scholarly journals Effects of Hand Vibration on Motor Output in Chronic Hemiparesis

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Sibele de Andrade Melo ◽  
Andreea Iancu ◽  
Joseph-Omer Dyer ◽  
Robert Forget
Keyword(s):  
Motor Evoked Potentials ◽  
Force Production ◽  
Thenar Eminence ◽  
Voluntary Contraction ◽  
Corticospinal Excitability ◽  
Motor Output ◽  
Control Subjects ◽  
Pinch Grip ◽  
First Dorsal Interosseous Muscle ◽  
Healthy Control

Background. Muscle vibration has been shown to increase the corticospinal excitability assessed by transcranial magnetic stimulation (TMS) and to change voluntary force production in healthy subjects. Objectives. To evaluate the effect of vibration on corticospinal excitability using TMS and on maximal motor output using maximal voluntary contraction (MVC) in individuals with chronic hemiparesis. Methodology. Nineteen hemiparetic and 17 healthy control subjects participated in this study. Motor evoked potentials (MEPs) and MVC during lateral pinch grip were recorded at first dorsal interosseous muscle in a single session before, during, and after one-minute trials of 80 Hz vibration of the thenar eminence. Results. In hemiparetic subjects, vibration increased MEP amplitudes to a level comparable to that of control subjects and triggered a MEP response in 4 of 7 patients who did not have a MEP at rest. Also, vibration increased the maximal rate of force production (dF/dtmax⁡) in both control and hemiparetic subjects but it did not increase MVC. Conclusion. Motor response generated with a descending cortical drive in chronic hemiparetic subjects can be increased during vibration. Vibration could be used when additional input is needed to reveal motor responses and to increase rate of force generation.

scholarly journals Corticospinal excitability of the biceps brachii is shoulder position dependent

2017 ◽  
Vol 118 (6) ◽  
pp. 3242-3251 ◽  
Author(s):  
Brandon Wayne Collins ◽  
Edward W. J. Cadigan ◽  
Lucas Stefanelli ◽  
Duane C. Button
Keyword(s):  
Evoked Potentials ◽  
Maximal Voluntary Contraction ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Voluntary Contraction ◽  
Corticospinal Excitability ◽  
State Dependent ◽  
Shoulder Flexion ◽  
Erb’S Point ◽  
Shoulder Position

The purpose of this study was to examine the effect of shoulder position on corticospinal excitability (CSE) of the biceps brachii during rest and a 10% maximal voluntary contraction (MVC). Participants ( n = 9) completed two experimental sessions with four conditions: 1) rest, 0° shoulder flexion; 2) 10% MVC, 0° shoulder flexion; 3) rest, 90° shoulder flexion; and 4) 10% MVC, 90° shoulder flexion. Transcranial magnetic, transmastoid electrical, and Erb’s point stimulation were used to induce motor-evoked potentials (MEPs), cervicomedullary MEPs (CMEPs), and maximal muscle compound potentials (Mmax), respectively, in the biceps brachii in each condition. At rest, MEP, CMEP, and Mmax amplitudes increased ( P < 0.01) by 509.7 ± 118.3%, 113.3 ± 28.3%, and 155.1 ± 47.9%, respectively, at 90° compared with 0°. At 10% MVC, MEP amplitudes did not differ ( P = 0.08), but CMEP and Mmax amplitudes increased ( P < 0.05) by 32.3 ± 10.5% and 127.9 ± 26.1%, respectively, at 90° compared with 0°. MEP/Mmax increased ( P < 0.01) by 224.0 ± 99.1% at rest and decreased ( P < 0.05) by 51.3 ± 6.7% at 10% MVC at 90° compared with 0°. CMEP/Mmax was not different ( P = 0.22) at rest but decreased ( P < 0.01) at 10% MVC by 33.6 ± 6.1% at 90° compared with 0°. EMG increased ( P < 0.001) by 8.3 ± 2.0% at rest and decreased ( P < 0.001) by 21.4 ± 4.4% at 10% MVC at 90° compared with 0°. In conclusion, CSE of the biceps brachii was dependent on shoulder position, and the pattern of change was altered within the state in which it was measured. The position-dependent changes in Mmax amplitude, EMG, and CSE itself all contribute to the overall change in CSE of the biceps brachii. NEW & NOTEWORTHY We demonstrate that when the shoulder is placed into two common positions for determining elbow flexor force and activation, corticospinal excitability (CSE) of the biceps brachii is both shoulder position and state dependent. At rest, when the shoulder is flexed from 0° to 90°, supraspinal factors predominantly alter CSE, whereas during a slight contraction, spinal factors predominantly alter CSE. Finally, the normalization techniques frequently used by researchers to investigate CSE may under- and overestimate CSE when shoulder position is changed.

