Recovery of motor disability and spasticity in post-stroke after repetitive transcranial magnetic stimulation (rTMS)

Efficacy of coupling repetitive transcranial magnetic stimulation and physical therapy to reduce upper-limb spasticity in patients with stroke: a randomized controlled trial

OBJECTIVE

To assess the efficacy of inhibitory repetitive transcranial magnetic stimulation (rTMS) for decreasing upper-limb muscle tone after chronic stroke.

DESIGN

A randomized sham-controlled trial with a 4-week follow-up.

SETTING

Research hospital.

PARTICIPANTS

Patients with stroke (N=20) with poststroke upper limb spasticity.

INTERVENTIONS

The experimental group received rTMS to the primary motor cortex of the unaffected side (1500 pulses; 1Hz; 90% of resting motor threshold for the first dorsal interosseous muscle) in 10 sessions, 3d/wk, and physical therapy (PT). The control group received sham stimulation and PT.

MAIN OUTCOME MEASURES

Modified Ashworth scale (MAS), upper-extremity Fugl-Meyer assessment, FIM, range of motion, and stroke-specific quality-of-life scale. All outcomes were measured at baseline, after treatment (postintervention), and at a 4-week follow-up. A clinically important difference was defined as a reduction of ≥1 in the MAS score.

RESULTS

Friedman test revealed that PT is efficient for significantly reducing the upper limb spasticity of patients only when it is associated with rTMS. In the experimental group, 90% of the patients at postintervention and 55.5% at follow-up showed a decrease of ≥1 in the MAS score, representing clinically important differences. In the control group, 30% of the patients at postintervention and 22.2% at follow-up experienced clinically meaningful changes. There were no differences between the groups at any time for any of the other outcome measures, indicating that both groups demonstrated similar behaviors over time for all variables.

CONCLUSIONS

rTMS associated with PT can be beneficial in reducing poststroke spasticity. However, more studies are needed to clarify the clinical changes underlying the reduction in spasticity induced by noninvasive brain stimulations.

Functional cortical reorganization after low-frequency repetitive transcranial magnetic stimulation plus intensive occupational therapy for upper limb hemiparesis: evaluation by functional magnetic resonance imaging in poststroke patients

BACKGROUND

Low-frequency repetitive transcranial magnetic stimulation of the nonlesional hemisphere combined with occupational therapy significantly improves motor function of the affected upper limb in poststroke hemiparetic patients, but the recovery mechanism remains unclear.

AIMS

To investigate the recovery mechanism using functional magnetic resonance imaging.

METHODS

Forty-seven poststroke hemiparetic patients were hospitalized to receive 12 sessions of 40-min low-frequency repetitive transcranial magnetic stimulation over the nonlesional hemisphere and daily occupational therapy for 15 days. Motor function was evaluated with the Fugl-Meyer Assessment and Wolf Motor Function Test. The functional magnetic resonance imaging with motor tasks was performed at admission and discharge. The laterality index of activated voxel number in Brodmann areas 4 and 6 on functional magnetic resonance imaging was calculated (laterality index range of -1 to +1). Patients were divided into two groups based on functional magnetic resonance imaging findings before the intervention: group 1: patients who showed bilateral activation (n = 27); group 2: patients with unilateral activation (n = 20).

RESULTS

Treatment resulted in improvement in Fugl-Meyer Assessment and Wolf Motor Function Test in the two groups (P < 0·01). The treatment also resulted in a significant increase in laterality index in group 1 (P < 0·05), suggesting a shift in activated voxels to the lesional hemisphere. Patients of group 2 showed a significant increase in lesional hemisphere activation (P < 0·05).

CONCLUSIONS

The results of serial functional magnetic resonance imaging indicated that our proposed treatment can induce functional cortical reorganization, leading to motor functional recovery of the affected upper limb. Especially, it seems that neural activation in the lesional hemisphere plays an important role in such recovery in poststroke hemiparetic patients.

Effect of low-frequency rTMS on motor neuron excitability after stroke

OBJECTIVES

The purpose of this study was to test the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) over the non-lesional hemisphere on motor neuron excitability of the paretic upper limb in post-stroke patients by electrophysiological examination.

