Analysis of electrode locations on limb condition effect for myoelectric pattern recognition.

BACKGROUND: Gesture recognition using surface electromyography (sEMG) has garnered significant attention due to its potential for intuitive and natural control in wearable human-machine interfaces. However, ensuring robustness remains essential and is currently the primary challenge for practical applications. METHODS: This study investigates the impact of limb conditions and analyzes the influence of electrode placement. Both static and dynamic limb conditions were examined using electrodes positioned on the wrist, elbow, and the midpoint between them. Initially, we compared classification performance across various training conditions at these three electrode locations. Subsequently, a feature space analysis was conducted to quantify the effects of limb conditions. Finally, strategies for group training and feature selection were explored to mitigate these effects. RESULTS: The results indicate that with the state-of-the-art method, classification performance at the wrist was comparable to that at the middle position, both of which outperformed the elbow, consistent with the findings from the feature space analysis. In inter-condition classification, training under dynamic limb conditions yielded better results than training under static conditions, especially at the positions covered by dynamic training. Additionally, fast and slow movement speeds produced similar performance outcomes. To mitigate the effects of limb conditions, adding more training conditions reduced classification errors; however, this reduction plateaued after four conditions, resulting in classification errors of 22.72%, 22.65%, and 26.58% for the wrist, middle, and elbow, respectively. Feature selection further improved classification performance, reducing errors to 19.98%, 19.75%, and 27.14% at the respective electrode locations, using three optimal features derived from single-condition training. CONCLUSIONS: The study demonstrated that the impact of limb conditions was mitigated when electrodes were placed near the wrist. Dynamic limb condition training, combined with feature optimization, proved to be an effective strategy for reducing this effect. This work contributes to enhancing the robustness of myoelectric-controlled interfaces, thereby advancing the development of wearable intelligent devices.

Evaluation of the non-auditory responses in individuals with auditory brainstem implant.

OBJECTIVES: After auditory brainstem implant (ABI) surgery, stimulation of certain cranial nerves may result in a non-auditory response, and the electrodes that stimulate these nerves may be deactivated. The goals of this study are to compare the number of active electrodes in the initial activation and the last fitting, to investigate non-auditory response types and their frequency as a result of non-auditory stimulation, to compare the placements of deactivated electrodes as a result of non-auditory stimulation in the initial activation and the last fitting. METHODS: The computer software system was used to perform a retrospective analysis of the fitting data of 69 ABI users who underwent auditory brainstem implant surgery between January 1997 and January 2019. The non-auditory response types, deactive electrodes, and the positioning of the deactive electrodes horizontally and vertically were recorded in these users during the initial activation and the last fitting. RESULTS: There was no statistically significant difference between the number of active electrodes in the initial activation and the last fitting. The proportion of the users with deactive electrodes in the initial activation and the last fitting was not statistically significant different. In the horizontal and vertical placement classification, the placement of the deactive electrodes was not statistically different between initial activation and last fitting. The most common type of non-auditory response was facial nerve stimulation at the initial activation and no auditory perception at the last fitting. According to the difference between the number of active and deactive electrodes in the initial activation and the last fitting, as well as the auditory and non-auditory responses, it was found that the ABI users were statistically different between the initial activation and the last fitting. CONCLUSION: The results of this study show that not only auditory but also non-auditory responses occur in most ABI users. In addition, to the best of our knowledge, this study is the first to examine the frequencies of non-auditory response types, and the placement of the electrodes that cause these responses according to horizontal and vertical classifications.

Non-Standard Electrode Placement Strategies for ECG Signal Acquisition.

