Stimulation In Healthy Subjects Research Articles

Age-related changes in laser-evoked potentials following trigeminal and hand stimulation in healthy subjects.

This study aimed to evaluate age-related changes in laser-evoked potential (LEP) features, including habituation, via trigeminal and hand stimulation in a large group of healthy volunteers. We recorded the LEPs by right-hand stimulation in 237 healthy subjects and by stimulation of the right supraorbital zone in 170 cases. The subjects ranged in age from 7 to 72years and were divided into six groups by age. At the trigeminal level, the N2 and P2 latencies were significantly shorter and the N2-P2 amplitude was significantly larger in the 7-17 age group than in the other groups. The N2-P2 amplitude of the responses evoked by hand stimulation was significantly larger in the 7-40 age range than in the older subjects. The N1 amplitude and latency were not significantly different among the groups. The N2-P2 habituation increased with age, but no significant changes among groups were revealed by the Bonferroni test. Trigeminal vertex LEPs have greater amplitudes and appear earlier in children, while a progressive age-related amplitude decrease characterizes the N2-P2 waves associated with hand stimulation. The N2-P2 habituation increases in older people. The N1 latency and amplitude seem to remain stable during ageing and are therefore potentially reliable and useful patterns for nociceptive system examination. Standardization of age-related changes in trigeminal and hand LEPs is possible and should improve their reliability in the objective assessment of pain pathways.

Strengthening of Quadriceps by Neuromuscular Magnetic Stimulation in Healthy Subjects

BackgroundQuadriceps muscle strengthening is one of the rehabilitation strategies for improving walking in some people with gait impairments, and neuromuscular electrical stimulation (NMES) has been used for that reason. The strengthening effect of neuromuscular magnetic stimulation (NMMS) on the quadriceps has been demonstrated in various conditions, but not specifically for gait training. The purpose of this study was to determine whether the effect of NMMS is clinically applicable. ObjectiveTo determine the effect of NMMS on quadriceps muscle strength, cross-sectional area (CSA) and thickness in healthy subjects. DesignSingle-blind, prospective, case-control study. SettingTertiary academic hospital setting. ParticipantsA total of 40 healthy volunteers were randomly assigned to an NMMS (n = 20) or control group (n = 20). InterventionsFifteen minutes of quadriceps NMMS of at maximum tolerable intensity, 3 times per week for 5 weeks. Main Outcome MeasurementsAt baseline and after the intervention, the CSA and thicknesses of the rectus femoris and vastus intermedius were measured by ultrasound. Isometric and isokinetic maximal and average peak torques of the dominant side knee extensors were also measured at pre- and postintervention. ResultsThere were no between-group differences in strength, CSA, or muscle thickness at baseline. Isometric maximum and average peak torque of NMMS group were increased significantly after 5 weeks of intervention (P < .001). The isokinetic maximum and average peak torque of NMMS group were increased significantly at both angle velocities of 60°/sec and 120°/sec after 5 weeks of intervention (P < .001). However, neither group showed a significant difference in cross-sectional area or thickness after training. ConclusionNMMS can be a useful strengthening method for large skeletal muscles such as the quadriceps. Level of EvidenceII

65. Intracortical and interhemispheric changes induced by Transcutaneous spinal Direct Current Stimulation (tsDCS)

Transcutaneous spinal Direct Current Stimulation (tsDCS) is a new and safe technique for modulating spinal cord excitability. We evaluated the effects of supraspinal and cortical stimulation in healthy subjects before (T0) and at different intervals (T1, T2) after anodal, cathodal and sham tsDCS (20′, 2.0 mA) applied over the thoracic spinal cord (T10–T12). We studied the effects of tsDCS on cortical Silent Period (cSP), paired-pulse short intracortical inhibition (SICI, interstimulus interval = 3 ms), intracortical facilitation (ICF, ISI = 10 ms), interhemispheric motor connectivity and visual processing (ipsilateral Silent Period, iSP; Transcallosal Conduction Time, TCT; hemifield Visual Evoked Potentials, hVEPs). Cathodal tsDCS (c-tsDCS) decreased SICI, while anodal one elicited opposite effects (FDI: p = 0.0023; TA: p = 0.0004); conversely, tsDCS left ICF and cSP duration unchanged. Moreover, anodal tsDCS increased TCT (p < 0.001) and the interhemispheric delay for both the main VEP components (N1: p = 0.0003; P1: p < 0.0001), dampening at the same time iSP duration (APB: p < 0.0001; AH: p = 0.0005; deltoid: p < 0.0001), while cathodal stimulation had opposite effects (p < 0.0001). tsDCS a useful approach, complementary to either SCS or non-invasive brain stimulation techniques, to restore spinal drive through supra-spinal modulating mechanisms; tsDCS could also represent an early rehabilitation strategy in patients with sub-acute brain lesions, when transcranial stimulation is avoided due to safety concerns.