Investigation of Neuromuscular Transmission in Some Rare Types of Migraine

Cephalalgia ◽  
2007 ◽  
Vol 27 (11) ◽  
pp. 1201-1205 ◽  
Author(s):  
MB Baslo ◽  
A Coban ◽  
B Baykan ◽  
K Tutkavul ◽  
N Karli ◽  
...  
Keyword(s):  
Neuromuscular Transmission ◽  
Primary Headache ◽  
Normal Subjects ◽  
Familial Hemiplegic Migraine ◽  
Single Fibre ◽  
Voluntary Contraction ◽  
Hemiplegic Migraine ◽  
Control Subjects ◽  
Healthy Control ◽  
Patient Groups

The aim of this study was to delineate any dysfunction of neuromuscular transmission (NMT) by single-fibre electromyography (SFEMG) in some rare types of migraine. Recent studies have shown subclinical dysfunction of NMT in migraine with aura and cluster headache by using SFEMG, whereas another recent study has shown NMT to be normal in familial hemiplegic migraine (FHM) with CACNA1A mutations. Thirty patients with rare primary headache syndromes [18 with sporadic hemiplegic migraine (SHM), six with FHM and six with basilar-type migraine (BM)] and 15 healthy control subjects without any headache complaints underwent nerve conduction studies, EMG and SFEMG during voluntary contraction of the extensor digitorum communis muscle. Ten to 20 different potential pairs were recorded and individual jitter values calculated. The results obtained from patient groups were compared with those from the normal subjects. Of 600 individual jitter values of the patients, 27 (4.5%) were abnormally high, whereas only 3/205 (1.5%) jitter values from normal subjects were abnormal. Abnormal NMT was found in 4/30 (13.3%) patients (three SHM and one BM), but in none of the control subjects. Only in SHM patients was the number of individual abnormal jitter values slightly but significantly different from normal controls. The present study demonstrates that subclinical NMT abnormality is slightly present in only SHM and BM patients, but not in FHM patients.

scholarly journals Global Corticospinal Excitability as Assessed in A Non-Exercised Upper Limb Muscle Compared Between Concentric and Eccentric Modes of Leg Cycling

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Joel A. Walsh ◽  
Paul J. Stapley ◽  
Jonathan B. H. Shemmell ◽  
Romuald Lepers ◽  
Darryl J. McAndrew
Keyword(s):  
Perceived Exertion ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Moderate Intensity ◽  
Response Curves ◽  
Large Variability ◽  
Physiological Variables ◽  
Leg Cycling ◽  
First Dorsal Interosseous Muscle ◽  
The Right

