symmetry or natural walking patterns) are still unclear. The objective of this exploratory study was to investigate the relations of modular neuromuscular framework and gait quality measures in chronic stroke individuals.

Methods: Sixteen chronic post-stroke individuals participated in this study. Full lower body three-dimensional kinematics and electromyography (EMG) were concurrently measured during overground walking at a comfortable speed. We first examined changes in gait quality measures across the number of muscle modules using linear regression model. Then, a stepwise multiple regression was used to investigate the optimal combination of the neuromuscular parameters that associates with gait quality measures.

Results: We observed that subjects who had a lower number of muscle modules revealed reduced function (i.e., speed) and greater asymmetry in the kinematic parameters including limb length, footpath area, knee flexion/extension, and hip abduction/adduction (all p < 0.05). We also found that the combination of input variables from the modular neuromuscular control framework significantly associated with gait quality measures (average [Formula: see text]). Those variables included variability accounted for ([Formula: see text]) information from the muscle modules and area under the EMG envelope curves of the quadriceps (i.e., rectus femoris and vastus lateralis) and tibialis anterior muscles.

Conclusions: The results suggest that there exists a significant correlation between the neuromuscular control framework and the gait quality measures. This study helps to understand the underlying mechanism of disturbances in gait quality and provides insight for a more comprehensive outcome measure to assess gait impairment after stroke.
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http://dx.doi.org/10.1186/s12984-021-00860-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028248PMC
April 2021

Rapid Screening of Physiological Changes Associated With COVID-19 Using Soft-Wearables and Structured Activities: A Pilot Study.

IEEE J Transl Eng Health Med 2021 11;9:4900311. Epub 2021 Feb 11.

Shirley Ryan AbilityLabChicagoIL60611USA.

Objective: Controlling the spread of the COVID-19 pandemic largely depends on scaling up the testing infrastructure for identifying infected individuals. Consumer-grade wearables may present a solution to detect the presence of infections in the population, but the current paradigm requires collecting physiological data continuously and for long periods of time on each individual, which poses limitations in the context of rapid screening. Technology: Here, we propose a novel paradigm based on recording the physiological responses elicited by a short (~2 minutes) sequence of activities (i.e. "snapshot"), to detect symptoms associated with COVID-19. We employed a novel body-conforming soft wearable sensor placed on the suprasternal notch to capture data on physical activity, cardio-respiratory function, and cough sounds.

Results: We performed a pilot study in a cohort of individuals (n=14) who tested positive for COVID-19 and detected altered heart rate, respiration rate and heart rate variability, relative to a group of healthy individuals (n=14) with no known exposure. Logistic regression classifiers were trained on individual and combined sets of physiological features (heartbeat and respiration dynamics, walking cadence, and cough frequency spectrum) at discriminating COVID-positive participants from the healthy group. Combining features yielded an AUC of 0.94 (95% CI=[0.92, 0.96]) using a leave-one-subject-out cross validation scheme. Conclusions and Clinical Impact: These results, although preliminary, suggest that a sensor-based snapshot paradigm may be a promising approach for non-invasive and repeatable testing to alert individuals that need further screening.
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http://dx.doi.org/10.1109/JTEHM.2021.3058841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924653PMC
May 2021

Characterization of Motor-Evoked Responses Obtained with Transcutaneous Electrical Spinal Stimulation from the Lower-Limb Muscles after Stroke.

Brain Sci 2021 Feb 26;11(3). Epub 2021 Feb 26.

Shirley Ryan AbilityLab, Chicago, IL 60611, USA.