BACKGROUND: Wearable technologies for monitoring cardiovascular parameters, including electrocardiography (ECG) and impedance cardiography (ICG), propose a challenging research subject. The expectancy for wearable devices to be unobtrusive and miniaturized sets a goal to develop smarter devices and better methods for signal acquisition, processing, and decision-making. METHODS: In this work, non-standard electrode placement configurations (EPC) on the thoracic area and single arm were experimented for ECG signal acquisition. The locations were selected for joint acquisition of ECG and ICG, targeted to suitability for integrating into wearable devices. The methodology for comparing the detected signals of ECG was developed, presented, and applied to determine the R, S, and T waves and RR interval. An algorithm was proposed to distinguish the R waves in the case of large T waves. RESULTS: Results show the feasibility of using non-standard EPCs, manifesting in recognizable signal waveforms with reasonable quality for post-processing. A considerably lower median sensitivity of R wave was verified (27.3%) compared with T wave (49%) and S wave (44.9%) throughout the used data. The proposed algorithm for distinguishing R wave from large T wave shows satisfactory results. CONCLUSIONS: The most suitable non-standard locations for ECG monitoring in conjunction with ICG were determined and proposed.

Robot-assisted stereoelectroencephalography electrode placement in twenty-three pediatric patients: a high-resolution analysis of individual lead placement time and accuracy at a single institution.

PURPOSE: We describe a detailed evaluation of predictors associated with individual lead placement efficiency and accuracy for 261 stereoelectroencephalography (sEEG) electrodes placed for epilepsy monitoring in twenty-three children at our institution. METHODS: Intra- and post-operative data was used to generate a linear mixed model to investigate predictors associated with three outcomes (lead placement time, lead entry error, lead target error) while accounting for correlated observations from the same patients. Lead placement time was measured using electronic time-stamp records stored by the ROSA software for each individual electrode; entry and target site accuracy was measured using postoperative stereotactic CT images fused with preoperative electrode trajectory planning images on the ROSA computer software. Predictors were selected from a list of variables that included patient demographics, laterality of leads, anatomic location of lead, skull thickness, bolt cap device used, and lead sequence number. RESULTS: Twenty-three patients (11 female, 48%) of mean age 11.7 (± 6.1) years underwent placement of intracranial sEEG electrodes (median 11 electrodes) at our institution over a period of 1 year. There were no associated infections, hemorrhages, or other adverse events, and successful seizure capture was obtained in all monitored patients. The mean placement time for individual electrodes across all patients was 6.56 (± 3.5) min; mean target accuracy was 4.5 (± 3.5) mm. Lesional electrodes were associated with 25.7% (95% CI: 6.7-40.9%, p = 0.02) smaller target point errors. Larger skull thickness was associated with larger error: for every 1-mm increase in skull thickness, there was a 4.3% (95% CI: 1.2-7.5%, p = 0.007) increase in target error. Bilateral lead placement was associated with 26.0% (95% CI: 9.9-44.5%, p = 0.002) longer lead placement time. The relationship between placement time and lead sequence number was nonlinear: it decreased consistently for the first 4 electrodes, and became less pronounced thereafter. CONCLUSIONS: Variation in sEEG electrode placement efficiency and accuracy can be explained by phenomena both within and outside of operator control. It is important to keep in mind the factors that can lead to better or worse lead placement efficiency and/or accuracy in order to maximize patient safety while maintaining the standard of care.

Comparison of clinical outcomes and accuracy of electrode placement between robot-assisted and conventional deep brain stimulation of the subthalamic nucleus: a single-center study.

BACKGROUND: Several surgical methods are used for deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD). This study aimed to compare clinical outcomes and electrode placement accuracy after robot-assisted (RAS) versus frame-based stereotactic (FSS) STN DBS in Parkinson's disease. METHODS: In this single-center open-label study, we prospectively collected data from 48 consecutive PD patients who underwent RAS (Neuromate®; n = 20) or FSS (n = 28) STN DBS with the same MRI-based STN targeting between October 2016 and December 2018 in the university neurological hospital of Lyon, France. Clinical variables were assessed before and 1 year after surgery. The number of electrode contacts within the STN was determined by merging post-operative CT and pre-operative MRI using Brainlab® GUIDE™XT software. RESULTS: One year after surgery, the improvement of motor manifestations (p = 0.18), motor complications (p = 0.80), and quality of life (p= 0.30) and the reduction of dopaminergic treatment (p = 0.94) and the rate of complications (p = 0.99) were similar in the two groups. Surgery duration was longer in the RAS group (p = 0.0001). There was no difference in the number of electrode contacts within the STN. CONCLUSION: This study demonstrates that RAS and FSS STN DBS for PD provide similar clinical outcomes and accuracy of electrode placement.

