scholarly journals Cortical Excitability Measured with nTMS and MEG during Stroke Recovery

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jyrki P. Mäkelä ◽  
Pantelis Lioumis ◽  
Kristina Laaksonen ◽  
Nina Forss ◽  
Turgut Tatlisumak ◽  
...  
Keyword(s):  
Cortical Excitability ◽  
Intracortical Inhibition ◽  
Stroke Recovery ◽  
Motor Threshold ◽  
Beta Band ◽  
Stroke Patients ◽  
Intracortical Facilitation ◽  
Source Areas ◽  
Somatosensory Evoked Fields ◽  
Evoked Fields

Objective. Stroke alters cortical excitability both in the lesioned and in the nonlesioned hemisphere. Stroke recovery has been studied using transcranial magnetic stimulation (TMS). Spontaneous brain oscillations and somatosensory evoked fields (SEFs) measured by magnetoencephalography (MEG) are modified in stroke patients during recovery.Methods. We recorded SEFs and spontaneous MEG activity and motor threshold (MT) short intracortical inhibition (SICI) and intracortical facilitation (ICF) with navigated TMS (nTMS) at one and three months after first-ever hemispheric ischemic strokes. Changes of MEG and nTMS parameters attributed to gamma-aminobutyrate and glutamate transmission were compared.Results. ICF correlated with the strength and extent of SEF source areas depicted by MEG at three months. The nTMS MT and event-related desynchronization (ERD) of beta-band MEG activity and SICI and the beta-band MEG event-related synchronization (ERS) were correlated, but less strongly.Conclusions. This first report using sequential nTMS and MEG in stroke recovery found intra- and interhemispheric correlations of nTMS and MEG estimates of cortical excitability. ICF and SEF parameters, MT and the ERD of the lesioned hemisphere, and SICI and ERS of the nonlesioned hemisphere were correlated. Covarying excitability in the lesioned and nonlesioned hemispheres emphasizes the importance of the hemispheric balance of the excitability of the sensorimotor system.

Abstract TMP43: Differential Cortical Effect Modulated by Anodal, Cathodal and Bihemispheric Transcranial Direct Current Stimulation (tDCS) in Patients With Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Pratik Y Chhatbar ◽  
William DeVries ◽  
Emily Grattan ◽  
Steven A Kautz ◽  
Wuwei Feng
Keyword(s):  
Ischemic Stroke ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Intracortical Inhibition ◽  
Motor Threshold ◽  
Stroke Patients ◽  
Intracortical Facilitation ◽  
Abductor Pollicis Brevis ◽  
Resting Motor Threshold

Introduction: The differential brain modulatory effects across hemispheres from different montages in stroke patients is not well established. We aimed to investigate the cortical excitability on lesional and contra-lesional hemisphere modulated by anodal, cathodal and bihemispheric montage at 4 mA tDCS strengths. Hypothesis: Bihemispheric tDCS montage induces more cortical excitability on the lesional hemisphere. Methods: Eighteen aging stroke patients with unilateral ischemic stroke of 6 or more months and inducible motor evoked potentials (MEP) underwent 3 sessions of 30 minutes 4 mA tDCS combined with occupational therapy. Each session was at least 2 days apart and consisted of one of the 3 different montages: anodal (Anode: lesional C3/C4, Cathode: non-lesional FP1/FP2), cathodal (Anode: lesional FP1/FP2, Cathode: non-lesional C3/C4), or bihemispheric (Anode: lesional C3/C4, Cathode: non-lesional C3/C4). We collected MEP size, short intracortical inhibition (SICI, 3 ms) and intracortical facilitation (ICF, 15 ms) on bilateral abductor pollicis brevis (APB) muscles using single or paired pulse TMS at 5 timepoints (baseline and four post-tDCS 12 minutes apart sessions). Results: All 18 subjects had comparable resting motor threshold (rMT) across 3 montages (see A). Bihemispheric tDCS montage offered significantly larger peak-to-peak MEP responses on the lesioned cortex (ANOVA, F=8.97, P<0.01) but not on the non-lesioned cortex (ANOVA, F=0.86, P=0.42). These differences were apparent in single pulse, SICI and ICF (see B). Conclusion: Our findings support that bihemispheric montage is better suited in post-stroke motor recovery tDCS applications.