AbstractThis study investigated the effects of eccentric (ECC) and concentric (CON) semi-recumbent leg cycling on global corticospinal excitability (CSE), assessed through the activity of a non-exercised hand muscle. Thirteen healthy male adults completed two 30-min bouts of moderate intensity ECC and CON recumbent cycling on separate days. Power output (POutput), heart rate (HR) and cadence were monitored during cycling. Global CSE was assessed using transcranial magnetic stimulation to elicit motor-evoked potentials (MEP) in the right first dorsal interosseous muscle before (‘Pre’), interleaved (at 10 and 20 mins, t10 and t20, respectively), immediately after (post, P0), and 30-min post exercise (P30). Participants briefly stopped pedalling (no more than 60 s) while stimulation was applied at the t10 and t20 time-points of cycling. Mean POutput, and rate of perceived exertion (RPE) did not differ between ECC and CON cycling and HR was significantly lower during ECC cycling (P = 0.01). Group mean MEP amplitudes were not significantly different between ECC and CON cycling at P0, t10, t20, and P30 and CON (at P > 0.05). Individual participant ratios of POutput and MEP amplitude showed large variability across the two modes of cycling, as did changes in slope of stimulus-response curves. These results suggest that compared to ‘Pre’ values, group mean CSE is not significantly affected by low-moderate intensity leg cycling in both modes. However, POutput and CSE show wide inter-participant variability which has implications for individual neural responses to CON and ECC cycling and rates of adaptation to a novel (ECC) mode. The study of CSE should therefore be analysed for each participant individually in relation to relevant physiological variables and account for familiarisation to semi-recumbent ECC leg cycling.

Corticospinal Excitability Is Lower During Rhythmic Arm Movement Than During Tonic Contraction

2006 ◽  
Vol 95 (2) ◽  
pp. 914-921 ◽  
Author(s):  
Timothy J. Carroll ◽  
Evan R. L. Baldwin ◽  
David F. Collins ◽  
E. Paul Zehr
Keyword(s):  
Motor Cortex ◽  
Neural Control ◽  
Motor Evoked Potentials ◽  
Arm Movement ◽  
Voluntary Contraction ◽  
Tonic Contraction ◽  
H Reflex ◽  
Corticospinal Excitability ◽  
Arm Cycling ◽  
Subcortical Regions

Humans perform rhythmic, locomotor movements with the arms and legs every day. Studies using reflexes to probe the functional role of the CNS suggest that spinal circuits are an important part of the neural control system for rhythmic arm cycling and walking. Here, by studying motor-evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS) of the motor cortex, and H-reflexes induced by electrical stimulation of peripheral nerves, we show a reduction in corticospinal excitability during rhythmic arm movement compared with tonic, voluntary contraction. Responses were compared between arm cycling and tonic contraction at four positions, while participants generated similar levels of muscle activity. Both H-reflexes and MEPs were significantly smaller during arm cycling than during tonic contraction at the midpoint of arm flexion ( F = 13.51, P = 0.006; F = 11.83, P = 0.009). Subthreshold TMS significantly facilitated the FCR H-reflex during tonic contractions, but did not significantly modulate H-reflex amplitude during arm cycling. The data indicate a reduction in the responsiveness of cells constituting the fast, monosynaptic, corticospinal pathway during arm cycling and suggest that the motor cortex may contribute less to motor drive during rhythmic arm movement than during tonic, voluntary contraction. Our results are consistent with the idea that subcortical regions contribute to the control of rhythmic arm movements despite highly developed corticospinal projections to the human upper limb.

Decreased corticospinal excitability after subthreshold 1 Hz rTMS over lateral premotor cortex

Neurology ◽  
2001 ◽  
Vol 57 (3) ◽  
pp. 449-455 ◽  
Author(s):  
Willibald Gerschlager ◽  
Hartwig R. Siebner ◽  
John C. Rothwell
Keyword(s):  
Motor Cortex ◽  
Parietal Cortex ◽  
Motor Evoked Potentials ◽  
Premotor Cortex ◽  
Corticospinal Excitability ◽  
First Dorsal Interosseous ◽  
First Dorsal Interosseous Muscle ◽  
The Right ◽  
Hand Area ◽  
Dorsal Interosseous Muscle

