A Comparison of Primed Low-frequency Repetitive Transcranial Magnetic Stimulation Treatments in Chronic Stroke

Applications of Repetitive Transcranial Magnetic Stimulation to Improve Upper Limb Motor Performance After Stroke: A Systematic Review

BACKGROUND

Noninvasive brain stimulation (NIBS) is a promising technique for improving upper limb motor performance post-stroke. Its application has been guided by the interhemispheric competition model and typically involves suppression of contralesional motor cortex. However, the bimodal balance recovery model prompts a more tailored application of NIBS based on ipsilesional corticomotor function.

OBJECTIVE

To review and assess the application of repetitive transcranial magnetic stimulation (rTMS) protocols that aimed to improve upper limb motor performance after stroke.

METHODS

A PubMed search was conducted for studies published between 1st January 2005 and 1st November 2022 using rTMS to improve upper limb motor performance of human adults after stroke. Studies were grouped according to whether facilitatory or suppressive rTMS was applied to the contralesional hemisphere.

RESULTS

Of the 492 studies identified, 70 were included in this review. Only 2 studies did not conform to the interhemispheric competition model, and facilitated the contralesional hemisphere. Only 21 out of 70 (30%) studies reported motor evoked potential (MEP) status as a biomarker of ipsilesional corticomotor function. Around half of the studies (37/70, 53%) checked whether rTMS had the expected effect by measuring corticomotor excitability (CME) after application.

CONCLUSION

The interhemispheric competition model dominates the application of rTMS post-stroke. The majority of recent and current studies do not consider bimodal balance recovery model for the application of rTMS. Evaluating CME after the application rTMS could confirm that the intervention had the intended neurophysiological effect. Future studies could select patients and apply rTMS protocols based on ipsilesional MEP status.

Repetitive Transcranial Magnetic Stimulation of Primary Motor Cortex for stroke upper limb motor sequelae rehabilitation: A systematic review

BACKGROUND: Repetitive Transcranial Magnetic Stimulation (rTMS) over the primary motor cortex (M1) has been used to treat stroke motor sequelae regulating cortical excitability. Early interventions are widely recommended, but there is also evidence showing interventions in subacute or chronic phases are still useful. OBJECTIVE: To synthetize the evidence of rTMS protocols to improve upper limb motor function in people with subacute and/or chronic stroke. METHODS: Four databases were searched in July 2022. Clinical trials investigating the effectiveness of different rTMS protocols on upper limb motor function in subacute or chronic phases post-stroke were included. PRISMA guidelines and PEDro scale were used. RESULTS: Thirty-two studies representing 1137 participants were included. Positive effects of all types of rTMS protocols on upper limb motor function were found. These effects were heterogeneous and not always clinically relevant or related to neurophysiological changes but produced evident changes if evaluated with functional tests. CONCLUSION: rTMS interventions over M1 are effective for improving upper limb motor function in people with subacute and chronic stroke. When rTMS protocols were priming physical rehabilitation better effects were achieved. Studies considering minimal clinical differences and different dosing will help to generalize the use of these protocols in clinical practice.

Safety and feasibility of transcranial direct current stimulation stratified by corticospinal organization in children with hemiparesis

Children with hemiparesis (CWH) due to stroke early in life face lifelong impairments in motor function. Transcranial direct current stimulation (tDCS) may be a safe and feasible adjuvant therapy to augment rehabilitation. Given the variability in outcomes following tDCS, tailored protocols of tDCS are required. We evaluated the safety, feasibility, and preliminary effects of a single session of targeted anodal tDCS based on individual corticospinal tract organization on corticospinal excitability. Fourteen CWH (age = 13.8 ± 3.63) were stratified into two corticospinal organization subgroups based on transcranial magnetic stimulation (TMS)-confirmed motor evoked potentials (MEP): ipsilesional MEP presence (MEPIL+) or absence (MEPIL-). Subgroups were randomized to real anodal or sham tDCS (1.5 mA, 20 min) applied to the ipsilesional (MEPIL + group) or contralesional (MEPIL- group) hemisphere combined with hand training. Safety was assessed with questionnaires and motor function evaluation, and corticospinal excitability was assessed at baseline and every 15 min for 1 h after tDCS. No serious adverse events occurred and anticipated minor side effects were reported and were self-limiting. Six of 14 participants had consistent ipsilesional MEPs (MEPIL + group). Paretic hand MEP amplitude increased in 5/8 participants who received real anodal tDCS to either the ipsilesional or contralesional hemisphere (+80% change). Application of tDCS based on individual corticospinal organization was safe and feasible with expected effects on excitability, indicating the potential for tailored tDCS protocols for CWH. Additional research involving expanded experimental designs is needed to confirm these effects and to determine if this approach can be translated into a clinically relevant intervention.