Effect of attentional focus on the motor system excitability assessed by single pulsed transcranial magnetic stimulation in healthy subjects: A pilot study

Effect of attentional focus on the motor system excitability assessed by single pulsed transcranial magnetic stimulation in healthy subjects: A pilot study

Normative data of cortical excitability measurements obtained by transcranial magnetic stimulation in healthy subjects

The assessment of cortical excitability (CE) measurements has been increasingly used in neuropsychiatric research. However, there is scant information on the normative values of these measurements, as well as the possible effect of hemisphere laterality, gender and age on these variables. To obtain normative data for CE measurements by transcranial magnetic stimulation, to assess inter-/intra-investigator variability and the influence of sex, age and oral contraception use. A sample of 216healthy volunteers matched according to age and gender was evaluated. Bilateral rest motor thresholds, motor evoked potentials (MEP), intracortical inhibition and facilitation were measured in the first dorsal interosseous muscle area representation of the primary motor cortex with a circular transcranial magnetic stimulation coil delivering biphasic pulses. Normative data were obtained for 200participants (in a 1:1 male:female ratio) in a balanced proportion between five age groups (18-30; 31-40; 41-50; 51-60; >60years). Inter/intra-investigator variability was assessed in 20healthy volunteers in two sessions performed within a 30-minute interval. Measurements were also performed in a subgroup of 16healthy female volunteers, using oral contraception and during the menstrual phase. Age had a dichotomous effect on CE measurements, providing significantly different normative data for subjects <50 and >50years old, with smaller MEP's and intracortical inhibition in older individuals. There were no differences between genders or between left and right hemispheres. Also, CE parameters did not significantly differ with use of contraceptive treatment compared to the menstrual phase of the cycle. The inter-/intra-investigator reliability assessment showed some variability that may not be clinically significant. Age had a non-linear effect on CE. There were non-significant differences between genders, hemispheres or with use of oral contraceptives. There was good inter-/intra-investigator correlation for rest motor thresholds and motor evoked potentials while intracortical inhibition and facilitation had low correlations but acceptable reliability.

Neuromagnetic effects of pico-Tesla stimulation

We used a double-blind experimental design to look for an effect of pico-Tesla magnetic stimulation in healthy subjects. Pico-Tesla stimulation is thought to increase the dominant frequency of 2–7 Hz oscillations in the human brain. We used magnetoencephalography to measure resting state brain activity. Each subject had two separate recording sessions consisting of three runs in between which they were given real or sham pT stimulation. We then tried to predict the real and sham stimulation sessions based on changes in the mean peak frequency in the 2–7 Hz band. Our predictions for these individual runs were 8 out of 14 at chance level (p = 0.39). After unblinding, we found no significant effect (p = 0.11) of an increase in the frequency range (2–7 Hz) across the subject group. Finally, we performed a Bayesian model comparison between the effect size predicted from previous clinical studies and a null model. Even though this study had a sensitivity advantage of at least one order of magnitude over previous work, we found the null model to be significantly (2000 times) more likely.

Complex regional pain syndrome (CRPS) or continuous unilateral distal experimental pain stimulation in healthy subjects does not bias visual attention towards one hemifield.

In natural life pain automatically draws attention towards the painful body part suggesting that it interacts with different attentional mechanisms such as visual attention. Complex regional pain syndrome (CRPS) patients who typically report on chronic distally located pain of one extremity may suffer from so-called neglect-like symptoms, which have also been linked to attentional mechanisms. The purpose of the study was to further evaluate how continuous pain conditions influence visual attention. Saccade latencies were recorded in two experiments using a common visual attention paradigm whereby orientating saccades to cued or uncued lateral visual targets had to be performed. In the first experiment saccade latencies of healthy subjects were measured under two conditions: one in which continuous experimental pain stimulation was applied to the index finger to imitate a continuous pain situation, and one without pain stimulation. In the second experiment saccade latencies of patients suffering from CRPS were compared to controls. The results showed that neither the continuous experimental pain stimulation during the experiment nor the chronic pain in CRPS led to an unilateral increase of saccade latencies or to a unilateral increase of the cue effect on latency. The results show that unilateral, continuously applied pain stimuli or chronic pain have no or only very limited influence on visual attention. Differently from patients with visual neglect, patients with CRPS did not show strong side asymmetries of saccade latencies or of cue effects on saccade latencies. Thus, neglect-like clinical symptoms of CRPS patients do not involve the allocation of visual attention.

