IS 29. Effect of rTMS on Freezing of Gait

e48

Society Proceedings / Clinical Neurophysiology 124 (2013) e39–e187

IS 27. Brain stimulation in stroke therapy—F.C. Hummel (Universitätsklinikum Hamburg-Eppendorf, Abteilung für Neurologie, Hamburg, Germany) Non-invasive brain stimulation has shown its potential to modulate brain plasticity and enhance the effects of training in humans (Zimerman et al., Ann Neurol; 2012). Endeavour has been made to utilize brain stimulation in neurological diseases to enhance adaptive processes and prevent potential maladaptive ones. First studies presented evidence that non-invasive brain stimulation might not only transiently improve functions of the paretic hand, but can also modulate processes of learning (Zimerman et al., Stroke; 2012), a basis to achieve longer lasting effects. Based on this enhancement of functional recovery of both, sensorimotor and higher cognitive impairment (such as aphasia and neglect), by brain stimulation has been addressed in stroke. In the present talk, an update of the field of non-invasive brain stimulation to improve motor and higher cognitive functions in patients suffering from stroke will be presented. The recent pathophysiological grounds for therapeutic approaches based on brain stimulation will be provided in the framework of the actual controversial discussion of the field. At the end briefly the potential developments and future directions of this research topic will be discussed. doi:10.1016/j.clinph.2013.04.046

IS 28. Non-invasive brain stimulation in Parkinson’s disease—R. Chen (University of Toronto, Catherine Manson Chair in Movement Disorders, Professor of Medicine (Neurology), Toronto, Canada) Paired transcranial magnetic stimulation (TMS) has been used to investigate the pathophysiology of Parkinson’s disease (PD). While previous studies reported conflicting results on short-interval intracortical inhibition (SICI, related to GABAA receptor inhibition) in PD, a detailed study found decreased SICI and increased short-interval intracortical facilitation (SICF) in the off medication state. SICI increased with dopaminergic medications. Normalization of SICF with dopaminergic medications correlated with the degree of motor improvement. The interaction between long-interval intracortical inhibition (LICI, related to GABAB receptor inhibition) and SICI, likely mediated by presynaptic inhibition, is impaired in PD and did not improve with medications. The excitability of the cerebellothalamocortical pathway is also reduced in PD. Sensorimotor integration measured with short (SAI) and long (LAI) latency afferent inhibition are decreased in PD and normalized with subthalamic nucleus deep brain stimulation (STN DBS). Cortical plasticity measured with paired-associative stimulation is decreased in PD, increased with medications in non-dyskinetic patients and is improved by STN DBS. The results of theta burst stimulation and other plasticity studies in PD may depend on the disease stage and medication status. Many studies tested non-invasive brain stimulation as a treatment for PD. A double-blinded, sham-controlled trial of anodal transcranial direct current stimulation in PD showed no effect on gait and Unified Parkinson’s Disease Rating Scale, although bradykinesia measured by a timed test was slightly improved. A meta-analysis found that high frequency (>1 Hz) repetitive TMS (rTMS) had beneficial effect while low frequency (1 Hz or lower) rTMS did not change PD motor signs. Cortical low frequency (1 Hz) rTMS or cerebellar rTMS are potential treatments for levodopa-induced dyskinesias. However, the published rTMS studies in PD are small and the protocols used are highly variable. The efficacy of rTMS in PD needs to be examined in a large, sham-controlled study. In summary, non-invasive brain stimulation techniques provide is useful methods to investigate the pathophysiology and effects of

treatment in PD. Further studies are needed to determine whether it is a useful treatment for PD. doi:10.1016/j.clinph.2013.04.047

IS 29. Effect of rTMS on Freezing of Gait—Y.-H. Kim a, W.H. Chang a, S.Y. Lee a, J.-Y. Youn b, J.-W. Cho b, S.Y. Jang a (a Sungkyunkwan University School of Medicine, Department of Physical and Rehabilitation Medicine, Stroke and Cerebrovascular Center, Samsung Medical Center, Seoul, Republic of Korea, b Sungkyunkwan University School of Medicine, Department of Neurology, Samsung Medical Center, Seoul, Republic of Korea) Freezing of Gait (FOG) is a disabling symptom that commonly affects patients with Parkinson’s disease (PD) and current treatments are very limited. Previous studies have reported that repetitive transcranial magnetic stimulation (rTMS) can improve the motor symptoms of various neurologic diseases. In this experiment, we investigated the site-specific modulation effects of rTMS on FOG in PD. Twenty patients with PD were recruited. All participants received randomly arranged 4 sessions of rTMS with more than 24 h. of washout period between the session. In each session, 10 Hz rTMS (90% of RMT, total 1000 pulses) was applied with double cone coil over the primary motor cortex (M1) for lower limb, the supplementary motor cortex, or the dorsolateral prefrontal cortex (DLPFC) of dominant hemisphere. Sham rTMS was performed with the coil at an angle of 90 degrees from the tangential plane to the vertex using the same stimulation parameters. Unified Parkinson’s Disease Rating Scale (UPDRS), timed 6 m walk test, and SS-180° turning test were evaluated before and immediately after each rTMS session. Motor cortical excitability was also assessed. When rTMS was given over M1, significant beneficial effects on UPDRS and gait speed were observed (p < 0.05). After rTMS over M1 and DLPFC, there was significant improvements in SS-180° turning test (p < 0.05). Cortical excitability showed significantly higher MEP amplitude and enhanced intracortical facilitation after M1 and DLPFC stimulation (p < 0.05). These results support the perspective of the M1 as a target for improving motor function and FOG in PD, and DLPFC as a possible target for FOG (Supported by Samsung Medical Center Grant (#CRO112051) and by the NRF of Korea grant (No. 2011-0016960). doi:10.1016/j.clinph.2013.04.048

IS 30. Predicting recovery of motor function after stroke-an essential role for TMS—C. Stinear a,b, S.J. Ackerley a,b, M.A. Petoe a,b, P.A. Barber a,b, W.D. Byblow b,c (a The University of Auckland, Neurology Research Group, Department of Medicine, Auckland, New Zealand, b The University of Auckland, Centre for Brain Research, Auckland, New Zealand, c The University of Auckland, Movement Neuroscience Laboratory, Department of Sport & Exercise Science, Auckland, New Zealand) Introduction: Accurate prognosis of motor recovery assists rehabilitation planning and efficient resource allocation by clinicians and patients. However, the relationship between initial impairment and subsequent recovery is highly variable, making accurate prognosis for individual patients difficult. Neurophysiological and neuroimaging techniques offer more predictive power than clinical assessment, and can be used to identify patients with previously unrecognised potential for recovery. Objectives: We have recently developed the PREP algorithm for Predicting Recovery Potential after stroke, which uses TMS to test the functional integrity of descending motor pathways to the paretic upper limb. The algorithm had positive predictive power of 88%,