Objective: To study whether trains of subthreshold 1 Hz repetitive transcranial magnetic stimulation (rTMS) over premotor, prefrontal, or parietal cortex can produce changes in excitability of motor cortex that outlast the application of the train.Background: Prolonged 1 Hz rTMS over the motor cortex can suppress the amplitude of motor-evoked potentials (MEP) for several minutes after the end of the train. Because TMS can produce effects not only at the site of stimulation but also at distant sites to which it projects, the authors asked whether prolonged stimulation of sites distant but connected to motor cortex can also lead to lasting changes in MEP.Methods: Eight subjects received 1500 magnetic stimuli given at 1 Hz over the left lateral frontal cortex, the left lateral premotor cortex, the hand area of the left motor cortex, and the left anterior parietal cortex on four separate days. Stimulus intensity was set at 90% active motor threshold. Corticospinal excitability was probed by measuring the amplitude of MEP evoked in the right first dorsal interosseous muscle by single suprathreshold stimuli over the left motor hand area before, during, and after the conditioning trains.Results: rTMS over the left premotor cortex suppressed the amplitude of MEP in the right first dorsal interosseous muscle. The effect was maximized (approximately 50% suppression) after 900 pulses and outlasted the full train of 1500 stimuli for at least 15 minutes. Conditioning rTMS over the other sites did not modify the size of MEP. A control experiment showed that left premotor cortex conditioning had no effect on MEP evoked in the left first dorsal interosseous muscle.Conclusions: Subthreshold 1 Hz rTMS of the left premotor cortex induces a short-lasting inhibition of corticospinal excitability in the hand area of the ipsilateral motor cortex. This may provide a model for studying the functional interaction between premotor and motor cortex in healthy subjects and patients with movement disorders.

scholarly journals Impaired crossed facilitation of the corticospinal pathway after cervical spinal cord injury

2012 ◽  
Vol 107 (10) ◽  
pp. 2901-2911 ◽  
Author(s):  
Karen L. Bunday ◽  
Monica A. Perez
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Voluntary Contraction ◽  
Facilitatory Effect ◽  
Corticospinal Pathway ◽  
Control Subjects ◽  
Cord Injury ◽  
Healthy Control ◽  
Hand Muscle ◽  
Voluntary Contractions

In uninjured humans, it is well established that voluntary contraction of muscles on one side of the body can facilitate transmission in the contralateral corticospinal pathway. This crossed facilitatory effect may favor interlimb coordination and motor performance. Whether this aspect of corticospinal function is preserved after chronic spinal cord injury (SCI) is unknown. Here, using transcranial magnetic stimulation, we show in patients with chronic cervical SCI (C5–C8) that the size of motor evoked potentials (MEPs) in a resting intrinsic hand muscle remained unchanged during increasing levels of voluntary contraction with a contralateral distal or proximal arm muscle. In contrast, MEP size in a resting hand muscle was increased during the same motor tasks in healthy control subjects. The magnitude of voluntary electromyography was negatively correlated with MEP size after chronic cervical SCI and positively correlated in healthy control subjects. To examine the mechanisms contributing to MEP crossed facilitation we examined short-interval intracortical inhibition (SICI), interhemispheric inhibition (IHI), and motoneuronal behavior by testing F waves and cervicomedullary MEPs (CMEPs). During strong voluntary contractions SICI was unchanged after cervical SCI and decreased in healthy control subjects compared with rest. F-wave amplitude and persistence and CMEP size remained unchanged after cervical SCI and increased in healthy control subjects compared with rest. In addition, during strong voluntary contractions IHI was unchanged in cervical SCI compared with rest. Our results indicate that GABAergic intracortical circuits, interhemispheric glutamatergic projections between motor cortices, and excitability of index finger motoneurons are neural mechanisms underlying, at least in part, the lack of crossed corticospinal facilitation observed after SCI. Our data point to the spinal motoneurons as a critical site for modulating corticospinal transmission after chronic cervical SCI.

scholarly journals Voluntary Breathing Influences Corticospinal Excitability of Nonrespiratory Finger Muscles

2011 ◽  
Vol 105 (2) ◽  
pp. 512-521 ◽  
Author(s):  
Sheng Li ◽  
William Zev Rymer
Keyword(s):  
Electrical Stimulation ◽  
Motor Evoked Potentials ◽  
Force Production ◽  
Voluntary Contraction ◽  
Breath Hold ◽  
Force Response ◽  
Finger Extension ◽  
Finger Flexion ◽  
Abductor Digiti Minimi ◽  
Clinical Experiments

