Benchtop Performance of Novel Mixed Ionic-Electronic Conductive Electrode Form Factors for Biopotential Recordings.

Background: Traditional gel-based (wet) electrodes for biopotential recordings have several shortcomings that limit their practicality for real-world measurements. Dry electrodes may improve usability, but they often suffer from reduced signal quality. We sought to evaluate the biopotential recording properties of a novel mixed ionic-electronic conductive (MIEC) material for improved performance. Methods: We fabricated four MIEC electrode form factors and compared their signal recording properties to two control electrodes, which are electrodes commonly used for biopotential recordings (Ag-AgCl and stainless steel). We used an agar synthetic skin to characterize the impedance of each electrode form factor. An electrical phantom setup allowed us to compare the recording quality of simulated biopotentials with ground-truth sources. Results: All MIEC electrode form factors yielded impedances in a similar range to the control electrodes (all <80 kΩ at 100 Hz). Three of the four MIEC samples produced similar signal-to-noise ratios and interfacial charge transfers as the control electrodes. Conclusions: The MIEC electrodes demonstrated similar and, in some cases, better signal recording characteristics than current state-of-the-art electrodes. MIEC electrodes can also be fabricated into a myriad of form factors, underscoring the great potential this novel material has across a wide range of biopotential recording applications.

Predictors of catheter-free voiding after spinal cord injury.

CONTEXT: Despite a high prevalence of neurogenic bladder (NGB) in patients with spinal cord injury (SCI), clinicians are unable to predict long-term bladder outcomes due to variable phenotypes of bladder dysfunction. This study investigates if early bladder events, infections, and spinal cord injury characteristics during rehabilitation admission affect bladder outcomes one year after SCI. METHODS: This retrospective study included patients with SCI admitted to a tertiary rehabilitation center between 1 January 2016 and 1 January 2020. Data was collected on early bladder management, comorbidities, infections and injury characteristics; level of injury, American Spinal Injury Association Impairment Scale (AIS) classification, and International Standards for Neurological Classification of Spinal Cord Injury lower extremity motor score (LEMS). RESULTS: Seventy-two patients met inclusion criteria; 63% (45/72) patients had cervical SCI and 31% (22/72) were complete injuries. Twenty-two percent (16/72) did not use an internal catheter to empty the bladder, improving to 41% (29/72) at one year. On multivariate logistic regression accounting for age, sex, Charlson comorbidity index, LEMS, and infections during admission, higher LEMS (OR 1.104, 95%, CI 1.037-1.176, P = 0.002) associated with catheter-free voiding (CFV) at one year while male sex (OR 0.091, 95% CI 0.012-0.713, P = 0.0225), and non-urologic infections (OR 0.088, 95% CI 0.010-0.768, P = 0.0279) were negatively associated. CONCLUSIONS: Preserved LEMS early after SCI associates with CFV at one year while male sex and early non-urologic infections such as pneumonia are associated with persistent urinary retention. This can be used to counsel SCI patients on expected bladder recovery and outcomes.

Human primary motor cortex indexes the onset of subjective intention in brain-machine-interface mediated actions.

Self-initiated behavior is accompanied by the experience of willing our actions. Here, we leverage the unique opportunity to examine the full intentional chain - from will (W) to action (A) to environmental effects (E) - in a tetraplegic person fitted with a primary motor cortex (M1) brain machine interface (BMI) generating hand movements via neuromuscular electrical stimulation (NMES). This combined BMI-NMES approach allowed us to selectively manipulate each element of the intentional chain (W, A, and E) while performing extra-cellular recordings and probing subjective experience. Our results reveal single-cell, multi-unit, and population-level dynamics in human M1 that encode W and may predict its subjective onset. Further, we show that the proficiency of a neural decoder in M1 reflects the degree of W-A binding, tracking the participant's subjective experience of intention in (near) real time. These results point to M1 as a critical node in forming the subjective experience of intention and demonstrate the relevance of intention-related signals for translational neuroprosthetics.

Toward a Consensus for Musculoskeletal Ultrasonography Education in Physical Medicine and Rehabilitation: A National Poll of Residency Directors.