Direct visualization of deep brain stimulation targets in patients with Parkinson's disease via 3-T quantitative susceptibility mapping.

BACKGROUND: The direct visualization of brain nuclei on magnetic resonance (MR) images is important for target localization during deep brain stimulation (DBS) in patients with Parkinson's disease (PD). We demonstrated the superiority of 3-T high-resolution submillimeter voxel size quantitative susceptibility mapping (QSM) for delineating the subthalamic nucleus (STN) and the globus pallidus internus (GPi). METHODS: Preoperative 3-T QSM and T2 weighted (T2w) images were obtained from ten patients with PD. Qualitative visualization scores were analyzed by two neurosurgeons on both images using a 4-point and 5-point scale, respectively. Images were also compared with regard to contrast-to-noise ratios (CNRs) and edge detection power for the STN and GPi. The Wilcoxon rank-sum test and the signed-rank test were used to compare measurements between the two images. RESULTS: Visualization scores for the STN and GPi, the mean CNR of the STN relative to the zona incerta (ZI) and the substantia nigra, and the mean CNR of the GPi relative to the internal capsule (IC) and the globus pallidum externum, were significantly higher on QSM images than on T2w images (P < 0.01). The edge detection powers of the STN-ZI and GPi-IC on QSM were significantly larger (by 2.6- and 3.8-fold, respectively) than those on T2w images (P < 0.01). QSM detected asymmetry of the STN in two patients. CONCLUSIONS: QSM images provided improved delineation ability for the STN and GPi when compared to T2w images. Our findings are important for patients with PD who undergo DBS surgery, particularly those with asymmetric bilateral nuclei.

Electrode Size and Placement for Surface EMG Bipolar Detection from the Brachioradialis Muscle: A Scoping Review.

The brachioradialis muscle (BRD) is one of the main elbow flexors and is often assessed by surface electromyography (sEMG) in physiology, clinical, sports, ergonomics, and bioengineering applications. The reliability of the sEMG measurement strongly relies on the characteristics of the detection system used, because of possible crosstalk from the surrounding forearm muscles. We conducted a scoping review of the main databases to explore available guidelines of electrode placement on BRD and to map the electrode configurations used and authors' awareness on the issues of crosstalk. One hundred and thirty-four studies were included in the review. The crosstalk was mentioned in 29 studies, although two studies only were specifically designed to assess it. One hundred and six studies (79%) did not even address the issue by generically placing the sensors above BRD, usually choosing large disposable ECG electrodes. The analysis of the literature highlights a general lack of awareness on the issues of crosstalk and the need for adequate training in the sEMG field. Three guidelines were found, whose recommendations have been compared and summarized to promote reliability in further studies. In particular, it is crucial to use miniaturized electrodes placed on a specific area over the muscle, especially when BRD activity is recorded for clinical applications.

Accuracy of Electrode Position in Sphenopalatine Ganglion Stimulation in Correlation With Clinical Efficacy.