MATERIALS AND METHODS

Thirteen post-stroke patients with spastic upper limb hemiparesis were studied (age, 57.5 ± 11.1 years; time after stroke, 55.2 ± 51.4 months). Low-frequency rTMS of 1 Hz was applied for 20 min to the motor cortex of the non-lesional hemisphere. The M-response amplitude and F-wave parameters were recorded in the abductor pollicis brevis muscle following stimulation of the median nerve in both the affected and unaffected upper limbs. The F-wave frequency, F-max/M ratio (ratio of maximum F-wave amplitude to M-response amplitude), and F-mean/M ratio (the ratio of mean F-wave amplitude to the M-response amplitude) were measured before and after the 20-min rTMS, analyzed for both limbs.

RESULTS

Application of low-frequency rTMS did not result in significant changes in the frequency of F-wave and F-max/M ratio in both upper limbs, but significantly decreased F-mean/M ratio in the affected upper limb (P < 0.005), but not in the unaffected limb.

CONCLUSIONS

Low-frequency rTMS applied to the non-lesional hemisphere might be potentially useful therapeutically for post-stroke patients with spastic upper limb hemiparesis.

F-wave suppression induced by suprathreshold high-frequency repetitive trascranial magnetic stimulation in poststroke patients with increased spasticity

OBJECTIVE

High-intensity and high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex was carried out in poststroke patients with increased spasticity, and the changes in F-wave parameters in comparison with M-wave parameters induced by rTMS were examined.

METHODS

Ten-hertz rTMS pulses were delivered to the primary motor cortex of the lesion side at 110% intensity of the resting motor threshold, and F-waves were obtained from the first dorsal interosseous muscle. F-waves were recorded before (pre-stim) and immediately after the end of rTMS (post-stim) in poststroke patients.

RESULTS

F-wave persistence and F/M Amp.Ratio increased significantly in patients with lesions in upper motor tract as compared with healthy subjects (Wilcoxon rank sum test, p = 0.00023 and p = 0.0073, respectively). After the rTMS application, both F-wave persistence and F/M Amp.Ratio decreased significantly (paired t-test, p = 0.0095 and p = 0.037, respectively). However, the F-wave amplitude did not show a statistically significant variance in poststroke patients.

CONCLUSIONS

High-frequency suprathreshold rTMS may suppress the F-waves by enhancing the inhibitory effect on spinal excitability through the corticospinal tract, and F-wave persistence and F/M Amp.Ratio can be used to determine the effect of rTMS on patients with increased spasticity.

Noninvasive brain stimulation for motor recovery after stroke: mechanisms and future views

Repetitive transcranial magnetic stimulation and transcranial direct current stimulation are noninvasive brain stimulation (NIBS) techniques that can alter excitability of the human cortex. Considering the interhemispheric competition occurring after stroke, improvement in motor deficits can be achieved by increasing the excitability of the affected hemisphere or decreasing the excitability of the unaffected hemisphere. Many reports have shown that NIBS application improves motor function in stroke patients by using their physiological peculiarity. For continuous motor improvement, it is important to impart additional motor training while NIBS modulates the neural network between both hemispheres and remodels the disturbed network in the affected hemisphere. NIBS can be an adjuvant therapy for developed neurorehabilitation strategies for stroke patients. Moreover, recent studies have reported that bilateral NIBS can more effectively facilitate neural plasticity and induce motor recovery after stroke. However, the best NIBS pattern has not been established, and clinicians should select the type of NIBS by considering the NIBS mechanism. Here, we review the underlying mechanisms and future views of NIBS therapy and propose rehabilitation approaches for appropriate cortical reorganization.

Transcranial Magnetic Stimulation Combined With Physiotherapy in Rehabilitation of Poststroke Hemiparesis

Background. Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the contralesional primary motor cortex (M1) may improve recovery in patients with hemiparetic stroke. Objective. To evaluate the effectiveness of applying 1 Hz rTMS to the contralesional M1 in addition to physiotherapy during early rehabilitation for stroke patients with hand hemiparesis in a randomized, sham-controlled, double-blind study. Methods. Forty patients with moderate upper extremity hemiparesis were randomized to receive 3 weeks of motor training (45 minutes daily) preceded by 30 minutes of 1 Hz rTMS applied to the contralesional M1 or 30 minutes of sham rTMS. Functional assessment of the paretic hand using the Wolf Motor Function Test was performed before, immediately after, and 3 months after completing treatment. Results. No statistically significant differences were found between the experimental and the control group for hand function (Wolf Motor Function Test; P = .92) or the level of neurological deficit ( National Institutes of Health Stroke Scale [NIHSS]; P = .82) after treatment. Effect sizes for the experimental ( d = 0.5) and the control group ( d = 0.47) were small. Similar results were observed at the 3-month follow-up. Conclusions. The findings did not suggest that rTMS suppression of the contralesional motor cortex augments the effect of early neurorehabilitation for upper limb hemiparesis. Larger trials that stratify subjects based on residual motor function or physiological measures of excitation and inhibition may identify responders in the future.

