Effect of TMS coil orientation on the spatial distribution of motor evoked potentials in an intrinsic hand muscle

2018 ◽  
Vol 63 (6) ◽  
pp. 635-645 ◽  
Author(s):  
Victor Hugo Souza ◽  
Taian Martins Vieira ◽  
André Salles Cunha Peres ◽  
Marco Antonio Cavalcanti Garcia ◽  
Claudia Domingues Vargas ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Amplitude Distribution ◽  
Central Sulcus ◽  
Abductor Pollicis Brevis ◽  
Detection Volume ◽  
Open Issue ◽  
Intrinsic Hand Muscle ◽  
The Relationship

Abstract Previous reports on the relationship between coil orientation and amplitude of motor evoked potential (MEP) in transcranial magnetic stimulation (TMS) did not consider the effect of electrode arrangement. Here we explore this open issue by investigating whether TMS coil orientation affects the amplitude distribution of MEPs recorded from the abductor pollicis brevis (APB) muscle with a bi-dimensional grid of 61 electrodes. Moreover, we test whether conventional mono- and bipolar montages provide representative MEPs compared to those from the grid of electrodes. Our results show that MEPs with the greatest amplitudes were elicited for 45° and 90° coil orientations, i.e. perpendicular to the central sulcus, for all electrode montages. Stimulation with the coil oriented at 135° and 315°, i.e. parallel to the central sulcus, elicited the smallest MEP amplitudes. Additionally, changes in coil orientation did not affect the spatial distribution of MEPs over the muscle extent. It has been shown that conventional electrodes with detection volume encompassing the APB belly may detect representative MEPs for optimal coil orientations. In turn, non-optimal orientations were identified only with the grid of electrodes. High-density electromyography may therefore provide new insights into the effect of coil orientation on MEPs from the APB muscle.

scholarly journals Peculiarities of motor evoked potential in healthy children of different age

2019 ◽  
Vol 19 (4) ◽  
pp. 228-231
Author(s):  
Vladislav B. Voitenkov ◽  
N. V. Skripchenko ◽  
A. V. Klimkin ◽  
A. I. Aksenova
Keyword(s):  
Normative Data ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Pediatric Population ◽  
Motor Evoked Potential ◽  
Conduction Time ◽  
Healthy Children ◽  
Abductor Hallucis ◽  
Abductor Pollicis Brevis ◽  
Pediatric Disorders

Aim of the work The implementation of the database for reference values of motor evoked potentials (MEP) in healthy children of different ages. Methods 95 healthy children were enrolled. Age ranged from 1 to 204 months. Three subgroups were established: children of 1-12 months (n=31, 18 males, 13 females), 12-144 months (n=27, 14 males, 13 females) and 144-204 (n=37, 20 males, 17 females) months. All children were healthy. Diagnostic transcranial magnetic stimulation (TMS) was performed in all patients. MEP shape, threshold, latency and amplitudes were recorded for hands (m. Abductor pollicis brevis) and legs (m. Abductor Hallucis). Central motor conduction time (CMCT) was calculated. Results. Along with age there was observed the elongation of MEP latency, gain in amplitudes and shape normalization. There were significant differences in the elongation of MEP latency between children aged of 1-12 months and children from two other subgroups (12-144 and 144-204 months). Conclusions. Our normative data can be usedfor comparative studies in the broad spectrum of pediatric disorders. Age restrictions have to be taken in a consideration when performing the TMS in pediatric population.

scholarly journals Associative plasticity in the human motor cortex is enhanced by concurrently targeting separate muscle representations with excitatory and inhibitory protocols

2016 ◽  
Vol 115 (4) ◽  
pp. 2191-2198 ◽  
Author(s):  
Marc R. Kamke ◽  
Abbey S. Nydam ◽  
Martin V. Sale ◽  
Jason B. Mattingley
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Control Experiment ◽  
Motor Evoked Potentials ◽  
Spillover Effects ◽  
Abductor Pollicis Brevis ◽  
Human Motor Cortex ◽  
Before And After ◽  
Abductor Digiti Minimi ◽  
Intrinsic Hand Muscle

