- Email: [email protected]
P639: Effect of combined repetitive transcranial and peripheral magnetic stimulation on functional state of the brain in stroke patients
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
P636 Comparison between adaptive and fixed stimulus paired-pulse TMS in normal subjects H. Axelson, M. Isberg, R. Flink, Å. Amandusson Uppsala University Hospital, Clinical Neurophysiology, Uppsala, Sweden Question: Paired-pulse TMS (ppTMS) is used to examine cortical excitability. Typically, ppTMS consists of a facilitating or inhibiting conditioning stimulus followed by a test pulse delivered at a constant strength. Alternatively, the test pulse stimulus intensity can be adjusted to produce a MEP response of a certain amplitude. Such adaptive techniques (requiring statistical calculation at runtime) have been introduced to overcome some shortcomings with conventional ppTMS. At our institution, we have tried one adaptive method (“best-PEST”) for ppTMS, however, before changing our protocol we decided to compare results from the two different techniques. Methods: Twenty healthy subjects were examined with ppTMS in two sessions (fixed stimulus ppTMS followed by adaptive ppTMS). Shortinterval intracortical inhibition (SICI), intracortical facilitation (ICF) and long-interval intracortical inhibition (LICI) were examined. The conditioning stimuli where the same for the two methods. In the first session, the test pulse was delivered at 120% resting motor threshold. In the second session, the stimulus intensity was set to produce a 0.5 mV MEP response (according to a maximum likelihood model). MEP responses were recorded from the dominant first interosseus muscle. Results: There were significant intraindividual correlations between the two methods regarding SICI (p=0.01), ICF (p<0.01) and LICI (p=0.02) measures. Adaptive SICI and ICF test pulse intensities were highly correlated to the motor threshold and seem to require normalization. “Conventional” SICI data tended to cluster at near maximum inhibition (i.e., a well-known ceiling effect) which was not observed in adaptive ppTMS. ICF was, on the other hand, more difficult to establish with the used adaptive protocol. Conclusions: Adaptive ppTMS excitability measures clearly correlated with those obtained with constant stimulus ppTMS. Some advantages with the adaptive technique were observed but also potential problems.
P637 Primary motor cortex theta burst stimulation does not enhance motor skill transfer from one trained hand to the other untrained hand 1
1
1,2,3
1
1
T. Ringer , J. Blessin , K. Schulz , R. Spanke , F. Naumann , O.W. Witte 1,3 , R. Lange 4 , F. Hamzei 1,2,3 1 University Hospital Jena, Neurology, Jena, Germany; 2 Moritzclinic, Neurology, Bad Klosterlausnitz, Germany; 3 University Hospital, Center of sepsis control and care, Jena, Germany; 4 Clinic Nuremberg, Neurology, Nuremberg, Germany Question: The human motor cortex is organized in a segregated integrative network with connected long-distance association fibers, e.g. between both hemispheres. This organization adapts to a changing environment according to Hebb (1949), for example during motor skill training. Training skill improvement of one hand also enhances training skill performance of the opposite non trained hand, termed as motor transfer. The aim of this study was, first to investigate whether a non-invasive transcranial magnetic stimulation (TMS) enhances retrieval of the trained motor skill from one trained hand to the other untrained hand, and second, whether such an influence is age-dependent, because it is suggested that during ageing white matter changes appear which may delay motor transfer. Methods: 39 healthy right handed subjects were included. Subjects was separated into three young groups (n=27; 27±6 years mean ± sd) and one old group (n=12; 63±6 years mean ± sd). In one young group subjects were stimulated with intermittent theta burst stimulation (iTBS; termed as young-iTBS), one further group was stimulated with the continuous TBS (young-cTBS) and the third group was sham stimulated (young-sham). The old group was stimulated with iTBS (old-iTBS). ITBS and cTBS were applied over the contralateral M1 to the trained right hand (M1-left) after the training session. All subjects trained the Jebson-Taylor-Hand-FunctionTest (JTHFT) ten times repetitively with their dominant right hand. The training effect of JHFT was tested for both hands before and after the stimulation. Results: Time to perform the JTHFT was slower in older subjects throughout the whole training (initially 28.7 seconds vs. 26.8 seconds; at the end of training 21.8 seconds vs. 19.9 seconds, one-factorial ANOVA, p=0.019 respectively p=0.031). In all groups the time of the JTHFT improved signif-
S223
icantly for the trained right hand (motor skill learning) as well as for the untrained left hand (motor transfer), whereas there were no differences in the relative amount of motor skill learning or transfer between young and old subjects. iTBS (young-iTBS and old-iTBS) over the M1left did not significantly enhance the time of JTHFT of the left hand. The young-cTBS group also did not show a decrease of time for the JTHFT. Conclusions: TBS stimulation over M1left neither in young nor in old subjects did enhance manual motor transfer. We conclude and suggest that the premotor cortex rather than M1 is involved in information processing of manual transfer.