INTRODUCTION: Sphenopalatine ganglion (SPG) stimulation is an efficient treatment for cluster headache. The target for the SPG microstimulator in the pterygopalatine fossa lies between the vidian canal and foramen rotundum, ideally two contacts should be placed in this area. However, placement according to the manufacturers recommendations is frequently not possible. It is not known whether a suboptimal electrode placement interferes with postoperative outcomes. MATERIALS AND METHODS: SPG stimulation was performed in 13 patients between 2015 and 2018 in a single center. Lead location was determined by intraoperative computed tomography scan and correlated with the planned lead position as well as clinical data and stimulation parameters. Patients with a reduction of 50% or more in pain intensity or frequency were considered responsive. RESULTS: Eleven patients (84.6%) responded to SPG stimulation with eight being frequency responders (61.5%). In seven cases, there were less than two electrodes between vidian canal and foramen rotundum, there was no significant correlation with negative stimulation results (p = 0.91). The mean distance of lead location between pre- and postoperative images did not correlate with clinical outcomes (p = 0.84) and was even bigger in responders (4.91 mm vs. 4.53 mm). The closest electrode contact to the vidian canal was in the stimulation area in all but one patient, regardless of its overall distance to canal. The distance of the closest electrode to the vidian canal was, however, not significantly correlated to the percentage of frequency (p = 0.68) or intensity reduction (p = 0.61). CONCLUSION: There was no significant correlation regarding aberrations of lead position from the planned position with clinical outcome. However, this study might be underpowered to detect such a correlation. The closest electrode contact to the vidian canal was in the stimulation area in all but one patient in the final programming. This indicates that, overall, the lead location does play a crucial role in SPG stimulation for cluster headache.

Comparison of the performance of six stimulus paradigms in visual acuity assessment based on steady-state visual evoked potentials.

PURPOSE: There are several stimulus paradigms used in objective visual acuity assessment based on steady-state visual evoked potentials (SSVEPs). The aim of this study was to explore the difference and performance of common used six stimulus paradigms (reverse vertical sinusoidal gratings, reverse horizontal sinusoidal gratings, reverse vertical square-wave gratings, brief-onset vertical sinusoidal gratings, reversal checkerboards and oscillating expansion-contraction concentric-rings) of SSVEP acuity assessment. METHODS: We tested subjective visual acuity both by tumbling E and Freiburg Visual Acuity and Contrast Test (FrACT) in 11 subjects. SSVEPs were induced by 11 spatial frequencies for each paradigm, and then a threshold determination criterion was used to define the objective SSVEP visual acuity. RESULTS: After SSVEP signal analysis, we found there was difference in SSVEP response of harmonic components and no difference in sensitive electrode placement for the six paradigms. We selected six electrodes (PO3, POz, PO4, O1, Oz and O2) as the sensitive electrodes to use in data processing for each paradigm. The results showed that except for brief-onset vertical sinusoidal gratings, the correlation and agreement between objective SSVEP and subjective FrACT acuity were all quite good, demonstrating good performance in acuity detection for the rest five paradigms. CONCLUSION: Except for brief-onset vertical sinusoidal gratings, all the five stimulus paradigms of reverse vertical sinusoidal gratings, reverse horizontal sinusoidal gratings, reverse vertical square-wave gratings, reversal checkerboards and oscillating expansion-contraction concentric-rings performed quite well in objective SSVEP visual acuity assessment.

Cardiovascular nurses' adherence to practice standards in in-hospital telemetry monitoring.

BACKGROUND: Correct electrode placement and proper skin preparation for cardiac telemetry monitoring of patients at risk for arrhythmias increase the quality of the arrhythmic surveillance. Inconsistent arrhythmia surveillance can compromise patient safety and care outcomes. An inspection of international literature demonstrates that nurses generally do not adhere to cardiac monitoring standards. AIM: The aims of this study were to determine cardiovascular nurses' knowledge of and adherence to practice standards for cardiac surveillance and whether their knowledge and practice improves over time. STUDY DESIGN: A comparative study design was applied, and data were obtained by survey methodology. METHODS: Nurse delegates at the Annual National Congress on Cardiovascular Nursing in Norway completed surveys in 2011 and 2017 (delegates from 44 and 38 hospitals, respectively). RESULTS: In total, 363 cardiac nurses (70%) responded to the questionnaires. Of these, 95% were female, with a mean age of 41 years. In 2011, 97% of participants were unaware of international practice standards. However, by 2017 unawareness decreased to 78% (P < .001). Despite their lack of knowledge of practice standards, 94% of participants often or always prepared patients' skin for telemetry; this improved from 2011 to 2017 (P = .001). Overall, 73% of nurses never or seldom scrubbed or washed the patients' skin before electrode placement, and 38% of the electrodes were misplaced. In 2011, 49% of nurses used protective telemetry covers; this increased to 80% in 2017 (P < .001). Overall, 64% always informed patients of the purpose of cardiac monitoring. CONCLUSION: A significant percentage of nurses fail to adhere to recommendations for electrode placement, skin preparation and providing patients with telemetry information. In order to raise the quality of arrhythmic surveillance, investment in educational programmes in cardiac telemetry monitoring is required. RELEVANCE TO CLINICAL PRACTICE: Improved in-hospital telemetry practice is required to ensure patient safety and better care outcomes.