The present study aimed to investigate neurophysiologic mechanisms mediating the newly discovered phenomenon of respiratory–motor interactions and to explore its potential clinical application for motor recovery. First, young and healthy subjects were instructed to breathe normally (NORM); to exhale (OUT) or inhale (IN) as fast as possible in a self-paced manner; or to voluntarily hold breath (HOLD). In experiment 1 ( n = 14), transcranial magnetic stimulation (TMS) was applied during 10% maximal voluntary contraction (MVC) finger flexion force production or at rest. The motor-evoked potentials (MEPs) were recorded from flexor digitorum superficialis (FDS), extensor digitorum communis (EDC), and abductor digiti minimi (ADM) muscles. Similarly, in experiment 2 ( n = 11), electrical stimulation (ES) was applied to FDS or EDC during the described four breathing conditions while subjects maintained 10%MVC of finger flexion or extension and at rest. In the exploratory clinical experiments ( experiment 3), four patients with chronic neurological disorders (three strokes, one traumatic brain injury) received a 30-min session of breathing-controlled ES to the impaired EDC. In experiment 1, the EDC MEP magnitudes increased significantly during IN and OUT at both 10%MVC and rest; the FDS MEPs were enhanced only at 10%MVC, whereas the ADM MEP increased only during OUT, compared with NORM for both at rest and 10%MVC. No difference was found between NORM and HOLD for all three muscles. In experiment 2, when FDS was stimulated, force response was enhanced during both IN and OUT, but only at 10%MVC. When EDC was stimulated, force response increased at both 10%MVC and rest, only during IN, but not OUT. The averaged response latency was 83 ms for the finger extensors and 79 ms for the finger flexors. After a 30-min intervention of ES to EDC triggered by forced inspiration in experiment 3, we observed a significant reduction in finger flexor spasticity. The spasticity reduction lasted for ≥4 wk in all four patients. TMS and ES data, collectively, support the phenomenon that there is an overall respiration-related enhancement on the motor system, with a strong inspiration–finger extension coupling during voluntary breathing. As such, breathing-controlled electrical stimulation (i.e., stimulation to finger extensors delivered during the voluntary inspiratory phase) could be applied for enhancing finger extension strength and finger flexor spasticity reduction in poststroke patients.

scholarly journals Changes in motoneuron afterhyperpolarization duration in stroke survivors

2014 ◽  
Vol 112 (6) ◽  
pp. 1447-1456 ◽  
Author(s):  
Aneesha K. Suresh ◽  
Xiaogang Hu ◽  
Randall K. Powers ◽  
C. J. Heckman ◽  
Nina L. Suresh ◽  
...  
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Force Production ◽  
Motor Units ◽  
Surface Emg ◽  
Stroke Survivors ◽  
Single Motor Unit ◽  
Control Subjects ◽  
First Dorsal Interosseous Muscle ◽  
Hemiparetic Stroke

Hemispheric brain injury resulting from a stroke is often accompanied by muscle weakness in limbs contralateral to the lesion. In the present study, we investigated whether weakness in contralesional hand muscle in stroke survivors is partially attributable to alterations in motor unit activation, including alterations in firing rate modulation range. The afterhyperpolarization (AHP) potential of a motoneuron is a primary determinant of motoneuron firing rate. We examined differences in AHP duration in motoneurons innervating paretic and less impaired (contralateral) limb muscles of hemiparetic stroke survivors as well as in control subjects. A novel surface EMG (sEMG) electrode was used to record motor units from the first dorsal interosseous muscle. The sEMG data were subsequently decomposed to derive single-motor unit events, which were then utilized to produce interval (ISI) histograms of the motoneuron discharges. A modified version of interval death rate (IDR) analysis was used to estimate AHP duration. Results from data analyses performed on both arms of 11 stroke subjects and in 7 age-matched control subjects suggest that AHP duration is significantly longer for motor units innervating paretic muscle compared with units in contralateral muscles and in units of intact subjects. These results were supported by a coefficient of variation (CV) analysis showing that paretic motor unit discharges have a lower CV than either contralateral or control units. This study suggests that after stroke biophysical changes occur at the motoneuron level, potentially contributing to lower firing rates and potentially leading to less efficient force production in paretic muscles.

