Long-term monitoring of stimulated lower leg skeletal muscle forces compared with voluntary contractions in myopathy patients - A five-year follow-up report on 5 adults.

OBJECTIVE: Long-term assessments of lower leg muscle forces in ambulant patients with distal myopathies. METHODS AND MATERIALS: Over a five-year period, we measured involuntary, nerve-stimulated, isometric torques of the ankle dorsiflexors in a group of ambulant patients with myopathies and compared results with voluntary Manual Muscle Tests (MMT). RESULTS: From ten recruited patients, five could finish the five-year protocol. Twenty-seven force measurements sessions (one per year; 1,5 hours duration each) were performed. These patients exhibited low, stable torques or increased minimally (0.2 Newtonmeter, versus 0.1 Nm, ns; 0.7 vs. 1.0, ns; 3.4 vs. 3.5, ns; 0.2 vs. 0.1, ns; 0.8 vs. 1.5, P 0.0004 initial values vs. 5-year values, [norm: 3.9-5.7 Nm]). A 6th patient, eliciting low torque values (0.1 Nm) early passed away. Contraction times inversely correlated with MMT. MMT provided similar overall force abilities. CONCLUSIONS: Long-term monitoring of lower leg muscle forces in ambulant patients is limited by the patient's health status. In a small group of patients, stimulated lower leg forces did not worsen over many years relative to their diagnosed myopathies. Tracking involuntary forces, could be a useful monitoring providing phenotypic information, in addition to MMT. Future devices should be small and be simply self-applying, designed for subjects' domestic use and web-based data transfer. CLINICALTRIALS: gov NCT00735384.

Face anthropometry for filtering facepiece respirators: analysis of the association between facial dimensions and respirator fit.

OBJECTIVE: Ensuring proper respirator fit for individuals remains a persistent challenge in occupational environments, yet there is limited knowledge about how respirators interact with the face to "'fit." Previous studies have attempted to understand the association between face dimensions and respirator fit using traditional head/face anthropometry not specifically tailored for respirators. The purpose of this study was to assess and compare the ability of filtering facepiece respirator (FFR)-specific face anthropometry with traditional head/face anthropometry in exploring the relationship between facial dimensions and the fit of FFR. METHODS: The study utilized 3D face scans and quantitative fit factor scores from 56 participants to investigate the relationship between face anthropometry and FFR fit. Both FFR-specific and traditional anthropometric measurements were obtained through 3D anthropometric software. Intra-correlation of anthropometry was analyzed to evaluate the efficiency and effectiveness of FFR-specific and traditional anthropometry respectively. Principal component analysis (PCA) was conducted to test the usefulness of the PCA method for investigating various facial features. Logistic regression was used to develop fit association models by estimating the relationship between each face measurement set and the binary outcome of the fit test result. The prediction accuracy of the developed regression models was tested. RESULTS: FFR-specific face anthropometry consists of a set of measurements that can inform the detailed facial shape associated with the FFRs more effectively than traditional head/face anthropometry. While PCA may have been effective in reducing the variable dimensions for the relatively large parts of the human body such as upper and lower bodies in previous literature, PCA results of FFR-specific and traditional anthropometry were inconsistent and insufficient to describe face dimensions with complex anatomy in a small-detailed area, suggesting that facial shape should be understood through a variety of approaches including statistical methods. Logistic regression analysis results confirmed that the association models of FFR-specific face anthropometry were significant with higher prediction accuracy and had a better model's goodness of fit than those of traditional head/face anthropometry in 3 conditions inputting all measurements, all PC scores, or top 5 measurements from PCA. CONCLUSIONS: The findings showed that the FFR fit association model enables an understanding of the detailed association between face and respirator fit and allows for the development of a system to predict respirator fit success or failure based on facial dimensions. Future research would include testing the validity of the model and FFR-specific measurement set on different respirator types, expanding the population set, and developing an integrated approach using automated and machine learning technologies to inform FFR selection for occupation workers and the general population.

Protective Masks Utilizing Nonendangered Components.