Simulation and experiment of asymmetric electrode placement for electrophoretic exclusion in a microdevice.

Electrophoretic exclusion (EE) is a counterflow gradient technique that exploits hydrodynamic flow and electrophoretic forces to exclude, enrich, and separate analytes. Resolution for this technique has been theoretically examined and the smallest difference in electrophoretic mobilities that can be completely separated is estimated to be 10-13  cm2 /Vs. Traditional and mesoscale systems have been used, whereas microfluidics offers a greater range of geometries and configurations towards approaching this theoretical limit. To begin to understand the impact of seemingly subtle changes to the entrance flow and the electric field configurations, three closely related microfluidic interfaces were modeled, fabricated, and tested. These interfaces consisted of systematically varying placement of an asymmetric electrode relative to a channel entrance: leading electrode placed outside the channel entrance, leading electrode aligned with the channel, and leading electrode placed within the channel. A charged fluorescent dye is used as a sensitive and accurate probe for the model and to test the concentration variation at these interfaces. Models and experiments focused on visualizing the concentration profile in areas of high temporal dynamics, thus providing a severe test of the models. Experimental data and simulation results showed strong qualitative agreement. The complexity of the electric and flow fields about this interface and the agreement between models and testing suggests the theoretical assessment capabilities can be used to faithfully design novel and more efficient interfaces.

Common source of miscalculation and misclassification of P-wave negativity and P-wave terminal force in lead V1.

BACKGROUND: P-wave terminal force (PTF) > 4000 ms·µV and deep terminal negativity (DTN) are ECG markers of left atrial abnormality associated with both atrial fibrillation and stroke. When the precordial lead V1 is placed higher than the correct position in the fourth intercostal space, it may cause increased PTF and DTN. Several studies have documented that electrode misplacement, especially high placement, is common. The influence of electrode misplacement on these novel ECG markers has not previously been quantified. OBJECTIVE: The objective was to assess the influence of electrode misplacement on PTF and DTN. METHOD: 12-Lead ECGs were recorded in 29 healthy volunteers from the Department of Cardiology at the Copenhagen University Hospital of Bispebjerg. The precordial electrode V1 was placed in the fourth, third and second intercostal space, giving a total of 3 ECGs per subject. Continuous variables were compared using Dunnett's post-hoc test and categorical variables were compared using Fischer's exact test. RESULTS: High placement of V1 electrodes resulted in a more than three-fold increase of PTF (IC4 = 2267 ms·µV, IC2 = 7996 ms·µV, p-value < 0.001). There was a similar increase of DTN (IC4 = 0%, IC2 = 28%, p-value < 0.001). P-wave area and amplitude of the negative deflection increased, and P-wave area and amplitude of the positive deflection decreased. The P-wave shape changed from being predominantly positive or biphasic in IC4 to 90% negative in IC2. The PR-duration and P-wave duration were not altered by electrode placement. CONCLUSION: High electrode placement results in significant alteration of PTF and DTN in lead V1.

Multicenter randomized controlled trial of bifrontal, bitemporal, and right unilateral electroconvulsive therapy in major depressive disorder.