An increasing number of studies suggests that a novel neuromodulation technique targeting the spinal circuitry enhances gait rehabilitation, but research on its application to stroke survivors is limited. Therefore, we investigated the characteristics of spinal motor-evoked responses (sMERs) from lower-limb muscles obtained by transcutaneous spinal cord stimulation (tSCS) after stroke compared to age-matched and younger controls without stroke. Thirty participants (ten stroke survivors, ten age-matched controls, and ten younger controls) completed the study. By using tSCS applied between the L1 and L2 vertebral levels, we compared sMER characteristics (resting motor threshold (RMT), slope of the recruitment curve, and latency) of the tibialis anterior (TA) and medial gastrocnemius (MG) muscles among groups. A single pulse of stimulation was delivered in 5 mA increments, increasing from 5 mA to 250 mA or until the subjects reached their maximum tolerance. The stroke group had an increased RMT (27-51%) compared to both age-matched (TA: = 0.032; MG: = 0.005) and younger controls (TA: 0.001; MG: <0.001). For the TA muscle, the paretic side demonstrated a 13% increased latency compared to the non-paretic side in the stroke group ( = 0.010). Age-matched controls also exhibited an increased RMT compared to younger controls (TA: = 0.002; MG: = 0.007), suggesting that altered sMER characteristics present in stroke survivors may result from both stroke and normal aging. This observation may provide implications for altered spinal motor output after stroke and demonstrates the feasibility of using sMER characteristics as an assessment after stroke.
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http://dx.doi.org/10.3390/brainsci11030289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996860PMC
February 2021

Evaluation of a lower-extremity robotic exoskeleton for people with knee osteoarthritis.

Assist Technol 2021 Apr 20:1-14. Epub 2021 Apr 20.

Dept of Surgery, Division of Orthopedic Surgery, CHU de Québec-Université Laval, Québec, Québec City, Canada.

A multi-site study was conducted to evaluate the efficacy of the Keeogo™ exoskeleton as a mobility assist device for use in the clinic and at home in people with knee osteoarthritis (KOA). Twenty-four participants were randomized in a two-stage cross-over design that evaluated the immediate effects of using the exoskeleton in the clinic and the cumulative effects of training and home use. Immediate effects were quantified by comparing 1) physical performance with|without (W|WO) the device during a battery of mobility tests, and 2) physical activity levels at home (actigraphy) for one month, two weeks W|WO the device. Cumulative effects were quantified as change in physical performance W and WO over time. WOMAC and other self-report scales were measured and usability assessed. There were no immediate effects on physical performance or physical activity at home; however, there were cumulative effects as indicated by improved stair time ( = .001) as well as improved WOMAC pain ( = .004) and function ( = .003). There was a direct relationship between improved physical function and improved WOMAC pain (r = -.677, < .001) and stiffness (r = .537, = .007). Weight and battery life were identified as important to usability. A full-scale RCT with more participants, longer study period, and better usage monitoring is warranted.
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http://dx.doi.org/10.1080/10400435.2021.1887400DOI Listing
April 2021

Effect of using of a lower-extremity exoskeleton on disability of people with multiple sclerosis.

Disabil Rehabil Assist Technol 2021 Jan 27:1-8. Epub 2021 Jan 27.

Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Charlestown, MA, USA.

Background: Although ongoing exercise is known to reduce disability in people with multiple sclerosis (MS), participation in lower-extremity exercise programs can be limited by their existing mobility impairments. Lower-extremity exoskeletons could address this problem by facilitating home and community locomotion and enhancing exercise capability but little data is available on the potential of this technology for reducing disability of people with MS.

Methods: We evaluated the Keeogo™ exoskeleton for people with MS using an open-label randomised cross-over design. The trial design allowed us to quantify rehabilitation effects (tested without device) and training effects (tested with device) using functional outcomes: 6-minute walk test (6MWT), timed stair test (TST), and timed up-and-go (TUG). Baseline and post-study self-report instruments included Medical Outcomes Survey Short Form-36 (SF36), MS Walking Scale (MSWS), and others. Amount of home use was documented by daily activity log. Partial correlation analysis was used to explore the relationships between changes in functional outcomes and self-report disability, controlling for amount of home use of the device.

Results: Twenty-nine participants with MS completed the trial. Change scores for MSWS, SF36 physical function and SF36 emotional well-being correlated positively with changes in 6MWT which was explained by amount of home use.

