Development of a training paradigm for voluntary control of the peri-auricular muscles: a feasibility study.

BACKGROUND: Spinal cord injury (SCI) can lead to severe and permanent functional deficits. In humans, peri-auricular muscles (PAMs) do not serve any physiological function, though their innervation is preserved in even high level SCI. Auricular control systems provide a good example of leveraging contemporary technologies (e.g., sEMG controlled computer games) to enable those with disabilities. Our primary objective is to develop and test the effectiveness of an auricular muscle training protocol to facilitate isolated and coordinated, bilateral voluntary control that could be used in individuals without volitional control of the vestigial PAMs. METHODS: Seventeen non-disabled persons were screened; 13 were eligible and 10 completed the entire protocol. The facilitation phase, included one session of sub-motor threshold, sensory electrical stimulation followed by neuromuscular electrical stimulation paired with ear movement feedback for up to 8 additional sessions. Participants progressed to the skill acquisition phase where they dawned an auricular control device that used sEMG signals to control movements of a cursor through three levels of computer games, each requiring increasingly more complex PAM coordination. RESULTS: The 10 who completed the protocol, finished the facilitation phase in 3 to 9 sessions and achieved some level of voluntary auricle movement that ranged between 1 and 5 mm. Qualitative analysis of longitudinal post-session auricular movement, revealed two subgroups of learners. Six successfully completed all 3 games-the "Learners". Two were partially successful in game completion and two were unable to complete a single game--"Poor/Non-Learners". Quantitative analysis revealed a significant group difference in auricular amplitude for both facilitation and skill phases (p < .05), and a significant relationship between performance in the two phases (R2 = 0.84, p = 0.004). CONCLUSION: Sixty percent of those who completed the facilitation phase were able to learn and demonstrate functional voluntary control of the vestigial PAMs. Those who progressed the fastest through facilitation were also those who were most proficient in skill acquisition with the device. There was considerable variability in progression through the two-phase protocol, with 20% deemed Poor/Non-Learners and unable to complete even the most basic game following training. There were no serious adverse events. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02358915 , first posted February 9, 2015.

Effectiveness of neuromuscular electrical stimulation for management of shoulder subluxation post-stroke: a systematic review with meta-analysis.

OBJECTIVES: To examine the effectiveness of neuromuscular electrical stimulation (NMES) for the management of shoulder subluxation after stroke including assessment of short (1 hour or less) and long (more than one hour) daily treatment duration. DATA SOURCES: MEDLINE, CENTRAL, CINAHL, WOS, KoreaMed, RISS and reference lists from inception to January 2017 Review methods: We considered randomized controlled trials that reported neuromuscular electrical stimulation for the treatment of shoulder subluxation post-stroke. Two reviewers independently selected trials for inclusion, assessed trial quality, and extracted data. RESULTS: Eleven studies were included (432 participants); seven studies were good quality, four were fair. There was a significant treatment effect of neuromuscular electrical stimulation for reduction of subluxation for persons with acute and subacute stroke (SMD:-1.11; 95% CI:-1.53, -0.68) with either short (SMD:-0.91; 95% CI:-1.43, -0.40) or long (SMD:-1.49; 95% CI:-2.31, -0.67) daily treatment duration. The effect for patients with chronic stroke was not significant (SMD:-1.25; 95% CI:-2.60, 0.11). There was no significant effect of neuromuscular electrical stimulation on arm function or shoulder pain. CONCLUSION: This meta-analysis suggests a beneficial effect of neuromuscular electrical stimulation, with either short or long daily treatment duration, for reducing shoulder subluxation in persons with acute and subacute stroke. No significant benefits were observed for persons with chronic stroke or for improving arm function or reducing shoulder pain.

Therapeutic application of electrical stimulation and constraint induced movement therapy in perinatal brachial plexus injury: A case report.

Infants and children with perinatal brachial plexus injury (PBPI) have motion limitations in the shoulder, elbow, forearm and hand that are dependent on the level of injury and degree of recovery. The injury and subsequent recovery period occur during critical periods of central and spinal neural development placing infants and children at-risk for developmental disregard and disuse of the affected arm and hand. A case report outlines the therapy and surgical interventions provided in the first 2 years of life for a child with global PBPI and a positive Horner's sign. Electrical stimulation and constraint induced movement therapy provided sequentially were effective therapy interventions. Neurosurgery to repair the brachial plexus was performed at an optimal time period.(2) The Assisting Hand Assessment,(12) Modified Mallet(13) and Active Movement Scale(14) are effective outcome measures in PBPI and served as valuable guides for therapy intervention. Oxford Level of Evidence: 3b; Individual Case Control Study.