scholarly journals 2190 Longitudinal changes in EEG power envelope connectivity are proportional to motor recovery in chronic stroke patients

2018 ◽  
Vol 2 (S1) ◽  
pp. 17-17
Author(s):  
Joseph B. Humphries ◽  
David T. Bundy ◽  
Eric C. Leuthardt ◽  
Thy N. Huskey
Keyword(s):  
Motor Cortex ◽  
Motor Imagery ◽  
Stroke Rehabilitation ◽  
Brain Computer Interface ◽  
Chronic Stroke ◽  
Motor Recovery ◽  
Stroke Recovery ◽  
Computer Interface ◽  
Beta Band ◽  
Stroke Patients

OBJECTIVES/SPECIFIC AIMS: The objective of this study is to determine the degree to which the use of a contralesionally-controlled brain-computer interface for stroke rehabilitation drives change in interhemispheric motor cortical activity. METHODS/STUDY POPULATION: Ten chronic stroke patients were trained in the use of a brain-computer interface device for stroke recovery. Patients perform motor imagery to control the opening and closing of a motorized hand orthosis. This device was sent home with patients for 12 weeks, and patients were asked to use the device 1 hour per day, 5 days per week. The Action Research Arm Test (ARAT) was performed at 2-week intervals to assess motor function improvement. Before the active motor imagery task, patients were asked to quietly rest for 90 seconds before the task to calibrate recording equipment. EEG signals were acquired from 2 electrodes—one each centered over left and right primary motor cortex. Signals were preprocessed with a 60 Hz notch filter for environmental noise and referenced to the common average. Power envelopes for 1 Hz frequency bands (1–30 Hz) were calculated through Gabor wavelet convolution. Correlations between electrodes were then calculated for each frequency envelope on the first and last 5 runs, thus generating one correlation value per subject, per run. The chosen runs approximately correspond to the first and last week of device usage. These correlations were Fisher Z-transformed for comparison. The first and last 5 run correlations were averaged separately to estimate baseline and final correlation values. A difference was then calculated between these averages to determine correlation change for each frequency. The relationship between beta-band correlation changes (13–30 Hz) and the change in ARAT score was determined by calculating a Pearson correlation. RESULTS/ANTICIPATED RESULTS: Beta-band inter-electrode correlations tended to decrease more in patients achieving greater motor recovery (Pearson’s r=−0.68, p=0.031). A similar but less dramatic effect was observed with alpha-band (8–12 Hz) correlation changes (Pearson’s r=−0.42, p=0.22). DISCUSSION/SIGNIFICANCE OF IMPACT: The negative correlation between inter-electrode power envelope correlations in the beta frequency band and motor recovery indicates that activity in the motor cortex on each hemisphere may become more independent during recovery. The role of the unaffected hemisphere in stroke recovery is currently under debate; there is conflicting evidence regarding whether it supports or inhibits the lesioned hemisphere. These findings may support the notion of interhemispheric inhibition, as we observe less in common between activity in the 2 hemispheres in patients successfully achieving recovery. Future neuroimaging studies with greater spatial resolution than available with EEG will shed further light on changes in interhemispheric communication that occur during stroke rehabilitation.

Abstract TMP30: SICI During Voluntary Movement Reveals Persistent Impairment in Cortical Stroke

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Carolynn Patten ◽  
Qian Ding ◽  
Manjeshwar Sahana S Kamath ◽  
William J Triggs
Keyword(s):  
Interstimulus Interval ◽  
Magnetic Stimulation ◽  
Voluntary Movement ◽  
Intracortical Inhibition ◽  
Natural Course ◽  
Stroke Recovery ◽  
Motor Threshold ◽  
Motor Tasks ◽  
Active Motor ◽  
Cortical Stroke