Conclusions: The benefits in physical functioning and emotional well-being from using the exoskeleton at home were linked to amount of device usage. Low-profile robotic exoskeletons could be used to deliver facilitated exercise while assisting with locomotor activities of daily living, such as walking and stair climbing in the home and community environment.IMPLICATIONS FOR REHABILITATIONExoskeletons for home use may have the potential to benefit people with MS in terms of physical functioning and emotional well-being.The benefits in physical functioning and emotional well-being appeared to be linked to amount of usage.Exoskeletons might be useful for delivering facilitated exercise while assisting with walking and stair climbing in the home.
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http://dx.doi.org/10.1080/17483107.2021.1874064DOI Listing
January 2021

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights from 2020.

J Cardiothorac Vasc Anesth 2021 04 21;35(4):993-1005. Epub 2020 Oct 21.

Division of Cardiovascular and Thoracic Anesthesiology, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN.

THIS SPECIAL article is the 13th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr Kaplan, and the editorial board for the opportunity to continue this series; namely, the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2020 are outlined in this introduction, and each highlight is reviewed in detail in the main body of the article. The literature highlights in the specialty for 2020 begin with an update on valvular disease, with a focus on updates in management of aortic and mitral valve disorders. The second major theme is an update on coronary artery disease, with discussion of both medical and surgical management. The third major theme is focused on the perioperative management of patients with coronavirus disease 2019 (COVID-19), with the authors highlighting literature discussing medical, surgical, and anesthetic considerations for their cardiac care. The fourth major theme is an update in heart failure, with discussion of medical, psychosocial, and procedural aspects of this complicated disease process. The fifth and final theme focuses on the latest analyses regarding survival in heart transplantation. The themes selected for this 13th special article are only a few of the diverse advances in the specialty during 2020. These highlights will inform the reader of key updates on a variety of topics, leading to improvement of perioperative outcomes for patients with cardiothoracic and vascular disease.
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http://dx.doi.org/10.1053/j.jvca.2020.10.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575453PMC
April 2021

Controllable modulation of precursor reactivity using chemical additives for systematic synthesis of high-quality quantum dots.

Nat Commun 2020 11 12;11(1):5748. Epub 2020 Nov 12.

Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois, 61801, USA.

The optical and electronic performance of quantum dots (QDs) are affected by their size distribution and structural quality. Although the synthetic strategies for size control are well established and widely applicable to various QD systems, the structural characteristics of QDs, such as morphology and crystallinity, are tuned mostly by trial and error in a material-specific manner. Here, we show that reaction temperature and precursor reactivity, the two parameters governing the surface-reaction kinetics during growth, govern the structural quality of QDs. For conventional precursors, their reactivity is determined by their chemical structure. Therefore, a variation of precursor reactivity requires the synthesis of different precursor molecules. As a result, existing precursor selections often have significant gaps in reactivity or require synthesis of precursor libraries comprising a large number of variants. We designed a sulfur precursor employing a boron-sulfur bond, which enables controllable modulation of their reactivity using commercially available Lewis bases. This precursor chemistry allows systematic optimization of the reaction temperature and precursor reactivity using a single precursor and grows high-quality QDs from cores of various sizes and materials. This work provides critical insights into the nanoparticle growth process and precursor designs, enabling the systematic preparation of high-quality QD of any sizes and materials.
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http://dx.doi.org/10.1038/s41467-020-19573-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7665041PMC
November 2020

Clinician Perceptions of Robotic Exoskeletons for Locomotor Training After Spinal Cord Injury: A Qualitative Approach.

Arch Phys Med Rehabil 2021 02 7;102(2):203-215. Epub 2020 Nov 7.

Northwestern University Feinberg School of Medicine, Department of Physical Medicine & Rehabilitation, Chicago, IL.

Objective: To describe the experiences of clinicians who have used robotic exoskeletons in their practice and acquire information that can guide clinical decisions and training strategies related to robotic exoskeletons.

Design: Qualitative, online survey study, and 4 single-session focus groups followed by thematic analysis to define themes.