Neural control of hand movements.

Most of our daily actions involve movements of the hand. The neuronal pathway contributing to the control of hand movements are complex and not yet completely understood. Recent studies highlight how task-dependent changes in cortical and subcortical pathways driven by contralateral and ipsilateral influences may open avenues to further understand the complexity of hand actions in healthy and disease. In the following section studies using transcranial magnetic and electrical stimulation in healthy subjects and in individuals with chronic incomplete spinal cord injury will be highlighted to further understand neuronal pathways involved in the control of voluntary activity by hand muscles.

Subjective Visual Vertical during Caloric Stimulation in Healthy Subjects: Implications to Research and Neurorehabilitation

Background. The subjective visual vertical (SVV) is a perception often impaired in patients with neurologic disorders and is considered a sensitive tool to detect otolithic dysfunctions. However, it remains unclear whether the semicircular canals (SCCs) are also involved in the visual vertical perception. Objective. The aim of this study was to analyze the influence of horizontal SCCs on SVV by caloric stimulation in healthy subjects. Methods. SVV was performed before and during the ice-cold caloric stimulation (4°C, right ear) in 30 healthy subjects. Results. The mean SVV tilts before and during the caloric stimulation were 0.31° ± 0.39 and −0.28° ± 0.40, respectively. There was no significant difference between the mean SVV tilts before and during stimulation (p = 0.113). Conclusion. These results suggest that horizontal SCCs do not influence SVV. Therefore, investigations and rehabilitation approaches for SVV misperceptions should be focused on otolithic and cognitive strategies.

Cerebral oxygenation in health and disease.

Monitoring cerebral blood flow (CBF) and oxygenation has implications for both clinical practice and research interests; e.g., to provide insight into functional neurovascular coupling, to better understand orthostatic hypotension, and to evaluate the influence of vasopressors on cerebral oxygenation during anesthesia and/or surgery. These topics, and others, are addressed in this e-book by presenting original research, reviews, and opinion papers covering new, exciting but also controversial issues related to cerebral oxygenation in health and disease as evaluated by near-infrared spectroscopy (NIRS).

O28: Comparison of the language lateralizations suggested by magnetoencephalography and navigated transcranial magnetic stimulation in healthy subjects using a picture naming task

O28: Comparison of the language lateralizations suggested by magnetoencephalography and navigated transcranial magnetic stimulation in healthy subjects using a picture naming task

P240: Brain correlates of sustained pressure stimulation in healthy subjects: an fMRI perspective

P240: Brain correlates of sustained pressure stimulation in healthy subjects: an fMRI perspective

Processing past tense in the left cerebellum

We report the case of a patient with ischemic lesion of the left cerebellum, who showed specific deficits in processing past versus future tense of action verbs. These findings confirm, in the presence of cerebellar damage, previous results obtained with transcranial magnetic stimulation in healthy subjects and suggest a specificity of the left cerebellum for preparation of responses to the past tense of action verbs. As part of the procedural brain, the cerebellum could play a role in applying the linguistic rules for selection of morphemes typical of past and future tense formation.

Age-related and sex-related changes in perfusion index in response to noxious electrical stimulation in healthy subjects

BackgroundEven though pain is a subjective phenomenon, its objective evaluation in humans is important because subjects requiring pain evaluation may be unable to describe their pain intensity because of decreased awareness or impaired cognitive function. Previous reports indicate that the perfusion index (PI), which is calculated from pulse oximeter waveforms, has some utility in assessing pain. However, age-associated and sex-associated differences in change of PI have hitherto not been evaluated for assessment of pain. Therefore, we aimed to estimate the utility of age-related differences in PI change among healthy volunteers subjected to electrical stimulation.MethodsWe measured PI and pulse rate in 70 healthy volunteers exposed to gradually increasing electrical stimulation. The subjects were classified into four groups, ie, young men, young women, aged men, and aged women. Stimulation was stopped when subjects reached their pain tolerance threshold. The average PI and pulse rate were calculated 10 seconds before and after electrical stimulation and compared across the four groups. Changes in PI and pulse rate were analyzed using the paired t-test.ResultsThe PI was significantly decreased in response to pain stimulation in young men (P<0.0001), young women (P=0.0002), and aged men (P=0.0158). However, aged women failed to show significant changes in PI before or after stimulation. The pulse rate was not significantly altered in any of the groups.ConclusionPI may be an independent parameter reflecting the perception of noxious stimuli and could be used for objective evaluation of pain perception in healthy volunteers, except when it is used for pain evaluation in elderly women.