OBJECTIVES: The aims of the study were to evaluate integration of musculoskeletal ultrasonography education in physical medicine and rehabilitation training programs in 2014-2015, when the American Academy of Physical Medicine & Rehabilitation and Accreditation Council for Graduate Medical Education Residency Review Committee both recognized it as a fundamental component of physiatric practice, to identify common musculoskeletal ultrasonography components of physical medicine and rehabilitation residency curricula, and to identify common barriers to integration. DESIGN: Survey of 78 Accreditation Council for Graduate Medical Education-accredited physical medicine and rehabilitation residency programs was conducted. RESULTS: The 2015 survey response rate was more than 50%, and respondents were representative of programs across the United States. Most programs (80%) reported teaching musculoskeletal ultrasonography, whereas a minority (20%) required mastery of ultrasonography skills for graduation. Ultrasonography curricula varied, although most programs agreed that the scope of resident training in physical medicine and rehabilitation should include diagnostic and interventional musculoskeletal ultrasonography, especially for key joints (shoulder, elbow, knee, wrist, hip, and ankle) and nerves (median, ulnar, fibular, tibial, radial, and sciatic). Barriers to teaching included insufficient expertise of instructors, poor access to equipment, and lack of a structured curriculum. CONCLUSIONS: Musculoskeletal ultrasonography has become a required component of physical medicine and rehabilitation residency training. Based on survey responses and expert recommendations, we propose a structure for musculoskeletal ultrasonography curricular standards and milestones for trainee competency.

A wearable neural interface for detecting and decoding attempted hand movements in a person with tetraplegia.

We are developing a wearable neural interface based on high-density surface electromyography (HDEMG) for detecting and decoding signals from spared motor units in the forearms of people with tetraplegia after spinal cord injury (SCI). A lightweight, form-fitting garment containing 150 disc electrodes and covering the entire forearm was used to map the myoelectric activity of forearm muscles during a wide range of voluntary tasks of a person with chronic tetraplegia after SCI (C5 motor and C6 sensory American Spinal Injury Association Impairment Scale B spinal cord injury). Despite exhibiting no overt finger motion, myoelectric signals were detectable for attempted movements of individual digits and were highly discriminable. Motor unit decomposition was used to identify the activity of >30 motor neurons, active specifically during rotation, pronation of the wrist (4 units), and flexion of the elbow joint (7 units), and during attempted movements of individual hand digits (1-5 units). In addition, we performed a neural connectivity analysis based on the power of the common oscillations of the identified motor neurons in the delta (~5Hz), alpha (~6-12 Hz), and beta bands (~15-30 Hz). This analysis showed clear common synaptic inputs to the identified motor neurons in all the analyzed frequency bands. This neural interface offers a new potential for the control of assistive technologies, whereby the motor neurons spared after SCI may serve as a direct readout of motor intent that allows proportional control over several distinct degrees of freedom. Moreover, this framework can be used to study the reorganization and recovery of spinal networks after injury and rehabilitation.

The Current State of Musculoskeletal Ultrasound Education in Physical Medicine and Rehabilitation Residency Programs.

BACKGROUND: Exposure to musculoskeletal ultrasound (MSUS) is now a mandatory component of physical medicine and rehabilitation (PM&R) residency training. However, reports on the extent of the implementation and efficacy of MSUS education are lacking in the literature. OBJECTIVE: To determine the extent to which PM&R residencies are implementing MSUS education. DESIGN: Cross-sectional. SETTING: Institutional. PARTICIPANTS: Thirty-six of the 78 United States PM&R residency programs accredited by the Accreditation Council for Graduate Medical Education. METHODS: All 78 programs were solicited with an online survey via the residency program director and coordinator in July 2014. The 25 questions on the survey were aimed at determining program MSUS educational characteristics and their effectiveness. MAIN OUTCOME MEASURES: Description of teaching methods used for MSUS, residency demographics, characteristics of MSUS faculty expertise, and faculty-perceived competency in MSUS examinations and procedures among residents. Data were analyzed using both descriptive statistics and tests for independence to identify correlations between program characteristics and resident MSUS competency. RESULTS: A response was received from 36 of the 78 residency programs (46.2%). Of the 36 residency programs that responded, 97.2% provide exposure to MSUS (a figure that drops to 44.9% when nonrespondents are included); 61% had mandatory MSUS training (28.2% when including nonrespondents); and 44.4% had a formal curriculum (20.5% when including nonrespondents). The most common MSUS educational tools used were lecture (88.9%), outpatient clinic (86.1%), and hands-on workshops (86.1%). Sixty-one percent of responding programs evaluate residents with formal assessment tools. Overall, faculty at 38.8% and 44.4% of programs believed that at least 50% of residents who graduate are competent in diagnostic and interventional MSUS, respectively. These rates were significantly associated with the use of formal assessment. CONCLUSION: MSUS education is growing in PM&R, but many programs still have not adopted a formal educational curriculum. Formal assessment to evaluate resident MSUS skills significantly improves faculty-perceived MSUS competency.