Setting: Focus groups were conducted at 3 regional rehabilitation hospitals and 1 Veteran's Administration (VA) Medical Center.

Participants: Clinicians (N=40) reported their demographic characteristics and clinical experience using robotic exoskeletons. Twenty-nine clinicians participated in focus groups at regional hospitals that use robotic exoskeletons, as well as 1 VA Medical Center.

Interventions: Not applicable.

Main Outcome Measure: Clinicians' preferences, experiences, training strategies, and clinical decisions on how robotic exoskeleton devices are used with Veterans and civilians with spinal cord injury.

Results: Clinicians had an average of 3 years of experience using exoskeletons in clinical and research settings. Major themes emerging from focus group discussions included appropriateness of patient goals, patient selection criteria, realistic patient expectations, patient and caregiver training for use of exoskeletons, perceived benefits, preferences regarding specific exoskeletons, and device limitations and therapy recommendations.

Conclusions: Clinicians identified benefits of exoskeleton use including decreased physical burden and fatigue while maximizing patient mobility, increased safety of clinicians and patients, and expanded device awareness and preferences. Suitability of exoskeletons for patients with various characteristics and managing expectations were concerns. Clinicians identified research opportunities as technology continues to advance toward safer, lighter, and hands-free devices.
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http://dx.doi.org/10.1016/j.apmr.2020.08.024DOI Listing
February 2021

Microprocessor Controlled Knee Ankle Foot Orthosis (KAFO) vs Stance Control vs Locked KAFO: A Randomized Controlled Trial.

Arch Phys Med Rehabil 2021 02 22;102(2):233-244. Epub 2020 Sep 22.

Max Näder Lab for Rehabilitation Technologies & Outcomes Lab, Shirley Ryan AbilityLab (formerly the Rehabilitation Institute of Chicago), Chicago, IL; Center for Bionic Medicine, Shirley Ryan AbilityLab, Chicago, IL; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL. Electronic address:

Objective: To evaluate the potential of a microprocessor swing and stance controlled knee-ankle-foot orthosis (MPO) to improve balance, functional mobility, and quality of life in individuals with lower-extremity impairments as compared to a stance-control-orthosis (SCO) and conventional knee-ankle-foot orthosis (KAFO) over a use-period of a month.

Design: Randomized crossover study.

Setting: Ambulatory research laboratory and home and community for community-dwelling adults.

Participants: Persons (N=18) who actively used a unilateral KAFO or SCO for impairments due to neurologic or neuromuscular disease, orthopedic disease, or trauma.

Intervention: Participants were trained to acclimate and use SCO and MPO.

Main Outcome Measures: The 6-minute walk test (6MWT), 10-m walk test, Berg Balance Scale (BBS), functional gait assessment (FGA), hill assessment index, stair assessment index (SAI), Five Times Sit to Stand Test, crosswalk test, Modified Falls Efficacy Scale, Orthotic and Prosthetic User's Survey (OPUS), and World Health Organization Quality of Life (WHQOL)-BREF Scale.

Results: Significant changes were observed in participants' self-selected gait speed (P=.023), BBS (P=.01), FGA (P=.002), and SAI (P<.001) between baseline and post-MPO assessment. Similar significant differences were seen when comparing post-MPO with post-SCO data. During the 6MWT, persons using the MPO walked significantly longer (P=.013) than when using their baseline device. Participants reported higher quality of life scores in the OPUS (P=.02) and physical health domain of the WHOQOL-BREF (P=.037) after using the MPO. Participants reported fewer falls when wearing the MPO (5) versus an SCO (38) or locked KAFO (15).

Conclusions: The MPO may contribute to improved quality of life and health status of persons with lower-extremity impairments by providing the ability to have better walking speed, endurance, and functional balance.
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http://dx.doi.org/10.1016/j.apmr.2020.08.013DOI Listing
February 2021

Users with spinal cord injury experience of robotic Locomotor exoskeletons: a qualitative study of the benefits, limitations, and recommendations.