AIM: Electroconvulsive therapy (ECT) has been shown to be the most effective and rapid treatment for severe depression. Electrode placement is one of the most important factors that affect ECT's efficacy and side-effects profile. Bifrontal, bitemporal, and unilateral are the three most used electrode placements. Very few studies have directly compared the efficacy and cognitive side-effects of the three placements. The aim of this study was to compare the efficacy and cognitive side-effects associated with bifrontal, bitemporal, and unilateral electrode placements. METHODS: This multicenter randomized, blinded, controlled trial included 40 patients in each of the three groups. Most of the patients (94.8%) completed six ECT treatments. We used mixed-model analyses to compare differences in 17-item Hamilton Depression Rating Scale (HAMD-17) and Clinical Global Impression (CGI) scores among the three groups and the five times series (baseline, Week 1, Week 2, Week 3, and Week 4). The cognitive outcome was Mini-Mental State Examination (MMSE) score. RESULTS: HAMD-17 and CGI scores did not differ significantly across the groups (HAMD-17 scores: z = -1.13, P = 0.259; CGI scores: z = -0.35, P = 0.729). MMSE scores at pre- and post-ECT were similar across the three groups (F = 2.06, P = 0.133). However, subgroup analysis using paired t-tests showed that MMSE scores improved in the right unilateral and bifrontal groups (t = 2.745, P = 0.0098; t = 2.464, P = 0.0204), but did not change in the bitemporal group (t = 1.188, P = 0.2461). CONCLUSION: The efficacy of right unilateral and bifrontal ECT placement was similar to that of bitemporal ECT. The physical side-effects were also similar across the three groups. Right unilateral and bifrontal ECT placement were associated with improved cognitive outcomes, but bitemporal ECT placement was not.

Intraoperative Neuromonitoring in Percutaneous Spinal Cord Stimulator Placement.

INTRODUCTION: Placement of spinal cord stimulation (SCS) paddles under general anesthesia using intraoperative neuromonitoring (IONM) has been shown to be associated with equivocal or superior clinical outcomes in comparative studies. The value of IONM in percutaneous permanent SCS placement has not been demonstrated. METHODS: Outcomes for patients under percutaneous SCS placement performed with IONM were prospectively collected. Descriptive outcomes included numerical rating scale (NRS), the Oswestry disability index (ODI), McGill pain questionnaire, pain catastrophizing scale score (PCS), and Beck Depression Inventory. We also assessed satisfaction, willingness to repeat surgery, complication rates, and opioid use at baseline and follow-up using chart data and the New York Internet System for Tracking Over-Prescribing data base. RESULTS: The mean follow-up for our 46 patients was 22.04 ± 15.03 months (range 6-52 months). There were 10 patients (21.3%) who underwent revisions or removals with a mean time to revision/explant of 11.4 ± 11.7 months. About 85% of patients were satisfied with surgery. A total of 24 of 46 patients were on opioids at baseline. Following surgery, 17 of 24 (70.83%) patients demonstrated decreased opioid use in Morphine Milligram Equivalents. Of the 17 patients that reduced opioid use, 14 (82.35%) ceased opioid use entirely. Improvement from baseline was noted in NRS, ODI, and PCS (p < .05). CONCLUSIONS: Permanent percutaneous implantation of a SCS system using IONM with general anesthesia demonstrates results within range to those in the literature. Patients demonstrated statistically significant improvement in outcomes and opioid use was reduced in 71% of patients who were using opioids at baseline. We recommend its use in patients with morbid obesity, sleep apnea, and considerable anxiety. Further research is warranted to define the possible future role for percutaneous SCS implantation under IONM.

A Preliminary Study on Precision Image Guidance for Electrode Placement in an EEG Study.

Conventional methods for positioning electroencephalography electrodes according to the international 10/20 system are based on the manual identification of the principal 10/20 landmarks via visual inspection and palpation, inducing intersession variations in their determined locations due to structural ambiguity or poor visibility. To address the variation issue, we propose an image guidance system for precision electrode placement. Following the electrode placement according to the 10/20 system, affixed electrodes are laser-scanned together with the facial surface. For subsequent procedures, the laser scan is conducted likewise after positioning the electrodes in an arbitrary manner, and following the measurement of fiducial electrode locations, frame matching is performed to determine a transformation from the coordinate frame of the position tracker to that of the laser-scanned image. Finally, by registering the intra-procedural scan of the facial surface to the reference scan, the current tracking data of the electrodes can be visualized relative to the reference goal positions without manually measuring the four principal landmarks for each trial. The experimental results confirmed that use of the electrode navigation system significantly improved the electrode placement precision compared to the conventional 10/20 system (p < 0.005). The proposed system showed the possibility of precise image-guided electrode placement as an alternative to the conventional manual 10/20 system.