Subclinical Neuromuscular Transmission Abnormality Detected by Single-Fibre EMG is More Pronounced in Cluster Headache Than in Migraine With Aura

Cephalalgia ◽  
2007 ◽  
Vol 27 (7) ◽  
pp. 788-792 ◽  
Author(s):  
A Coban ◽  
MB Baslo ◽  
B Baykan ◽  
K Tutkavul ◽  
EK Orhan ◽  
...  
Keyword(s):  
Cluster Headache ◽  
Migraine With Aura ◽  
Neuromuscular Transmission ◽  
Primary Headache ◽  
Single Fibre ◽  
Voluntary Contraction ◽  
Functional Abnormality ◽  
Control Subjects ◽  
Healthy Control ◽  
Abnormal Individual

The aim was to investigate neuromuscular transmission (NMT) by single-fibre EMG (SFEMG) in a large series of patients having migraine with aura (MA) or cluster headache (CH). Recent studies using SFEMG have shown subclinical dysfunction of NMT in MA and CH. Forty-three patients having MA, 51 with CH and 38 healthy control subjects underwent nerve conduction studies, EMG and SFEMG during voluntary contraction of the extensor digitorum communis muscle. Twenty different potential pairs were recorded and individual, mean and total abnormal individual jitter values were calculated. The results obtained from MA patients were compared with those from CH patients. In MA patients, 32 of 860 jitters were abnormally high, whereas 73 of 1020 of the jitters showed this abnormality in CH patients. None of the control subjects, five MA patients (11.6%) and 11 CH patients (21.6%) were designated as having subclinical NMT abnormality. Thus, patients having junction dysfunction were significantly more common in the CH group. The subclinical NMT abnormality shown by SFEMG is more common in CH than in MA. These two primary headache syndromes may have some shared functional abnormality of NMT constituents which is more evident in CH.

Enhancement of Platelet Sensitivity to ADP-Aggregation by Isometric Exercise in Arteriosclerotic Patients and its Prevention

1977 ◽  
Vol 37 (02) ◽  
pp. 329-338 ◽  
Author(s):  
Tadahiro Sano ◽  
Takeshi Motomiya ◽  
Hiroh Yamazaki ◽  
Takio Shimamoto
Keyword(s):  
Cyclic Amp ◽  
Mechanical Stress ◽  
Optical Density ◽  
Platelet Function ◽  
Isometric Exercise ◽  
Phosphodiesterase Inhibitor ◽  
New Method ◽  
Platelet Aggregability ◽  
Control Subjects ◽  
Healthy Control

SummaryA new method for assessment of platelet sensitivity to ADP-aggregation was devised. Its reproducibility and the correlations between the values obtained by this method, the optical density (O. D.) method, and the screen filtration pressure (SFP) method were assessed. In summary, this method may be said to have three main points:1. It can be performed without centrifugation, avoiding mechanical stress to platelets, using only 0.8 ml. of blood and inexpensive equipment.2. It may reflect different aspects of platelet function from the O. D. method and the SFP method, despite the positive significant correlations between the values obtained by these three methods.3. It was proved to be highly reproducible and is thought to be useful clinically.By using this method, the effect of sustained isometric exercise by handgripping on platelet aggregability was assessed in coronary sclerotic and cerebral arteriosclerotic patients on placebo and EG-626, a newly synthesized cyclic AMP phosphodiesterase inhibitor. On placebo, an enhancement of platelet sensitivity was observed after isometric exercise in coronary and cerebral arteriosclerotic patients but not in healthy control subjects. The enhancement was prevented by pretreatment of EG-626, administered orally 1.5 hours prior to exercise.

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