J Neuroeng Rehabil 2020 09 11;17(1):124. Epub 2020 Sep 11.

Northwestern University, Chicago, USA.

Background: Persons with spinal cord injury (SCI) may experience both psychological and physiological benefits from robotic locomotor exoskeleton use, and knowledgeable users may have valuable perspectives to inform future development. The objective of this study is to gain insight into the experiences, perspectives, concerns, and suggestions on the use of robotic locomotor exoskeletons by civilians and veterans living with SCI.

Methods: Participants reported their demographic characteristics and the extent of robotic exoskeleton use in an online survey. Then, 28 experienced robotic locomotor exoskeleton users participated in focus groups held at three regional hospitals that specialize in rehabilitation for persons with SCI. We used a qualitative description approach analysis to analyze the data, and included thematic analysis.

Results: Participants expressed that robotic exoskeletons were useful in therapy settings but, in their current form, were not practical for activities of daily living due to device limitations. Participants detailed the psychological benefits of being eye-level with their non-disabled peers and family members, and some reported physiologic improvements in areas such as bowel and bladder function. Participants detailed barriers of increased fatigue, spasticity, and spasms and expressed dissatisfaction with the devices due to an inability to use them independently and safely. Participants provided suggestions to manufacturers for technology improvements.

Conclusions: The varied opinions and insights of robotic locomotor exoskeletons users with SCI add to our knowledge of device benefits and limitations.
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http://dx.doi.org/10.1186/s12984-020-00752-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7488437PMC
September 2020

Nanocrystal Precursor Incorporating Separated Reaction Mechanisms for Nucleation and Growth to Unleash the Potential of Heat-up Synthesis.

ACS Nano 2020 09 4;14(9):11579-11593. Epub 2020 Sep 4.

Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States.

A heat-up method for quantum dots (QDs) synthesis holds distinctive benefits for large-scale production with its simplicity, scalability, and high reproducibility. Its applications, however, have been limited because it inevitably yields a strong overlap between the nucleation and the growth stages. We addressed this long-standing problem by introducing a precursor having separated reaction paths for nucleation and growth. Unlike existing precursors, which employ a shared intermediate for both reactions, 9-mercapto-9-borabicyclo[3.3.1]nonane (BBN-SH) induces growth surface-assisted conversion and drives nucleation cluster formation in solution. Furthermore, this precursor chemistry embeds an efficient mechanism to suppress nucleation during growth. As such, BBN-SH allows heat-up-based growth of high-quality shells that are comparable to those created by the injection method. It is also notable that BBN-SH-based heat-up synthesis shows mitigated sensitivity to temperature fluctuation; therefore, it is highly suitable for industrial-scale reactions. We established a simple, scalable, and economic scheme for core/shell QDs by streamlining quantitative core synthesis and heat-up-based shell growth and showed that the scheme produces QDs of comparable quality to those produced by the traditional method. Here, we introduce a precursor that drives a distinctive mode of nanoparticle growth. We anticipate our study to inspire the design of other precursors and unleash the full potential of heat-up synthesis.
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http://dx.doi.org/10.1021/acsnano.0c04091DOI Listing
September 2020

Controller synthesis and clinical exploration of wearable gyroscopic actuators to support human balance.

Sci Rep 2020 06 26;10(1):10412. Epub 2020 Jun 26.

Department of Biomechanical Engineering, Delft University of Technology, Delft, 2628 CD, The Netherlands.

