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Motor Evoked Potentials

Faisal R Jahangiri, Sami Al Eissa, Samir Sayegh, Fahad Al Helal, Shomoukh A Al-Sharif, Monerah M Annaim, Sheryar Muhammad, Tanweer Aziz
A 16-year-old male patient with Ehler-Danlos syndrome (EDS) and a back deformity since birth presented with severe kyphoscoliosis. The patient was neurologically intact but had respiratory and cardiac insufficiencies. A two-stage vertebral column resection (VCR) at T9-T10 with multiple level fusion with multimodality intraoperative neurophysiological monitoring (IONM) was planned.  During the first stage, pedicle screws were placed at multiple spinal levels above and below the VCR level. Upper and lower somatosensory evoked potentials (SSEP), transcranial electrical motor evoked potentials (TCeMEP), and electromyography were monitored continuously and showed no significant changes...
August 31, 2016: Curēus
Nathan D Nuzum, Ashlee M Hendy, Aaron P Russell, Wei-Peng Teo
Individual responses to transcranial direct current stimulation (tDCS) are varied and therefore potentially limit its application. There is evidence that this variability is related to the contributions of Indirect waves (I-waves) recruited in the cortex. The latency of motor-evoked potentials (MEPs) can be measured through transcranial magnetic stimulation (TMS), allowing an individual's responsiveness to tDCS to be determined. However, this single-pulse method requires several different orientations of the TMS coil, potentially affecting its reliability...
2016: Frontiers in Human Neuroscience
Matthew Sykes, Natalie A Matheson, Philip W Brownjohn, Alexander D Tang, Jennifer Rodger, Jonathan B H Shemmell, John N J Reynolds
Repetitive transcranial magnetic stimulation (rTMS) is primarily used in humans to change the state of corticospinal excitability. To assess the efficacy of different rTMS stimulation protocols, motor evoked potentials (MEPs) are used as a readout due to their non-invasive nature. Stimulation of the motor cortex produces a response in a targeted muscle, and the amplitude of this twitch provides an indirect measure of the current state of the cortex. When applied to the motor cortex, rTMS can alter MEP amplitude, however, results are variable between participants and across studies...
2016: Frontiers in Neural Circuits
Kaori Tamura, Takaaki Mizuba, Tsuyoshi Okamoto, Mayumi Matsufuji, Sachio Takashima, Keiji Iramina
INTRODUCTION: The level of residual cognitive function in patients with early brain injury is a key factor limiting rehabilitation and the quality of life. Although understanding residual function is necessary for appropriate rehabilitation, the extent of its effects on cognitive improvement remains unknown. The present study evaluated cognitive function in patients with severe motor and intellectual disabilities after early brain injuries due to cerebral hemorrhage (CH) or periventricular leukomalacia (PVL)...
October 18, 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
Richard A Normann, Eduardo Fernandez
This paper briefly describes some of the recent progress in the development of penetrating microelectrode arrays and highlights the use of two of these devices, Utah electrode arrays and Utah slanted electrode arrays, in two therapeutic interventions: recording volitional skeletal motor commands from the central nervous system, and recording motor commands and evoking somatosensory percepts in the peripheral nervous system (PNS). The paper also briefly explores other potential sites for microelectrode array interventions that could be profitably pursued and that could have important consequences in enhancing the quality of life of patients that has been compromised by disorders of the central and PNSs...
October 20, 2016: Journal of Neural Engineering
Nathan D Crosby, John J Janik, Warren M Grill
Kilohertz-frequency spinal cord stimulation (KHF-SCS) is a potential paresthesia-free treatment for chronic pain. However, the effects of KHF-SCS on spinal dorsal column (DC) axons and its mechanisms of action remain unknown. The objectives of this study were to quantify activation and conduction block of DC axons by KHF-SCS across a range of kHz frequencies (1, 5, 10, or 20 kHz) and waveforms (biphasic pulses or sinusoids). Custom platinum electrodes delivered SCS to the T10/T11 DCs of anesthetized male Sprague-Dawley rats...
October 19, 2016: Journal of Neurophysiology
Francesco Della Gatta, Francesca Garbarini, Guglielmo Puglisi, Antonella Leonetti, Annamaria Berti, Paola Borroni
During the rubber hand illusion (RHI), subjects experience an artificial hand as part of their own body, while the real hand is subject to a sort of 'disembodiment'. Can this altered belief about the body also affect physiological mechanisms involved in body-ownership, such as motor control? Here we ask whether the excitability of the motor pathways to the real (disembodied) hand are affected by the illusion. Our results show that the amplitude of the motor-evoked potentials recorded from the real hand is significantly reduced, with respect to baseline, when subjects in the synchronous (but not in the asynchronous) condition experience the fake hand as their own...
