Ipsilesional High Frequency Repetitive Transcranial Magnetic Stimulation Add-On Therapy Improved Diffusion Parameters of Stroke Patients with Motor Dysfunction: A Preliminary DTI Study

Lack of effects of eight-week left dorsolateral prefrontal theta burst stimulation on white matter macro/microstructure and connection in autism

Whether brain stimulation could modulate brain structure in autism remains unknown. This study explored the impact of continuous theta burst stimulation (cTBS) over the left dorsolateral prefrontal cortex (DLPFC) on white matter macro/microstructure in intellectually able children and emerging adults with autism. Sixty autistic participants were randomized (30 active) and received active or sham cTBS for eight weeks twice per week, 16 total sessions using a double-blind (participant-, rater-, analyst-blinded) design. All participants received high-angular resolution diffusion MR imaging at baseline and week 8. Twenty-eight participants in the active group and twenty-seven in the sham group with good imaging quality entered the final analysis. With longitudinal fixel-based analysis and network-based statistics, we found no significant difference between the active and sham groups in changes of white matter macro/microstructure and connections following cTBS. In addition, we found no association between baseline white matter macro/microstructure and autistic symptom changes from baseline to week 8 in the active group. In conclusion, we did not find a significant impact of left DLPFC cTBS on white matter macro/microstructure and connections in children and emerging adults with autism. These findings need to be interpreted in the context that the current intellectually able cohort in a single university hospital site limits the generalizability. Future studies are required to investigate if higher stimulation intensities and/or doses, other personal factors, or rTMS parameters might confer significant brain structural changes visible on MRI in ASD.

Repetitive Transcranial Magnetic Stimulation-Induced Neuroplasticity and the Treatment of Psychiatric Disorders: State of the Evidence and Future Opportunities

Neuroplasticity, or activity-dependent neuronal change, is a crucial mechanism underlying the mechanisms of effect of many therapies for neuropsychiatric disorders, one of which is repetitive transcranial magnetic stimulation (rTMS). Understanding the neuroplastic effects of rTMS at different biological scales and on different timescales and how the effects at different scales interact with each other can help us understand the effects of rTMS in clinical populations and offers the potential to improve treatment outcomes. Several decades of research in the fields of neuroimaging and blood biomarkers is increasingly showing its clinical relevance, allowing measurement of the synaptic, functional, and structural changes involved in neuroplasticity in humans. In this narrative review, we describe the evidence for rTMS-induced neuroplasticity at multiple levels of the nervous system, with a focus on the treatment of psychiatric disorders. We also describe the relationship between neuroplasticity and clinical effects, discuss methods to optimize neuroplasticity, and identify future research opportunities in this area.

Case report: High-frequency repetitive transcranial magnetic stimulation for treatment of hereditary spastic paraplegia type 11

Hereditary spastic paraplegia (HSP) is a heterogeneous group of inherited neurodegenerative disorders that currently have no cure. HSP type 11 (SPG11-HSP) is a complex form carrying mutations in the SPG11 gene. Neuropathological studies demonstrate that motor deficits in these patients are mainly attributed to axonal degeneration of the corticospinal tract (CST). Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique that can induce central nervous system plasticity and promote neurological recovery by modulating the excitability of cortical neuronal cells. Although rTMS is expected to be a therapeutic tool for neurodegenerative diseases, no previous studies have applied rTMS to treat motor symptoms in SPG11-HSP. Here, we report a case of SPG11-HSP with lower extremity spasticity and gait instability, which were improved by applying high-frequency rTMS (HF-rTMS) at the primary motor cortex (M1). Clinical and physiological features were measured throughout the treatment, including the Modified Ashworth Scale (MAS), Berg Balance Scale (BBS), the timed up and go (TUG) test and the 10-meter walk test time (10 MWT). The structure and excitability of the CST were assessed by diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS), respectively. After treatment, the patient gained 17 points of BBS, along with a gradual decrease in MAS scores of the bilateral lower extremity. In addition, the TUG test and 10 MWT improved to varying degrees. TMS assessment showed increased motor evoked potential (MEP) amplitude, decreased resting motor threshold (RMT), decreased central motor conduction time (CMCT), and decreased difference in the cortical silent period (CSP) between bilateral hemispheres. Using the DTI technique, we observed increased fractional anisotropy (FA) values and decreased mean diffusivity (MD) and radial diffusivity (RD) values in the CST. It suggests that applying HF-rTMS over the bilateral leg area of M1 (M1-LEG) is beneficial for SPG11-HSP. In this study, we demonstrate the potential of rTMS to promote neurological recovery from both functional and structural perspectives. It may provide a clinical rationale for using rTMS in the rehabilitation of HSP patients.