At the beginning of the COVID-19 pandemic when traditional N95 respirators were in short supply in the United States, there was a need for alternative products that did not rely on traditional avenues of sourcing and manufacturing. The purpose of this research was to develop and test alternatives to N95 respirators that could be produced locally without specialized materials and processes. Through an interdisciplinary team of experts, new mask designs that use repurposed filtration media and commercially available components were developed and tested for filtration and fit against current N95 standards. Filtration efficiency test results showed that the filtration media can be used for high-quality facemasks and quantitative fit testing demonstrated that the new mask designs could be viable alternatives to traditional N95 facemasks when those masks are in short supply. Manufacturing viability was tested utilizing a workforce to create 6000 masks over 10 days. The ability to quickly produce masks at scale using a workforce without specialized skills demonstrated the feasibility of the mask designs and manufacturing approach to address shortages of critical healthcare equipment, mitigate risk for healthcare and essential workers, and minimize the transmission and spread of disease.

Design considerations for protective mask development: A remote mask usability evaluation.

The design of N95 filtering facepiece respirators (FFRs) continues to pose usability concerns for healthcare workers, which have been exacerbated by the COVID-19 pandemic. The aim of this study was to develop a holistic model to guide mask design improvement. Dental students (n = 38) with experience wearing N95 FFRs participated in a randomized wear trial of three alternative protective masks. A mixed methods survey was used to examine usability of individual mask design components, the relationship of facial/head area to mask features, and overall mask design. Survey results indicated MNmask v1 demonstrated higher usability in seal confidence (M = 3.46), while MNmask v2 performed higher in satisfactory fit (M = 3.50). Design components of nose wire and head/neck bands were the most problematic, while conditions of skin irritation and tight/loose fit created an unfavorable wear experience. To consider healthcare workers' needs in improving the usability of protective masks, a model is presented to consider characteristics of fit, comfort, material, and design.

A video game based hand grip system for measuring muscle force in children.

BACKGROUND: While new therapies are continuously introduced to treat muscular dystrophy, current assessment tests are challenging to quantify, cannot be used in non-ambulatory patients, or can de-motivate pediatric patients. We developed a simple, engaging, upper-limb assessment tool that measures muscle strength and fatigue in children, including children with muscular dystrophy. The device is a bio-feedback grip sensor that motivates children to complete maximal and fatiguing grip protocols through a game-based interface. METHODS: To determine if the new system provided the same maximum grip force as what is reported in the literature, data was collected from 311 participants without muscle disease (186 M, 125 F), ages 6 to 30, each of whom played the four minute grip game once. We compared maximum voluntary contraction at the start of the test to normative values reported in the literature using Welch's unequal variances t-tests. In addition, we collected data on a small number of participants with muscle disease to determine if the assessment system could be used by the target patient population. RESULTS: Of the 311 participants without muscle disease that started the test, all but one completed the game. The maximum voluntary contraction data, when categorized by age, matched literature values for hand grip force within an acceptable range. Grip forced increased with age and differed by gender, and most participants exhibited fatigue during the game, including a degradation in tracking ability as the game progressed. Of the 13 participants with muscle disease, all but one completed the game. CONCLUSIONS: The study demonstrated the technical feasibility and validity of the new hand grip device, and indicated that the device can be used to assess muscle force and fatigue in longitudinal studies of children with muscular dystrophy.

Bone-Inspired Bending Soft Robot.

Bending soft robots must be structured and predictable to be used in applications such as a grasping hand. We developed soft robot fingers with embedded bones to improve the performance of a puppetry robot with haptic feedback. The manufacturing process for bone-inspired soft robots is described, and two mathematical models are reported: one to predict the stiffness and natural frequency of the robot finger and the other for trajectory planning. Experiments using different prototypes were used to set model parameters. The first model, which had a fourth-order lumped mass-spring-damper configuration, was able to predict the natural frequency of the soft robot with a maximum error of 18%. The model and the experimental data demonstrated that bone-inspired soft robots have higher natural frequency, lower phase shift, better controllability, and higher stiffness compared with traditional fiber-reinforced bending soft robots. We also showed that the dynamic performance of a bending soft robot is independent of whether water or air is used for the media and independent of the media pressure. Results from the second model showed that the path of a bone-inspired soft robot is a function of the relative lengths of the bone segments, which means that the model can be used to direct the design of the robot to achieve the desired trajectory. This model was able to correctly predict the trajectory path of the robot.