Effects of sequential inhibitory and facilitatory repetitive transcranial magnetic stimulation on neurological and functional recovery of a patient with chronic stroke: A case report and literature review

Background and purpose

The effects of conventional protocols of repetitive transcranial magnetic stimulation (rTMS) in the chronic phase of stroke are limited. This study aimed to apply the sequential inhibitory and facilitatory rTMS for upper limb motor dysfunction post-stroke to observe the efficacy and explore the possible neurophysiological mechanism. We hypothesize that this protocol would both enhance the excitability of affected M1 and promote connections among motor areas.

Case description

We reported a 55-year-old female patient with a 1-year chronic stroke and right-sided hemiplegia, who underwent the 14-session rTMS with seven sessions of low frequency (LF) and with seven sessions of high frequency (HF). Clinical scales mainly including Fugl-Meyer Assessment of Upper Extremity (FMA-UE), Action Research Arm Test (ARAT), neurophysiological measures, and functional near-infrared spectroscopy (fNIRS) were assessed before (T0), at the midpoint (T1), and after the intervention (T2).

Outcomes

The patient exhibited post-intervention improvement in upper extremity function. There was increased excitability in the ipsilesional hemisphere and the opposite in the contralesional hemisphere. The interhemispheric inhibition (IHI) ratio increased from 2.70 to 10.81 and finally decreased to 1.34. Oxy-Hb signal was significantly decreased in affected M1 and mildly decreased in unaffected M1, while that of PMC and SMA on the affected side increased significantly.

Conclusion

The sequential inhibitory and facilitatory rTMS significantly promoted motor recovery in the patient. Related mechanisms include upregulation of excitability in the ipsilesional hemisphere, return of interhemispheric balance, and neuroplasticity-induced cortical reorganization.

Comparative Efficacy of Different Repetitive Transcranial Magnetic Stimulation Protocols for Stroke: A Network Meta-Analysis

Background

Although repetitive transcranial magnetic stimulation (rTMS) has been proven to be effective in the upper limb motor function and activities of daily living (ADL), the therapeutic effects of different stimulation protocols have not been effectively compared. To fill this gap, this study carried out the comparison of the upper limb motor function and ADL performance of patients with stroke through a network meta-analysis.

Methods

Randomized controlled trials (RCTs) on the rTMS therapy for stroke were searched from various databases, including PubMed, web of science, Embase, Cochrane Library, ProQuest, Wanfang database, the China National Knowledge Infrastructure (CNKI), and VIP information (www.cqvip.com). The retrieval period was from the establishment of the database to January 2021. Meanwhile, five independent researchers were responsible for the study selection, data extraction, and quality evaluation. The outcome measures included Upper Extremity Fugl-Meyer Assessment (UE-FMA), Wolf Motor Function Test (WMFT), Modified Barthel Index (MBI), the National Institute of Health stroke scale (NIHSS), and adverse reactions. The Gemtc 0.14.3 software based on the Bayesian model framework was used for network meta-analysis, and funnel plots and network diagram plots were conducted using Stata14.0 software.

Results

Ninety-five studies and 5,016 patients were included ultimately. The intervention measures included were as follows: placebo, intermittent theta-burst stimulation (ITBS), continuous theta-burst stimulation (CTBS),1 Hz rTMS,3–5 Hz rTMS, and ≥10 Hz rTMS. The results of the network meta-analysis show that different rTMS protocols were superior to placebo in terms of UE-FMA, NIHSS, and MBI outcomes. In the probability ranking results, ≥10 Hz rTMS ranked first in UE-FMA, WMFT, and MBI. For the NIHSS outcome, the ITBS ranked first and 1 Hz rTMS ranked the second. The subgroup analyses of UE-FMA showed that ≥10 Hz rTMS was the best stimulation protocol for mild stroke, severe stroke, and the convalescent phase, as well as ITBS was for acute and subacute phases. In addition, it was reported in 13 included studies that only a few patients suffered from adverse reactions, such as headache, nausea, and emesis.