Proteinuric effect of transcranial magnetic stimulation in healthy subjects and diabetic patients with Stage 3-4 CKD

Many authors have investigated the numerous connections between the nervous system and kidneys, and recent literature has indicated that these similar systems are interconnected. Recent scientific works have shown that there is similarity between the cerebral cortex 'viscera representation' and the 'motor omunculus'. We studied the connection between the brain and kidney in vivo using repetitive transcranial magnetic stimulation (rTMS). Proteinuria and albuminuria were used as markers of renal response in patients with diabetes (DP) and in a group of healthy subjects (HSs) who received rTMS for 5 consecutive days. The study population consists of the following four groups: Group A (HS stimulated), Group B (HS sham), Group C (DP stimulated) and Group D (DP sham). All subjects in Groups A and C underwent rTMS delivered at a frequency corresponding to 90% of the threshold at rest for 5 consecutive days. All subjects in Groups B and D underwent rTMS delivered with the coil placed on the scalp without delivering electromagnetic stimuli, while another coil at a distance of ∼2 m emitted stimuli at a very low intensity. This strategy ensured that brain stimulation would not occur, so that the subjects felt the vibrations produced by the click of the TMS coil. The proteinuria and albuminuria of 24 h and creatinine clearance were measured at time 0 (T0), after the first session (T1), at the end of the treatment (T5) and 24 h after the last stimulation (Post 24 h). In Group A, there was a statistically significant increase in albuminuria (5.65 ± 0.52 versus 12 ± 0.55 mg/24 h, P = 0.0001) and proteinuria (6.05 ± 0.48 versus 13.1 ± 0.60 mg/24 h, P = 0.0001) at the end of the treatment (T5) compared with the baseline values (T0). In Group C, the albuminuria was statistically higher at T5 than the baseline T0 (416.22 ± 181 versus 677.25 ± 280 mg/24 h, P = 0.04), as was proteinuria (561.37 ± 86 versus 865.125 ± 104 mg/24 h, P = 0.0001); in Group C, the increase in albuminuria (T0 versus post 24 h, P = 0.02) and proteinuria (T0 versus 24 h post, P = 0.0002) persisted at 24 h post. In Groups B and D, statistically significant changes were not found in proteinuria (Group B T0 versus T5, P = 0.61; Group D: T0 versus T5, P = 0.66) and albuminuria (Group B T0 versus T5, P = 0.15; Group D T0 versus T5, P = 0.44) measured at the same times. Consecutive rTMS is able to induce a statistically significant increase in albuminuria and proteinuria in HS and DP. A functional link between the brain and kidney is possible. For the first time, the results have indicated an increase of proteinuria in subjects undergoing transcranial stimulation.

Comparison of auditory P300 responses in healthy elderly, people with mild cognitive impairment and people with Alzheimer's disease

Background: The role of beta responses in cognitive load was least understood in comparison to other frequency bands. The aim of the present study is to investigate the role of beta response oscillations upon cognitive load in healthy subjects and in subjects with mild cognitive impairment (MCI). Methods: Seventeen consecutive patients with MCI (mean age 70,76 65,62years) according to Petersen’s criteria and Seventeen ageand education-matched normal elderly controls (mean age 68,49 65,48 years) were included in the study. Visual oddball paradigm was used in the experiments. Oscillatory responses were recorded from F 3, F z, F 4, C 3, C z, C 4, TP 7, TP 8, P 3, P z, P 4, O 1, O z and O 2 scalp electrodes. EEG-evoked power, inter-trial phase synchronization and event related beta responses filtered in 15-20 Hz were obtained in response to target and non-target stimuli for both groups of subjects. Results: EEG-evoked beta power, inter-trial phase synchronization of beta responses and event related filtered beta responses were significantly higher in response target stimulation in comparison to non-target stimulation in healthy subjects (p<0,05). On the other hand, there were no evoked beta power differences between target and non target stimuli in MCI patients. Furthermore, upon presentation of visual oddball paradigm occipital electrodes enhanced higher beta response in comparison to other electrode sites (p< 0,0001). Conclusions: The results of the present study clearly indicated that target stimulation elicited higher event related beta power, event related beta phase locking and event related filtered beta responses than non-target stimulation in all electrode sites in healthy subjects. Event related beta increase could be related to attention and cognitive activity. The increased beta response upon presentation of target stimuli in healthy subjects implies that beta oscillations could shift the system to an attention state and had important function in cognitive activity. This may, in future, open the way to consider the beta activity as universal operator in the brain in cognitive processes.