P638 Slow oscillatory stimulation simulating gait rhythm induces LTP-like effects on corticospinal excitability in foot S. Koganemaru 1,2 , Y. Mikami 1 , H. Fukuyama 1 , T. Mima 1 1 Kyoto Universtiy, Human Brain Research Center, Kyoto, Japan; 2 Kyoto Universtiy, Integrative Brain Science, Kyoto, Japan Human bipedal gait requires supraspinal motor control in addition to subcortical pattern generator system. In previous human studies, the corticospinal tracts from the primary motor cortex (M1) contribute to control foot flexors rather than extensors during gait. In animal studies, when monkeys were forced to walk by two hindlimbs, M1 neurons fired rhythmically according to gait cycle. Recently, slow oscillatory stimulation (SOS) over M1 hand area (0.8Hz) by transcranial electrical current stimulation induced LTP-like effects. Now, we investigated whether SOS given over M1 foot area simulating gait cycle can induce plastic changes of corticospinal tracts engaged in bipedal gait. Nine healthy subjects participated in the study. In the experiments, they were given SOS during gait (SOS+gait) and on another day, given sham stimulation during gait (Sham+gait). As a result, they showed significant enhancement of corticospinal excitability in TA muscles of the stimulated site immediately and 30 min after SOS+gait, but not after Sham+gait. We considered that SOS simulating gait cycle induced LTP-like effects in corticospinal excitability of foot and that it might be a promising method for enhancement of the supraspinal control during gait, especially in patients with gait disturbance from central nerve disorder.
P639 Effect of combined repetitive transcranial and peripheral magnetic stimulation on functional state of the brain in stroke patients S. Kuznetsova, V. Kuznetsov, N. Skachkova SI “Gerontology Institute named after D.F. Chebotarev of NAMS of Ukraine”, Neurological, Kiev, Ukraine Question: Repetitive transcranial magnetic stimulation (rTMS) induces functional cortical reorganization in stroke patients. It was also recently shown that repetitive peripheral magnetic stimulation (rPMS) promotes a functional reorganization of the motor cortex in healthy subjects. Based on this information we investigated the effect of combined rTMS and rPMS on functional state of the brain in stroke patients. Methods: 77 patients (mean age – 63.02±1.21 years) with cerebral hemispheric ischemic stroke were randomized to receive 1 Hz real or sham rTMS and rPMS for 10 consecutive days against the background of conventional rehabilitation and drug therapy. Single-pulse TMS and electroencephalography (EEG) were performed before and after treatment. Results: Real stimulation group (RSG) showed a significant increase of motor evoked potential (MEP) amplitude and reduce resting motor threshold (rMT) of the affected hemisphere. No significant changes were observed of MEP amplitude and rMT of both affected and intact hemispheres of the sham group (SG), as well as the intact hemisphere of the RSG. The power spectral EEG analysis revealed the hemispheric differences in EEG changes of both RSG and SG. In the RSG patients with left-side stroke observed a significant increase in alpha-1 band power in the affected and the intact hemispheres, increase in alpha-2 band power and increase in alpha rhythm frequency in the affected hemisphere. In the SG patients with left-side stroke observed a significant increase in alpha rhythm frequency in the intact hemisphere. In the RSG patients with right-side stroke observed a significant decrease in theta band power in the affected and the intact hemispheres, increase in alpha-2 band power in the intact hemisphere and increase in alpha rhythm frequency in the affected and the intact hemispheres. In the SG patients with right-side stroke observed a signifi-
S224
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
cant increase in theta band power and alpha-1 band power in the intact hemisphere and alpha-2 band power of both the affected and the intact hemispheres. Conclusions: Combined rTMS and rPMS increased cortical excitability of the affected hemisphere and harmonized electrical activity of the brain of both the affected and the intact hemispheres in stroke patients.