Conclusion

Overall, ≥10 Hz rTMS may be the best stimulation protocol for improving the upper limb motor function and ADL performance in patients with stroke. Considering the impact of stroke severity and phase on the upper limb motor function, ≥10 Hz rTMS may be the preferred stimulation protocol for mild stroke, severe stroke, and for the convalescent phase, and ITBS for acute and subacute phases.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier [CRD42020212253].

Effects of transcranial magnetic stimulation in modulating cortical excitability in patients with stroke: a systematic review and meta-analysis

Background

Transcranial magnetic stimulation (TMS) has attracted plenty of attention as it has been proved to be effective in facilitating motor recovery in patients with stroke. The aim of this study was to systematically review the effects of repetitive TMS (rTMS) and theta burst stimulation (TBS) protocols in modulating cortical excitability after stroke.

Methods

A literature search was carried out using PubMed, Medline, EMBASE, CINAHL, and PEDro, to identify studies that investigated the effects of four rTMS protocols—low and high frequency rTMS, intermittent and continuous TBS, on TMS measures of cortical excitability in stroke. A random-effects model was used for all meta-analyses.

Results

Sixty-one studies were included in the current review. Low frequency rTMS was effective in decreasing individuals’ resting motor threshold and increasing the motor-evoked potential of the non-stimulated M1 (affected M1), while opposite effects occurred in the stimulated M1 (unaffected M1). High frequency rTMS enhanced the cortical excitability of the affected M1 alone. Intermittent TBS also showed superior effects in rebalancing bilateral excitability through increasing and decreasing excitability within the affected and unaffected M1, respectively. Due to the limited number of studies found, the effects of continuous TBS remained inconclusive. Motor impairment was significantly correlated with various forms of TMS measures.

Conclusions

Except for continuous TBS, it is evident that these protocols are effective in modulating cortical excitability in stroke. Current evidence does support the effects of inhibitory stimulation in enhancing the cortical excitability of the affected M1.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-00999-4.

Examination and treatment of unilateral spatial neglect using virtual reality in three-dimensional space

Here, we developed a method that randomly generates balloons in the left-right, up-down, and near-far spaces on a monitor using a head-mounted display. In this study, we evaluated a lack of stimulus-driven attention case that was undetected by conventional assessments such as the Behavioral Inattention Test. We could identify mild neglect with our virtual reality method, as later confirmed using the Catherine Bergego scale. After repeated practice under a tilted background space condition, the patient demonstrated a reduction in the time needed to perceive the appearing balloons, suggesting a therapeutic effect.

The effects of continuous oromotor activity on speech motor learning: speech biomechanics and neurophysiologic correlates

Sustained limb motor activity has been used as a therapeutic tool for improving rehabilitation outcomes and is thought to be mediated by neuroplastic changes associated with activity-induced cortical excitability. Although prior research has reported enhancing effects of continuous chewing and swallowing activity on learning, the potential beneficial effects of sustained oromotor activity on speech improvements is not well-documented. This exploratory study was designed to examine the effects of continuous oromotor activity on subsequent speech learning. Twenty neurologically healthy young adults engaged in periods of continuous chewing and speech after which they completed a novel speech motor learning task. The motor learning task was designed to elicit improvements in accuracy and efficiency of speech performance across repetitions of eight-syllable nonwords. In addition, transcranial magnetic stimulation was used to measure the cortical silent period (cSP) of the lip motor cortex before and after the periods of continuous oromotor behaviors. All repetitions of the nonword task were recorded acoustically and kinematically using a three-dimensional motion capture system. Productions were analyzed for accuracy and duration, as well as lip movement distance and speed. A control condition estimated baseline improvement rates in speech performance. Results revealed improved speech performance following 10 min of chewing. In contrast, speech performance following 10 min of continuous speech was degraded. There was no change in the cSP as a result of either oromotor activity. The clinical implications of these findings are discussed in the context of speech rehabilitation and neuromodulation.