October 20, 2016: ELife
Michael Pickell, Stephen M Mann, Rajesh Chakravertty, Daniel P Borschneck
BACKGROUND: This is a prospective observational study examining the use of a surgeon-driven intraoperative neurophysiologic monitoring system. Intraoperative neurophysiologic monitoring is becoming the standard of care for spinal surgeries with potential post-operative neurologic deficits. This standard applies to both adult and pediatric spinal surgery, but a shortage of appropriately trained and certified technologists and physiologists can compromise monitoring capabilities in some centers...
September 2016: J Spine Surg
Siavash S Haghighi, Donald J Blaskiewicz, Bertha Ramirez, Richard Zhang
BACKGROUND: C5 nerve root palsy is a known complication after cervical laminectomy or laminoplasty, characterized by weakness of the deltoid and bicep brachii muscles. The efficacy of intraoperative monitoring of these muscles is currently unclear. In the current prospective study, intraoperative monitoring through somatosensory (SSEPs), motor (TcMEPs) evoked potentials and real-time electromyography activity (EMG) were analyzed for their ability to detect or prevent deltoid muscle weakness after surgery...
September 2016: J Spine Surg
Marc Jubeau, Thomas Rupp, John Temesi, Stéphane Perrey, Bernard Wuyam, Guillaume Y Millet, Samuel Verges
PURPOSE: Prolonged cycling exercise performance in normoxia is limited due to both peripheral and central neuromuscular impairments. It has been reported that cerebral perturbations are greater during short-duration exercise in hypoxia compared to normoxia. The purpose of this study was to test the hypothesis that central deficits are accentuated in hypoxia compared to normoxia during prolonged (3 bouts of 80 min separated by 25 min) whole-body exercise at the same relative intensity...
October 6, 2016: Medicine and Science in Sports and Exercise
Yasuaki Imajo, Tsukasa Kanchiku, Hidenori Suzuki, Masahiro Funaba, Norihiro Nishida, Kazuhiro Fujimoto, Toshihiko Taguchi
INTRODUCTION: Lumbar spinal stenosis (LSS) typically presents with neurogenic intermittent claudication (NIC). The aim is to investigate cauda equina conduction time (CECT) in patients with NIC caused by LSS and its relationship with age and body height in normal subjects. METHODS: The study included 172 normal subjects (mean age 44.1 ± 16.6 years; mean height 163.7 ± 8.9 cm). (Group C) 47 patients (mean age 71.3 ± 8.7 years; mean height 158.8 ± 11.2 cm) underwent surgery due to NIC in cauda equina type for LSS...
October 5, 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
L Angius, B Pageaux, J Hopker, S M Marcora, A R Mauger
Transcranial direct current stimulation (tDCS) can increase cortical excitability of a targeted brain area, which may affect endurance exercise performance. However, optimal electrode placement for tDCS remains unclear. We tested the effect of two different tDCS electrode montages for improving exercise performance. Nine subjects underwent a control (CON), placebo (SHAM) and two different tDCS montage sessions in a randomised design. In one tDCS session, the anodal electrode was placed over the left motor cortex and the cathodal on contralateral forehead (HEAD), while for the other montage the anodal electrode was placed over the left motor cortex and cathodal electrode above the shoulder (SHOULDER)...
October 14, 2016: Neuroscience
Qing Yue, Tyson Hale, Aaron Knecht, Jennifer Laidacker
BACKGROUND: Foot drop secondary to L5 root injury is a rare complication associated with lumbar surgery. To date, it is still not clear whether intraoperative neuromonitoring can detect such an injury. CASE DESCRIPTION: A 54-year-old man who had had bilateral chronic L5 radiculopathy underwent L4-S1 lumbosacral decompression and fusion. During the surgery, the patient lose transcranial electrical motor evoked potential (tceMEPs) from left tibialis anterior (TA) at the time of L5-S1 intervertebral cage placement...