P640 Effect of static magnetic field stimulation (tSMS) over parietal cortex on somatosensory evoked potentials in humans M.D.C. Carrasco-Lopez 1 , V. Soto-Leon 1 , P. Profice 2 , G. Foffani 1 , A. Oliviero 1 1 Hospital Nacional de Paraplejicos, FENNSI, Toledo, Spain; 2 Univeritá Cattolica, Neurology Department, Rome, Italy Objective: To study the effect of transcranial static magnetic field stimulation (tSMS) over the parietal cortex on the size of somatosensory evoked potentials (SEPs) in humans. Methods: SEPs were elicited by electrical stimulation of right median nerve at the wrist before, during and after tSMS (or sham) in 8 healthy subjects. tSMS was applied for 20 min to the left parietal cortex using a neodimium cylindric magnet with a diameter of 6 cm and height of 3 cm. Sham stimulation was obtained by applying for 20 min to the left parietal cortex a steel cylinder with a diameter of 6 cm and height of 3 cm. Results: Amplitudes of N20/P25 and P25/N30 following right median nerve stimulation were significantly modified for at least 10 min after the end of tSMS, whereas P14/N20 were unaffected. There was no effect on SEPs evoked by right median nerve stimulation after sham stimulation. Conclusions: tSMS over the sensorimotor cortex can induce a long-lasting changes in cortical components of SEPs. Significance: tSMS can modulate cortical somatosensory processing in humans.
of patients that may benefit from tDCS as an adjuvant treatment for pain (or other NIBS treated disorders).
P642 Modulating the interplay between exploration and exploitation in instrumental learning by prefrontal transcranial direct current stimulation Z. Turi, A. Opitz, M. Popkes, W. Paulus, A. Antal Georg-August University of Goettingen, University Medical Center, Clinical Neurophysiology, Goettingen, Germany Question: Accumulating experimental evidence indicate that instrumental learning situations in humans recruit both the striatal and the working memory system. However, the role of working memory system in instrumental learning is still not well understood. Methods: In order to address this issue, we applied transcranial direct current stimulation (tDCS) optimized for targeting dorsolateral prefrontal cortex (see Fig. 1), a key region in working memory for 15 minutes using 1.0 mA intensity. By following a double-blinded, repeated-measures study design, 16 male participants took part in a sham and anodal tDCS session separated by 1 week. Accuracy, reaction time and the number of behavioral shiftings (trial-to-trial changes after positive and negative outcomes) were taken as dependent variables. Results: Although general accuracy and reaction time was not influenced by tDCS, we observed significantly greater amount of behavioral shifting in the active condition compared to the sham condition.
P641 Tele-medicine approach in non-invasive brain simulation: case report in a pain patient Y.A. Perez-Borrego, M. Campolo, I. Rodriguez-Carrion, V. Soto-León, A. Oliviero Hospital Nacional de Paraplejicos, FENNSI, Toledo, Spain Question: Chronic pain often shows insufficient response to pharmacological treatments. Non-invasive brain stimulation (NIBS) of the motor cortex has been proposed as an alternative therapeutic approach. Methods: We present a case of a patient treated in our Hospital using tDCS with good pain relief after 5 tDCS daily sessions, and with maintenance of the positive analgesic effects for more than one year with a single tDCS session every 7 days. The patient lives very far away from our Hospital and we decided to use modern information technology to start a Tele-NIBS treatment approach. Case presentation: Our patient, a 56 years-old male, was diagnosed of macrophagic myofasciitis. Macrophagic myofasciitis is a rare condition with few hundreds of definite cases identified in France, and isolated cases recorded in other countries. The main clinical complaints of our patient were pain and chronic fatigue. Pain was intense (mean VAS of 8, VAS scale scored pain from 0 to 10, where 10 meant worst possible pain) and the patient was treated with many different protocols of analgesic drugs. All these treatments failed. For this reason, the patient was screened as a possible candidate for NIBS. We received the patient 2 years ago and we decided to treat the patient with a tDCS protocol. The NIBS consisted of 20 minutes of anodal stimulation (with an intensity of 1.5 mA) over both motor cortices. This stimulation protocol was repeated on five consecutive days and maintained for months with one weekly session. Once the patient reached a good pain control, he stopped the treatment and VAS started to go up again in few months (VAS=5). The reason why the patient stopped the treatment was that he lived very far from the Hospital (about300 Km) and it was difficult for him to reach our Hospital. Few months ago, we repeated the 5 days tDCS sessions with the same protocol and the patient’s pain diminished again (VAS=2±1). After more than one year of successful treatment, we decided – together with the patient – to use modern information technology to start a Tele-NIBS treatment approach. Conclusions: Here we report a case of a successful tele-NIBS approach using “at home” tDCS to treat pain. This strategy may increase the number
Figure 1
Conclusion: In line with previous findings, our results suggest that the working memory system may influence instrumental learning by actively maintaining reinforcement history and adjusting behavior on trial-to-trial bases.