Resting motor threshold in the course of hand motor recovery after stroke: a systematic review

Background

Resting motor threshold is an objective measure of cortical excitability. Numerous studies indicate that the success of motor recovery after stroke is significantly determined by the direction and extent of cortical excitability changes. A better understanding of this topic (particularly with regard to the level of motor impairment and the contribution of either cortical hemisphere) may contribute to the development of effective therapeutical strategies in this cohort.

Objectives

This systematic review collects and analyses the available evidence on resting motor threshold and hand motor recovery in stroke patients.

Methods

PubMed was searched from its inception through to 31/10/2020 on studies investigating resting motor threshold of the affected and/or the non-affected hemisphere and motor function of the affected hand in stroke cohorts.

Results

Overall, 92 appropriate studies (including 1978 stroke patients and 377 healthy controls) were identified. The analysis of the data indicates that severe hand impairment is associated with suppressed cortical excitability within both hemispheres and with great between-hemispheric imbalance of cortical excitability. Favorable motor recovery is associated with an increase of ipsilesional motor cortex excitability and reduction of between-hemispheric imbalance. The direction of change of contralesional motor cortex excitability depends on the amount of hand motor impairment. Severely disabled patients show an increase of contralesional motor cortex excitability during motor recovery. In contrast, recovery of moderate to mild hand motor impairment is associated with a decrease of contralesional motor cortex excitability.

Conclusions

This data encourages a differential use of rehabilitation strategies to modulate cortical excitability. Facilitation of the ipsilesional hemisphere may support recovery in general, whereas facilitation and inhibition of the contralesional hemisphere may enhance recovery in severe and less severely impaired patients, respectively.

Current perspectives on the benefits, risks, and limitations of noninvasive brain stimulation (NIBS) for post-stroke dysphagia

INTRODUCTION

Studies have shown that noninvasive brain stimulation (NIBS), including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), can promote neuroplasticity, which is considered important for functional recovery of swallowing after stroke. Despite extensive studies on NIBS, there remains a gap between research and clinical practice.

AREAS COVERED

In this article, we update the current knowledge on the benefits and challenges of rTMS and tDCS for post-stroke dysphagia. We identify some key limitations of these techniques that hinder the translation from clinical trials to routine practice. Finally, we discuss the future of NIBS as a treatment for post-stroke dysphagia in real-world settings.

EXPERT OPINION

Current evidence suggests that rTMS and tDCS show promise as a treatment for post-stroke dysphagia. However, these techniques are limited by the response variability, uncertainty on the safety in patients with comorbidities and difficulties in clinical study designs. Such limitations call for further work to enhance their utility through individualized approaches. Despite this, the last decade has seen a growing acceptance toward these techniques among clinical personnel. As such, we advocate caution but support optimism that NIBS will gradually be recognized as a mainstream treatment approach for post-stroke dysphagia in the future.

Reliability of transcallosal inhibition measurements for the lower limb motor cortex in stroke

Transcallosal inhibition (TCI) is a measure of between-hemisphere inhibitory control that can be evaluated with the ipsilateral silent period (iSP) transcranial magnetic stimulation (TMS) paradigm. The study of iSP for the lower extremity has been limited possibly due to the close orientation of the lower extremity motor representations. Change in TCI can provide insights into pathophysiological mechanisms underlying the asymmetry in corticomotor excitability in stroke. Here, we describe a method for iSP quantification and report reliability of iSP parameters for the tibialis anterior (TA) muscle in stroke. 26 individuals with stroke attended three sessions where single pulse TMS was used to measure TCI from the lesioned to non-lesioned hemisphere. A double cone coil was used for stimulating the ipsilateral motor cortex while the participant maintained an isometric contraction of the non-paretic TA. Absolute and relative reliability were computed for iSP latency, duration and area. iSP latency showed the lowest measurement error (absolute reliability) and iSP latency, duration and area showed good relative reliability (intraclass correlation coefficients > 0.6). This study suggests that iSP parameters for the tibialis anterior are reliable and attempts to provide a guideline for evaluating TCI for the lower extremity in stroke and other clinical populations.