Clinical location of the fourth and fifth intercostal spaces as a percent of the length of the sternum.

OBJECTIVES: To verify accurate placement of the precordial ECG leads by identifying the 4th and 5th intercostal spaces as a function of the length of the sternum. This should decrease the percentage of lead misplacement leading to misdiagnoses. METHODS: The population consisted of patients and healthy volunteers. The proposed method compared palpation of the 4th and 5th intercostal spaces to a percentile of the sternal length. Location of the 4th and 5th intercostal space using a simple device was evaluated to assist in proper placement of the precordial leads to obtain accurate diagnosis. RESULTS: The location of the 4th and 5th intercostal space is related to the length of the sternum. It is 77% of the sternal length that measures 15cm for the 4th intercostal space. The position of the V1 and V2 electrodes decreases to 57% when the sternal length is 26cm. Similar data was obtained to locate the 5th intercostal space with proper position of V4-V6 electrodes. Tables are provided to facilitate this process. An instrument was designed to measure the 4th and 5th intercostal space as a function of the sternal length. CONCLUSIONS: The location of the 4th and 5th intercostal space is identified based on the length of the sternum.

Identification of forearm skin zones with similar muscle activation patterns during activities of daily living.

BACKGROUND: A deeper knowledge of the activity of the forearm muscles during activities of daily living (ADL) could help to better understand the role of those muscles and allow clinicians to treat motor dysfunctions more effectively and thus improve patients' ability to perform activities of daily living. METHODS: In this work, we recorded sEMG activity from 30 spots distributed over the skin of the whole forearm of six subjects during the performance of 21 representative simulated ADL from the Sollerman Hand Function Test. Functional principal component analysis and hierarchical cluster analysis (HCA) were used to identify forearm spots with similar muscle activation patterns. RESULTS: The best classification of spots with similar activity in simulated ADL consisted in seven muscular-anatomically coherent groups: (1) wrist flexion and ulnar deviation; (2) wrist flexion and radial deviation; (3) digit flexion; (4) thumb extension and abduction/adduction; (5) finger extension; (6) wrist extension and ulnar deviation; and (7) wrist extension and radial deviation. CONCLUSION: The number of sEMG sensors could be reduced from 30 to 7 without losing any relevant information, using them as representative spots of the muscular activity of the forearm in simulated ADL. This may help to assess muscle function in rehabilitation while also simplifying the complexity of prosthesis control.

Long-Term Outcome Following Implanted Pulse Generator Change in Patients Treated With Sacral Nerve Modulation for Fecal Incontinence.

BACKGROUND: Long-term outcome of sacral nerve modulation (SNM) patients after implanted pulse generator (IPG) change for fecal incontinence (FI) is unknown. This study reported the outcome and long-term satisfaction after a change of an exhausted IPG, questioning the need to concurrently change the electrode and looking for factors involved in the maintenance of treatment efficiency. METHODS: Patients with fecal incontinence and with a Medtronic IPG implanted in a single center (2001-2016) were prospectively followed up. Satisfaction was graded according to a patient-reported outcome measure from 0 to 10. A pre- and postreplacement FI severity score (Cleveland Clinic Fecal Incontinence Score) and Fecal Incontinence Quality of Life questionnaire were also collected. RESULTS: In 170 patients with SNM, 39 had an IPG replacement. At a median of 29 month after replacement, 32 and 7 patients reported respectively a similar and reduced satisfaction (7.6 ± 1.62 vs. 5.5 ± 0.87), p < .001. Satisfied patients were younger (65 years vs. 76 years, p < .001). Cleveland Clinic Fecal Incontinence Scores were not significantly different, but the satisfied group had a significantly better Fecal Incontinence Quality of Life score (p = .047). Only 5 patients needed an electrode change at the time of the IPG replacement or later. CONCLUSIONS: Patient satisfaction and efficiency remain high after IPG replacement. Older age has a negative impact on the outcome. Electrode replacement is rarely required and does not need to be performed routinely when an IPG is exhausted. CONFLICT OF INTEREST: Paul-Antoine Lehur has a consulting agreement with Medtronic SA. This had no impact with the results of the study. The other authors have no conflict of interests to declare.