Effects of HF-rTMS on microglial polarization and white matter integrity in rats with poststroke cognitive impairment

Poststroke cognitive impairment (PSCI) occurs frequently after stroke, but effective treatments are lacking. Previous studies have revealed that high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) has a beneficial effect on PSCI, but the mechanism is unclear. This study aimed to evaluate the effect of 10 and 20 Hz HF-rTMS on PSCI and the possible mechanisms. An ischemic stroke rat model was established by transient middle cerebral artery occlusion (tMCAO). The modified neurological deficit score (mNSS) and Morris water maze tests were conducted to assess neurological function and cognitive function. Luxol Fast Blue (LFB) staining was performed to evaluate white matter damage. Proinflammatory and anti-inflammatory cytokines were measured using enzyme-linked immunosorbent assays (ELISA). Immunofluorescence was used to assess microglial activation and polarization. Western blotting was performed to measure JAK2-STAT3 pathway-related protein expression. We found that HF-rTMS decreased the neurological deficit score. Compared with 10 Hz HF-rTMS, 20 Hz HF-rTMS more markedly improved the cognitive function of tMCAO rats at day 28 after operation. Furthermore, 20 Hz HF-rTMS attenuates white matter lesion, decreased proinflammatory cytokine levels, and increased anti-inflammatory cytokine levels. It also decreased the number of CD68- and CD16/32-positive microglia and increased the number of CD206-positive microglia. In addition, p-JAK2, JAK2, p-STAT3 and STAT3 expression was increased. These findings suggest that HF-rTMS improves cognitive function and attenuates white matter lesion in tMCAO rats by shifting microglia toward the M2 phenotype. Mechanisms may be related to regulation JAK2-STAT3 pathways.

Ischemic stroke rehabilitation through optogenetic modulation of parvalbumin neurons in the contralateral motor cortex

BACKGROUND

Based on the theory of interhemispheric inhibition and the bimodal balance-recovery model in stroke, we explored the effects of excitation/inhibition (E/I) of parvalbumin (PV) neurons in the contralateral primary motor cortex (cM1) connecting the ipsilateral M1 (iM1) via the corpus callosum (cM1-CC-iM1) of ischemic stroke rats by optogenetic stimulation.

METHODS

We tested this by injecting anterograde and retrograde virus in rats with middle cerebral artery occlusion (MCAO), and evaluated the neurological scores, motor behavior, volume of cerebral infarction and the E/I balance of the bilateral M1 two weeks after employing optogenetic treatment.

RESULTS

We found that concentrations of Glu and GABA decreased and increased, respectively, in the iM1 of MCAO rats, and that the former increased in the cM1, suggesting E/I imbalance in bilateral M1 after ischemic stroke. Interestingly, optogenetic stimulation improved M1 E/I imbalance, as illustrated by the increase of Glu in the iM1 and the decrease of GABA in both iM1 and cM1, which were accompanied by an improvement in neurological deficit and motor dysfunction. In addition, we observed a reduced infarct volume, an increase in the expression of the NMDAR and AMPAR, and a decrease in GAD67 in the iM1 after intervention.