Gyroscopic actuators are appealing for wearable applications due to their ability to provide overground balance support without obstructing the legs. Multiple wearable robots using this actuation principle have been proposed, but none has yet been evaluated with humans. Here we use the GyBAR, a backpack-like prototype portable robot, to investigate the hypothesis that the balance of both healthy and chronic stroke subjects can be augmented through moments applied to the upper body. We quantified balance performance in terms of each participant's ability to walk or remain standing on a narrow support surface oriented to challenge stability in either the frontal or the sagittal plane. By comparing candidate balance controllers, it was found that effective assistance did not require regulation to a reference posture. A rotational viscous field increased the distance healthy participants could walk along a 30mm-wide beam by a factor of 2.0, compared to when the GyBAR was worn but inactive. The same controller enabled individuals with chronic stroke to remain standing for a factor of 2.5 longer on a narrow block. Due to its wearability and versatility of control, the GyBAR could enable new therapy interventions for training and rehabilitation.
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http://dx.doi.org/10.1038/s41598-020-66760-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320159PMC
June 2020

The ReWalk ReStore™ soft robotic exosuit: a multi-site clinical trial of the safety, reliability, and feasibility of exosuit-augmented post-stroke gait rehabilitation.

J Neuroeng Rehabil 2020 06 18;17(1):80. Epub 2020 Jun 18.

Department of PM&R, Northwestern University, Chicago, IL, USA.

Background: Atypical walking in the months and years after stroke constrain community reintegration and reduce mobility, health, and quality of life. The ReWalk ReStore™ is a soft robotic exosuit designed to assist the propulsion and ground clearance subtasks of post-stroke walking by actively assisting paretic ankle plantarflexion and dorsiflexion. Previous proof-of-concept evaluations of the technology demonstrated improved gait mechanics and energetics and faster and farther walking in users with post-stroke hemiparesis. We sought to determine the safety, reliability, and feasibility of using the ReStore™ during post-stroke rehabilitation.

Methods: A multi-site clinical trial (NCT03499210) was conducted in preparation for an application to the United States Food and Drug Administration (FDA). The study included 44 users with post-stroke hemiparesis who completed up to 5 days of training with the ReStore™ on the treadmill and over ground. In addition to primary and secondary endpoints of safety and device reliability across all training activities, an exploratory evaluation of the effect of multiple exposures to using the device on users' maximum walking speeds with and without the device was conducted prior to and following the five training visits.

Results: All 44 study participants completed safety and reliability evaluations. Thirty-six study participants completed all five training days. No device-related falls or serious adverse events were reported. A low rate of device malfunctions was reported by clinician-operators. Regardless of their reliance on ancillary assistive devices, after only 5 days of walking practice with the device, study participants increased both their device-assisted (Δ: 0.10 ± 0.03 m/s) and unassisted (Δ: 0.07 ± 0.03 m/s) maximum walking speeds (P's < 0.05).

Conclusions: When used under the direction of a licensed physical therapist, the ReStore™ soft exosuit is safe and reliable for use during post-stroke gait rehabilitation to provide targeted assistance of both paretic ankle plantarflexion and dorsiflexion during treadmill and overground walking.

Trial Registration: NCT03499210. Prospectively registered on March 28, 2018.
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http://dx.doi.org/10.1186/s12984-020-00702-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301475PMC
June 2020

Extracorporeal Membrane Oxygenation in Lung Transplantation: Analysis of Techniques and Outcomes.

J Cardiothorac Vasc Anesth 2021 Feb 21;35(2):644-661. Epub 2020 May 21.

Division of Cardiovascular and Thoracic Anesthesiology, Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN. Electronic address:

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http://dx.doi.org/10.1053/j.jvca.2020.05.014DOI Listing
February 2021

Inpatient stroke rehabilitation: prediction of clinical outcomes using a machine-learning approach.

J Neuroeng Rehabil 2020 06 10;17(1):71. Epub 2020 Jun 10.

Max Nader Lab for Rehabilitation Technologies and Outcomes Research, Shirley Ryan AbilityLab, 355 E. Erie St., Chicago, IL, 60611, USA.

Background: In clinical practice, therapists often rely on clinical outcome measures to quantify a patient's impairment and function. Predicting a patient's discharge outcome using baseline clinical information may help clinicians design more targeted treatment strategies and better anticipate the patient's assistive needs and discharge care plan. The objective of this study was to develop predictive models for four standardized clinical outcome measures (Functional Independence Measure, Ten-Meter Walk Test, Six-Minute Walk Test, Berg Balance Scale) during inpatient rehabilitation.