Cortical blindness associated with autonomic dysreflexia in a man with tetraplegia: a rare but serious complication.

CONTEXT: To describe a case of a 44-year-old man with complete C4 tetraplegia who developed transient cortical blindness in the subacute setting following episodes of autonomic dysreflexia. FINDINGS: Transient cortical blindness the day after surgery for appendicitis that had resulted in severe autonomic dysreflexia (AD) requiring aggressive blood pressure management. Imaging showed no evidence of acute stroke, but did show vasospasm in the occipital lobes. Vision improved over the next couple of months. CONCLUSION/CLINICAL RELEVANCE: This case illustrates a possible profound vasomotor phenomenon (cortical blindness) associated with AD and its symptomatic treatment. Early recognition of AD and treatment of its underlying cause cannot be overemphasized.

Severe trismus as a complication of cerebrovascular accident: a case report.

Spastic hypertonia is a common sequelae after a cerebrovascular accident (CVA) and is a component of an upper motoneuron lesion. Management of spastic hypertonia may involve the use of centrally acting agents, peripheral blockade, and ablative therapies. We report a case of spastic hypertonia leading to severe trismus after CVA that was successfully treated with botulinum toxin type A. Severe trismus is a potentially life-threatening condition that may lead to permanent functional impairment if not promptly diagnosed and treated. Using electromyography for botulinum toxin muscle selection in this case appears to have helped decrease the dose of botulinum toxin given as well as minimize potential side effects.

Cost-effectiveness of duplex ultrasound surveillance in spinal cord injury.

OBJECTIVE: To determine cost-effectiveness of surveillance with duplex ultrasound for thromboembolic disease in individuals with acute traumatic spinal cord injury at admission to rehabilitation. DESIGN: In this retrospective sequential case series study, individuals with traumatic spinal cord injury admitted to our rehabilitation facility between July 1, 1988, and December 31, 1998, were identified. Cost at our institution for treatment of thromboembolic disease was tabulated in 2001-2002 dollar amounts. Using this cost information, in a statistical model founded on available medical evidence, analysis for cost-effectiveness was then performed. RESULTS: A total of 369 subjects met inclusion criteria. Based on the statistical model, the cost and estimated mortality from thromboembolic disease per subject when performing admission duplex ultrasounds was $449.28 and 0.016%, respectively. The estimated total cost per subject when not performing admission duplex ultrasounds was $136.29, with predicted mortality of 0.524% due to thromboembolic disease. Therefore, cost of one life saved when performing admission duplex ultrasound surveillance is calculated to be $61,542, with cost per life year gained between $1193 and $9050, depending on age at time of injury and severity of injury. CONCLUSION: Duplex ultrasound is a cost-effective tool for deep venous thrombosis surveillance in individuals with acute traumatic spinal cord injury admitted to rehabilitation programs.

Monitoring of creatinine kinase during weaning of intrathecal baclofen and with symptoms of early withdrawal.

Abrupt withdrawal from intrathecal baclofen (ITB) can result in severe rebound spasticity, confusion, and seizures. It has been recently recognized that abrupt withdrawal from ITB may, in rare cases, result in life-threatening rhabdomyolysis, hyperthermia, autonomic disturbances, and sepsis-like presentations. Early recognition of the most severe forms of the withdrawal syndrome is essential for effective intervention. The common and unique features in such individuals seem to be severe increased spasticity and marked elevation in creatinine kinase levels. This case of an individual with T4 paraplegia with recurrent episodes of ITB withdrawal associated with severe spasticity and elevated creatinine kinase levels who required rapid weaning of high-dose ITB to allow removal of an infected pump and catheter illustrates the value of monitoring creatinine kinase levels in evaluation of suspected ITB withdrawal and during rapid weaning of ITB when necessary.