Paired associative stimulation (PAS) induces changes in the excitability of human sensorimotor cortex that outlast the procedure. PAS typically involves repeatedly pairing stimulation of a peripheral nerve that innervates an intrinsic hand muscle with transcranial magnetic stimulation over the representation of that muscle in the primary motor cortex. Depending on the timing of the stimuli (interstimulus interval of 25 or 10 ms), PAS leads to either an increase (PAS25) or a decrease (PAS10) in excitability. Both protocols, however, have been associated with an increase in excitability of nearby muscle representations not specifically targeted by PAS. Based on these spillover effects, we hypothesized that an additive, excitability-enhancing effect of PAS25 applied to one muscle representation may be produced by simultaneously applying PAS25 or PAS10 to a nearby representation. In different experiments prototypical PAS25 targeting the left thumb representation [abductor pollicis brevis (APB)] was combined with either PAS25 or PAS10 applied to the left little finger representation [abductor digiti minimi (ADM)] or, in a control experiment, with PAS10 also targeting the APB. In an additional control experiment PAS10 targeted both representations. The plasticity effects were quantified by measuring the amplitude of motor evoked potentials (MEPs) recorded before and after PAS. As expected, prototypical PAS25 was associated with an increase in MEP amplitude in the APB muscle. This effect was enhanced when PAS also targeted the ADM representation but only when a different interstimulus timing (PAS10) was used. These results suggest that PAS-induced plasticity is modified by concurrently targeting separate motor cortical representations with excitatory and inhibitory protocols.

scholarly journals Onset Latency of Motor Evoked Potentials in Motor Cortical Mapping with Neuronavigated Transcranial Magnetic Stimulation

2015 ◽  
Vol 9 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Elisa Kallioniemi ◽  
Minna Pitkänen ◽  
Laura Säisänen ◽  
Petro Julkunen
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Cortical Mapping ◽  
Abductor Pollicis Brevis ◽  
Motor Pathways ◽  
Motor Mapping ◽  
Cortical Motor ◽  
Abductor Digiti Minimi

Cortical motor mapping in pre-surgical applications can be performed using motor evoked potential (MEP) amplitudes evoked with neuronavigated transcranial magnetic stimulation. The MEP latency, which is a more stable parameter than the MEP amplitude, has not so far been utilized in motor mapping. The latency, however, may provide information about the stress in damaged motor pathways, e.g. compression by tumors, which cannot be observed from the MEP amplitudes. Thus, inclusion of this parameter could add valuable information to the presently used technique of MEP amplitude mapping. In this study, the functional cortical representations of first dorsal interosseous (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles were mapped in both hemispheres of ten healthy righthanded volunteers. The cortical muscle representations were evaluated by the area and centre of gravity (CoG) by using MEP amplitudes and latencies. As expected, the latency and amplitude CoGs were congruent and were located in the centre of the maps but in a few subjects, instead of a single centre, several loci with short latencies were observed. In conclusion, MEP latencies may be useful in distinguishing the cortical representation areas with the most direct pathways from those pathways with prolonged latencies. However, the potential of latency mapping to identify stressed motor tract connections at the subcortical level will need to be verified in future studies with patients.

Intraoperative facial motor evoked potential monitoring for pontine cavernous malformation resection

2020 ◽  
Vol 132 (1) ◽  
pp. 265-271
Author(s):  
Ridzky Firmansyah Hardian ◽  
Tetsuya Goto ◽  
Yu Fujii ◽  
Kohei Kanaya ◽  
Tetsuyoshi Horiuchi ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Cavernous Malformation ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Warning Signs ◽  
Constant Current ◽  
Karnofsky Performance Scale ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Cavernous Malformations

OBJECTIVEThe aim of this study was to predict postoperative facial nerve function during pontine cavernous malformation surgery by monitoring facial motor evoked potentials (FMEPs).METHODSFrom 2008 to 2017, 10 patients with pontine cavernous malformations underwent total resection via the trans–fourth ventricle floor approach with FMEP monitoring. House-Brackmann grades and Karnofsky Performance Scale (KPS) scores were obtained pre- and postoperatively. The surgeries were performed using one of 2 safe entry zones into the brainstem: the suprafacial triangle and infrafacial triangle approaches. Six patients underwent the suprafacial triangle approach, and 4 patients underwent the infrafacial triangle approach. A cranial peg screw electrode was used to deliver electrical stimulation for FMEP by a train of 4 or 5 pulse anodal constant current stimulation. FMEP was recorded from needle electrodes on the ipsilateral facial muscles and monitored throughout surgery by using a threshold-level stimulation method.RESULTSFMEPs were recorded and analyzed in 8 patients; they were not recorded in 2 patients who had severe preoperative facial palsy and underwent an infrafacial triangle approach. Warning signs appeared in all patients who underwent the suprafacial triangle approach. However, after temporarily stopping the procedures, FMEP findings during surgery showed recovery of the thresholds. FMEPs in patients who underwent the infrafacial triangle approach were stable during the surgery. House-Brackmann grades were unchanged postoperatively in all patients. Postoperative KPS scores improved in 3 patients, decreased in 1, and remained the same in 6 patients.CONCLUSIONSFMEPs can be used to monitor facial nerve function during surgery for pontine cavernous malformations, especially when the suprafacial triangle approach is performed.