Evidence for interhemispheric imbalance in stroke patients as revealed by combining transcranial magnetic stimulation and electroencephalography

Interhemispheric interactions in stroke patients are frequently characterized by abnormalities, in terms of balance and inhibition. Previous results showed an impressive variability, mostly given to the instability of motor-evoked potentials when evoked from the affected hemisphere. We aim to find reliable interhemispheric measures in stroke patients with a not-evocable motor-evoked potential from the affected hemisphere, by combining transcranial magnetic stimulation (TMS) and electroencephalography. Ninteen stroke patients (seven females; 61.26 ± 9.8 years) were studied for 6 months after a first-ever stroke in the middle cerebral artery territory. Patients underwent four evaluations: clinical, cortical, corticospinal, and structural. To test the reliability of our measures, the evaluations were repeated after 3 weeks. To test the sensitivity, 14 age-matched healthy controls were compared to stroke patients. In stroke patients, stimulation of the affected hemisphere did not result in any inhibition onto the unaffected. The stimulation of the unaffected hemisphere revealed a preservation of the inhibition mechanism onto the affected. This resulted in a remarkable interhemispheric imbalance, whereas this mechanism was steadily symmetric in healthy controls. This result was stable when cortical evaluation was repeated after 3 weeks. Importantly, patients with a better recovery of the affected hand strength were the ones with a more stable interhemispheric balance. Finally, we found an association between microstructural integrity of callosal fibers, suppression of interhemispheric TMS-evoked activity and interhemispheric connectivity. We provide direct and sensitive cortical measures of interhemispheric imbalance in stroke patients. These measures offer a reliable means of distinguishing healthy and pathological interhemispheric dynamics.

Low-intensity contralesional electrical theta burst stimulation modulates ipsilesional excitability and enhances stroke recovery

Targeting interhemispheric inhibition using brain stimulation has shown potential for enhancing stroke recovery. Following stroke, increased inhibition originating from the contralesional hemisphere impairs motor activation in ipsilesional areas. We have previously reported that low-intensity electrical theta burst stimulation (TBS) applied to an implanted electrode in the contralesional rat motor cortex reduces interhemispheric inhibition, and improves functional recovery when commenced three days after cortical injury. Here we apply this approach at more clinically relevant later time points and measure recovery from photothrombotic stroke, following three weeks of low-intensity intermittent TBS (iTBS), continuous TBS (cTBS) or sham stimulation applied to the contralesional motor cortex. Interhemispheric inhibition and cellular excitability were measured in the same rats from single pyramidal neurons in the peri-infarct area, using in vivo intracellular recording. A minimal dose of iTBS did not enhance motor function when applied beginning one month after stroke. However both a high and a low dose of iTBS improved recovery to a similar degree when applied 10 days after stroke, with the degree of recovery positively correlated with ipsilesional excitability. The final level of interhemispheric inhibition was negatively correlated with excitability, but did not independently correlate with functional recovery. In contrast, contralesional cTBS left recovery unaltered, but decreased ipsilesional excitability. These data support focal contralesional iTBS and not cTBS as an intervention for enhancing stroke recovery and suggest that there is a complex relationship between functional recovery and interhemispheric inhibition, with both independently associated with ipsilesional excitability.

Safety and Feasibility of Transcranial Magnetic Stimulation as an Exploratory Assessment of Corticospinal Connectivity in Infants After Perinatal Brain Injury: An Observational Study

BACKGROUND

Perinatal brain injuries often impact the corticospinal system, leading to motor impairment and cerebral palsy. Although transcranial magnetic stimulation (TMS) has been widely used to study corticospinal connectivity in adults and older children, similar studies of young infants are limited.

OBJECTIVES

The objective was to establish the safety and feasibility of advanced TMS assessments of the corticospinal connectivity of young infants with perinatal brain injury.

DESIGN

This was a pilot, cross-sectional study of 3- to 12-month-old (corrected age) infants with perinatal stroke or intracranial hemorrhage.

METHODS

Six participants (2 term, 4 preterm) were assessed with stereotactic neuronavigation-guided TMS. Single-pulse TMS was applied to each hemisphere and responses were recorded simultaneously from both upper limbs. During data collection, vital signs and stress responses were measured to assess safety. Developmental motor outcomes were evaluated using the General Movements Assessment and Bayley Scales of Infant and Toddler Development (3rd edition). A clinical diagnosis of cerebral palsy was recorded, if available.

