Motor cortex disinhibition in acute stroke

Liepert, Joachim; Storch, Peter; Fritsch, Antonia; Weiller, Cornelius

doi:10.1016/s1388-2457(99)00312-0

Cited by 273 publications

(200 citation statements)

References 45 publications

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“…It is often considered that disinhibition present after stroke on the AH [4,15] leads to rapid clinical improvement, while some structural contributors as well as the uncontrolled input from UH may also affect [23]. In the present study, the asymmetry in rMT began to diminish with time, approached values of normal population after about 31 days after stroke onset in the APB muscles and tended to reduce more towards 6 months ( Figure 2).…”

Section: Discussionsupporting

confidence: 50%

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Julkunen

Könönen

Määttä

et al. 2016

Neuroscience Letters

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Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke, Neuroscience Letters http://dx.doi.org/10. 1016/j.neulet.2016.02.014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractCorticospinal excitability (CSE) is modulated by stroke-induced lesions affecting the brain. This modulation is known to be dependent on the timing of the evaluation, and strongest abnormalities are often found in the acute stage. Our study aimed to characterize changes in CSE asymmetry between the affected and the unaffected hemisphere (AH and UH) during the first month after stroke onset and at 6 month follow-up. Neuronavigated transcranial magnetic stimulation (nTMS) was used to assess the CSE of the abductor pollicis brevis (APB) muscle of the hand and tibialis anterior (TA) muscle of the leg in 16 patients over 5 time-points. AH excitability recovered significantly during 6 months, whereas interhemispheric asymmetry remained significant up to 1 month post-stroke in the APB muscle. Greater initial CSE was associated with good motor function at 6 months. The motor cortical excitatory recovery initiated within week of the stroke and was most prominent within 1 month after stroke onset. Lesion size correlated with CSE of the UH at 10 days, while overall severity of the symptoms correlated inversely with CSE of the AH. This study demonstrates the quick improvement in the CSE via estimation of interhemispheric asymmetry; however, the recovery in the asymmetry continues to normalize even after reaching the threshold for normal values in CSE.

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Section: Discussionsupporting

confidence: 50%

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Julkunen

Könönen

Määttä

et al. 2016

Neuroscience Letters

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“…1,13,14 We now found that this abnormality may persist into the chronic stage of the disease in patients with good recovery when compared to healthy age-matched controls. A recent report showed no differences in resting SICI in the healthy and affected hemisphere in patients 2 to 96 months after stroke but patients' results in that study were not compared to age-matched controls.…”

Section: Discussionmentioning

confidence: 64%

“…For example, in patients with dystonia, premovement SICI and SICI at rest showed substantially different effects with reduction in SICI at rest and persistent lack of modulation of SICI during movement preparation. 7 Previous studies evaluating motor cortex excitability in the acute and subacute stages after stroke 1,3,[13][14][15][16][17][18] showed decreased resting SICI in the ipsilesional M1, an abnormality that may normalize in the chronic stage. 15,[17][18][19] Movement-related changes in SICI in stroke patients intending to move the paretic hand have not been investigated.…”

mentioning

confidence: 98%

Deficient intracortical inhibition (SICI) during movement preparation after chronic stroke

Hummel

Steven²,

Hoppe³

et al. 2009

Neurology

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“…These two transcranial magnetic stimulation (TMS) studies yielded conflicting results, because the latter found a reduction in the motor maps of immobilized muscles, while the former reported maps of normal area, but greater responses to TMS. Data from stroke patients, treated with constraint-induced therapy (Taub et al, 2002) are able to add little information on the topic, because motor stroke per se is capable of inducing very extensive bilateral cortical reorganization (Liepert et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Modulation of motor cortex excitability after upper limb immobilization

Zanette

Manganotti

Fiaschi

et al. 2004

Clinical Neurophysiology

102

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Objective: To examine the mechanisms of disuse-induced plasticity following long-term limb immobilization. Methods: We studied 9 subjects, who underwent left upper limb immobilization for unilateral wrist fractures. All subjects were examined immediately after splint removal. Cortical motor maps, resting motor threshold (RMT), motor evoked potential (MEP) latency and MEP recruitment curves were studied from abductor pollicis brevis (APB) and flexor carpi radialis (FCR) muscles with single pulse transcranial magnetic stimulation (TMS). Paired pulse TMS was used to study intracortical inhibition and facilitation. Compound muscle action potentials (CMAPs) and F waves were obtained after median nerve stimulation. In 4/9 subjects the recording was repeated after 35 -41 days.Results: CMAP amplitude and RMT were reduced in APB muscle on the immobilized sides in comparison to the non-immobilized sides and controls after splint removal. CMAP amplitude and RMT were unchanged in FCR muscle. MEP latency and F waves were unchanged. MEP recruitment was significantly greater on the immobilized side at rest, but the asymmetry disappeared during voluntary muscle contraction. Paired pulse TMS showed an imbalance between inhibitory and excitatory networks, with a prevalence of excitation on the immobilized sides. A slight, non-significant change in the strength of corticospinal projections to the non-immobilized sides was found. TMS parameters were not correlated with hand dexterity. These abnormalities were largely normalized at the time of retesting in the four patients who were followed-up.Conclusions: Hyperexcitability occurs within the representation of single muscles, associated with changes in RMT and with an imbalance between intracortical inhibition and facilitation. These findings may be related to changes in the sensory input from the immobilized upper limb and/or in the discharge properties of the motor units.Significance: Different mechanisms may contribute to the reversible neuroplastic changes, which occur in response to long-term immobilization of the upper-limbs.

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Motor cortex disinhibition in acute stroke

Cited by 273 publications

References 45 publications

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

Deficient intracortical inhibition (SICI) during movement preparation after chronic stroke

Modulation of motor cortex excitability after upper limb immobilization

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