scholarly journals Insights Into the Correspondence Between Land Use Pattern and Spatial Distribution of Rail Transit Services

2021 ◽  
Author(s):  
Zhongqi Wang ◽  
Qi Han ◽  
Bauke de Vries ◽  
Li Dai
Keyword(s):  
Land Use ◽  
Spatial Distribution ◽  
Operations Management ◽  
Latent Variable ◽  
Structural Equation ◽  
Equation Modeling ◽  
Rail Transit ◽  
Land Use Patterns ◽  
Transit Services ◽  
The Relationship

AbstractThe identification of the relationship between land use and transport lays the foundation for integrated land use and transport planning and management. This work aims to investigate how rail transit is linked to land use. The research on the relationship between land use and rail-based transport is dominated by the impacts of rail projects on land use, without an in-depth understanding of the reverse. However, it is important to note that issues of operation management rather than new constructions deserve greater attention for regions with established rail networks. Given that there is a correspondence between land use patterns and spatial distribution of heavy railway transit (HRT) services at such regions, the study area (i.e., the Netherlands) is partitioned by the Voronoi diagram of HRT stations and the causal relationship between land use and HRT services is examined by structural equation modeling (SEM). The case study of Helmond (a Dutch city) shows the potential of the SEM model for discussing the rail station selection problem in a multiple transit station region (MTSR). Furthermore, in this study, the node place model is adapted with the derivatives of the SEM model (i.e., the latent variable scores for rail service levels and land use characteristics), which are assigned as node and place indexes respectively, to analyze and differentiate the integration of land use and HRT services at the regional level. The answer to whether and how land use affects rail transit services from this study strengthens the scientific basis for rail transit operations management. The SEM model and the modified node place model are complementary to be used as analytical and decision-making tools for rail transit-oriented regional development.

scholarly journals Long-term motor deficit in brain tumour surgery with preserved intra-operative motor-evoked potentials

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Davide Giampiccolo ◽  
Cristiano Parisi ◽  
Pietro Meneghelli ◽  
Vincenzo Tramontano ◽  
Federica Basaldella ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Tumour ◽  
Evoked Potential ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Motor Deficit ◽  
Motor Deficits ◽  
Brain Tumour Surgery

Abstract Muscle motor-evoked potentials are commonly monitored during brain tumour surgery in motor areas, as these are assumed to reflect the integrity of descending motor pathways, including the corticospinal tract. However, while the loss of muscle motor-evoked potentials at the end of surgery is associated with long-term motor deficits (muscle motor-evoked potential-related deficits), there is increasing evidence that motor deficit can occur despite no change in muscle motor-evoked potentials (muscle motor-evoked potential-unrelated deficits), particularly after surgery of non-primary regions involved in motor control. In this study, we aimed to investigate the incidence of muscle motor-evoked potential-unrelated deficits and to identify the associated brain regions. We retrospectively reviewed 125 consecutive patients who underwent surgery for peri-Rolandic lesions using intra-operative neurophysiological monitoring. Intraoperative changes in muscle motor-evoked potentials were correlated with motor outcome, assessed by the Medical Research Council scale. We performed voxel–lesion–symptom mapping to identify which resected regions were associated with short- and long-term muscle motor-evoked potential-associated motor deficits. Muscle motor-evoked potentials reductions significantly predicted long-term motor deficits. However, in more than half of the patients who experienced long-term deficits (12/22 patients), no muscle motor-evoked potential reduction was reported during surgery. Lesion analysis showed that muscle motor-evoked potential-related long-term motor deficits were associated with direct or ischaemic damage to the corticospinal tract, whereas muscle motor-evoked potential-unrelated deficits occurred when supplementary motor areas were resected in conjunction with dorsal premotor regions and the anterior cingulate. Our results indicate that long-term motor deficits unrelated to the corticospinal tract can occur more often than currently reported. As these deficits cannot be predicted by muscle motor-evoked potentials, a combination of awake and/or novel asleep techniques other than muscle motor-evoked potentials monitoring should be implemented.