CONCLUSIONS

Optogenetic modulation of PV neurons of the iM1-CC-cM1 improve E/I balance, leading to reduced neurological deficit and improved motor dysfunction following ischemic stroke in rats.

Clinical Effectiveness of Non-Immersive Virtual Reality Tasks for Post-Stroke Neuro-Rehabilitation of Distal Upper-Extremities: A Case Report

A library of non-immersive Virtual Reality (VR) tasks were developed for post-stroke rehabilitation of distal upper extremities. The objective was to evaluate the rehabilitation impact of the developed VR-tasks on a patient with chronic stroke. The study involved a 50-year-old male patient with chronic (13 month) stroke. Twenty VR therapy sessions of 45 min each were given. Clinical scales, cortical-excitability measures, functional MRI (fMRI), and diffusion tensor imaging (DTI) data were acquired pre-and post-therapy to evaluate the motor recovery. Increase in Fugl-Meyer Assessment (wrist/hand) by 2 units, Barthel Index by 5 units, Brunnstrom Stage by 1 unit, Addenbrooke's Cognitive Examination by 3 units, Wrist Active Range of Motion by 5° and decrease in Modified Ashworth Scale by 1 unit were observed. Ipsilesional Motor Evoked Potential (MEP) amplitude (obtained using Transcranial Magnetic Stimulation) was increased by 60.9µV with a decrease in Resting Motor Threshold (RMT) by 7%, and contralesional MEP amplitude was increased by 56.2µV with a decrease in RMT by 7%. The fMRI-derived Laterality Index of Sensorimotor Cortex increased in precentral-gyrus (from 0.28 to 0.33) and in postcentral-gyrus (from 0.07 to 0.3). The DTI-derived FA-asymmetry decreased in precentral-gyrus (from 0.029 to 0.024) and in postcentral-gyrus (from 0.027 to 0.017). Relative reduction in task-specific performance metrics, i.e., time taken to complete the task (31.6%), smoothness of trajectory (76.7%), and relative percentage error (80.7%), were observed from day 1 to day 20 of the VR therapy. VR therapy resulted in improvement in clinical outcomes in a patient with chronic stroke. The research also gives insights to further improve the overall system of rehabilitation.

Repetitive Transcranial Magnetic Stimulation Induces Quantified Functional and Structural Changes in Subcortical Stroke: A Combined Arterial Spin Labeling Perfusion and Diffusion Tensor Imaging Study

Purpose

To explore the changes of cerebral blood flow (CBF) and fractional anisotropy (FA) in stroke patients with motor dysfunction after repetitive transcranial magnetic stimulation (rTMS) treatment, and to better understand the role of rTMS on motor rehabilitation of subcortical stroke patients from the perfusion and structural level.

Materials and Methods

In total, 23 first-episode acute ischemic stroke patients and sixteen healthy controls (HCs) were included. The patients were divided into the rTMS and sham group. The rehabilitation assessments and examination of perfusion and structural MRI were performed before and after rTMS therapy for each patient. Voxel-based analysis was used to detect the difference in CBF and FA among all three groups. The Pearson correlation analysis was conducted to evaluate the relationship between the CBF/FA value and the motor scales.

Results

After rTMS, significantly increased CBF was found in the ipsilesional supplementary motor area, postcentral gyrus, precentral gyrus, pons, medulla oblongata, contralesional midbrain, superior cerebellar peduncle, and middle cerebellar peduncle compared to that during the prestimulation and in the sham group, these fasciculi comprise the cortex-pontine-cerebellum-cortex (CPC) loop. Besides, altered CBF in the ipsilesional precentral gyrus, postcentral gyrus, and pons was positively associated with the improved Fugl-Meyer assessment (FMA) scores. Significantly decreased FA was found in the contralesional precentral gyrus, increased FA was found in the ipsilesional postcentral gyrus, precentral gyrus, contralesional supplementary motor area, and bilateral cerebellum, these fasciculi comprise the corticospinal tract (CST). The change of FMA score was positively correlated with altered FA value in the ipsilesional postcentral gyrus and negatively correlated with altered FA value in the contralesional precentral gyrus.