Crystal structures of {1,1,1-tris-[(salicylaldimino)-meth-yl]ethane}-gallium as both a pyridine solvate and an aceto-nitrile 0.75-solvate and {1,1,1-tris[(salicylaldimino)-meth-yl]ethane}-indium di-chloro-methane solvate.

The sexa-dentate ligand 1,1,1-tris-[(salicyl-idene-amino)-meth-yl]ethane has been reported numerous times in its triply deprotonated form coordinated to transition metals and lanthanides, yet it has been rarely employed with main-group elements, including in substituted forms. Its structures with gallium and indium are reported as solvates, namely, ({[(2,2-bis-{[(2-oxido-benzyl-idene)amino-κ2 N,O]meth-yl}prop-yl)imino]-meth-yl}phenololato-κ2 N,O)gallium(III) pyridine monosolvate, [Ga(C26H24N3O3)]·C5H5N, the aceto-nitrile 0.75-solvate, [Ga(C26H24N3O3)]·0.75C2H3N, and ({[(2,2-bis-{[(2-oxido-benzyl-idene)amino-κ2 N,O]meth-yl}prop-yl)imino]-meth-yl}phenololato-κ2 N,O)indium(III) di-chloro-methane monosolvate, [In(C26H24N3O3)]·CH2Cl2. All three metal complexes are pseudo-octa-hedral and each structure contains multiple weak C-H⋯O and/or C-H⋯N inter-molecular hydrogen-bonding inter-actions. The syntheses and additional characterization in the forms of melting points, high-resolution mass spectra, infra-red (IR) spectra, and 1H and 13C NMR spectra are also reported.

Cardiac patient-specific three-dimensional models as surgical planning tools.

BACKGROUND: Three-dimensional printing is an additive manufacturing method that builds objects from digitally generated computational models. Core technologies behind three-dimensional printing are evolving rapidly with major advances in materials, resolution, and speed that enable greater realism and higher accuracy. These improvements have led to novel applications of these processes in the medical field. METHODS: The process of going from a medical image data set (computed tomography, magnetic resonance imaging, ultrasound) to a physical three-dimensional print includes several steps that are described. Medical images originate from Digital Imaging and Communications in Medicine files or data sets, the current standard for storing and transmitting medical images. Via Digital Imaging and Communications in Medicine manipulation software packages, a segmentation process, and manual intervention by an expert user, three-dimensional digital and printed models can be constructed in great detail. RESULTS: Cardiovascular medicine is one of the fastest growing applications for medical three-dimensional printing. The technology is more frequently being used for patient and clinician education, preprocedural planning, and medical device design and prototyping. We report on three case studies, describing how our three-dimensional printing has contributed to the care of cardiac patients at the University of Minnesota. CONCLUSION: Medical applications of computational three-dimensional modeling and printing are already extensive and growing rapidly and are routinely used for visualizing complex anatomies from patient imaging files to plan surgeries and create surgical simulators. Studies are needed to determine whether three-dimensional printed models are cost effective and can consistently improve clinical outcomes before they become part of routine clinical practice.

Home-based transcranial direct current stimulation plus tracking training therapy in people with stroke: an open-label feasibility study.

BACKGROUND: Transcranial direct current stimulation (tDCS) is an effective neuromodulation adjunct to repetitive motor training in promoting motor recovery post-stroke. Finger tracking training is motor training whereby people with stroke use the impaired index finger to trace waveform-shaped lines on a monitor. Our aims were to assess the feasibility and safety of a telerehabilitation program consisting of tDCS and finger tracking training through questionnaires on ease of use, adverse symptoms, and quantitative assessments of motor function and cognition. We believe this telerehabilitation program will be safe and feasible, and may reduce patient and clinic costs. METHODS: Six participants with hemiplegia post-stroke [mean (SD) age was 61 (10) years; 3 women; mean (SD) time post-stroke was 5.5 (6.5) years] received five 20-min tDCS sessions and finger tracking training provided through telecommunication. Safety measurements included the Digit Span Forward Test for memory, a survey of symptoms, and the Box and Block test for motor function. We assessed feasibility by adherence to treatment and by a questionnaire on ease of equipment use. We reported descriptive statistics on all outcome measures. RESULTS: Participants completed all treatment sessions with no adverse events. Also, 83.33% of participants found the set-up easy, and all were comfortable with the devices. There was 100% adherence to the sessions and all recommended telerehabilitation. CONCLUSIONS: tDCS with finger tracking training delivered through telerehabilitation was safe, feasible, and has the potential to be a cost-effective home-based therapy for post-stroke motor rehabilitation. TRIAL REGISTRATION: NCT02460809 (ClinicalTrials.gov).