scholarly journals Double parton distributions in the pion from lattice QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gunnar S. Bali ◽  
Luca Castagnini ◽  
Markus Diehl ◽  
Jonathan R. Gaunt ◽  
Benjamin Gläßle ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Matrix Elements ◽  
Parton Distributions ◽  
Almost All ◽  
The Relationship

Abstract We perform a lattice study of double parton distributions in the pion, using the relationship between their Mellin moments and pion matrix elements of two local currents. A good statistical signal is obtained for almost all relevant Wick contractions. We investigate correlations in the spatial distribution of two partons in the pion, as well as correlations involving the parton polarisation. The patterns we observe depend significantly on the quark mass. We investigate the assumption that double parton distributions approximately factorise into a convolution of single parton distributions.

scholarly journals Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2803
Author(s):  
Evridiki Asimakidou ◽  
Pablo Alvarez Abut ◽  
Andreas Raabe ◽  
Kathleen Seidel
Keyword(s):  
Scoping Review ◽  
Predictive Value ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Critical Duration ◽  
Motor Deficit ◽  
Warning Sign ◽  
Outcome Reporting ◽  
Scoping Reviews ◽  
Warning Criteria

During intraoperative monitoring of motor evoked potentials (MEP), heterogeneity across studies in terms of study populations, intraoperative settings, applied warning criteria, and outcome reporting exists. A scoping review of MEP warning criteria in supratentorial surgery was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Sixty-eight studies fulfilled the eligibility criteria. The most commonly used alarm criteria were MEP signal loss, which was always a major warning sign, followed by amplitude reduction and threshold elevation. Irreversible MEP alterations were associated with a higher number of transient and persisting motor deficits compared with the reversible changes. In almost all studies, specificity and Negative Predictive Value (NPV) were high, while in most of them, sensitivity and Positive Predictive Value (PPV) were rather low or modest. Thus, the absence of an irreversible alteration may reassure the neurosurgeon that the patient will not suffer a motor deficit in the short-term and long-term follow-up. Further, MEPs perform well as surrogate markers, and reversible MEP deteriorations after successful intervention indicate motor function preservation postoperatively. However, in future studies, a consensus regarding the definitions of MEP alteration, critical duration of alterations, and outcome reporting should be determined.

scholarly journals Men's health: non-communicable chronic diseases and social vulnerability

2016 ◽  
Vol 24 (0) ◽  
Author(s):  
Daniele Natália Pacharone Bertolini Bidinotto ◽  
Janete Pessuto Simonetti ◽  
Silvia Cristina Mangini Bocchi
Keyword(s):  
Spatial Distribution ◽  
Chronic Diseases ◽  
Glucose Intolerance ◽  
Social Vulnerability ◽  
Medical Records ◽  
Urban Areas ◽  
International Classification Of Diseases ◽  
Classification Of Diseases ◽  
Mixed Approach ◽  
The Relationship

ABSTRACT Objectives: to evaluate the relationship between absences in scheduled appointments and the number of non-communicable chronic diseases and to investigate the relationship between spatial distribution of these diseases and social vulnerability, using geoprocessing. Method: a quantitative study of sequential mixed approach by analyzing 158 medical records of male users to relate the absences and 1250 medical records for geoprocessing Results: the higher the number of absences in the scheduled medical appointments, the less were the number of non-communicable chronic diseases and the ones listed in the International Classification of Diseases in single men. There were 21 significant geostatistically cases of glucose intolerance in the urban area. Of these, 62% lived in a region with a social vulnerability rating of Very Low, Medium 19%, 14% Low and 5% High. Conclusion: it was observed that the older the men, the greater is the number of chronic diseases and the less they miss scheduled appointments. Regarding the use of geoprocessing, we obtained a significant number of cases of glucose intolerance in urban areas, the majority classified as Very Low social vulnerability. It was possible to relate the spatial distribution of these diseases with the social vulnerability classification; however, it was not possible to perceive a relationship of them with the higher rates of social vulnerability.

scholarly journals Spatial distribution of sunflower cultivars and the relationship between growth features

2012 ◽  
Vol 43 (2) ◽  
pp. 338-345 ◽  
Author(s):  
Thomas Newton Martin ◽  
Paulo Sérgio Pavinato ◽  
Leandro Homrich Lorentz ◽  
Renice Paula Zielinski ◽  
Rosana Refatti
Keyword(s):  
Spatial Distribution ◽  
Growth Features ◽  
The Relationship
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