scholarly journals Diagnostic and Prognostic Value of Transcranial Magnetic Stimulation in Mucopolysaccharidosis-Related Cervical Myelopathy

2019 ◽  
Author(s):  
Mariagiovanna Cantone ◽  
Giuseppe Lanza ◽  
Alice Le Pira ◽  
Rita Barone ◽  
Giovanni Pennisi ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Cervical Myelopathy ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Hot Spot ◽  
Lower Limbs ◽  
Conduction Time ◽  
Variable Degree ◽  
Monitoring Methods ◽  
The Difference

Background: Cervical myelopathy (CM) is a common cause of morbidity and disability in patients with mucopolysaccharidosis (MPS) and, therefore, early detection is crucial for best surgical intervention and follow-up. Transcranial Magnetic Stimulation (TMS) non-invasively evaluates the conductivity along the cortico-spinal tract, also allowing preclinical diagnosis and monitoring. Methods: motor evoked potentials (MEPs) to TMS were recorded in a group of 8 patients with MPS-related CM. Responses were obtained during mild tonic contraction through a circular coil applied over the “hot spot” of the first dorsal interosseous and tibialis anterior muscles, bilaterally. Central motor conduction time was estimated as the difference between MEP cortical latency and the peripheral motor conduction time by cervical or lumbar magnetic stimulation. Peak-to-peak MEP amplitude to cortical stimulation and right-to-left difference of each parameter were also measured. Results: TMS revealed abnormal findings from both upper and lower limbs compatible with axonal damage and demyelination in 6 of them. Notably, a subclinical cervical spinal disease was detected before the occurrence of an overt CM in two patients, whereas TMS signs compatible with a CM of variable degree persisted despite surgery in all treated subjects. Conclusions: TMS screening should be performed in MPS patients, before and after surgery.

scholarly journals Adjunct Diagnostic Value of Transcranial Magnetic Stimulation in Mucopolysaccharidosis-Related Cervical Myelopathy: A Pilot Study

2019 ◽  
Vol 9 (8) ◽  
pp. 200 ◽  
Author(s):  
Mariagiovanna Cantone ◽  
Giuseppe Lanza ◽  
Alice Le Pira ◽  
Rita Barone ◽  
Giovanni Pennisi ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Cervical Myelopathy ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Hot Spot ◽  
Diagnostic Value ◽  
Lower Limbs ◽  
Conduction Time ◽  
Variable Degree ◽  
Monitoring Methods

Background: Cervical myelopathy (CM) is a common cause of morbidity and disability in patients with mucopolysaccharidosis (MPS) and, therefore, early detection is crucial for the best surgical intervention and follow-up. Transcranial magnetic stimulation (TMS) non-invasively evaluates the conduction through the cortico-spinal tract, also allowing preclinical diagnosis and monitoring. Methods: Motor evoked potentials (MEPs) to TMS were recorded in a group of eight patients with MPS-related CM. Responses were obtained during mild tonic muscular activation by means of a circular coil held on the “hot spot” of the first dorsal interosseous and tibialis anterior muscles, bilaterally. The motor latency by cervical or lumbar magnetic stimulation was subtracted from the MEP cortical latency to obtain the central motor conduction time. The MEP amplitude from peak to peak to cortical stimulation and the interside difference of each measure were also calculated. Results: TMS revealed abnormal findings from both upper and lower limbs compatible with axonal damage and demyelination in six of them. Notably, a subclinical cervical spinal disease was detected before the occurrence of an overt CM in two patients, whereas TMS signs compatible with a CM of variable degree persisted despite surgery in all treated subjects. Conclusions: TMS can be viewed as an adjunct diagnostic test pending further rigorous investigations.

scholarly journals Motor disability in patients with multiple sclerosis: transcranial magnetic stimulation study

2020 ◽  
Vol 56 (1) ◽  
Author(s):  
Anssam Bassem Mohy ◽  
Aqeel Kareem Hatem ◽  
Hussein Ghani Kadoori ◽  
Farqad Bader Hamdan
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Lower Limb ◽  
Magnetic Stimulation ◽  
Motor Evoked Potential ◽  
Invasive Procedure ◽  
Single Pulse ◽  
Lower Limbs ◽  
Control Group ◽  
Conduction Time ◽  
Motor Disability