Methods: Fifty stroke survivors admitted to a United States inpatient rehabilitation hospital participated in this study. Predictors chosen for the clinical discharge scores included demographics, stroke characteristics, and scores of clinical tests at admission. We used the Pearson product-moment and Spearman's rank correlation coefficients to calculate correlations among clinical outcome measures and predictors, a cross-validated Lasso regression to develop predictive equations for discharge scores of each clinical outcome measure, and a Random Forest based permutation analysis to compare the relative importance of the predictors.

Results: The predictive equations explained 70-77% of the variance in discharge scores and resulted in a normalized error of 13-15% for predicting the outcomes of new patients. The most important predictors were clinical test scores at admission. Additional variables that affected the discharge score of at least one clinical outcome were time from stroke onset to rehabilitation admission, age, sex, body mass index, race, and diagnosis of dysphasia or speech impairment.

Conclusions: The models presented in this study could help clinicians and researchers to predict the discharge scores of clinical outcomes for individuals enrolled in an inpatient stroke rehabilitation program that adheres to U.S. Medicare standards.
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http://dx.doi.org/10.1186/s12984-020-00704-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7288489PMC
June 2020

Role of data measurement characteristics in the accurate detection of Parkinson's disease symptoms using wearable sensors.

J Neuroeng Rehabil 2020 04 20;17(1):52. Epub 2020 Apr 20.

Max Nader Lab for Rehabilitation Technologies and Outcomes, Shirley Ryan AbilityLab, Chicago, IL, 60611, USA.

Background: Parkinson's disease (PD) is a progressive neurological disease, with characteristic motor symptoms such as tremor and bradykinesia. There is a growing interest to continuously monitor these and other symptoms through body-worn sensor technology. However, limited battery life and memory capacity hinder the potential for continuous, long-term monitoring with these devices. There is little information available on the relative value of adding sensors, increasing sampling rate, or computing complex signal features, all of which may improve accuracy of symptom detection at the expense of computational resources. Here we build on a previous study to investigate the relationship between data measurement characteristics and accuracy when using wearable sensor data to classify tremor and bradykinesia in patients with PD.

Methods: Thirteen individuals with PD wore a flexible, skin-mounted sensor (collecting tri-axial accelerometer and gyroscope data) and a commercial smart watch (collecting tri-axial accelerometer data) on their predominantly affected hand. The participants performed a series of standardized motor tasks, during which a clinician scored the severity of tremor and bradykinesia in that limb. Machine learning models were trained on scored data to classify tremor and bradykinesia. Model performance was compared when using different types of sensors (accelerometer and/or gyroscope), different data sampling rates (up to 62.5 Hz), and different categories of pre-engineered features (up to 148 features). Performance was also compared between the flexible sensor and smart watch for each analysis.

Results: First, there was no effect of device type for classifying tremor symptoms (p > 0.34), but bradykinesia models incorporating gyroscope data performed slightly better (up to 0.05 AUROC) than other models (p = 0.01). Second, model performance decreased with sampling frequency (p < 0.001) for tremor, but not bradykinesia (p > 0.47). Finally, model performance for both symptoms was maintained after substantially reducing the feature set.

Conclusions: Our findings demonstrate the ability to simplify measurement characteristics from body-worn sensors while maintaining performance in PD symptom detection. Understanding the trade-off between model performance and data resolution is crucial to design efficient, accurate wearable sensing systems. This approach may improve the feasibility of long-term, continuous, and real-time monitoring of PD symptoms by reducing computational burden on wearable devices.
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http://dx.doi.org/10.1186/s12984-020-00684-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7168958PMC
April 2020

Appraisals of robotic locomotor exoskeletons for gait: focus group insights from potential users with spinal cord injuries.

Disabil Rehabil Assist Technol 2020 10 7;15(7):762-772. Epub 2020 Apr 7.

Center for Rehabilitation Outcomes Research, Shirley Ryan AbilityLab, Chicago, IL, USA.