Introduction: Short intracortical inhibition (SICI) is a GABAa-mediated phenomenon argued to mediate motor selectivity. SICI is markedly reduced, producing motor disinhibition, in the sub-acute period following cortical (CORT), but not subcortical (SC), stroke. Previous work suggests SICI may normalize as part of the natural course of recovery. Importantly, SICI is typically measured at rest complicating our understanding of its role in motor control and recovery following stroke. Here we investigated task-dependent differences in SICI in chronic stroke survivors. Hypothesis: We hypothesized: i) differences between SICI measured at rest and during voluntary movement and ii) SICI during voluntary movement would reveal persistent impairments following CORT stroke. Methods: We tested 13 adults (65±8.5 yr, 11 male) with chronic (72.8±52.6 mo) stroke (5 CORT, 8 SC) and 7 controls (CON)(58±6.9 yr, 4 male) using paired-pulse transcranial magnetic stimulation during 3 tasks: rest, grip, box & blocks (B&B). Motor evoked responses (MEPs) were measured from the first dorsal interosseous of the paretic and non-dominant hands of stroke and CON, respectively. SICI was induced by conditioning the test MEP at 0.8 resting or 0.7 active, motor threshold at the interstimulus interval producing maximal SICI at R (3 ms CON, 3.7 ms Stroke) and quantified as the ratio of conditioned/unconditioned MEParea. Stimulation intensity was adjusted to maintain test MEP amplitude at 1mV pk-pk across tasks. Results: At rest, SICI was similar between groups (p > 0.5). However during grip, CORT revealed significantly less SICI than CON or SC (p’s .05). During B&B, CORT again revealed less SICI than CON (p =.04); however SICI was similar between CORT and SC (p >.05). Across tasks, SICI produced by CON and SC was similar (p >.05) while CORT revealed less SICI during both grip and B&B (p’s <.005) compared to rest. Conclusions: Measured at rest, SICI is similar across groups suggesting GABAa circuits are normalized as part of the natural course of stroke recovery. However, SICI measured during voluntary motor tasks reveals persistent impairments, which are more widespread following CORT stroke and may interfere with rehabilitation involving voluntary movement.

scholarly journals Cortical disinhibition in Parkinson’s disease

Brain ◽  
2020 ◽  
Vol 143 (11) ◽  
pp. 3408-3421 ◽  
Author(s):  
Claudia Ammann ◽  
Michele Dileone ◽  
Cristina Pagge ◽  
Valentina Catanzaro ◽  
David Mata-Marín ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Magnetic Stimulation ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Motor Threshold ◽  
Intracortical Facilitation ◽  
Low Intensity ◽  
Resting Motor Threshold ◽  
Conditioning Stimuli

Abstract In Parkinson’s disease, striatal dopamine depletion produces profound alterations in the neural activity of the cortico-basal ganglia motor loop, leading to dysfunctional motor output and parkinsonism. A key regulator of motor output is the balance between excitation and inhibition in the primary motor cortex, which can be assessed in humans with transcranial magnetic stimulation techniques. Despite decades of research, the functional state of cortical inhibition in Parkinson’s disease remains uncertain. Towards resolving this issue, we applied paired-pulse transcranial magnetic stimulation protocols in 166 patients with Parkinson’s disease (57 levodopa-naïve, 50 non-dyskinetic, 59 dyskinetic) and 40 healthy controls (age-matched with the levodopa-naïve group). All patients were studied OFF medication. All analyses were performed with fully automatic procedures to avoid confirmation bias, and we systematically considered and excluded several potential confounding factors such as age, gender, resting motor threshold, EMG background activity and amplitude of the motor evoked potential elicited by the single-pulse test stimuli. Our results show that short-interval intracortical inhibition is decreased in Parkinson’s disease compared to controls. This reduction of intracortical inhibition was obtained with relatively low-intensity conditioning stimuli (80% of the resting motor threshold) and was not associated with any significant increase in short-interval intracortical facilitation or intracortical facilitation with the same low-intensity conditioning stimuli, supporting the involvement of cortical inhibitory circuits. Short-interval intracortical inhibition was similarly reduced in levodopa-naïve, non-dyskinetic and dyskinetic patients. Importantly, intracortical inhibition was reduced compared to control subjects also on the less affected side (n = 145), even in de novo drug-naïve patients in whom the less affected side was minimally symptomatic (lateralized Unified Parkinson’s Disease Rating Scale part III = 0 or 1, n = 23). These results suggest that cortical disinhibition is a very early, possibly prodromal feature of Parkinson’s disease.