Aerophagia as a cause of ineffective phrenic nerve pacing in high tetraplegia: a case report.

We report an unusual case of aerophagia after traumatic spinal cord injury (SCI), which shows the profound effects of abdominal distension on respiratory ability in such individuals. In this case, abdominal distension resulting from aerophagia reduced the effectiveness of phrenic nerve pacing on diaphragm function necessitating greater use of positive-pressure ventilatory (PPV) support. Reduction of postprandial gastric air and abdominal distension with insertion of a percutaneous endoscopic gastrostomy tube ameliorated the condition and allowed for more effective phrenic nerve pacing and greater PPV-free breathing. We are unaware of a similar case involving an individual with an SCI.

Early recognition of neuroleptic malignant syndrome during traumatic brain injury rehabilitation.

Neuroleptic malignant syndrome is a rare disorder that manifests with hyperthermia, muscle rigidity and autonomic instability. Presented is a case series of individuals with traumatic brain injury and agitation who, when treated with neuroleptics, developed neuroleptic malignant syndrome. Although the incidence of this syndrome is rare, it is associated with significant morbidity and mortality. The onset of symptoms inconsistent with the patient's current level of recovery should alert the clinician to consider other possible diagnosis and failure to distinguish the features of neuroleptic malignant syndrome from post-traumatic agitation will delay appropriate intervention for this potentially life-threatening disorder.

Surveillance with duplex ultrasound in traumatic spinal cord injury on initial admission to rehabilitation.

OBJECTIVE: To determine the prevalence of deep vein thrombosis (DVT) by surveillance duplex ultrasound in the traumatic spinal cord injury (SCI) population on admission to rehabilitation. DESIGN: Retrospective sequential case series. SETTING: Midwest regional, university-based, Commission on Accreditation of Rehabilitation Facilities-accredited acute rehabilitation center. METHODS: Charts of all patients with traumatic SCI admitted and discharged from January 1, 1996 through December 31, 1998 were reviewed. Preadmission data were collected on demographics, severity of injury, and DVT prophylaxis information, along with rehabilitation duplex ultrasound results and incidence of thromboembolic events. RESULTS: Ninety-two participants met the inclusion criteria. There were 68 men and 24 women with a mean age on admission of 32.4 years. On admission, 45 participants (49%) were classified as tetraplegic and 47 (51%) were classified as paraplegic; 63 (69%) had motor-complete lesions and 29 (31%) had motor-incomplete lesions. Of all the participants, 8 (8.7%) were found to have DVT on admission to rehabilitation. There were no statistically significant differences among participants with regard to age, sex, level of injury, or completeness of injury, when comparing those participants with DVT on admission, those without DVT on admission, and those with thromboembolic events diagnosed later in their hospitalization. Of the 84 participants who had negative duplex ultrasounds on admission, 4 individuals (4.8%) were found to have DVT and 4 (4.8%) had pulmonary emboli subsequently. In these 84 participants, DVT prophylaxis with low-molecular-weight heparin was found to be more effective than was adjusted-dose heparin in preventing thromboembolic phenomenon. CONCLUSION: Incidence of DVT remains high despite prophylaxis in traumatic SCI patients. Two thirds of DVT diagnosed in rehabilitation was identified on admission and one third was diagnosed later. Duplex ultrasound is an effective and valuable tool that assists in the diagnosis of asymptomatic DVT in patients with traumatic SCI who are initiating in-patient rehabilitation.

Hypothermia associated with autonomic dysreflexia after traumatic spinal cord injury.

Individuals with traumatic upper thoracic and cervical spinal cord injuries are at increased risk for the development of both thermoregulatory dysfunction and autonomic dysreflexia. It is unclear, however, what effect reflex autonomic sympathetic outflow has on thermoregulatory dysfunction during episodes of autonomic dysreflexia. The following case of an individual with C5 tetraplegia and both thermoregulatory dysfunction and autonomic dysreflexia illustrates the profound effects that the autonomic nervous system may have on body temperature in individuals at risk for this complication.