P643 Safety and characterization of a novel multi-channel TMS stimulator Y. Roth 1 , A. Zangen 1 , G. Pell 1,2 , Y. Levkovitz 3 , M. Ankry 2 Ben Gurion University, Life Sciences, Be’er Sheva, Israel; 2 Brainsway Ltd, Jerusalem, Israel; 3 Shalvata Mental Health Care Center, The Emotion-Cognition Research Center, Hod-Hasharon, Israel 1
Question: Currently available TMS stimulators have a single channel operating a single coil. This study presents benefits of a novel multi-channel stimulator, comprising five channels with independently controllable stimulation parameters. Methods: Simultaneous and sequential operation of various channels was tested in healthy volunteers. Paired pulses schemes with various interstimulus intervals (ISIs) were studied for the hand APB and the leg AH muscles. Energy consumption and coil heating rates with simultaneous operation of 4 channels was compared to a figure-8 coil. Results: Repetitive operation of separate channels with different stimulation parameters is demonstrated. The operations of various channels can be combined simultaneously or sequentially to induce multiple pulses with ISIs of μs resolution. A universal pattern of inhibition and facilitation as a function of ISI was found, with some dependence on coils configurations and on pulse widths. A strong dependence of the induced inhibition on the relative orientation of the conditioning and test pulses was discovered. The ability of this method to induce inhibition in shallow brain region but not in deeper region is demonstrated. Significant reductions in energy consumption and coil heating were demonstrated for several channels operated simultaneously compared to a standard figure-8 coil. Conclusions: The multi-channel stimulator enables the synchronized induction of different excitability modulations to different brain regions using
P636 Comparison between adaptive and fixed stimulus paired-pulse TMS in normal subjects H. Axelson, M. Isberg, R. Flink, Å. Amandusson Uppsala University Hospital, Clinical Neurophysiology, Uppsala, Sweden Question: Paired-pulse TMS (ppTMS) is used to examine cortical excitability. Typically, ppTMS consists of a facilitating or inhibiting conditioning stimulus followed by a test pulse delivered at a constant strength. Alternatively, the test pulse stimulus intensity can be adjusted to produce a MEP response of a certain amplitude. Such adaptive techniques (requiring statistical calculation at runtime) have been introduced to overcome some shortcomings with conventional ppTMS. At our institution, we have tried one adaptive method (“best-PEST”) for ppTMS, however, before changing our protocol we decided to compare results from the two different techniques. Methods: Twenty healthy subjects were examined with ppTMS in two sessions (fixed stimulus ppTMS followed by adaptive ppTMS). Shortinterval intracortical inhibition (SICI), intracortical facilitation (ICF) and long-interval intracortical inhibition (LICI) were examined. The conditioning stimuli where the same for the two methods. In the first session, the test pulse was delivered at 120% resting motor threshold. In the second session, the stimulus intensity was set to produce a 0.5 mV MEP response (according to a maximum likelihood model). MEP responses were recorded from the dominant first interosseus muscle. Results: There were significant intraindividual correlations between the two methods regarding SICI (p=0.01), ICF (p<0.01) and LICI (p=0.02) measures. Adaptive SICI and ICF test pulse intensities were highly correlated to the motor threshold and seem to require normalization. “Conventional” SICI data tended to cluster at near maximum inhibition (i.e., a well-known ceiling effect) which was not observed in adaptive ppTMS. ICF was, on the other hand, more difficult to establish with the used adaptive protocol. Conclusions: Adaptive ppTMS excitability measures clearly correlated with those obtained with constant stimulus ppTMS. Some advantages with the adaptive technique were observed but also potential problems.
