Mapping cortical hand motor representation using TMS: A method to assess brain plasticity and a surrogate marker for recovery of function after stroke?

OBJECTIVE: Stroke is associated with reorganization within motor areas of both hemispheres. Mapping the cortical hand motor representation using transcranial magnetic stimulation may help to understand the relationship between motor cortex reorganization and motor recovery of the affected hand after stroke. METHODS: A standardized review of the pertinent literature was performed. RESULTS: We identified 20 trials, which analyzed the relationship between the extent and/or location of cortical hand motor representation using transcranial magnetic stimulation and motor function and recovery of the affected hand. Several correlations were found between cortical reorganization and measures of hand motor impairment and recovery. CONCLUSION: A better understanding of the relationships between the extent and location of cortical hand motor representation and the motor impairment and motor recovery of the affected hand after stroke may contribute to a targeted use of non-invasive brain stimulation protocols. In the future motor mapping may help to guide brain stimulation techniques to the most effective motor area in an affected individual.

Repetitive transcranial magnetic stimulation for motor recovery of the upper limb after stroke.

OBJECTIVE: Repetitive transcranial magnetic stimulation changes excitability of the motor cortex and it has hereby the potential to modulate changes in neural processing which impede motor recovery after stroke. METHODS: This chapter presents an up-to-day systematic review of the treatment effects of repetitive transcranial magnetic stimulation (rTMS) in promoting motor recovery of the affected upper limb after stroke. RESULTS: Thirty-seven trials were included in the analysis. The selected studies involved a total of 871 stroke subjects. All stimulation protocols pride on interhemispheric imbalance model. INTERPRETATION: rTMS enhances motor recovery of the affected hand after stroke; however, the data available until today is too limited to support its routine use.

The Effectiveness of 1 Hz rTMS Over the Primary Motor Area of the Unaffected Hemisphere to Improve Hand Function After Stroke Depends on Hemispheric Dominance.

OBJECTIVE: Inhibition of motor cortex excitability of the contralesional hemisphere may improve dexterity of the affected hand after stroke. METHODS: 40 patients (17 dominant hemispheric stroke, 23 non-dominant hemispheric stroke) with a mild to moderate upper limb motor impairment were enrolled in a double-blind, randomized, placebo-controlled trial with two parallel-groups. Both groups received 15 daily sessions of motor training preceded by either 1 Hz rTMS or sham rTMS. Behavioral and neurophysiological evaluations were performed at baseline, after the first week and after the third week of treatment, and after a 6 months follow-up. RESULTS: In both groups motor function of the affected hand improved significantly. Patients with stroke of the non-dominant hemisphere made a similar improvement, regardless of whether the motor training was preceded by sham or 1 Hz rTMS. Patients with stroke of the dominant hemisphere had a less favorable improvement than those with stroke of the non-dominant hemisphere after motor training preceded by sham rTMS. However, when 1 Hz rTMS preceded the motor training, patients with stroke of the dominant hemisphere made a similar improvement as those with stroke of the non-dominant hemisphere. INTERPRETATION: Motor recovery of the affected upper limb after stroke is determined by dominance of the affected hemisphere. Stroke of the dominant hemisphere is associated with per se poorer improvement of the affected hand. 1 Hz rTMS over the contralesional M1 significantly improves dexterity of the affected hand in patients with stroke of the dominant hemisphere, but not in those with stroke of the non-dominant hemisphere.

Transcranial direct current stimulation for motor recovery of upper limb function after stroke.

BACKROUND: Changes in neural processing after stroke have been postulated to impede recovery from stroke. Transcranial direct current stimulation has the potential to alter cortico-spinal excitability and thereby might be beneficial in stroke recovery. METHODS: We review the pertinent literature prior to 30/09/2013 on transcranial direct current stimulation in promoting motor recovery of the affected upper limb after stroke. RESULTS: We found overall 23 trials (they included 523 participants). All stimulation protocols pride on interhemispheric imbalance model. In a comparative approach, methodology and effectiveness of (a) facilitation of the affected hemisphere, (b) inhibition of the unaffected hemisphere and (c) combined application of transcranial direct current stimulation over the affected and unaffected hemispheres to treat impaired hand function after stroke are presented. CONCLUSIONS: Transcranial direct current stimulation is associated with improvement of the affected upper limb after stroke, but current evidence does not support its routine use.

The influence of weaning duration on rehabilitative outcome in early neurological rehabilitation.