Modulation of electroencephalograph activity by manual acupuncture stimulation in healthy subjects: An autoregressive spectral analysis

To investigate whether and how manual acupuncture (MA) modulates brain activities, we design an experiment where acupuncture at acupoint ST36 of the right leg is used to obtain electroencephalograph (EEG) signals in healthy subjects. We adopt the autoregressive (AR) Burg method to estimate the power spectrum of EEG signals and analyze the relative powers in delta (0 Hz–4 Hz), theta (4 Hz–8 Hz), alpha (8 Hz–13 Hz), and beta (13 Hz–30 Hz) bands. Our results show that MA at ST36 can significantly increase the EEG slow wave relative power (delta band) and reduce the fast wave relative powers (alpha and beta bands), while there are no statistical differences in theta band relative power between different acupuncture states. In order to quantify the ratio of slow to fast wave EEG activity, we compute the power ratio index. It is found that the MA can significantly increase the power ratio index, especially in frontal and central lobes. All the results highlight the modulation of brain activities with MA and may provide potential help for the clinical use of acupuncture. The proposed quantitative method of acupuncture signals may be further used to make MA more standardized.

Phosphene Thresholds Elicited by Transcorneal Electrical Stimulation in Healthy Subjects and Patients with Retinal Diseases

To evaluate electrically evoked phosphene thresholds (EPTs) in healthy subjects and in patients with retinal disease and to assess repeatability and possible correlations with common ophthalmologic tests. In all, 117 individuals participated: healthy subjects (n = 20) and patients with retinitis pigmentosa (RP, n = 30), Stargardt's disease (STG, n = 14), retinal artery occlusion (RAO, n = 20), nonarteritic anterior ischemic optic neuropathy (NAION, n = 16), and primary open-angle glaucoma (POAG, n = 17). EPTs were determined at 3, 6, 9, 20, 40, 60, and 80 Hz with 5 + 5-ms biphasic current pulses using DTL electrodes. Subjects were examined twice (test-retest range: 1-6 weeks). An empirical model was developed to describe the current-frequency relationship of EPTs. Visual acuity, visual field (kinetic + static), electrophysiology (RP, RAO, STG: Ganzfeld-electroretinography [ERG]/multifocal-ERG; POAG: pattern-ERG; NAION: VEP), slit-lamp biomicroscopy, fundus examination, and tonometry were assessed. EPTS varied between disease groups (20 HZ: healthy subjects: 0.062 ± 0.038 mA; STG: 0.102 ± 0.097 mA; POAG: 0.127 ± 0.09 mA; NAION: 0.244 ± 0.126 mA; RP: 0.371 ± 0.223 mA; RAO: 0.988 ± 1.142 mA). In all groups EPTs were lowest at 20 Hz. In patients with retinal diseases and across all frequencies EPTs were significantly higher than those in healthy subjects, except in STG at 20 Hz (P = 0.09) and 40 Hz (P = 0.17). Test-retest difference at 20 Hz was 0.006 mA in the healthy group and 0.003-0.04 mA in disease groups. Considering the fast, safe, and reliable practicability of EPT testing, this test might be used more often under clinical circumstances. Determination of EPTs could be potentially useful in elucidation of the progress of ophthalmologic diseases, either in addition to standard clinical assessment or under conditions in which these standard tests cannot be used meaningfully. (ClinicalTrials.gov number, NCT00804102.).