Abstract Background Transcranial magnetic stimulation (TMS) is a non-invasive procedure used in a small targeted region of the brain via electromagnetic induction and used diagnostically to measure the connection between the central nervous system (CNS) and skeletal muscle to evaluate the damage that occurs in MS. Objectives The study aims to investigate whether single-pulse TMS measures differ between patients with MS and healthy controls and to consider if these measures are associated with clinical disability. Patients and methods Single-pulse TMS was performed in 26 patients with MS who hand an Expanded Disability Status Scale (EDSS) score between 0 and 9.5 and in 26 normal subjects. Different TMS parameters from upper and lower limbs were investigated. Results TMS disclosed no difference in all MEP parameters between the right and left side of the upper and lower limbs in patients with MS and controls. In all patients, TMS parameters were different from the control group. Upper limb central motor conduction time (CMCT) was prolonged in MS patients with pyramidal signs. Upper and lower limb CMCT and CMCT-f wave (CMCT-f) were prolonged in patients with ataxia. Moreover, CMCT and CMCT-f were prolonged in MS patients with EDSS of 5–9.5 as compared to those with a score of 0–4.5. EDSS correlated with upper and lower limb cortical latency (CL), CMCT, and CMCT-f whereas motor evoked potential (MEP) amplitude not. Conclusion TMS yields objective data to evaluate clinical disability and its parameters correlated well with EDSS.

scholarly journals Clinical, Neurophysiological, and MRI Markers of Fampridine Responsiveness in Multiple Sclerosis—An Explorative Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Sepehr Mamoei ◽  
Henrik Boye Jensen ◽  
Andreas Kristian Pedersen ◽  
Mikkel Karl Emil Nygaard ◽  
Simon Fristed Eskildsen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Longitudinal Study ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Step Test ◽  
Conduction Time ◽  
Lesion Load ◽  
Clinical Trial Registration ◽  
Peripheral Motor

Objective: Persons with multiple sclerosis (PwMS), already established as responders or non-responders to Fampridine treatment, were compared in terms of disability measures, physical and cognitive performance tests, neurophysiology, and magnetic resonance imaging (MRI) outcomes in a 1-year explorative longitudinal study.Materials and Methods: Data from a 1-year longitudinal study were analyzed. Examinations consisted of the timed 25-foot walk test (T25FW), six spot step test (SSST), nine-hole peg test (9-HPT), five times sit-to-stand test (5-STS), symbol digit modalities test (SDMT), transcranial magnetic stimulation (TMS) elicited motor evoked potentials (MEP) examining central motor conduction times (CMCT), peripheral motor conduction times (PMCT) and their amplitudes, electroneuronography (ENG) of the lower extremities, and brain structural MRI measures.Results: Forty-one responders and eight non-responders to Fampridine treatment were examined. There were no intergroup differences except for the PMCT, where non-responders had prolonged conduction times compared to responders to Fampridine. Six spot step test was associated with CMCT throughout the study. After 1 year, CMCT was further prolonged and cortical MEP amplitudes decreased in both groups, while PMCT and ENG did not change. Throughout the study, CMCT was associated with the expanded disability status scale (EDSS) and 12-item multiple sclerosis walking scale (MSWS-12), while SDMT was associated with number of T2-weighted lesions, lesion load, and lesion load normalized to brain volume.Conclusions: Peripheral motor conduction time is prolonged in non-responders to Fampridine when compared to responders. Transcranial magnetic stimulation-elicited MEPs and SDMT can be used as markers of disability progression and lesion activity visualized by MRI, respectively.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03401307.

Role of Sustained Excitability of the Leg Motor Cortex After Transcranial Magnetic Stimulation in Associative Plasticity

2007 ◽  
Vol 98 (2) ◽  
pp. 657-667 ◽  
Author(s):  
François D. Roy ◽  
Jonathan A. Norton ◽  
Monica A. Gorassini
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Cortical Neurons ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Low Frequency ◽  
Single Pulse ◽  
Common Peroneal Nerve ◽  
Lower Limbs ◽  
Sensory Inputs