Conclusion

Our results suggested that rTMS could facilitate the motor recovery of stroke patients. High frequency could promote the improvement of functional activity of ipsilesional CPC loop and the recovery of the microstructure of CST.

Insight Into the Effects of Clinical Repetitive Transcranial Magnetic Stimulation on the Brain From Positron Emission Tomography and Magnetic Resonance Imaging Studies: A Narrative Review

Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a therapeutic tool to alleviate symptoms for neurological and psychiatric diseases such as chronic pain, stroke, Parkinson’s disease, major depressive disorder, and others. Although the therapeutic potential of rTMS has been widely explored, the neurological basis of its effects is still not fully understood. Fortunately, the continuous development of imaging techniques has advanced our understanding of rTMS neurobiological underpinnings on the healthy and diseased brain. The objective of the current work is to summarize relevant findings from positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques evaluating rTMS effects. We included studies that investigated the modulation of neurotransmission (evaluated with PET and magnetic resonance spectroscopy), brain activity (evaluated with PET), resting-state connectivity (evaluated with resting-state functional MRI), and microstructure (diffusion tensor imaging). Overall, results from imaging studies suggest that the effects of rTMS are complex and involve multiple neurotransmission systems, regions, and networks. The effects of stimulation seem to not only be dependent in the frequency used, but also in the participants characteristics such as disease progression. In patient populations, pre-stimulation evaluation was reported to predict responsiveness to stimulation, while post-stimulation neuroimaging measurements showed to be correlated with symptomatic improvement. These studies demonstrate the complexity of rTMS effects and highlight the relevance of imaging techniques.

Cognitive Dysfunction in White Matter Disorders: New Perspectives in Treatment and Recovery

White matter disorders are increasingly appreciated as capable of disrupting cognitive function, and this impairment may be sufficiently severe to produce the syndrome of white matter dementia. Although recognizing this problem is important for diagnostic accuracy, the treatment of cognitive dysfunction and dementia in the white matter disorders has received relatively little attention. Similarly, few data are available regarding the potential for cognitive recovery in these disorders. Recent clinical and laboratory advances, however, indicate that effective treatment and meaningful recovery may be achievable goals for many patients with macrostructural or microstructural white matter pathology. One recent observation is that leukoaraiosis has been observed to regress with treatment of hypertension, often with concomitant improvement in cognition. Equally novel is emerging evidence that white matter exhibits substantial plasticity related to activity-dependent myelination and that this phenomenon may produce clinical benefit. These insights suggest that noninvasive and inexpensive interventions targeting white matter are warranted for a wide range of cognitively impaired patients. Moreover, given the well-established risk that vascular white matter pathology portends for developing dementia-including both vascular dementia and Alzheimer's disease-the application of these principles before dementia onset may also be efficacious for prevention. In view of the increasingly compelling case for early white matter involvement in the etiopathogenesis of late-life dementia and the continuing lack of disease-modifying therapy, progress in treating cognitive disturbances arising from white matter disorders offers the prospect that this approach may enhance the prevention of dementia as well as the treatment of cognitive dysfunction.