scholarly journals Rehabilitation and Biomarkers of Stroke Recovery: Study Protocol for a Randomized Controlled Trial

2021 ◽  
Vol 11 ◽  
Author(s):  
Alessandro Picelli ◽  
Mirko Filippetti ◽  
Lidia Del Piccolo ◽  
Federico Schena ◽  
Leonardo Chelazzi ◽  
...  
Keyword(s):  
Study Protocol ◽  
Functional Neuroimaging ◽  
Cortical Excitability ◽  
Care Pathway ◽  
Stroke Recovery ◽  
Routine Practice ◽  
Work Package ◽  
Stroke Patients ◽  
Subacute Stroke

Background: Stroke is a leading cause of disability. Nonetheless, the care pathway for stroke rehabilitation takes partially into account the needs of chronic patients. This is due in part to the lack of evidence about the mechanisms of recovery after stroke, together with the poor knowledge of related and influencing factors. Here we report on the study protocol “Rehabilitation and Biomarkers of Stroke Recovery,” which consists of 7 work-packages and mainly aim to investigate the effects of long-term neurorehabilitation on stroke patients and to define a related profile of (clinical-biological, imaging, neurophysiological, and genetic-molecular) biomarkers of long-term recovery after stroke. The work-package 1 will represent the main part of this protocol and aims to compare the long-term effects of intensive self-rehabilitation vs. usual (rehabilitation) care for stroke.Methods: We planned to include a total of 134 adult subacute stroke patients (no more than 3 months since onset) suffering from multidomain disability as a consequence of first-ever unilateral ischemic stroke. Eligible participants will be randomly assigned to one of the following groups: intensive self-rehabilitation (based on the principles of “Guided Self-Rehabilitation Contract”) vs. usual care (routine practice). Treatment will last 1 year, and patients will be evaluated every 3 months according to their clinical presentation. The following outcomes will be considered in the main work-package: Fugl-Meyer assessment, Cognitive Oxford Screen Barthel Index, structural and functional neuroimaging, cortical excitability, and motor and somatosensory evoked potentials.Discussion: This trial will deal with the effects of an intensive self-management rehabilitation protocol and a related set of biomarkers. It will also investigate the role of training intensity on long-term recovery after stroke. In addition, it will define a set of biomarkers related to post-stroke recovery and neurorehabilitation outcome in order to detect patients with greater potential and define long-term individualized rehabilitation programs.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04323501.

scholarly journals Investigating the Intervention Parameters of Endogenous Paired Associative Stimulation (ePAS)

2021 ◽  
Vol 11 (2) ◽  
pp. 224
Author(s):  
Gemma Alder ◽  
Nada Signal ◽  
Alain C. Vandal ◽  
Sharon Olsen ◽  
Mads Jochumsen ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Repeated Measures ◽  
Single Pulse ◽  
Stroke Recovery ◽  
Motor Threshold ◽  
Additive Interaction ◽  
Post Intervention ◽  
Paired Associative Stimulation ◽  
Intervention Efficacy ◽  
Movement Type