Isometric skeletal muscle force measurement in primary myopathies.

INTRODUCTION: In myopathy patients, it is useful to measure skeletal muscle forces. Conventional methods require voluntary muscle activation, which can be unreliable. We evaluated a device for nonvoluntary force assessment. METHODS: We tested 8 patients (unknown myopathy n = 2, inflammatory myopathy, facioscapulohumeral muscular dystrophy, mitochondrial myopathy, dysferlinopathy, multi-minicore disease, Becker-Kiener muscular dystrophy, n = 1 each). Isometric twitch torques of ankle dorsiflexors were measured after fibular nerve stimulation. RESULTS: Six patients had decreased torques vs. 8 controls (men: median Newton-meter 1.6 vs. 5.7, women: 0.2 vs. 3.9, both P < 0.0001). Values correlated with Manual Muscle Test results (r = 0.73; r(2) = 0.53; P < 0.0001). In weak dorsiflexors, torque could be measured despite lower signal-to-noise ratios. In 2 patients with hypertrophy, we measured increased torques. CONCLUSIONS: Nonvoluntary muscle force assessment can be used in patients with myopathies, and values correlate with voluntary forces determined by traditional methods. Muscle Nerve 53: 913-917, 2016.

Ipsilesional motor-evoked potential absence in pediatric hemiparesis impacts tracking accuracy of the less affected hand.

This study analyzed the relationship between electrophysiological responses to transcranial magnetic stimulation (TMS), finger tracking accuracy, and volume of neural substrate in children with congenital hemiparesis. Nineteen participants demonstrating an ipsilesional motor-evoked potential (MEP) were compared with eleven participants showing an absent ipsilesional MEP response. Comparisons of finger tracking accuracy from the affected and less affected hands and ipsilesional/contralesional (I/C) volume ratio for the primary motor cortex (M1) and posterior limb of internal capsule (PLIC) were done using two-sample t-tests. Participants showing an ipsilesional MEP response demonstrated superior tracking performance from the less affected hand (p=0.016) and significantly higher I/C volume ratios for M1 (p=0.028) and PLIC (p=0.005) compared to participants without an ipsilesional MEP response. Group differences in finger tracking accuracy from the affected hand were not significant. These results highlight differentiating factors amongst children with congenital hemiparesis showing contrasting MEP responses: less affected hand performance and preserved M1 and PLIC volume. Along with MEP status, these factors pose important clinical implications in pediatric stroke rehabilitation. These findings may also reflect competitive developmental processes associated with the preservation of affected hand function at the expense of some function in the less affected hand.

Preliminary design of a new device to measure muscle function.

A description and early results are presented for a novel device to estimate the torque-angle and torque-angular velocity properties of the quadriceps muscle group using electrical stimulation. The device straps to the shin and is moved by the operator while pulses of stimulation are applied to the motor point of the quadriceps. During stimulation, the operator raises and lowers the leg to the desired angle, and also can oscillate the leg to generate a rich velocity profile. The resulting muscle force is measured by a load cell contained in the device. In a preliminary study using 11 healthy subjects, normalized torque-angle and torque-velocity data for the quadriceps were consistent with literature results that used maximum voluntary contraction methods.

Inter-electrode tissue resistance is not affected by tissue oedema when electrically stimulating the lower limb of sepsis patients.

ICU patients typically are given large amounts of fluid and often develop oedema. The purpose of this study was to evaluate whether the oedema would change inter-electrode resistance and, thus, require a different approach to using non-invasive electrical stimulation of nerves to assess muscle force. Inter-electrode tissue resistance in the lower leg was measured by applying a 300 µs constant current pulse and measuring the current through and voltage across the stimulating electrodes. The protocol was administered to nine ICU patients with oedema, eight surgical patients without oedema and eight healthy controls. No significant difference in inter-electrode resistance was found between the three groups. For all groups, resistance decreased as stimulation current increased. In conclusion, inter-electrode resistance in ICU patients with severe oedema is the same as the resistance in regular surgical patients and healthy controls. This means that non-invasive nerve stimulation devices do not need to be designed to accommodate different resistances when used with oedema patients; however, surface stimulation does require higher current levels with oedema patients because of the increased distance between the skin surface and the targeted nerve or muscle.