Changes in the strength of corticospinal projections to muscles in the upper and lower limbs are induced in conscious humans after paired associative stimulation (PAS) to the motor cortex. We tested whether an intervention of PAS consisting of 90 low-frequency (0.1-Hz) stimuli to the common peroneal nerve combined with suprathreshold transcranial magnetic stimulation (TMS) produces specific changes to the motor-evoked potentials (MEPs) in lower leg muscles if the afferent volley from peripheral stimulation is timed to arrive at the motor cortex after TMS-induced firing of corticospinal neurons. Unlike PAS in the hand, MEP facilitation in the leg was produced when sensory inputs were estimated to arrive at the motor cortex over a range of 15 to 90 ms after cortical stimulation. We examined whether this broad range of facilitation occurred as a result of prolonged subthreshold excitability of the motor cortex after a single pulse of suprathreshold TMS so that coincident excitation from sensory inputs arriving many milliseconds after TMS can occur. We found that significant facilitation of MEP responses (>200%) occurred when the motor cortex was conditioned with suprathreshold TMS tens of milliseconds earlier. Likewise, it was possible to induce strong MEP facilitation (85% at 60 min) when afferent inputs were directly paired with subthreshold TMS. We argue that in the leg motor cortex, facilitation of MEP responses from PAS occurred over a large range of interstimulus intervals as a result of the paired activation of sensory inputs with sustained, subthreshold activity of cortical neurons that follow a pulse of suprathreshold TMS.

Magnifying the View of the Hand Changes Its Cortical Representation. A Transcranial Magnetic Stimulation Study

2018 ◽  
Vol 30 (8) ◽  
pp. 1098-1107 ◽  
Author(s):  
Elisabetta Ambron ◽  
Nicole White ◽  
Olufunsho Faseyitan ◽  
Sudha K. Kessler ◽  
Jared Medina ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Hot Spot ◽  
Short Interval ◽  
Body Part ◽  
Intracortical Inhibition ◽  
Cortical Representation ◽  
Motor Cortex Excitability

Changes in the perceived size of a body part using magnifying lenses influence tactile perception and pain. We investigated whether the visual magnification of one's hand also influences the motor system, as indexed by transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs). In Experiment 1, MEPs were measured while participants gazed at their hand with and without magnification of the hand. MEPs were significantly larger when participants gazed at a magnified image of their hand. In Experiment 2, we demonstrated that this effect is specific to the hand that is visually magnified. TMS of the left motor cortex did not induce an increase of MEPs when participants looked at their magnified left hand. Experiment 3 was performed to determine if magnification altered the topography of the cortical representation of the hand. To that end, a 3 × 5 grid centered on the cortical hot spot (cortical location at which a motor threshold is obtained with the lowest level of stimulation) was overlaid on the participant's MRI image, and all 15 sites in the grid were stimulated with and without magnification of the hand. We confirmed the increase in the MEPs at the hot spot with magnification and demonstrated that MEPs significantly increased with magnification at sites up to 16.5 mm from the cortical hot spot. In Experiment 4, we used paired-pulse TMS to measure short-interval intracortical inhibition and intracortical facilitation. Magnification was associated with an increase in short-interval intracortical inhibition. These experiments demonstrate that the visual magnification of one's hand induces changes in motor cortex excitability and generates a rapid remapping of the cortical representation of the hand that may, at least in part, be mediated by changes in short-interval intracortical inhibition.

scholarly journals Reliability of diaphragmatic motor-evoked potentials induced by transcranial magnetic stimulation

2020 ◽  
Vol 129 (6) ◽  
pp. 1393-1404
Author(s):  
Joseph F. Welch ◽  
Patrick J. Argento ◽  
Gordon S. Mitchell ◽  
Emily J. Fox
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Evoked Potentials ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Surface Emg ◽  
Noninvasive Technique ◽  
Large Variability ◽  
Adult Men ◽  
Latency Duration ◽  
Excellent Reproducibility

Transcranial magnetic stimulation (TMS) is a noninvasive technique to assess neural impulse conduction along the cortico-diaphragmatic pathway. The reliability of diaphragm motor-evoked potentials (MEP) induced by TMS is unknown. Notwithstanding large variability in MEP amplitude, we found good-to-excellent reproducibility of all MEP characteristics (latency, duration, amplitude, and area) both within- and between-day in healthy adult men and women. Our findings support the use of TMS and surface EMG to assess diaphragm activation in humans.

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