October 14, 2016: World Neurosurgery
Tamara Ius, Luca Turella, Giada Pauletto, Miriam Isola, Marta Maieron, Giovanni Sciacca, Riccardo Budai, Serena D'Agostini, Roberto Eleopra, Miran Skrap
BACKGROUND: Pre-operative diffusion tensor tractography (DTT) has recently been utilized to aid in the mapping of functional pathways in order to limit damage associated with resection of low-grade gliomas. OBJECTIVE: To assess the predictive capacity of DTT as a biomarker of post-operative motor outcomes in patients with low-grade gliomas (LGGs) involving the corticospinal tract (CST). CST parameters obtained using a quantitative fiber-tracking approach were used to investigate the reliability of the DTT biomarker by comparing their values in the tumoral (Tcst) and healthy (Hcst) hemispheres...
October 12, 2016: World Neurosurgery
Bethel C A Osuagwu, Leslie Wallace, Mathew Fraser, Aleksandra Vuckovic
OBJECTIVE: To compare neurological and functional outcomes between two groups of hospitalised patients with subacute tetraplegia. APPROACH: Seven patients received 20 sessions of brain computer interface (BCI) controlled functional electrical stimulation (FES) while five patients received the same number of sessions of passive FES for both hands. The neurological assessment measures were event related desynchronization (ERD) during movement attempt, Somatosensory evoked potential (SSEP) of the ulnar and median nerve; assessment of hand function involved the range of motion (ROM) of wrist and manual muscle test...
October 14, 2016: Journal of Neural Engineering
Mads Jochumsen, Imran K Niazi, Nada Signal, Rasmus W Nedergaard, Kelly Holt, Heidi Haavik, Denise Taylor
Learning new motor skills has been correlated with increased cortical excitability. In this study, different location of electrical stimulation (ES), nerve, or muscle, was paired with voluntary movement to investigate if ES paired with voluntary movement (a) would increase the excitability of cortical projections to tibialis anterior and (b) if stimulation location mattered. Cortical excitability changes were quantified using motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) at varying intensities during four conditions...
2016: Frontiers in Human Neuroscience
Dong Gun Kim, Young Doo Choi, Seung Hyun Jin, Chi Heon Kim, Kwang Woo Lee, Kyung Seok Park, Chun Kee Chung, Sung Min Kim
BACKGROUND AND PURPOSE: We studied the clinical significance of amplitude-reduction and disappearance alarm criteria for transcranial electric muscle motor-evoked potentials (MEPs) during cervical spinal surgery according to different lesion locations [intramedullary (IM) vs. nonintramedullary (NIM)] by evaluating the long-term postoperative motor status. METHODS: In total, 723 patients were retrospectively dichotomized into the IM and NIM groups. Each limb was analyzed respectively...
October 7, 2016: Journal of Clinical Neurology
Peter Milos, Kerstin Metcalf, Patrick Vigren, Hans Lindehammar, Malin Nilsson, Sverre Boström
Awake craniotomy for brain tumours  Awake neurosurgery is a useful method in lesions near eloquent brain areas, particularly low-grade gliomas.The aim is to maximise tumour resection and preserve neurological function. We performed 40 primary awake surgeries and 8 residual surgeries. Patients were operated awake throughout the procedure or with a laryngeal mask and general anaesthesia during the opening stage and then awake during intracerebral surgery. Language and motor function were mapped with direct cortical stimulation, motor evoked potential and standardised neurological testing...
October 11, 2016: Läkartidningen
Thomas Westphal, Stephan Woischnik, Daniela Adolf, Helmut Feistner, Stefan Piatek
BACKGROUND: Axillary nerve injuries after shoulder surgery are rare. In most studies, the frequency of injury is usually determined using clinical examinations, but results from intraoperative neuromonitoring studies have revealed higher than expected rates. Few studies have investigated this topic. Our aim was to determine the frequency of axillary nerve lesions after open reduction and internal fixation of proximal humeral fractures by using electrophysiological assessments and to provide a review of the relevant literature...
October 7, 2016: Journal of Shoulder and Elbow Surgery
Asif Jamil, Giorgi Batsikadze, Hsiao-I Kuo, Ludovica Labruna, Alkomiet Hasan, Walter Paulus, Michael A Nitsche
Contemporary non-invasive neuromodulatory techniques, such as transcranial direct current stimulation (tDCS), have shown promising potential in both restituting impairments in cortical physiology in clinical settings, as well as modulating cognitive abilities in the healthy population. However, neuroplastic after-effects of tDCS are highly dependent on stimulation parameters, relatively short lasting, and not expectedly uniform between individuals. The present study systematically investigates the full range of current intensity between 0...
October 10, 2016: Journal of Physiology
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