Placebo effect of rTMS on post-stroke motor rehabilitation: a meta-analysis

Previous studies have shown that placebo repetitive transcranial magnetic stimulation (rTMS) was effective on post-stroke motor rehabilitation. However, the placebo effect has not been systematically assessed. Therefore, this meta-analysis was conducted to resolve this issue and explore potential influencing factors further. PubMed, Embase, web of science and the Cochrane Library were searched for published randomised controlled trials (RCTs) with placebo rTMS treatment of stroke recovery until May 2019. The placebo effect size (Hedges' g) was estimated using the motor outcome of pre- and post- placebo rTMS treatment. Meta-regression analysis was also performed to explore potential influencing factors for the placebo effect. Twenty-six placebo-controlled trials (including 381 patients in placebo group) were selected. Effect size results (Hedges' g = 0.466, 95% CI 0.207-0.726; P < 0.05) showed a medium and significant placebo rTMS effect on improving post-stroke motor recovery. The mean ratio of the effect size of sham to real stimulation was 56%. Meta-regression analysis did not find significant result except for the treatment sessions, which was significantly correlated with the placebo effect size (r = 0.465, p = 0.031). In the follow-up observations (1, 2 and 3 months), the sham rTMS groups manifested gradually increased motor improvement, which was similar to the real group, but the amplitude was lower, which was sustained for at least 3 months. Placebo effect of rTMS on post-stroke motor recovery was medium but significant. Regarding different sham styles, the number of stimulation sessions had an impact on the effect.

Repetitive Transcranial Magnetic Stimulation on the Affected Hemisphere Enhances Hand Functional Recovery in Subacute Adult Stroke Patients: A Randomized Trial

Objectives: Either motor training or repetitive transcranial magnetic stimulation (rTMS) could modulate the neural plasticity after stroke. Therefore, synchronizing the two interventions may optimize the efficiency of recovery. In the present study, we aim to investigate the effect of rTMS along with hand grip training on the neurobehavioral and hand functional recovery in one cohort of subacute stroke patients. Methods: Thirty-nine stroke patients were enrolled in a single-center, single-blinded, randomized clinical trial. We tested different intervention effects of rTMS and hand grip training (group A), rTMS alone (group B), and hand grip training alone (group C). For the rTMS-treated groups, patients received 10 consecutive sessions of 5-Hz stimulation over the affected hemisphere with 750 pulses. Jebsen-Taylor Hand Function Test (JTHFT), Fugl-Meyer assessment of upper extremity (FMA-UE), grip strength, modified Barthel index (mBI), and ipsilesional motor evoked potential (iMEP) latency were assessed and compared across the groups. Results: We found that only rTMS along with hand grip training group all improved in JTHFT, FMA-UE, grip strength, and mBI (p ≤ 0.01) compared with the baseline among the three groups. Furthermore, this study demonstrated that rTMS plus hand grip training had much better results in improvement of neurobehavioral outcomes compared to the rTMS alone- and hand grip training alone-treated patients (p < 0.05). However, no significant differences were detected in neurophysiologic outcome between intra-groups and inter-groups (p > 0.05). Conclusion: These proof-of-concept results suggested that rTMS alone with hand grip training was a unique approach to promote hand functional recovery in stroke patients. It provided important information to design a large-scale multi-center clinical trial to further demonstrate the efficiency of the combination of central and peripheral stimulation. Clinical Trial Registration: http://www.chictr.org.cn (#ChiCTR1900023443).

The Effect of High-Frequency Repetitive Transcranial Magnetic Stimulation on Functional Indices of Affected Upper Limb in Patients with Subacute Stroke

Background:

Repetitive transcranial magnetic stimulation (rTMS) is a novel technique that may improve recovery in patients with stoke, but the role of rTMS as an applied and practical treatment modality for stroke rehabilitation has not been established yet.

Objective:

This study was conducted to determine the effects of a rehabilitation program (RP) in conjunction with rTMS on functional indices of the paretic upper limb in the subacute phase of stroke.

Material and Methods:

In this experimental study, twenty patients in the subacute phase of stroke were randomly assigned into two groups: The high frequency rTMS (HF-rTMS) in conjunction with RP (experimental group), and the RP group (control group). The experimental group received 10 sessions of 20 Hz rTMS on the affected primary motor cortex and the other group received 10 sessions of RP. In experimental group, RP for the paretic hand was conducted following rTMS session. Box and block test (BBT), Fugl-Meyer Motor Assessment for upper limb (FMA-UL), grip strength and pinch strength were used to assess motor function before the first session and after the last session of treatment.