Advances in our understanding of neural plasticity have prompted the emergence of neuromodulatory interventions, which modulate corticomotor excitability (CME) and hold potential for accelerating stroke recovery. Endogenous paired associative stimulation (ePAS) involves the repeated pairing of a single pulse of peripheral electrical stimulation (PES) with endogenous movement-related cortical potentials (MRCPs), which are derived from electroencephalography. However, little is known about the optimal parameters for its delivery. A factorial design with repeated measures delivered four different versions of ePAS, in which PES intensities and movement type were manipulated. Linear mixed models were employed to assess interaction effects between PES intensity (suprathreshold (Hi) and motor threshold (Lo)) and movement type (Voluntary and Imagined) on CME. ePAS interventions significantly increased CME compared to control interventions, except in the case of Lo-Voluntary ePAS. There was an overall main effect for the Hi-Voluntary ePAS intervention immediately post-intervention (p = 0.002), with a sub-additive interaction effect at 30 min’ post-intervention (p = 0.042). Hi-Imagined and Lo-Imagined ePAS significantly increased CME for 30 min post-intervention (p = 0.038 and p = 0.043 respectively). The effects of the two PES intensities were not significantly different. CME was significantly greater after performing imagined movements, compared to voluntary movements, with motor threshold PES (Lo) 15 min post-intervention (p = 0.012). This study supports previous research investigating Lo-Imagined ePAS and extends those findings by illustrating that ePAS interventions that deliver suprathreshold intensities during voluntary or imagined movements (Hi-Voluntary and Hi-Imagined) also increase CME. Importantly, our findings indicate that stimulation intensity and movement type interact in ePAS interventions. Factorial designs are an efficient way to explore the effects of manipulating the parameters of neuromodulatory interventions. Further research is required to ensure that these parameters are appropriately refined to maximise intervention efficacy for people with stroke and to support translation into clinical practice.

Effects of water immersion on short- and long-latency afferent inhibition, short-interval intracortical inhibition, and intracortical facilitation

2013 ◽  
Vol 124 (9) ◽  
pp. 1846-1852 ◽  
Author(s):  
Daisuke Sato ◽  
Koya Yamashiro ◽  
Takuya Yoshida ◽  
Hideaki Onishi ◽  
Yoshimitsu Shimoyama ◽  
...  
Keyword(s):  
Water Immersion ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Intracortical Facilitation ◽  
Afferent Inhibition ◽  
Long Latency

Abstract W P386: Matrix Metalloproteinase Levels May Mediate Ischemic Stroke Incidence and Recovery in Stroke Patients with Metabolic Syndrome

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Ashley B Petrone ◽  
Taura L Barr ◽  
Kelly Devlin ◽  
Sara B Fournier ◽  
Evan D Devallance ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Stroke Risk ◽  
Plasma Concentrations ◽  
Stroke Recovery ◽  
Ultrasound Images ◽  
Stroke Patients ◽  
Stroke Incidence ◽  
The Metabolic Syndrome ◽  
Diabetes Status ◽  
Increased Risk

Intro: The metabolic syndrome (MetS) is highly prevalent in the US characterized by a combination of risk factors that can lead to cardiovascular disease (CVD). While the association between CVD, inflammation, and stroke risk has been characterized, the immune mechanisms underlying increased risk of stroke in MetS is unclear. While stroke risk is higher among MetS, MetS individuals tend to have better stroke recovery than controls. The immune response may mediate these paradoxical observations in stroke. In particular, matrix metalloproteinases (MMP) enzymes play a role in stroke incidence and recovery. Similar to MetS, MMPs have a dual role in stroke, as they are harmful immediately after stroke, but play a vital role in brain repair and recovery following stroke. We hypothesize that elevated levels of MMPs in MetS may account for the paradoxical increased stroke risk, yet better recovery seen in stroke patients with MetS. Methods: MMP protein concentrations were obtained from fasting venous samples and quantified using a Multi-Analyte Profiling Kit (Millipore) on the Luminex®. Each subject was assigned a metabolic risk score (MRS) based on sex, age, SBP, treatment for hypertension, smoking and diabetes status, HDL, and total cholesterol. B-mode ultrasound images of the right common carotid artery were obtained to measure intima-medial thickness (cIMT). Spearman correlations were used to measure the relationship between MRS, cIMT, and MMP levels. Results: In n=68 subjects (60% female) with a mean age of 48+14 yrs, MRS of 25+12, and cIMT of 0.57+0.12 mm. MRS was significantly correlated with cIMT (r=0.39, p< .001). Further, cIMT was positively correlated with MMP1 (r=0.025, p=0.04), MMP7 (r=0.5, p=0.01), and MMP9 (r=0.31, p=0.01). Conclusion: Plasma concentrations of MMP1, 7, and 9 were significantly correlated with cIMT, indicating that increased severity of MetS is associated with increased inflammation. Elevated MMP protein levels may account for the increased stroke risk, yet better recovery seen in stroke patients with MetS.

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