NAIAD-2020: Characteristics of Motor Evoked Potentials After 3-Day Exposure to Dry Immersion in Women

As female astronauts participate in space flight more and more frequently, there is a demand for research on how the female body adapts to the microgravity environment. In particular, there is very little research on how the neuromuscular system reacts to gravitational unloading in women. We aimed to estimate changes in motor evoked potentials (MEPs) in the lower leg muscles in women after 3-day exposure to Dry Immersion (DI), which is one of the most widely used ground models of microgravity. Six healthy female volunteers (mean age 30.17 ± 5.5 years) with a natural menstrual cycle participated in this experiment. MEPs were recorded from the gastrocnemius and soleus muscles twice before DI, on the day of DI completion, and 3 days after DI, during the recovery period. To evoke motor responses, transcranial and trans-spinal magnetic stimulation was applied. We showed that changes in MEP characteristics after DI exposure were different depending on the stimulation site, but were similar for both muscles. For trans-spinal stimulation, MEP thresholds decreased compared to baseline values, and amplitudes, on the contrary, increased, resembling the phenomenon of hypogravitational hyperreflexia. This finding is in line with data observed in other experiments on both male and female participants. MEPs to transcranial stimulation had an opposing dynamic, which may have resulted from the small group size and large inter-subject variability, or from hormonal fluctuations during the menstrual cycle. Central motor conduction time remained unchanged, suggesting that pyramidal tract conductibility was not affected by DI exposure. More research is needed to explore the underlying mechanisms.

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Motor evoked potentials in clinically isolated syndrome suggestive of multiple sclerosis

Multiple Sclerosis Journal ◽

10.1177/1352458508099612 ◽

2009 ◽

Vol 15 (3) ◽

pp. 355-362 ◽

Cited By ~ 17

Author(s):

A Rico ◽

B Audoin ◽

J Franques ◽

A Eusebio ◽

F Reuter ◽

...

Keyword(s):

Multiple Sclerosis ◽

Evoked Potentials ◽

Amplitude Ratio ◽

Motor Evoked Potentials ◽

Clinically Isolated Syndrome ◽

Conduction Time ◽

Motor Pathway ◽

Clinical Sensitivity ◽

Conduction Failure ◽

Stimulation Technique

The aim of the present study was to determine the sensitivity and the profile of motor evoked potentials (MEP) in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). We measured the central motor conduction time (CMCT), amplitude ratio (AR), and surface ratio (SR) in tibialis anterior and first dorsal interosseous muscles in 22 patients with CIS. In 12 patients, the triple stimulation technique (TST) was also performed. AR was abnormal in 50% of patients, CMCT in 18% of patients, and TST in 25% of patients. AR had the highest sub-clinical sensitivity and the best positive predictive value. In the absence of clinical pyramidal signs, an early AR decrease seems to result from demyelination inducing excessive temporal dispersion of the MEP, while in territories with clinical pyramidal signs, it seems to result from conduction failure, which suggests that clinical pyramidal signs may be attributable to conduction failure. This study demonstrates that MEP, especially the AR, is sensitive to motor pathway dysfunction right from the early stages of MS.

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Determining the Corticospinal and Neuromuscular Responses Following a Warm-Up Protocol

The Journal of Science and Medicine ◽

10.37714/josam.v2i2.45 ◽

2020 ◽

Vol 2 (2) ◽

pp. 1-12

Author(s):

Rhys Painter ◽

Alan Pearce ◽

Mohamad Rostami ◽

Ashlyn Frazer ◽

Dawson Kidgell

Keyword(s):

Heart Rate ◽

Evoked Potentials ◽

Neuromuscular Transmission ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Corticospinal Excitability ◽

Muscle Temperature ◽

Conduction Time ◽

Warm Up ◽

Time To Peak

Background: The effect of warming-up prior to exercise on increased neuromuscular transmission speed remains largely untested. Objective: This study used transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS) to quantify neuromuscular transmission along the corticospinal tract (CST) before and after a warm-up protocol of the elbow flexors. Method: Using a single-group, pre-test-post-test design, 30 participants (20 male; 10 female; mean age 26.3 ± 7.4 years) completed four sets of bicep curls that aimed to increase heart rate (HR) and biceps brachii (BB) muscle temperature by a minimum of 40 beats per minute (bpm) and 1°C, respectively. Single-pulse TMS was applied to the primary motor cortex, and over the cervical and thoracic (C7-T1) areas of the spine to quantify motor evoked potentials (MEPs) and spinal evoked potentials (SEPs), respectively. Central motor conduction time (CMCT) was determined by calculating the difference in latency time of the onset of MEPs and SEPs. Peripheral motor conduction time (PMCT) was calculated following stimuli from Erb’s point to the onset of the maximal compound muscle action potential twitch (MMAX latency). MMAX time to peak twitch was also measured. MMAX amplitude was used to normalize the MEP to quantify corticospinal excitability. Results: Following the warm-up, significant increases in mean heart rate (44.8 ± 11.7 bpm; P < 0.001) and muscle temperature (1.4 ± 0.6°C; P < 0.001) were observed. No changes were seen in corticospinal excitability (P = 0.39), CMCT (P = 0.09), or MMAX latency (P = 0.24). However, MMAX time to peak twitch was significantly reduced (P = 0.003). Conclusion: This study has shown that exercise-based warm-ups improve neuromuscular conduction velocity via thermoregulatory processes that result in the onset of muscle contraction being more rapid, but not as a result of changes in the efficacy of neural transmission along the CST.