Results:

Significant improvement in BBT, FMA-UL, grip strength and pinch strength was observed in both groups. Improvement of BBT and grip strength was significantly greater in the experimental group rather than the control group (p<0.05). FMA-UL score and the pinch strength were greater in the experimental group, although the differences were not statistically significant.

Conclusion:

HF-rTMS in conjunction with RP is effective to improve the function of upper limb. It seems HF-rTMS is a novel feasible and safe technique for hemiparesis patients in the subacute phase of stroke.

An overview of fractional anisotropy as a reliable quantitative measurement for the corticospinal tract (CST) integrity in correlation with a Fugl-Meyer assessment in stroke rehabilitation

[Purpose] Understanding the essential mechanisms in post-stroke recovery not only provides important basic insights into brain function and plasticity but can also guide the development of new therapeutic approaches for stroke patients. This review aims to give an overview of how various variables of Magnetic Resonance-Diffusion Tensor Imaging (MR-DTI) metrics of fractional anisotropy (FA) can be used as a reliable quantitative measurement and indicator of corticospinal tract (CST) changes, particularly in relation to functional motor outcome correlation with a Fugl-Meyer assessment in stroke rehabilitation. [Methods] PubMed electronic database was searched for the relevant literature, using key words of diffusion tensor imaging (dti), corticospinal tract, and stroke. [Results] We reviewed the role of FA in monitoring CST remodeling and its role of predicting motor recovery after stroke. We also discussed the mechanism of CST remodeling and its modulation from the value of FA and FMA-UE. [Conclusion] Heterogeneity of post-stroke brain disorganization and motor impairment is a recognized challenge in the development of accurate indicators of CST integrity. DTI-based FA measurements offer a reliable and evidence-based indicator for CST integrity that would aid in predicting motor recovery within the context of stroke rehabilitation.

Axonal remodeling of the corticospinal tract during neurological recovery after stroke

Stroke remains the leading cause of long-term disability. Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor cortex. As the only direct descending motor pathway, the corticospinal tract (CST) is the primary pathway to innervate spinal motor neurons, and thus, forms the neuroanatomical basis to control the peripheral muscles for voluntary movements. Here, we review evidence from both experimental animals and stroke patients, regarding CST axonal damage, functional contribution of CST axonal integrity and remodeling to neurological recovery, and therapeutic approaches aimed to enhance CST axonal remodeling after stroke. The new insights gleaned from preclinical and clinical studies may encourage the development of more rational therapeutics with a strategy targeted to promote axonal rewiring for corticospinal innervation, which will significantly impact the current clinical needs of subacute and chronic stroke treatment.

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

Recovery from motor paralysis is facilitated by affected patients' recognition of the need for and practice of their own exercise goals. Neurorehabilitation has been proposed and used for the treatment of motor paralysis in stroke, and its effect has been verified. If an expected score for the neurorehabilitation effect can be calculated using the Fugl-Meyer Motor Assessment (FMA), a global assessment index, before neurorehabilitation, such a score will be useful for optimizing the treatment application criteria and for setting a goal to enhance the treatment effect. Therefore, this study verified whether the responsiveness to a treatment method, the NovEl intervention using repetitive transcranial magnetic stimulation and occupational therapy (NEURO), in patients with post-stroke upper extremity (UE) motor paralysis could be predicted by the pretreatment FMA score. No control group was established in this study for NEURO treatment. To analyze the recovery of the motor function in the UE, delta-FMA was calculated from the pre- and post-FMA scores obtained during NEURO treatment. The probability of three levels of treatment responsiveness was evaluated in association with delta-FMA score (<5, 5 ≤ delta-FMA <10, and ≥10 as non-responders; responders; and hyper-responders, respectively) according to the reported minimal clinically important difference (MCID). The association of the initial FMA scores with post-FMA scores, from the status of the treatment responsiveness, was determined by multinomial logistic regression analysis. Finally, 1,254 patients with stroke, stratified by FMA scores were analyzed. About 45% of the patients who had FMA scores ranging from 30 to 40 before treatment showed improvement over the MCID by NEURO treatment (odds ratio = 0.93, 95% CI = 0.92–0.95). Furthermore, more than 25% of the patients with more severe initial values, ranging from 26 to 30, improved beyond the MCID calculated in the acute phase (odds ratio = 0.87, 95% CI = 0.85–0.89). These results suggest that the evaluated motor function score of the UE before NEURO treatment can be used to estimate the possibility of a patient recovering beyond MCID in the chronic phase. This study provided clinical data to estimate the effect of NEURO treatment by the pretreatment FMA-UE score.