P637 Primary motor cortex theta burst stimulation does not enhance motor skill transfer from one trained hand to the other untrained hand 1
1
1,2,3
1
1
T. Ringer , J. Blessin , K. Schulz , R. Spanke , F. Naumann , O.W. Witte 1,3 , R. Lange 4 , F. Hamzei 1,2,3 1 University Hospital Jena, Neurology, Jena, Germany; 2 Moritzclinic, Neurology, Bad Klosterlausnitz, Germany; 3 University Hospital, Center of sepsis control and care, Jena, Germany; 4 Clinic Nuremberg, Neurology, Nuremberg, Germany Question: The human motor cortex is organized in a segregated integrative network with connected long-distance association fibers, e.g. between both hemispheres. This organization adapts to a changing environment according to Hebb (1949), for example during motor skill training. Training skill improvement of one hand also enhances training skill performance of the opposite non trained hand, termed as motor transfer. The aim of this study was, first to investigate whether a non-invasive transcranial magnetic stimulation (TMS) enhances retrieval of the trained motor skill from one trained hand to the other untrained hand, and second, whether such an influence is age-dependent, because it is suggested that during ageing white matter changes appear which may delay motor transfer. Methods: 39 healthy right handed subjects were included. Subjects was separated into three young groups (n=27; 27±6 years mean ± sd) and one old group (n=12; 63±6 years mean ± sd). In one young group subjects were stimulated with intermittent theta burst stimulation (iTBS; termed as young-iTBS), one further group was stimulated with the continuous TBS (young-cTBS) and the third group was sham stimulated (young-sham). The old group was stimulated with iTBS (old-iTBS). ITBS and cTBS were applied over the contralateral M1 to the trained right hand (M1-left) after the training session. All subjects trained the Jebson-Taylor-Hand-FunctionTest (JTHFT) ten times repetitively with their dominant right hand. The training effect of JHFT was tested for both hands before and after the stimulation. Results: Time to perform the JTHFT was slower in older subjects throughout the whole training (initially 28.7 seconds vs. 26.8 seconds; at the end of training 21.8 seconds vs. 19.9 seconds, one-factorial ANOVA, p=0.019 respectively p=0.031). In all groups the time of the JTHFT improved signif-
S223
icantly for the trained right hand (motor skill learning) as well as for the untrained left hand (motor transfer), whereas there were no differences in the relative amount of motor skill learning or transfer between young and old subjects. iTBS (young-iTBS and old-iTBS) over the M1left did not significantly enhance the time of JTHFT of the left hand. The young-cTBS group also did not show a decrease of time for the JTHFT. Conclusions: TBS stimulation over M1left neither in young nor in old subjects did enhance manual motor transfer. We conclude and suggest that the premotor cortex rather than M1 is involved in information processing of manual transfer.
P638 Slow oscillatory stimulation simulating gait rhythm induces LTP-like effects on corticospinal excitability in foot S. Koganemaru 1,2 , Y. Mikami 1 , H. Fukuyama 1 , T. Mima 1 1 Kyoto Universtiy, Human Brain Research Center, Kyoto, Japan; 2 Kyoto Universtiy, Integrative Brain Science, Kyoto, Japan Human bipedal gait requires supraspinal motor control in addition to subcortical pattern generator system. In previous human studies, the corticospinal tracts from the primary motor cortex (M1) contribute to control foot flexors rather than extensors during gait. In animal studies, when monkeys were forced to walk by two hindlimbs, M1 neurons fired rhythmically according to gait cycle. Recently, slow oscillatory stimulation (SOS) over M1 hand area (0.8Hz) by transcranial electrical current stimulation induced LTP-like effects. Now, we investigated whether SOS given over M1 foot area simulating gait cycle can induce plastic changes of corticospinal tracts engaged in bipedal gait. Nine healthy subjects participated in the study. In the experiments, they were given SOS during gait (SOS+gait) and on another day, given sham stimulation during gait (Sham+gait). As a result, they showed significant enhancement of corticospinal excitability in TA muscles of the stimulated site immediately and 30 min after SOS+gait, but not after Sham+gait. We considered that SOS simulating gait cycle induced LTP-like effects in corticospinal excitability of foot and that it might be a promising method for enhancement of the supraspinal control during gait, especially in patients with gait disturbance from central nerve disorder.