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DI-5-Cuffs: Lumbar Intervertebral Disc Proteoglycan and Water Content Changes in Humans after Five Days of Dry Immersion to Simulate Microgravity

International Journal of Molecular Sciences ◽

10.3390/ijms21113748 ◽

2020 ◽

Vol 21 (11) ◽

pp. 3748

Author(s):

Loïc Treffel ◽

Nastassia Navasiolava ◽

Karen Mkhitaryan ◽

Emmanuelle Jouan ◽

Kathryn Zuj ◽

...

Keyword(s):

Intervertebral Disc ◽

Water Content ◽

T2 Mapping ◽

Lumbar Region ◽

Gravitational Unloading ◽

Lumbar Intervertebral Disc ◽

Dry Immersion ◽

Disc Herniations ◽

Proteoglycan Content ◽

Underlying Mechanisms

Most astronauts experience back pain after spaceflight, primarily located in the lumbar region. Intervertebral disc herniations have been observed after real and simulated microgravity. Spinal deconditioning after exposure to microgravity has been described, but the underlying mechanisms are not well understood. The dry immersion (DI) model of microgravity was used with eighteen male volunteers. Half of the participants wore thigh cuffs as a potential countermeasure. The spinal changes and intervertebral disc (IVD) content changes were investigated using magnetic resonance imaging (MRI) analyses with T1-T2 mapping sequences. IVD water content was estimated by the apparent diffusion coefficient (ADC), with proteoglycan content measured using MRI T1-mapping sequences centered in the nucleus pulposus. The use of thigh cuffs had no effect on any of the spinal variables measured. There was significant spinal lengthening for all of the subjects. The ADC and IVD proteoglycan content both increased significantly with DI (7.34 ± 2.23% and 10.09 ± 1.39%, respectively; mean ± standard deviation), p < 0.05). The ADC changes suggest dynamic and rapid water diffusion inside IVDs, linked to gravitational unloading. Further investigation is needed to determine whether similar changes occur in the cervical IVDs. A better understanding of the mechanisms involved in spinal deconditioning with spaceflight would assist in the development of alternative countermeasures to prevent IVD herniation.

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031 Investigating motor evoked potentials as a biomarker for disease severity in hereditary spastic paraplegia

Journal of Neurology Neurosurgery & Psychiatry ◽

10.1136/jnnp-2018-anzan.30 ◽

2018 ◽

Vol 89 (6) ◽

pp. A13.2-A13

Author(s):

Sue-Faye Siow ◽

Carolyn Sue ◽

Kishore Kumar ◽

Sharon Coward ◽

Amy Lofts ◽

...

Keyword(s):