High-Resolution Multi-Scale Computational Model for Non-Invasive Cervical Vagus Nerve Stimulation.

OBJECTIVES: To develop the first high-resolution, multi-scale model of cervical non-invasive vagus nerve stimulation (nVNS) and to predict vagus fiber type activation, given clinically relevant rheobase thresholds. METHODS: An MRI-derived Finite Element Method (FEM) model was developed to accurately simulate key macroscopic (e.g., skin, soft tissue, muscle) and mesoscopic (cervical enlargement, vertebral arch and foramen, cerebral spinal fluid [CSF], nerve sheath) tissue components to predict extracellular potential, electric field (E-Field), and activating function along the vagus nerve. Microscopic scale biophysical models of axons were developed to compare axons of varying size (Aα-, Aß- and Aδ-, B-, and C-fibers). Rheobase threshold estimates were based on a step function waveform. RESULTS: Macro-scale accuracy was found to determine E-Field magnitudes around the vagus nerve, while meso-scale precision determined E-field changes (activating function). Mesoscopic anatomical details that capture vagus nerve passage through a changing tissue environment (e.g., bone to soft tissue) profoundly enhanced predicted axon sensitivity while encapsulation in homogenous tissue (e.g., nerve sheath) dulled axon sensitivity to nVNS. CONCLUSIONS: These findings indicate that realistic and precise modeling at both macroscopic and mesoscopic scales are needed for quantitative predictions of vagus nerve activation. Based on this approach, we predict conventional cervical nVNS protocols can activate A- and B- but not C-fibers. Our state-of-the-art implementation across scales is equally valuable for models of spinal cord stimulation, cortex/deep brain stimulation, and other peripheral/cranial nerve models.

Bitemporal v. high-dose right unilateral electroconvulsive therapy for depression: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Brief-pulse electroconvulsive therapy (ECT) is the most acutely effective treatment for severe depression though concerns persist about cognitive side-effects. While bitemporal electrode placement is the most commonly used form worldwide, right unilateral ECT causes less cognitive side-effects though historically it has been deemed less effective. Several randomized trials have now compared high-dose (>5× seizure threshold) unilateral ECT with moderate-dose (1.0-2.5× seizure threshold) bitemporal ECT to investigate if it is as effective as bitemporal ECT but still has less cognitive side-effects. We aimed to systematically review these trials and meta-analyse clinical and cognitive outcomes where appropriate. METHOD: We searched PubMed, PsycINFO, Web of Science, Cochrane Library and EMBASE for randomized trials comparing these forms of ECT using the terms 'electroconvulsive' OR 'electroshock' AND 'trial'. RESULTS: Seven trials (n = 792) met inclusion criteria. Bitemporal ECT did not differ from high-dose unilateral ECT on depression rating change scores [Hedges's g = -0.03, 95% confidence interval (CI) -0.17 to 0.11], remission (RR 1.06, 95% CI 0.93-1.20), or relapse at 12 months (RR 1.42, 95% CI 0.90-2.23). There was an advantage for unilateral ECT on reorientation time after individual ECT sessions (mean difference in minutes = -8.28, 95% CI -12.86 to -3.70) and retrograde autobiographical memory (Hedges's g = -0.46, 95% CI -0.87 to -0.04) after completing an ECT course. There were no differences for general cognition, category fluency and delayed visual and verbal memory. CONCLUSIONS: High-dose unilateral ECT does not differ from moderate-dose bitemporal ECT in antidepressant efficacy but has some cognitive advantages.