BACKGROUND: We investigated if longer weaning is associated with inferior rehabilitative outcome in critical illness polyneuropathy (CIP) and cerebrovascular diseases (CVD). METHODS: We analysed retrospectively weaning protocols and medical histories of 171 tracheotomized patients with CIP and CVD. We assessed weaning durations (WD), independence in activities of daily living, as assessed by the functional independence measure (FIM), mortality rates and discharge modalities in each cohort. Weaning was performed using synchronized intermittent mandatory ventilation (SIMV) with Autoflow® and assisted spontaneous ventilation (ASV). RESULTS: WD was significantly longer in CIP compared to CVD (p < 0.001). Despite shorter in-patient treatment and longer WD, patients with CIP acquired significantly greater gains of improvement than CVD (p = 0.015). Independent living at home was possible in 43% of patients with CIP and in 26% of CVD. Mortality was equal in both groups (13% vs. 6%, p > 0.05). Chronic obstructive pulmonary disease (COPD) showed a trend towards longer weaning durations in both entities (p = 0.06). Higher age significantly correlated with longer WD (p = 0.038, r = 0.16). Longer rehabilitation duration (RD) positively correlated with higher Delta-FIM (DFIM) in both entities (p = 0.006, r = 0.21). CONCLUSION: Longer weaning and its partly negative influence on rehabilitative outcome can be compensated by longer in-patient rehabilitation in CIP and CVD.

Recovery and outcome of frontal alien hand syndrome after anterior cerebral artery stroke.

Ischemic lesions within the territory of the anterior cerebral artery present with a variety of clinical signs and symptoms. Among these, frontal alien hand syndrome is rare and easily overlooked in the acute clinical setting, but significantly impacts on functional activities of daily life. Given its rareness, very little is known about its long-term outcome. To shade some more light onto this issue, clinical presentation, course of rehabilitation and outcome of two illustrative cases of frontal alien hand syndrome following anterior cerebral artery stroke are presented. Within seven and nine months from symptom onset, respectively, the clinical symptoms of frontal alien hand had resolved completely in both cases. We conclude that frontal alien hand syndrome has a favourable long-term outcome.

Functional neuromuscular stimulation to improve severe hand dysfunction after stroke: does inhibitory rTMS enhance therapeutic efficiency?

BACKGROUND: Novel strategies to improve hand function after stroke are needed. Electromyography-triggered functional neuromuscular stimulation (EMG-FNMS) and repetitive transcranial magnetic stimulation (rTMS) are promising techniques to facilitate recovery of sensory-motor hand dysfunction after stroke. OBJECTIVE: To investigate if 1Hz rTMS over the contralesional primary motor cortex enhances the effectiveness of EMG-triggered FNMS of the hand and finger extensors to improve severe sensory-motor hand dysfunction after stroke. METHODS: 24 subjects with a first stroke received 10 daily sessions of 20 min EMG-triggered FNMS of the hand and finger extensors of the affected forearm preceded by 15 min of either 1Hz rTMS (rTMS group, n = 12) or sham rTMS (control group, n = 12) over the contralesional primary motor cortex. Prior to and after each intervention motor function and spasticity were rated at both hands, and cortical excitability of the contralesional primary motor cortex was assessed. RESULTS: Motor function and spasticity of the affected hand were significantly improved by either intervention, whereas behavioural measures of the unaffected hand did not change. There were no significant differences between both intervention groups. Improvement of motor function of the affected hand was positively correlated with cortical excitability of the contralesional primary motor cortex after EMG-triggered FNMS preceded by 1Hz rTMS. CONCLUSIONS: 1Hz rTMS does not enhance the general effectiveness of EMG-FNMS to the wrist and finger extensors of the affected forearm after stroke. Motor recovery of the severely affected hand after stroke appears to depend on excitability of the contralesional primary motor cortex.

Noninvasive brain stimulation and motor recovery after stroke.

PURPOSE: Upper limb function is the best predictor of long-term disability after stroke. Despite extensive rehabilitation, recovery of upper limb motor function is frequently incomplete after stroke. METHODS: We review the pertinent literature on functional reorganization within the cerebral motor network after stroke and noninvasive techniques to modulate brain function towards beneficial plasticity. RESULTS: Direct current stimulation and repetitive transcranial magnetic stimulation are powerful tools to (i) modulate cortical excitability, (ii) induce remote changes within the cortical motor system and (iii) thereby improve upper limb motor function after stroke. Today no relevant side effects have been reported. CONCLUSIONS: Neuromodulation, by means of noninvasive brain stimulation techniques, has been shown to be a safe, feasible and effective method to promote recovery of motor function after stroke. However, several methodological and theoretical issues remain to be addressed in future work.