Interhemispheric inhibition in human wrist muscles

The interhemispheric interactions between homologous wrist extensor and flexor muscles representations in the right and left primary cortex (M1) were studied using a paired-pulse transcranial magnetic stimulation in healthy subjects. The magnitude of interhemispheric inhibition (IHI) was studied in 9 right-handed subjects at short (10ms, SIHI) and long (40ms, LIHI) interstimulus intervals between the magnetic conditioning (CS) and test stimulus in the motor dominant to non-dominant cortex and vice versa, while the right or left hand was at rest or performing a unimanual sustained tonic contraction (holding a pen with the hand contralateral to the CS). A bidirectional powerful interhemispheric inhibition could be elicited at the short and long IHI phases (SIHI and LIHI) in wrist extensor and flexor muscles in most of the subjects at rest. SIHI but not LIHI was significantly bidirectionally reduced during unimanual contraction of the hand contralateral to the CS stimulation in comparison with rest. The amount of IHI after the stimulation of the "non-dominant" right hemisphere was not reduced in comparison with IHI after stimulation of the "dominant" left hemisphere whatever the active or resting condition. IHI directed to the wrist muscles had a similar level than IHI directed to digit muscles (FDI) at rest. Our data indicate that contralateral wrist muscles activity evokes a global, bidirectional reduction in IHI which was more pronounced for SIHI. These results provide additional evidence that changes in interhemispheric interactions between the M1s are involved in the control of unimanual movements including suppression of unwanted motor activity in the opposite limb during unilateral movements.

Support of the concept of interhemispheric rivalry by two consecutive strokes occurring in both hemispheres: a case study

Several lines of evidence indicate that the motor systems of both hemispheres are interconnected and influence each other. Unilateral pinch grips with very low force reduce the motor cortical excitability of a contralateral hand muscle [1]. Magnetic stimulation over both hemispheres with an appropriate interstimulus interval demonstrated the presence of an interhemispheric inhibition [2]. The concept of interhemispheric rivalry suggests that, after a stroke, the non-lesioned hemisphere could exert an inhibitory influence on the affected hemisphere [3] and that this dysbalance could impair restitution of functions. Here, we report the case of a patient who had developed a right-sided hemiparesis due to left-hemispheric intracerebral hemorrhage. This hemiparesis rapidly improved after suffering a right-hemispheric ischemic stroke. The 78-year-old right-handed gentleman suffered a spontaneous hemorrhage mainly affecting the left supplementary motor area (SMA) (Fig. 1a) while being treated with acetyl salicylic acid due to coronary heart disease. Three weeks after the incident, he presented with a rightsided hemiparesis that had persisted almost unchanged over time. Degrees of strength (Medical Research Council Scale) were between 3 and 4 for movements of the right upper limb. However, the patient did not use the arm spontaneously and seemed to be unable to generate voluntary movements if not forced to do so. He denied any sensory deficits for the right side. There was no clinical indication of spatial neglect. Somatosensory evoked potentials induced by median nerve stimulation had normal latencies and amplitudes. Motor potentials after transcranial magnetic stimulation were recorded from the first dorsal interosseous muscle and showed normal latencies and amplitudes for both sides. Twenty-four days after the hemorrhage, the patient developed a sudden spatial neglect to his left side. A magnetic resonance imaging of the brain showed an acute ischemic stroke mainly affecting the parietal cortex in the right hemisphere (Fig. 1b). Within the subsequent 3 days, the right-sided neurological symptoms disappeared almost completely. He started to employ his right upper extremity for activities of daily living. Clinical examination showed nothing but a slightly impaired dexterity. The left-sided spatial neglect resolved within 8 days after the ischemic stroke. In our opinion, the initial disuse of the right arm can be explained by the SMA lesion since the SMA is known to be relevant for generation of volitional movements [4]. We assume that, prior to the second stroke, the right parietal cortex exerted an inhibition on the left parietal cortex, similar to what has been described in neglect patients [5]. Using transcranial magnetic stimulation in healthy subjects, it has also been shown that the right (but not left) human posterior parietal cortex exerts a strong inhibitory activity over the contralateral homologous area [6]. After the ischemic lesion, this inhibition was reduced, allowing a parieto-frontal network in the left hemisphere to be activated and to compensate for the disturbed function of the SMA. Due to the rapid improvement after 3 weeks of symptom persistence, our observation cannot be explained by spontaneous recovery. Moreover, MRI at the time of the ischemic stroke showed an almost unchanged size of the hemorrhage. R. Sauerbrei J. Liepert (&) Department of Neurorehabilitation, Kliniken Schmieder, Bereich Neurorehabilitation, Zum Tafelholz 8, 78476 Allensbach, Germany e-mail: j.liepert@kliniken-schmieder.de