P639 Effect of combined repetitive transcranial and peripheral magnetic stimulation on functional state of the brain in stroke patients S. Kuznetsova, V. Kuznetsov, N. Skachkova SI “Gerontology Institute named after D.F. Chebotarev of NAMS of Ukraine”, Neurological, Kiev, Ukraine Question: Repetitive transcranial magnetic stimulation (rTMS) induces functional cortical reorganization in stroke patients. It was also recently shown that repetitive peripheral magnetic stimulation (rPMS) promotes a functional reorganization of the motor cortex in healthy subjects. Based on this information we investigated the effect of combined rTMS and rPMS on functional state of the brain in stroke patients. Methods: 77 patients (mean age – 63.02±1.21 years) with cerebral hemispheric ischemic stroke were randomized to receive 1 Hz real or sham rTMS and rPMS for 10 consecutive days against the background of conventional rehabilitation and drug therapy. Single-pulse TMS and electroencephalography (EEG) were performed before and after treatment. Results: Real stimulation group (RSG) showed a significant increase of motor evoked potential (MEP) amplitude and reduce resting motor threshold (rMT) of the affected hemisphere. No significant changes were observed of MEP amplitude and rMT of both affected and intact hemispheres of the sham group (SG), as well as the intact hemisphere of the RSG. The power spectral EEG analysis revealed the hemispheric differences in EEG changes of both RSG and SG. In the RSG patients with left-side stroke observed a significant increase in alpha-1 band power in the affected and the intact hemispheres, increase in alpha-2 band power and increase in alpha rhythm frequency in the affected hemisphere. In the SG patients with left-side stroke observed a significant increase in alpha rhythm frequency in the intact hemisphere. In the RSG patients with right-side stroke observed a significant decrease in theta band power in the affected and the intact hemispheres, increase in alpha-2 band power in the intact hemisphere and increase in alpha rhythm frequency in the affected and the intact hemispheres. In the SG patients with right-side stroke observed a signifi-
S224
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
cant increase in theta band power and alpha-1 band power in the intact hemisphere and alpha-2 band power of both the affected and the intact hemispheres. Conclusions: Combined rTMS and rPMS increased cortical excitability of the affected hemisphere and harmonized electrical activity of the brain of both the affected and the intact hemispheres in stroke patients.
P640 Effect of static magnetic field stimulation (tSMS) over parietal cortex on somatosensory evoked potentials in humans M.D.C. Carrasco-Lopez 1 , V. Soto-Leon 1 , P. Profice 2 , G. Foffani 1 , A. Oliviero 1 1 Hospital Nacional de Paraplejicos, FENNSI, Toledo, Spain; 2 Univeritá Cattolica, Neurology Department, Rome, Italy Objective: To study the effect of transcranial static magnetic field stimulation (tSMS) over the parietal cortex on the size of somatosensory evoked potentials (SEPs) in humans. Methods: SEPs were elicited by electrical stimulation of right median nerve at the wrist before, during and after tSMS (or sham) in 8 healthy subjects. tSMS was applied for 20 min to the left parietal cortex using a neodimium cylindric magnet with a diameter of 6 cm and height of 3 cm. Sham stimulation was obtained by applying for 20 min to the left parietal cortex a steel cylinder with a diameter of 6 cm and height of 3 cm. Results: Amplitudes of N20/P25 and P25/N30 following right median nerve stimulation were significantly modified for at least 10 min after the end of tSMS, whereas P14/N20 were unaffected. There was no effect on SEPs evoked by right median nerve stimulation after sham stimulation. Conclusions: tSMS over the sensorimotor cortex can induce a long-lasting changes in cortical components of SEPs. Significance: tSMS can modulate cortical somatosensory processing in humans.
of patients that may benefit from tDCS as an adjuvant treatment for pain (or other NIBS treated disorders).
P642 Modulating the interplay between exploration and exploitation in instrumental learning by prefrontal transcranial direct current stimulation Z. Turi, A. Opitz, M. Popkes, W. Paulus, A. Antal Georg-August University of Goettingen, University Medical Center, Clinical Neurophysiology, Goettingen, Germany Question: Accumulating experimental evidence indicate that instrumental learning situations in humans recruit both the striatal and the working memory system. However, the role of working memory system in instrumental learning is still not well understood. Methods: In order to address this issue, we applied transcranial direct current stimulation (tDCS) optimized for targeting dorsolateral prefrontal cortex (see Fig. 1), a key region in working memory for 15 minutes using 1.0 mA intensity. By following a double-blinded, repeated-measures study design, 16 male participants took part in a sham and anodal tDCS session separated by 1 week. Accuracy, reaction time and the number of behavioral shiftings (trial-to-trial changes after positive and negative outcomes) were taken as dependent variables. Results: Although general accuracy and reaction time was not influenced by tDCS, we observed significantly greater amount of behavioral shifting in the active condition compared to the sham condition.