Systematic review of parameters of stimulation, clinical trial design characteristics, and motor outcomes in non-invasive brain stimulation in stroke

INTRODUCTION/OBJECTIVES

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation are two powerful non-invasive neuromodulatory therapies that have the potential to alter and evaluate the integrity of the corticospinal tract. Moreover, recent evidence has shown that brain stimulation might be beneficial in stroke recovery. Therefore, investigating and investing in innovative therapies that may improve neurorehabilitative stroke recovery are next steps in research and development. Participants/Materials and Methods: This article presents an up-to-date systematic review of the treatment effects of rTMS and tDCS on motor function. A literary search was conducted, utilizing search terms "stroke" and "transcranial stimulation." Items were excluded if they failed to: (1) include stroke patients, (2) study motor outcomes, or (3) include rTMS/tDCS as treatments. Other exclusions included: (1) reviews, editorials, and letters, (2) animal or pediatric populations, (3) case reports or sample sizes ≤2 patients, and (4) primary outcomes of dysphagia, dysarthria, neglect, or swallowing.

RESULTS

Investigation of PubMed English Database prior to 01/01/2012 produced 695 applicable results. Studies were excluded based on the aforementioned criteria, resulting in 50 remaining studies. They included 1314 participants (1282 stroke patients and 32 healthy subjects) evaluated by motor function pre- and post-tDCS or rTMS. Heterogeneity among studies' motor assessments was high and could not be accounted for by individual comparison. Pooled effect sizes for the impact of post-treatment improvement revealed consistently demonstrable improvements after tDCS and rTMS therapeutic stimulation. Most studies provided limited follow-up for long-term effects.

CONCLUSION

It is apparent from the available studies that non-invasive stimulation may enhance motor recovery and may lead to clinically meaningful functional improvements in the stroke population. Only mild to no adverse events have been reported. Though results have been positive results, the large heterogeneity across articles precludes firm conclusions.

rTMS Combined With Task-Oriented Training to Improve Symmetry of Interhemispheric Corticomotor Excitability and Gait Performance After Stroke

Background. The model of interhemispheric competition after stroke has been established for the upper but not for the lower extremity. Repetitive transcranial magnetic stimulation (rTMS) of the brain has been shown to modulate cortical excitability. Objective. The purpose of this study was to investigate the effects of rTMS followed by task-oriented training on cortical excitability and walking performance in individuals with chronic stroke. Methods. A total of 24 patients with average Fugl-Meyer lower limb scores of 17.88 ± 5.27 and average walking speeds of 63.81 ± 18.25 cm/s were randomized into an experimental group and a control group. Participants received rTMS (experimental group) or sham rTMS (control group) followed by task-oriented training (30 minutes) for 10 sessions over 2 weeks. Repetitive TMS was applied at a 1-Hz frequency over the leg area of the motor cortex of the unaffected hemisphere for 10 minutes. Outcomes, including motor-evoked potential (MEP), lower-extremity Fugl-Meyer score, and gait performance, were measured before and after training. Results. Decreased interhemispheric asymmetry of the amplitude of the MEP was noted after rTMS and task-oriented training. Improvement in spatial asymmetry of gait was comparable with increased symmetry in interhemispheric excitability. Motor control and walking ability were also significantly improved after rTMS and task-oriented training. Conclusions. rTMS enhances the effect of task-oriented training in those with chronic stroke, especially by increasing gait spatial symmetry and corticomotor excitability symmetry.

Corticospinal tract integrity correlates with knee extensor weakness in chronic stroke survivors

OBJECTIVE

Muscle weakness develops rapidly after stroke, adversely affecting motor performance, and contributing to reduced functional ability. While the contributions of structural and functional alterations in skeletal muscle to post-stroke weakness have been well described, the relationship between motor pathway integrity, measured using both radiological and electrophysiological techniques, and post-stroke muscle weakness is not clear. This study sought to determine the role of corticospinal tract (CST) integrity on knee extensor weakness in chronic stroke survivors.

METHODS

Knee extensor strength and activation testing were performed at 90° of knee flexion using an interpolated triplet technique. CST integrity was evaluated using data obtained from Diffusion Tensor Imaging and transcranial magnetic stimulation.