RESULTS

No adverse events occurred during TMS testing. All sessions were well tolerated. Contralateral motor evoked responses were detected in 4 of 6 participants. Both contralateral and ipsilateral responses were observed in 2 of 6 participants.

LIMITATIONS

TMS responses were not obtained in all participants. This could be related to the location of brain injury or developmental stage of the corticospinal system controlling the wrist flexor muscle group from which responses were recorded.

CONCLUSIONS

This study provides a summary of the framework for performing novel TMS assessments in infants with perinatal brain injury. Implementing this approach to measure corticospinal connectivity in hypothesis-driven studies in young infants appears to be justified. Such studies could inform the characterization of corticospinal development and the neural mechanisms driving recovery following early interventions.

Influence of Combined Transcranial Direct Current Stimulation and Motor Training on Corticospinal Excitability in Children With Unilateral Cerebral Palsy

Combined non-invasive brain stimulation (NIBS) and rehabilitation interventions have the potential to improve function in children with unilateral cerebral palsy (UCP), however their effects on developing brain function are not well understood. In a proof-of-principle study, we used single-pulse transcranial magnetic stimulation (TMS) to measure changes in corticospinal excitability and relationships to motor performance following a randomized controlled trial consisting of 10 days of combined constraint-induced movement therapy (CIMT) and cathodal transcranial direct current stimulation (tDCS) applied to the contralesional motor cortex. Twenty children and young adults (mean age = 12 years, 9 months, range = 7 years, 7 months, 21 years, 7 months) with UCP participated. TMS testing was performed before, after, and 6 months after the intervention to measure motor evoked potential (MEP) amplitude and cortical silent period (CSP) duration. The association between neurophysiologic and motor outcomes and differences in excitability between hemispheres were examined. Contralesional MEP amplitude decreased as hypothesized in five of five participants receiving active tDCS immediately after and 6 months after the intervention, however no statistically significant differences between intervention groups were noted for MEP amplitude [mean difference = −323.9 μV, 95% CI = (−989, 341), p = 0.34] or CSP duration [mean difference = 3.9 ms, 95% CI = (−7.7, 15.5), p = 0.51]. Changes in corticospinal excitability were not statistically associated with improvements in hand function after the intervention. Across all participants, MEP amplitudes measured in the more-affected hand from both contralesional (mean difference = −474.5 μV) and ipsilesional hemispheres (−624.5 μV) were smaller compared to the less-affected hand. Assessing neurophysiologic changes after tDCS in children with UCP provides an understanding of long-term effects on brain excitability to help determine its potential as a therapeutic intervention. Additional investigation into the neurophysiologic effects of tDCS in larger samples of children with UCP are needed to confirm these findings.

Stepping Up to Rethink the Future of Rehabilitation: IV STEP Considerations and Inspirations

BACKGROUND AND PURPOSE

The IV STEP conference challenged presenters and participants to consider the state of science in rehabilitation, highlighting key area of progress since the previous STEP conference related to prediction, prevention, plasticity, and participation in rehabilitation.

KEY POINTS

Emerging from the thought-provoking discussions was recognition of the progress we have made as a profession and a call for future growth. In this summary article, we present a recap of the key points and call for action. We review the information presented and the field at large as it relates to the 4 Ps: prediction, prevention, plasticity, and participation.

RECOMMENDATIONS FOR PRACTICE

Given that personalized medicine is an increasingly important approach that was clearly woven throughout the IV STEP presentations, we took the liberty of adding a fifth "P," Personalized, in our discussion of the future direction of the profession.