Evoked Potentials ◽

Disease Severity ◽

Lower Limb ◽

Hereditary Spastic Paraplegia ◽

Disease Duration ◽

Rating Scale ◽

Motor Evoked Potentials ◽

Conduction Time ◽

Spastic Paraplegia ◽

Resting Motor Threshold

IntroductionHereditary spastic paraplegia (HSP) encompasses a diverse group of neurodegenerative disorders that results in significant disability with no curative or disease-modifying treatment. The lack of standardised biomarkers of disease severity has limited the evaluation of potential therapeutic agents. Our aim is to investigate motor evoked potentials (MEPs) as a marker of HSP disease severity.MethodsWe studied 21 subjects (10 male, 11 female; mean age 54.3±13.8 years) with a clinical diagnosis of HSP (10 SPG4, 4 SPG7, 1 SPG3A, 1 SPG 30, 5 genetically undetermined). All patients underwent transcranial magnetic stimulation to measure central motor conduction time (CMCT), resting motor threshold (rMT) and MEP amplitude from the tibialis anterior (TA), abductor hallucis (AH) and abductor digiti minimi (ADM). Clinical disease severity was assessed with the Spastic Paraplegia Rating Scale (SPRS). Pearson correlation coefficient was used to assess correlation between variables, significance was defined as P value<0.05.ResultsTA CMCT was prolonged in 16/21 subjects (76%). AH CMCT was absent in 3/18 subjects (16.7%) and prolonged in 9/18 subjects (50%). ADM CMCT was measured in 19 subjects; all were normal. There was no significant correlation between SPRS scores and MEP amplitude, rMT or CMCT for TA or AH. There was also no significant correlation between these MEP measures and disease duration or patient age. Subgroup analysis of SPG4 HSP (10 subjects) revealed significant correlation between TA and AH CMCT with disease duration (r=0.841, p=0.001; r=0.930, p=0.001) but not SPRS scores.ConclusionLower limb CMCT was absent or prolonged in the majority of subjects. Despite being potentially useful as a diagnostic biomarker for HSP, this study only showed a correlation between lower limb CMCT and disease duration in the SPG4 subgroup. Further genotype-specific studies utilising larger numbers may clarify the relationship between MEP markers and clinical features.

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Physiotherapy Approaches in the Treatment of Ataxic Multiple Sclerosis: A Pilot Study

Neurorehabilitation and Neural Repair ◽

10.1177/154596830101500308 ◽

2001 ◽

Vol 15 (3) ◽

pp. 203-211 ◽

Cited By ~ 60

Author(s):

Kadriye Armutlu ◽

Rana Karabudak ◽

Gülay Nurlu

Keyword(s):

Multiple Sclerosis ◽

Evoked Potentials ◽

Motor Evoked Potentials ◽

Control Group ◽

Study Group ◽

Conduction Time ◽

Expanded Disability Status Scale ◽

Gait Parameters ◽

Significant Difference ◽

Disability Status

Objective: This study was planned to investigate the efficacy of neuromuscular rehabilitation and Johnstone Pressure Splints in the patients who had ataxic multiple sclerosis. Methods: Twenty-six outpatients with multiple sclerosis were the subjects of the study. The control group (n = 13) was given neuromuscular rehabilitation, whereas the study group (n = 13) was treated with Johnstone Pressure Splints in ad dition. Results: In pre- and posttreatment data, significant differences were found in sensation, anterior balance, gait parameters, and Expanded Disability Status Scale (p < 0.05). An important difference was observed in walking-on-two-lines data within the groups (p < 0.05). There also was a statistically significant difference in pendular movements and dysdiadakokinesia (p < 0.05). When the posttreatment values were compared, there was no significant difference between sensation, anterior balance, gait parameters, equilibrium and nonequilibrium coordination tests, Expanded Disability Status Scale, cortical onset latency, and central conduction time of somatosensory evoked potentials and motor evoked potentials (p > 0.05). Comparison of values re vealed an important difference in cortical onset-P37 peak amplitude of somatosen sory evoked potentials (right limbs) in favor of the study group (p < 0.05). Conclu sions : According to our study, it was determined that physiotherapy approaches were effective to decrease the ataxia. We conclude that the combination of suitable phys iotherapy techniques is effective multiple sclerosis rehabilitation. Key Words: Multi ple sclerosis—Ataxia—Physical therapy.

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Brainstem Dysfunction in Alternating Hemiplegia of Childhood

Cephalalgia ◽

10.1111/j.1468-2982.2006.01066.x ◽

2006 ◽

Vol 26 (5) ◽

pp. 511-519 ◽

Cited By ~ 9

Author(s):

S Rinalduzzi ◽

M Valeriani ◽

F Vigevano

Keyword(s):

Evoked Potentials ◽

Somatosensory Evoked Potentials ◽

Motor Evoked Potentials ◽

Normal Subjects ◽

Blink Reflex ◽

Conduction Time ◽

System Function ◽

Alternating Hemiplegia Of Childhood ◽

Brainstem Dysfunction ◽

Stimulation Of

Six patients with alternating hemiplegia of childhood (AHC) underwent motor evoked potentials (MEPs), somatosensory evoked potentials (SEPs) and blink reflex recording. No SEP abnormality was found. As for MEP recording, central conduction time did not differ between patients studied during either interictal or ictal phase, and normal subjects, suggesting that the pyramidal system function is spared. In blink reflex recording, the latencies of both the ipsilateral (iR2) and contralateral (cR2) R2 components were significantly longer ( P < 0.01) in patients during the interictal phase than in normal subjects. Moreover, the iR2 and cR2 areas were significantly reduced ( P < 0.01) in patients during the interictal phase, compared with normal subjects. During the ictal phase, the ipsilateral R2 latency was significantly decreased after stimulation of the hemiplegic side, compared with the interictal phase ( P < 0.05). The blink reflex abnormalities suggest a brainstem dysfunction, which may be linked to the pathophysiological mechanisms of the disease.

