P645: Case report: seizure induction by single-pulse transcranial magnetic stimulation after anodal transcranial direct current stimulation in a stroke patient

Abstract

s of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339 S225 Abstract P643 – Figure 1. Excitability modulation induced by paired pulses for the hand APB as a function of ISI for 4 capacitor combinations.P643 – Figure 1. Excitability modulation induced by paired pulses for the hand APB as a function of ISI for 4 capacitor combinations. Abstract P643 – Figure 2. Excitability modulation induced by paired pulses at ISIs of 200, 400 and 600 μs.P643 – Figure 2. Excitability modulation induced by paired pulses at ISIs of 200, 400 and 600 μs. different stimulation patterns in various channels. Multiple pulses operation with coils with various depth profiles can increase the focality of TMS effect in deep brain regions. P644 Anticipatory motor control is mediated via the left posterior parietal cortex (PPC) V. Krause, J. Weber, B. Pollok Heinrich-Heine-University, Institute of Clinical Neuroscience and Medical Psychology, Duesseldorf, Germany Question: Within the motor control network the posterior parietal cortex (PPC) has been related to anticipatory motor control while the primary motor cortex (M1) may be rather dedicated to movement execution. Assuming that cortical nodes within this network provide different contributions to motor control, the present study elucidates the specific relevance of left PPC for movement timing. Methods: Anodal vs. cathodal transcranial direct current stimulation (tDCS) was applied for 10 min over left PPC in right-handed subjects in separate sessions. Left M1 tDCS served as control condition. Anticipatory motor control was assessed by means of a synchronization task requiring subjects to synchronize their own finger taps with a regular auditory metronome. In addition, subjects performed a continuation task investigating interval reproduction and a simple auditory reaction task. Tasks were performed with the right and the left hand, respectively, prior to and immediately after tDCS. Results: Anodal left PPC tDCS decreased synchronization accuracy of either hand during the synchronization task. During continuation, cathodal left PPC tDCS increased the reproduced interval of the left hand but decreased the interval of the right hand. Reaction times were not significantly modulated by PPC stimulation. Left M1 tDCS was not efficient to significantly modulate performance in any of the tasks. Conclusions: The present data underline the superordinate role of left PPC for anticipatory motor control of either hand revealing a piece of evidence for left hemispheric PPC dominance. The observed effects cannot be explained by alterations of motor cortical excitability. P645 Case report: seizure induction by single-pulse transcranial magnetic stimulation after anodal transcranial direct current stimulation in a stroke patient S. Koganemaru1,2, A. Ikeda3, R. Takahashi3, H. Fukuyama1, T. Mima1 1Kyoto universtiy, Human Brain Research Center, Kyoto, Japan; 2Kyoto universtiy, Integrative Brain Science, Kyoto, Japan; 3Kyoto university, Neurology, Kyoto, Japan Transcranial direct current stimulation (tDCS) has been used as a safe therapeutic tool in neurological disorders, especially in stroke, because anodal stimulation given over the affected M1 area produces LTP-like effects on corticospinal excitability. Single-pulse transcranial magnetic stimulation (TMS) has been used as an evaluation tool of corticospinal excitability even in stroke, with a minimal risk of de novo seizure induction. Here, we report a 35 year-old male with postoperative subcortical hemorrhage in the left hemisphere, who developed a generalized convulsion starting from the affected upper limb after a single-pulse TMS subsequent to the anodal tDCS given over the ipsilesional M1 hand area for 10 minutes. He had no history of seizure or electroencephalogram (EEG) abnormality, and received several TMS tests without any side effects before tDCS intervention. EEG testing just after and 3 month after the event revealed no epileptiform discharges. He has been seizure-free at least for 3 months. The present case report raises the possibility that a single-pulse TMS after tDCS may be associated with a seizure risk in patients with brain lesion due to their accumulative excitatory effects. P646 Transcranial direct current stimulation (tDCS) in the treatment of adolescents with attention deficit hyperactivity disorder (ADHD) A. Sotnikova1, C. Soff1, K. Becker1, M. Siniatchkin2 1University of Marburg, Department of Child and Adolescents Psychiatry, Marburg, Germany; 2Goethe-University of Frankfurt, Department of Child and Adolescents Psychiatry, Frankfurt, Germany Question: The stimulation of the brain with weak direct current through the scalp (tDCS) is a safe, well tolerable and effective procedure which