Mechanical loading of rigid intramuscular implants.

Several groups are developing different versions of a new class of leadless, permanently implanted electronic devices with a size and form factor that allows them to be injected into muscles (BIONs). Their circuitry is protected from body fluids by thin-walled hermetic capsules made from rigid and brittle materials (glass or ceramic) that include feedthroughs to their electrodes. These packages experience repetitive stresses from the very contractions that they excite. We here provide a worst-case analysis of such stresses and methods for testing and validation of devices intended for such usage, along with the failure analysis and remediation strategy for a design that experienced unanticipated failures in vivo.

Recruitment and comfort of BION implanted electrical stimulation: implications for FES applications.

Restoration of motor function to paralyzed limbs by functional electrical stimulation (FES) has been hampered by the lack of precise and gradual control over muscle recruitment. A suitable interface should provide selective stimulation of individual muscles with graded recruitment of force. The BION was developed to enable neuromuscular stimulation through a miniature, self-contained implant designed to be injected in or near muscles and peripheral nerves. In this study, recruitment properties and comfort of the BION implanted electrical stimulation were systematically evaluated in subjects who participated in a clinical trial. Recruitment properties were qualitatively similar to other methods of implanted neuromuscular stimulation: thresholds and steepness of recruitment were negatively correlated and depended on stimulus charge (product of pulse current and duration). Perceived comfort was not affected by the choice of stimulus parameters, thus their choice can be based purely on technical considerations such as efficiency or resolution of recruitment.

The BION devices: injectable interfaces with peripheral nerves and muscles.

OBJECT: The purpose of this study was to describe a novel technology for implantable neuromuscular stimulation to treat complications of paralysis and disuse atrophy, including shoulder subluxation, hand contractures, drop foot, and osteoarthritis. The authors review the results so far of several pilot clinical studies of these muscle stimulation devices. METHODS: Miniature wireless stimulators received power and individually addressed command signals from an external radiofrequency transmission coil. One or more implants were injected through a 12-gauge hypodermic insertion tool into muscles or adjacent to motor nerves, where they provided the means to activate the muscles in any desired pattern of intensity and frequency. Randomized controlled studies in small numbers of patients are underway to identify efficacy, acceptability, best methods of practice, and any design changes that may be required to improve the technology. Fifty patients have been enrolled in five studies; 35 patients have undergone implantation of a total of 79 BION1 devices. Comparisons with surface stimulation in patients who have suffered a stroke with shoulder subluxation and hand contractures show similar improvements in objective measures of efficacy but higher comfort levels for stimulation by implants. CONCLUSIONS: Injected microstimulators represent a promising new class of technology for the rehabilitation of patients with upper motor neuropathies. As the technology evolves, practitioners may be able to use it to facilitate functional reanimation of paralyzed limbs.

Effect of an electric stimulation facilitation program on quadriceps motor unit recruitment after stroke.

OBJECTIVE: To compare maximum voluntary isometric torque (MVIT) and motor unit recruitment of the quadriceps after an electric stimulation facilitation program in persons affected by cerebrovascular accident (CVA). DESIGN: Three-week, randomized controlled trial with an electric stimulation facilitation program added to standard care. SETTING: Inpatient rehabilitation center. PARTICIPANTS: Twenty patients receiving rehabilitation for first-time CVA (51.8+/-15.2 y; days post-CVA, 38.4+/-40.0 d). Patients were randomly assigned to study and control groups. INTERVENTIONS: All patients received standard physical therapy (PT) care. In addition, the study group received an electric stimulation facilitation program during weight-bearing and ambulatory activities of the PT program. MAIN OUTCOME MEASURES: MVIT and motor unit recruitment measured by interpolated twitch testing. A 2 x 4 repeated-measures analysis of variance was performed on measurements at 4 intervals: pretest, 1 week, 2 weeks, and 3 weeks. RESULTS: MVIT increased by 77% in patients receiving electric stimulation, compared with a 31% increase for the control group. There was a significant effect for assessment time only. Motor unit recruitment increased from 35% to 53% for the study group, whereas the control group recorded no change in recruitment ability. A significant interaction was recorded, indicating improved motor unit recruitment for the study group. CONCLUSIONS: A brief and dynamic electric stimulation facilitation program significantly improved motor unit recruitment in persons after CVA.