Increase in Short-Interval Intracortical Facilitation of the Motor Cortex after Low-Frequency Repetitive Magnetic Stimulation of the Unaffected Hemisphere in the Subacute Phase after Stroke

Abstract

Low-frequency repetitive transcranial magnetic stimulation of the unaffected hemisphere (UH-LF-rTMS) in patients with stroke can decrease interhemispheric inhibition from the unaffected to the affected hemisphere and improve hand dexterity and strength of the paretic hand. The objective of this proof-of-principle study was to explore, for the first time, effects of UH-LF-rTMS as add-on therapy to motor rehabilitation on short-term intracortical inhibition (SICI) and intracortical facilitation (ICF) of the motor cortex of the unaffected hemisphere (M1UH) in patients with ischemic stroke. Eighteen patients were randomized to receive, immediately before rehabilitation treatment, either active or sham UH-LF-rTMS, during two weeks. Resting motor threshold (rMT), SICI, and ICF were measured in M1UH before the first session and after the last session of treatment. There was a significant increase in ICF in the active group compared to the sham group after treatment, and there was no significant differences in changes in rMT or SICI. ICF is a measure of intracortical synaptic excitability, with a relative contribution of spinal mechanisms. ICF is typically upregulated by glutamatergic agonists and downregulated by gabaergic antagonists. The observed increase in ICF in the active group, in this hypothesis-generating study, may be related to M1UH reorganization induced by UH-LF-rTMS.

Longitudinal study on modulated corticospinal excitability throughout recovery in supratentorial stroke

“…Again, possible resolution in the early recovery stage may explain the rapid changes in CSE in the acute stage [29]. Although, the apparent CSE recovery seen in figure 1 appears strong, some previous studies have concluded that the rMT is influenced by multiple structural and functional characteristics of both cortical and spinal neurons negatively affecting its ability to act as a reliable biomarker regarding inter-hemispheric differences in excitability [7,19].…”

Prediction of Motor Recovery in the Upper Extremity for Repetitive Transcranial Magnetic Stimulation and Occupational Therapy Goal Setting in Patients With Chronic Stroke: A Retrospective Analysis of Prospectively Collected Data

“…In other words, unbalanced excitement of the cerebrum on the non-lesioned hemisphere adversely affects functional improvement. Since nervous activity is suppressed by LF-rTMS, the activity of the non-lesional hemisphere can be suppressed by applying LF-rTMS to the motor cortex of the nonlesional hemisphere (42), and suppression of interhemispheric inhibition of the non-lesional hemisphere indirectly increases the activity of the lesional side (43). On the other hand, highfrequency (HF)-rTMS evokes nervous activity and stimulates the motor cortex of the lesional hemisphere to enhance activity at the lesional site directly (44).…”

MicroRNA‑22 alleviates inflammation in ischemic stroke via p38 MAPK pathways

“…However, the disability rate has also increased accordingly. Cognitive dysfunction often follows a stoke, and a clinical report has suggested it occurs in 50–75% of patients (4). The present study first examined how miRNA-22 expression is downregulated in ischemic stroke rats, compared with a control group.…”

“…Ischemic stroke is the second major factor leading to mortality and disability in patients. Specifically, 20–50% patients will succumb or suffer from despite receiving treatment within one month following a stroke (4). With the development of modern medical science, intensive studies on the mechanism of ischemic stroke have been performed at the cellular and molecular levels (5).…”