To describe appraisals of robotic exoskeletons for locomotion by potential users with spinal cord injuries, their perceptions of device benefits and limitations, and recommendations for manufacturers and therapists regarding device use. We conducted focus groups at three regional rehabilitation hospitals and used thematic analysis to define themes. Across four focus groups, 35 adults participated; they were predominantly middle-aged, male, and diverse in terms of race and ethnicity, well educated, and not working. Participants had been living with SCI an average of two decades. Most participants were aware of exoskeletons. Some were enthusiastic about the usability of the devices while others were more circumspect. They had many questions about device affordability and usability, and were discerning in their appraisal of benefits and suitability to their particular circumstances. They reflected on device cost, the need for caregiver assistance, use of hands, and environmental considerations. They weighed the functional benefits relative to the cost of preferred activities. Their recommendations focused on cost, battery life, and independent use. Potential users' appraisals of mobility technology reflect a nuanced appreciation of device costs; functional, social, and psychological benefits; and limitations. Results provide guidance to therapists and manufacturers regarding device use.Implications for RehabilitationPotential users of robotic locomotor exoskeletons with spinal cord injuries appreciate the functional, social, and psychological benefits that these devices may offer.Their appraisals reflect nuanced consideration of device cost and features, and the suitability of the assistive technology to their circumstances.They recommend that manufacturers focus on reducing cost, extending battery life, and features that allow independent use.
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http://dx.doi.org/10.1080/17483107.2020.1745910DOI Listing
October 2020

Budget impact analysis of robotic exoskeleton use for locomotor training following spinal cord injury in four SCI Model Systems.

J Neuroeng Rehabil 2020 01 10;17(1). Epub 2020 Jan 10.

Center for Rehabilitation Outcomes Research, Department of PM&R, Feinberg School of Medicine, Northwestern University, Evanston, USA.

Background: We know little about the budget impact of integrating robotic exoskeleton over-ground training into therapy services for locomotor training. The purpose of this study was to estimate the budget impact of adding robotic exoskeleton over-ground training to existing locomotor training strategies in the rehabilitation of people with spinal cord injury.

Methods: A Budget Impact Analysis (BIA) was conducted using data provided by four Spinal Cord Injury (SCI) Model Systems rehabilitation hospitals. Hospitals provided estimates of therapy utilization and costs about people with spinal cord injury who participated in locomotor training in the calendar year 2017. Interventions were standard of care walking training including body-weight supported treadmill training, overground training, stationary robotic systems (i.e., treadmill-based robotic gait orthoses), and overground robotic exoskeleton training. The main outcome measures included device costs, training costs for personnel to use the device, human capital costs of locomotor training, device demand, and the number of training sessions per person with SCI.

Results: Robotic exoskeletons for over-ground training decreased hospital costs associated with delivering locomotor training in the base case analysis. This analysis assumed no difference in intervention effectiveness across locomotor training strategies. Providing robotic exoskeleton overground training for 10% of locomotor training sessions over the course of the year (range 226-397 sessions) results in decreased annual locomotor training costs (i.e., net savings) between $1114 to $4784 per annum. The base case shows small savings that are sensitive to parameters of the BIA model which were tested in one-way sensitivity analyses, scenarios analyses, and probability sensitivity analyses. The base case scenario was more sensitive to clinical utilization parameters (e.g., how often devices sit idle and the substitution of high cost training) than device-specific parameters (e.g., robotic exoskeleton device cost or device life). Probabilistic sensitivity analysis simultaneously considered human capital cost, device cost, and locomotor device substitution. With probabilistic sensitivity analysis, the introduction of a robotic exoskeleton only remained cost saving for one facility.

Conclusions: Providing robotic exoskeleton for over-ground training was associated with lower costs for the locomotor training of people with SCI in the base case analyses. The analysis was sensitive to parameter assumptions.
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http://dx.doi.org/10.1186/s12984-019-0639-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6954546PMC
January 2020
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