RESULTS

Recordings in nine stroke subjects indicated substantial knee extensor weakness and activation deficits in the paretic legs of the stroke survivors. Regression analysis revealed that asymmetry in CST integrity was strongly related to between-leg differences in knee strength.

CONCLUSIONS

The results of this study suggest a strong link between CST integrity and lower extremity strength, and add to the growing evidence of substantial knee extensor weakness and activation impairments in stroke survivors.

SIGNIFICANCE

The findings from this study further our understanding of the anatomical and neurophysiological contributions to motor impairments after stroke, which may benefit clinicians and researchers in the field of stroke rehabilitation.

Effect of transcranial direct current stimulation on motor recovery in patients with subacute stroke

OBJECTIVE

To test the hypothesis that 10 sessions of transcranial direct current stimulation combined with occupational therapy elicit more improvement in motor function of the paretic upper limb than sham stimulation in patients with subacute stroke.

DESIGN

Eighteen patients with subacute stroke with hand motor impairment were randomly assigned to one of the three 10-day sessions of (a) anodal transcranial direct current stimulation over the affected motor cortex, (b) cathodal transcranial direct current stimulation over the unaffected motor cortex, or (c) sham stimulation. Blinded evaluators assessed upper limb motor impairment and global functional state with the Fugl-Meyer Assessment score and the Modified Barthel Index at baseline, 1 day after stimulation, and 6 mos after stimulation.

RESULTS

Baseline scores for Fugl-Meyer Assessment and Modified Barthel Index were comparable in all groups (P > 0.05). At 6-mo follow-up, cathodal transcranial direct current stimulation led to a greater improvement in Fugl-Meyer Assessment than the sham procedure (P < 0.05). There was a significant inverse correlation between baseline Fugl-Meyer Assessment and Fugl-Meyer Assessment increase at 6 mos (r = -0.846; P < 0.01).

CONCLUSIONS

Our results suggest a potentially beneficial effect of noninvasive cortical stimulation during rehabilitative motor training of patients who have suffered from subacute strokes.

Why do some promising brain-stimulation devices fail the next steps of clinical development?

Interest in techniques of noninvasive brain stimulation (NIBS) has been growing exponentially in the last decade. Recent studies have shown that some of these techniques induce significant neurophysiological and clinical effects. Although recent results are promising, there are several techniques that have been abandoned despite positive initial results. In this study, we performed a systematic review to identify NIBS methods with promising preliminary clinical results that were not fully developed and adopted into clinical practice, and discuss its clinical, research and device characteristics. We identified five devices (transmeatal cochlear laser stimulation, transcranial micropolarization, transcranial electrostimulation, cranial electric stimulation and stimulation with weak electromagnetic fields) and compared them with two established NIBS devices (transcranial magnetic stimulation and transcranial direct current stimulation) and with well-known drugs used in neuropsychiatry (pramipexole and escitalopram) in order to understand the reasons why they failed to reach clinical practice and further steps of research development. Finally, we also discuss novel NIBS devices that have recently showed promising results: brain ultrasound and transcranial high-frequency random noise stimulation. Our results show that some of the reasons for the failure of NIBS devices with promising clinical findings are the difficulty to disseminate results, lack of controlled studies, duration of research development, mixed results and lack of standardization.

Long-term effect of repetitive transcranial magnetic stimulation on motor function recovery after acute ischemic stroke

OBJECTIVE

Although there is evidence for short term benefits of rTMS in stroke, longer term effects have not been reported. The aim of the study was to evaluate the effect of two different frequencies of rTMS on motor recovery and on cortical excitability up to 1 year post-treatment.

METHODS

Forty-eight patients with acute ischemic stroke were randomly classified into three groups. The first two groups received real rTMS over motor cortex (3 and 10 Hz respectively) of the affected hemisphere and the third group received sham stimulation of the same site, daily for five consecutive days. Disability was assessed before, after fifth sessions, and then after 1, 2, 3 and 12 months. Cortical excitability was assessed for both hemispheres before and after the second and fifth sessions.

RESULTS

A significant 'rTMS x time' interaction was obtained indicating that real and sham rTMS had different effects on rating scales. This was because real rTMS produced greater improvement than sham that was evident even at one year follow-up. These improvements were associated with changes in cortical excitability over the period of treatment.

CONCLUSION

These results confirm that real rTMS over motor cortex can enhance and maintain recovery and may be a useful add on therapy in treatment of acute stroke patients.