MCD spectroscopy and TD-DFT calculations of low symmetry subnaphthalocyanine analogs.

Magnetic circular dichroism (MCD) spectroscopy and time-dependent density functional theory (TD-DFT) calculations are used to analyze the electronic structure and optical properties of low-symmetry subnaphthalocyanine analogs with AAB and ABB structures formed during mixed condensations of tetrafluorophthalonitrile and 2,3-naphthalenedicarbonitrile. The results demonstrate that trends observed in the properties of phthalocyanine analogs can be used to fine tune the optical properties so that the Q(0,0) bands lie in the red region, in a manner that does not significantly destabilize the highest occupied molecular orbital (HOMO) energy relative to that of the parent subphthalocyanine ligand. Attempts to study the spectroscopy of anion radical species proved unsuccessful, since they proved to be unstable.

Design of a portable hydraulic ankle-foot orthosis.

Small-scale hydraulics is ideal for powered human assistive devices including powered ankle foot orthoses because a large torque can be generated with an actuator that is small and light. A portable hydraulic ankle foot orthosis has been designed and is undergoing preliminary prototyping and engineering bench test evaluation. The device provides 90 Nm of ankle torque and has an operating pressure of 138 bar (2,000 psi). The battery-operated hydraulic power supply weighs about 3 kg and is worn at the waist. The ankle component weighs about 1.2 Kg and connects to the power supply with two hoses. Performance simulation and preliminary bench testing suggests that the device could be useful in certain rehabilitation applications.

Preliminary design of an energy storing orthosis for providing gait to people with spinal cord injury.

A new design is proposed for an energy storing orthosis (ESO) that restores walking to people with spinal cord injury by combining functional electrical stimulation of the quadriceps muscle with a mechanical brace that uses elastic elements to store and transfer energy between hip and knee joints. The new ESO is a variation of a previous design and uses constant force springs for energy storage. Based on the detailed design and on dynamic simulations, the concept has demonstrated preliminary technical feasibility.

Combined statistical analysis method assessing fast versus slow movement training in a patient with cerebellar stroke: a single-case study.

BACKGROUND: Gold standards of data analysis for single-case research do not currently exist. OBJECTIVE: The purpose of this study was to determine whether a combined statistical analysis method is more effective in assessing movement training effects in a patient with cerebellar stroke. DESIGN: A crossover single-case research design was conducted. METHODS: The patient was a 69-year-old man with a chronic cerebellar infarct who received two 5-week phases of finger tracking training at different movement rates. Changes were measured with the Box and Block Test, the Jebsen-Taylor test, the finger extension force test, and the corticospinal excitability test. Both visual analysis and statistical tests (including split-middle line method, t test, confidence interval, and effect size) were used to assess potential intervention effects. RESULTS: The results of the t tests were highly consistent with the confidence interval tests, but less consistent with the split-middle line method. Most results produced medium to large effect sizes. LIMITATIONS: The possibility of an incomplete washout effect was a confounding factor in the current analyses. CONCLUSIONS: The combined statistical analysis method may assist researchers in assessing intervention effects in single-case stroke rehabilitation studies.

Optimizing the effectiveness of a mechanical suture-based anulus fibrosus repair construct in an acute failure laboratory simulation.