Low-frequency rTMS of the unaffected hemisphere in stroke patients: A systematic review

The aim of this review was to summarize the evidence for the effectiveness of low-frequency (LF) repetitive transcranial magnetic stimulation (rTMS) over the unaffected hemisphere in promoting functional recovery after stroke. We performed a systematic search of the studies using LF-rTMS over the contralesional hemisphere in stroke patients and reviewed the 67 identified articles. The studies have been gathered together according to the time interval that had elapsed between the stroke onset and the beginning of the rTMS treatment. Inhibitory rTMS of the contralesional hemisphere can induce beneficial effects on stroke patients with motor impairment, spasticity, aphasia, hemispatial neglect and dysphagia, but the therapeutic clinical significance is unclear. We observed considerable heterogeneity across studies in the stimulation protocols. The use of different patient populations, regardless of lesion site and stroke aetiology, different stimulation parameters and outcome measures means that the studies are not readily comparable, and estimating real effectiveness or reproducibility is very difficult. It seems that careful experimental design is needed and it should consider patient selection aspects, rTMS parameters and clinical assessment tools. Consecutive sessions of rTMS, as well as the combination with conventional rehabilitation therapy, may increase the magnitude and duration of the beneficial effects. In an increasing number of studies, the patients have been enrolled early after stroke. The prolonged follow-up in these patients suggests that the effects of contralesional LF-rTMS can be long-lasting. However, physiological evidence indicating increased synaptic plasticity, and thus, a more favourable outcome, in the early enrolled patients, is still lacking. Carefully designed clinical trials designed are required to address this question. LF rTMS over unaffected hemisphere may have therapeutic utility, but the evidence is still preliminary and the findings need to be confirmed in further randomized controlled trials.

Effectiveness of repetitive transcranial magnetic stimulation (rTMS) after acute stroke: A one-year longitudinal randomized trial

AIMS

To evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) on motor recovery after stroke using a prospective, double-blind, randomized, sham-controlled study.

METHODS

Patients with unilateral subcortical infarction in the middle cerebral artery territory within 1 week after onset were enrolled. The patients were randomly divided into an rTMS treatment group and a sham group. We performed high-frequency rTMS or sham rTMS on the two groups. Motor functional scores were assessed pre- and post-rTMS/sham rTMS and at 1 month, 3 months, 6 months, and 1 year after stroke onset. The scores included the National Institutes of Health Stroke Scale (NIHSS), Barthel Index (BI), Fugl-Meyer Assessment Upper Limb/Lower Limb (FMA-UL/LL), modified Rank Score (mRS), and the resting motor threshold (RMT) of the hemiplegic limb.

RESULTS

At baseline, no significant differences were found between the two groups for motor functional scores. On the second day after rTMS treatment, score improvements of the NIHSS, BI, FMA-UL in the real treatment group were more significant than those in the sham group. In addition, similar results were obtained at 1 month. However, at 3 months, 6 months, and 1 year after onset, no significant differences in improvement were observed between the two groups, except for the FMA-UL score improvement.

CONCLUSION

rTMS facilitates motor recovery of acute stroke patients, and the effect can last to 1 month, except the function improvement on upper extremities could last for 1 year. A single course of rTMS in the acute stage may induce the improvement of upper extremities function lasted for 1 year.

Stepping Up to Rethink the Future of Rehabilitation: IV STEP Considerations and Inspirations

BACKGROUND AND PURPOSE

The IV STEP conference challenged presenters and participants to consider the state of science in rehabilitation, highlighting key area of progress since the previous STEP conference related to prediction, prevention, plasticity, and participation in rehabilitation.

KEY POINTS

Emerging from the thought-provoking discussions was recognition of the progress we have made as a profession and a call for future growth. In this summary article, we present a recap of the key points and call for action. We review the information presented and the field at large as it relates to the 4 Ps: prediction, prevention, plasticity, and participation.

RECOMMENDATIONS FOR PRACTICE

Given that personalized medicine is an increasingly important approach that was clearly woven throughout the IV STEP presentations, we took the liberty of adding a fifth "P," Personalized, in our discussion of the future direction of the profession.

Interhemispheric Inhibition Measurement Reliability in Stroke: A Pilot Study

OBJECTIVE

Reliable transcranial magnetic stimulation (TMS) measures for probing corticomotor excitability are important when assessing the physiological effects of noninvasive brain stimulation. The primary objective of this study was to examine test-retest reliability of an interhemispheric inhibition (IHI) index measurement in stroke.