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Motor Evoked Potentials and Disability in Secondary Progressive Multiple Sclerosis

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100033011 ◽

1997 ◽

Vol 24 (04) ◽

pp. 332-337 ◽

Cited By ~ 22

Author(s):

D. Facchetti ◽

R. Mai ◽

A. Micheli ◽

N. Marcianó ◽

R. Capra ◽

...

Keyword(s):

Evoked Potentials ◽

Lower Limb ◽

Evoked Potential ◽

Motor Evoked Potentials ◽

Functional System ◽

Conduction Time ◽

Lesion Load ◽

Secondary Progressive ◽

Spinal Motor ◽

Relapsing Remitting

ABSTRACT:Background:To investigate the mechanisms underlying disability in multiple sclerosis (MS), 40 patients with the relapsing-remitting form of the disease and 13 patients with secondary progressive MS underwent multimodal evoked potential (EP), motor evoked potential (MEP), and spinal motor conduction time evaluation. Clinical disability was evaluated by the expanded disability status scale (EDSS) and functional system scales. In secondary progressive MS patients, magnetic resonance imaging (MRI) was used to obtain a semiquantitative estimate of the total lesion load of the brain.Results:Spinal motor conduction time was significantly longer in secondary progressive MS patients than controls (p < 0.001) and relapsing-remitting MS patients (p < 0.05), but did not differ between relapsing-remitting patients and controls. Spinal motor conduction times also correlated directly with EDSS scores (p < 0.001) and pyramidal functional system scores (p < 0.001). Brain lesion load (4960.3 ± 3719.0 mm2) and the total number of lesions (67.7 ± 37.0) in secondary progressive MS did not correlate with disability scores. For the following EPs, the frequencies of abnormalities were significantly higher in secondary progressive MS patients than relapsing-remitting patients: visual evoked potentials (p < 0.05), somatosensory evoked potentials and upper limb motor evoked potentials (p < 0.01), and brainstem auditory evoked potentials, lower limb somatosensory evoked potentials and lower limb motor evoked potentials (p < 0.001).Conclusions:These findings suggest that disability in secondary progressive MS patients is mainly due to progressive involvement of corticospinal tract in the spinal cord.

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Neurophysiological evaluation of patients with degenerative diseases of the cervical spine

Vojnosanitetski pregled ◽

10.2298/vsp1103241i ◽

2011 ◽

Vol 68 (3) ◽

pp. 241-247

Author(s):

Tihomir Ilic ◽

Snezana Stankovic ◽

Nela Ilic ◽

Sanja Kostic ◽

Vlado Djajic ◽

...

Keyword(s):

Cervical Spine ◽

Evoked Potentials ◽

Motor Neurons ◽

Motor Evoked Potentials ◽

Diagnostic Evaluation ◽

Conduction Time ◽

Functional Evaluation ◽

Degenerative Diseases ◽

Dynamic Tests ◽

Neurophysiological Tests

Bacground/Aim. Diagnostic protocol for patients with degenerative diseases of the cervical spine demands, in parallel with neuroimaging methods, functional evaluation through neurophysiological methods (somatosensitive and motor evoked potentials and electromyoneurography) aiming to evaluate possible subclinical affection of spinal medula resulting in neurological signs of long tract abnormalities. Considering diversities of clinical outcomes for these patients, complex diagnostic evaluation provides a prognosis of the disease progression. Methods. The study included 21 patients (48.24 ? 11.01 years of age) with clinical presentation of cervical spondylarthropathy, without neuroradiological signs of myelopathy. For each patient, in addition to conventional neurophysiological tests (somatisensory evoked potentials - SSEP, motor evoked potentials - MEP, electromyoneurography - EMG, nerve conduction studies), we calculated central motor conduction time (CMCTF), as well the same parameter in relation to a different position of the head (maximal anteflexion and retroflexion), so-called dynamic tests. Results. Abnormalities of the peripheral motor neurone by conventional EMNeG was established in 2/3 of the patients, correponding to the findings of root condution time. Prolonged conventional CVMPF were found in 29% of the patients, comparing to 43% CVMPF abnormalities found with the dynamic tests. In addition, the SSEP findings were abnormal in 38% of the patients with degenerative diseases of the cervical spine. Conclusion. An extended neurophysiological protocol of testing corticospinal functions, including dynamic tests of central and periheral motor neurons are relevant for detection of subclinical forms of cervical spondylothic myelopathy, even at early stages. In addition to the conventional neurophysiological tests, we found usefull to include the dynamic motor tests and root conduction time measurement in diagnostic evaluation.

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