STUDY DESIGN: In vitro comparative, laboratory experiments. OBJECTIVE: This study developed a laboratory apparatus that measured resistance to failure using pressures similar to intradiscal pressure of a lumbar spinal disk. Various combinations of an anular repair device were compared. SUMMARY OF BACKGROUND CONTEXT: Herniated material of the intervertebral disk is removed during a lumbar discectomy; however, the defect in the anulus fibrosus remains and can provide a pathway for future herniation. Repairing the anulus fibrosus could mitigate this reherniation and improve patient outcomes. METHODS: A pneumatic cylinder was used to increase the pressure of a sealed chamber until artificial nucleus pulposus material was expulsed through either a 3-mm circular (diameter) or a 6-mm slit anular defect created in a surrogate anulus fibrosus. Each unrepaired condition was compared with 3 repaired conditions using a commercially available soft tissue repair system. The repaired conditions included: (1) a single tension band; (2) 2 tension bands in a cruciate pattern; or (3) 2 tension bands in a parallel pattern. Maximum pressure at the point of extrusion of the internal chamber material and failure or nonfailure of the repair was measured. RESULTS: Significant differences were detected (P<0.05) in maximum failure pressures for the nonrepaired (control) versus repaired conditions. With 1 or 2 tension bands repairing the circular defect, the maximum failure pressure increased by approximately 76% and 131%, respectively. In addition, the failure pressure for 2 tension bands in either a cruciate or parallel configuration was not different, and was approximately 32% higher (P<0.05) than a single tension band in the case of the circular defect. Similar results were seen for the slit defect, with the exception that no difference between the repaired conditions (ie, single vs. 2 tension bands) was detected. CONCLUSIONS: This laboratory simulation demonstrated that repairing the anulus fibrosus after a discectomy procedure can be beneficial for retaining intradiscal material. The use of 2 tension bands, versus a single tension band, in either a cruciate or parallel configuration may further improve the ability to retain disk material.

Complex versus simple ankle movement training in stroke using telerehabilitation: a randomized controlled trial.

BACKGROUND: Telerehabilitation allows rehabilitative training to continue remotely after discharge from acute care and can include complex tasks known to create rich conditions for neural change. OBJECTIVES: The purposes of this study were: (1) to explore the feasibility of using telerehabilitation to improve ankle dorsiflexion during the swing phase of gait in people with stroke and (2) to compare complex versus simple movements of the ankle in promoting behavioral change and brain reorganization. DESIGN: This study was a pilot randomized controlled trial. SETTING: Training was done in the participant's home. Testing was done in separate research labs involving functional magnetic resonance imaging (fMRI) and multi-camera gait analysis. PATIENTS: Sixteen participants with chronic stroke and impaired ankle dorsiflexion were assigned randomly to receive 4 weeks of telerehabilitation of the paretic ankle. INTERVENTION: Participants received either computerized complex movement training (track group) or simple movement training (move group). MEASUREMENTS: Behavioral changes were measured with the 10-m walk test and gait analysis using a motion capture system. Brain reorganization was measured with ankle tracking during fMRI. RESULTS: Dorsiflexion during gait was significantly larger in the track group compared with the move group. For fMRI, although the volume, percent volume, and intensity of cortical activation failed to show significant changes, the frequency count of the number of participants showing an increase versus a decrease in these values from pretest to posttest measurements was significantly different between the 2 groups, with the track group decreasing and the move group increasing. LIMITATIONS: Limitations of this study were that no follow-up test was conducted and that a small sample size was used. CONCLUSIONS: The results suggest that telerehabilitation, emphasizing complex task training with the paretic limb, is feasible and can be effective in promoting further dorsiflexion in people with chronic stroke.

A portable powered ankle-foot orthosis for rehabilitation.

Innovative technological advancements in the field of orthotics, such as portable powered orthotic systems, could create new treatment modalities to improve the functional out come of rehabilitation. In this article, we present a novel portable powered ankle-foot orthosis (PPAFO) to provide untethered assistance during gait. The PPAFO provides both plantar flexor and dorsiflexor torque assistance by way of a bidirectional pneumatic rotary actuator. The system uses a portable pneumatic power source (compressed carbon dioxide bottle) and embedded electronics to control the actuation of the foot. We collected pilot experimental data from one impaired and three nondisabled subjects to demonstrate design functionality. The impaired subject had bilateral impairment of the lower legs due to cauda equina syndrome. We found that data from nondisabled walkers demonstrated the PPAFO's capability to provide correctly timed plantar flexor and dorsiflexor assistance during gait. Reduced activation of the tibialis anterior during stance and swing was also seen during assisted nondisabled walking trials. An increase in the vertical ground reaction force during the second half of stance was present during assisted trials for the impaired subject. Data from nondisabled walkers demonstrated functionality, and data from an impaired walker demonstrated the ability to provide functional plantar flexor assistance.