P641 Tele-medicine approach in non-invasive brain simulation: case report in a pain patient Y.A. Perez-Borrego, M. Campolo, I. Rodriguez-Carrion, V. Soto-León, A. Oliviero Hospital Nacional de Paraplejicos, FENNSI, Toledo, Spain Question: Chronic pain often shows insufficient response to pharmacological treatments. Non-invasive brain stimulation (NIBS) of the motor cortex has been proposed as an alternative therapeutic approach. Methods: We present a case of a patient treated in our Hospital using tDCS with good pain relief after 5 tDCS daily sessions, and with maintenance of the positive analgesic effects for more than one year with a single tDCS session every 7 days. The patient lives very far away from our Hospital and we decided to use modern information technology to start a Tele-NIBS treatment approach. Case presentation: Our patient, a 56 years-old male, was diagnosed of macrophagic myofasciitis. Macrophagic myofasciitis is a rare condition with few hundreds of definite cases identified in France, and isolated cases recorded in other countries. The main clinical complaints of our patient were pain and chronic fatigue. Pain was intense (mean VAS of 8, VAS scale scored pain from 0 to 10, where 10 meant worst possible pain) and the patient was treated with many different protocols of analgesic drugs. All these treatments failed. For this reason, the patient was screened as a possible candidate for NIBS. We received the patient 2 years ago and we decided to treat the patient with a tDCS protocol. The NIBS consisted of 20 minutes of anodal stimulation (with an intensity of 1.5 mA) over both motor cortices. This stimulation protocol was repeated on five consecutive days and maintained for months with one weekly session. Once the patient reached a good pain control, he stopped the treatment and VAS started to go up again in few months (VAS=5). The reason why the patient stopped the treatment was that he lived very far from the Hospital (about300 Km) and it was difficult for him to reach our Hospital. Few months ago, we repeated the 5 days tDCS sessions with the same protocol and the patient’s pain diminished again (VAS=2±1). After more than one year of successful treatment, we decided – together with the patient – to use modern information technology to start a Tele-NIBS treatment approach. Conclusions: Here we report a case of a successful tele-NIBS approach using “at home” tDCS to treat pain. This strategy may increase the number
Figure 1
Conclusion: In line with previous findings, our results suggest that the working memory system may influence instrumental learning by actively maintaining reinforcement history and adjusting behavior on trial-to-trial bases.
P643 Safety and characterization of a novel multi-channel TMS stimulator Y. Roth 1 , A. Zangen 1 , G. Pell 1,2 , Y. Levkovitz 3 , M. Ankry 2 Ben Gurion University, Life Sciences, Be’er Sheva, Israel; 2 Brainsway Ltd, Jerusalem, Israel; 3 Shalvata Mental Health Care Center, The Emotion-Cognition Research Center, Hod-Hasharon, Israel 1
Question: Currently available TMS stimulators have a single channel operating a single coil. This study presents benefits of a novel multi-channel stimulator, comprising five channels with independently controllable stimulation parameters. Methods: Simultaneous and sequential operation of various channels was tested in healthy volunteers. Paired pulses schemes with various interstimulus intervals (ISIs) were studied for the hand APB and the leg AH muscles. Energy consumption and coil heating rates with simultaneous operation of 4 channels was compared to a figure-8 coil. Results: Repetitive operation of separate channels with different stimulation parameters is demonstrated. The operations of various channels can be combined simultaneously or sequentially to induce multiple pulses with ISIs of μs resolution. A universal pattern of inhibition and facilitation as a function of ISI was found, with some dependence on coils configurations and on pulse widths. A strong dependence of the induced inhibition on the relative orientation of the conditioning and test pulses was discovered. The ability of this method to induce inhibition in shallow brain region but not in deeper region is demonstrated. Significant reductions in energy consumption and coil heating were demonstrated for several channels operated simultaneously compared to a standard figure-8 coil. Conclusions: The multi-channel stimulator enables the synchronized induction of different excitability modulations to different brain regions using