MATERIALS AND METHODS

Ten subjects with chronic stroke (≥6 months) completed two IHI testing sessions per week for three weeks (six testing sessions total). A single investigator measured IHI in the contra-to-ipsilesional primary motor cortex direction and in the opposite direction using bilateral paired-pulse TMS. Weekly sessions were separated by 24 hours with a 1-week washout period separating testing weeks. To determine if motor-evoked potential (MEP) quantification method affected measurement reliability, IHI indices computed from both MEP amplitude and area responses were found. Reliability was assessed with two-way, mixed intraclass correlation coefficients (ICC_(3,k) ). Standard error of measurement and minimal detectable difference statistics were also determined.

RESULTS

With the exception of the initial testing week, IHI indices measured in the contra-to-ipsilesional hemisphere direction demonstrated moderate to excellent reliability (ICC = 0.725-0.913). Ipsi-to-contralesional IHI indices depicted poor or invalid reliability estimates throughout the three-week testing duration (ICC= -1.153-0.105). The overlap of ICC 95% confidence intervals suggested that IHI indices using MEP amplitude vs. area measures did not differ with respect to reliability.

CONCLUSIONS

IHI indices demonstrated varying magnitudes of reliability irrespective of MEP quantification method. Several strategies for improving IHI index measurement reliability are discussed.

Combining Robotic Training and Non-Invasive Brain Stimulation in Severe Upper Limb-Impaired Chronic Stroke Patients

Previous studies suggested that both robot-assisted rehabilitation and non-invasive brain stimulation can produce a slight improvement in severe chronic stroke patients. It is still unknown whether their combination can produce synergistic and more consistent improvements. Safety and efficacy of this combination has been assessed within a proof-of-principle, double-blinded, semi-randomized, sham-controlled trial. Inhibitory continuous Theta Burst Stimulation (cTBS) was delivered on the affected hemisphere, in order to improve the response to the following robot-assisted therapy via a homeostatic increase of learning capacity. Twenty severe upper limb-impaired chronic stroke patients were randomized to robot-assisted therapy associated with real or sham cTBS, delivered for 10 working days. Eight real and nine sham patients completed the study. Change in Fugl-Meyer was chosen as primary outcome, while changes in several quantitative indicators of motor performance extracted by the robot as secondary outcomes. The treatment was well-tolerated by the patients and there were no adverse events. All patients achieved a small, but significant, Fugl-Meyer improvement (about 5%). The difference between the real and the sham cTBS groups was not significant. Among several secondary end points, only the Success Rate (percentage of targets reached by the patient) improved more in the real than in the sham cTBS group. This study shows that a short intensive robot-assisted rehabilitation produces a slight improvement in severe upper-limb impaired, even years after the stroke. The association with homeostatic metaplasticity-promoting non-invasive brain stimulation does not augment the clinical gain in patients with severe stroke.

Effects of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper limb motor dysfunction in patients with subacute cerebral infarction

Studies have confirmed that low-frequency repetitive transcranial magnetic stimulation can decrease the activity of cortical neurons, and high-frequency repetitive transcranial magnetic stimulation can increase the excitability of cortical neurons. However, there are few studies concerning the use of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper-limb motor function after cerebral infarction. We hypothesized that different frequencies of repetitive transcranial magnetic stimulation in patients with cerebral infarction would produce different effects on the recovery of upper-limb motor function. This study enrolled 127 patients with upper-limb dysfunction during the subacute phase of cerebral infarction. These patients were randomly assigned to three groups. The low-frequency group comprised 42 patients who were treated with 1 Hz repetitive transcranial magnetic stimulation on the contralateral hemisphere primary motor cortex (M1). The high-frequency group comprised 43 patients who were treated with 10 Hz repetitive transcranial magnetic stimulation on ipsilateral M1. Finally, the sham group comprised 42 patients who were treated with 10 Hz of false stimulation on ipsilateral M1. A total of 135 seconds of stimulation was applied in the sham group and high-frequency group. At 2 weeks after treatment, cortical latency of motor-evoked potentials and central motor conduction time were significantly lower compared with before treatment. Moreover, motor function scores were significantly improved. The above indices for the low- and high-frequency groups were significantly different compared with the sham group. However, there was no significant difference between the low- and high-frequency groups. The results show that low- and high-frequency repetitive transcranial magnetic stimulation can similarly improve upper-limb motor function in patients with cerebral infarction.