Novel TMS for Stroke and Depression (NoTSAD): Accelerated Repetitive Transcranial Magnetic Stimulation as a Safe and Effective Treatment for Post-stroke Depression

Background: Post-stroke depression (PSD) affects up to 50% of stroke survivors, reducing quality of life, and increasing adverse outcomes. Conventional therapies to treat PSD may not be effective for some patients. Repetitive transcranial magnetic stimulation (rTMS) is well-established as an effective treatment for Major Depressive Disorder (MDD) and some small trials have shown that rTMS may be effective for chronic PSD; however, no trials have evaluated an accelerated rTMS protocol in a subacute stroke population. We hypothesized that an accelerated rTMS protocol will be a safe and viable option to treat PSD symptoms. Methods: Patients (N = 6) with radiographic evidence of ischemic stroke within the last 2 weeks to 6 months with Hamilton Depression Rating Scale (HAMD-17) scores >7 were recruited for an open label study using an accelerated rTMS protocol as follows: High-frequency (20-Hz) rTMS at 110% resting motor threshold (RMT) was applied to the left dorsolateral prefrontal cortex (DLPFC) during five sessions per day over four consecutive days for a total of 20 sessions. Safety assessment and adverse events were documented based on the patients' responses following each day of stimulation. Before and after the 4-days neurostimulation protocol, outcome measures were obtained for the HAMD, modified Rankin Scale (mRS), functional independence measures (FIM), and National Institutes of Health Stroke Scales (NIHSS). These same measures were obtained at 3-months follow up. Results: HAMD significantly decreased (Wilcoxon p = 0.03) from M = 15.5 (2.81)-4.17 (0.98) following rTMS, a difference which persisted at the 3-months follow-up (p = 0.03). No statistically significant difference in FIM, mRS, or NIHSS were observed. No significant adverse events related to the treatment were observed and patients tolerated the stimulation protocol well overall. Conclusions: This pilot study indicates that an accelerated rTMS protocol is a safe and viable option, and may be an effective alternative or adjunctive therapy for patients suffering from PSD. Future randomized, controlled studies are needed to confirm these preliminary findings. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04093843.

Brain networks and their relevance for stroke rehabilitation

Stroke has long been regarded as focal disease with circumscribed damage leading to neurological deficits. However, advances in methods for assessing the human brain and in statistics have enabled new tools for the examination of the consequences of stroke on brain structure and function. Thereby, it has become evident that stroke has impact on the entire brain and its network properties and can therefore be considered as a network disease. The present review first gives an overview of current methodological opportunities and pitfalls for assessing stroke-induced changes and reorganization in the human brain. We then summarize principles of plasticity after stroke that have emerged from the assessment of networks. Thereby, it is shown that neurological deficits do not only arise from focal tissue damage but also from local and remote changes in white-matter tracts and in neural interactions among wide-spread networks. Similarly, plasticity and clinical improvements are associated with specific compensatory structural and functional patterns of neural network interactions. Innovative treatment approaches have started to target such network patterns to enhance recovery. Network assessments to predict treatment response and to individualize rehabilitation is a promising way to enhance specific treatment effects and overall outcome after stroke.

The effect and optimal parameters of repetitive transcranial magnetic stimulation on motor recovery in stroke patients: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The primary aim of this meta-analysis was to evaluate the effects of repetitive transcranial magnetic stimulation (rTMS) on limb movement recovery post-stroke and cortex excitability, to explore the optimal parameters of rTMS and suitable stroke population. Second, adverse events were also included.

DATA SOURCES

The databases of PubMed, EBSCO, MEDLINE, the Cochrane Central Register of Controlled Trials, EBM Reviews-Cochrane Database, the Chinese National Knowledge Infrastructure, and the Chinese Science and Technology Journals Database were searched for randomized controlled trials exploring the effects of rTMS on limb motor function recovery post-stroke before December 2018.

REVIEW METHODS

The effect sizes of rTMS on limb motor recovery, the effect size of rTMS stimulation parameters, and different stroke population were summarized by calculating the standardized mean difference (SMD) and the 95% confidence interval using fixed/random effect models as appropriate.

RESULTS

For the motor function assessment, 42 eligible studies involving 1168 stroke patients were identified. The summary effect size indicated that rTMS had positive effects on limb motor recovery (SMD = 0.50, P < 0.00001) and activities of daily living (SMD = 0.82, P < 0.00001), and motor-evoked potentials of the stimulated hemisphere differed according to the stimulation frequency, that is, the high-frequency group (SMD = 0.57, P = 0.0006), except the low-frequency group (SMD = -0.27, P = 0.05). No significant differences were observed among the stimulation parameter subgroups except for the sessions subgroup ( P = 0.02). Only 10 included articles reported transient mild discomfort after rTMS.

CONCLUSIONS

rTMS promoted the recovery of limb motor function and changed the cortex excitability. rTMS may be better for early and pure subcortical stroke patients. Regarding different stimulation parameters, the number of stimulation sessions has an impact on the effect of rTMS.

Excitatory Repetitive Transcranial Magnetic Stimulation Induces Contralesional Cortico-Cerebellar Pathways After Acute Ischemic Stroke: A Preliminary DTI Study

Background: Repetitive transcranial magnetic stimulation (rTMS) is proved to be effective in facilitating stroke recovery. However, its therapeutic mechanism remains unclear. The present study aimed to investigate changes in white matter fractional anisotropy (FA) after excitatory rTMS to better understand its role in motor rehabilitation.

Materials and Methods: Acute stroke patients with unilateral subcortical infarction in the middle cerebral artery territory were recruited. The patients were randomly divided into an rTMS treatment group and a sham group. The treatment group received a 10-day 5 HZ rTMS applied over the ipsilesional primary motor area beginning at about 4 days after stroke onset. The sham group received sham rTMS. Diffusion tensor imaging (DTI) data were collected in every patient before and after the rTMS or sham rTMS. Voxel-based analysis was used to study the difference in FA between the two groups. The trial of this article has been registered on the ClinicalTrials.gov and the identifier is NCT03163758.

Results: Before the rTMS, there is no significant difference in FA between the two groups. Differently, after the treatment, the rTMS group showed increased FA in the contralesional corticospinal tract, the pontine crossing tract, the middle cerebellar peduncle, the contralesional superior cerebellar peduncle, the contralesional medial lemniscus, and the ipsilesional inferior cerebellar peduncle. These fasciculi comprise the cortex-pontine-cerebellum-cortex loop. Increased FA was also found in the body of corpus callosum and the contralesional cingulum of the treatment group compared with the sham.

Conclusion: The greater connectivity of contralesional cortico-cerebellar loop and the strengthening of interhemispheric connection may reflect contralesional compensation facilitated by the excitatory rTMS, which gives us a clue to understand the therapeutic mechanism of rTMS.