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ID 247 – Cortical modulation of thermal detection and pain thresholds in migraineurs
Abstracts / Clinical Neurophysiology 127 (2016) e18–e132
followed chronologically by other muscular segments of limbs or axial musculature we classified the event as propagated or generalized (NM GEN). Results: SNNM was observed in REM and NREM sleep phases. Conclusions: NM occurred more often during REM sleep than during NREM sleep. More studies are needed to demonstrate if a relation exists between the frequency of NM and medical conditions. doi:10.1016/j.clinph.2015.11.373
ID 202 – Characterising seizures in anti-NMDA-receptor encephalitis with Dynamic Causal Modelling—G.K. Cooray a,b, B. Sengupta a, P. Douglas a, M. Englund b, R. Wickstrom c, K. Friston a (a Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK, b Clinical Neurophysiology, Karolinska University Hospital, Stockholm, Sweden, c Neuropediatric Unit, Department of Women’s and Children’s Karolinska Institutet, Sweden) Objective: To characterise the pathophysiology of seizures in terms of slow fluctuations in synaptic efficacy in patients with anti-N-methyl-D-aspartate Receptor (NMDA-R) encephalitis. Method: Non-invasive clinical EEG recordings were obtained from two patients with anti-NMDA-R encephalitis with recurrent partial seizures (both females of age 19 and 33) using nine scalp electrodes positioned according to the 10–20 system. Electrographic seizure activity was localised using a Beamformer inversion. A virtual electrode at this position was used to estimate the underlying dynamics of the cortex using a Dynamic Causal Model (DCM). Results: The DCM generated activity with a close fit to measured seizure activity which allowed us to confidently track changes in both excitatory and inhibitory connectivity. Seizure initiation was induced with a disruption in both excitatory and inhibitory connectivity resulting in excitatory–inhibitory imbalance, with an increasing weight on excitation as the seizure progressed. Conclusion: Our findings suggest that seizures in anti-NMDA-R encephalitis are due to disruption in both inhibitory, GABA dependent, and excitatory, partly NMDA dependent, connectivity. Key message: This study illustrates the inversion of dynamic causal models of seizure activity – recorded from the scalp in a clinical setting – to identify the underlying pathophysiological mechanisms. doi:10.1016/j.clinph.2015.11.374
ID 247 – Cortical modulation of thermal detection and pain thresholds in migraineurs—M. Uglem a, P.M. Omland a, T. Sand a,b (a Department of Neuroscience, Norwegian University of Technology and Science, Trondheim, Norway, b Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim, Norway) Objective: To explore the effect of 10 Hz repetitive transcranial magnetic stimulation (rTMS) of secondary somatosensory cortex (S2) on thermal perception and pain in migraineurs. Methods: We measured thermal detection and pain thresholds on the hand and forehead before and after real and placebo rTMS in 26 interictal, 7 preictal migraineurs and 31 headache-free controls.
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Thresholds, defined as difference from baseline (32 °C), were analysed with repeated measures ANOVA. Results: rTMS of S2 increased hand heat pain thresholds in controls, but not in migraineurs (p = 0.042). The effect was not significant when compared to placebo stimulation. rTMS increased hand cold detection thresholds in both groups (p < 0.001). The effect of rTMS did not differ between interictal and preictal migraineurs. Conclusions: rTMS of S2 had an analgesic effect on heat pain in controls compared to migraineurs. The effect-size was not large, however, i.e. of similar magnitude as the effects caused by placebo. Stimulation of S2 seems to alter detection thresholds primarily, possibly because pain is modulated by deeper brain structures, namely the medial operculum and insula. Key message: rTMS of S2 had greater analgesic effect in controls compared to migraineurs, although not distinguishable from the placebo effect. doi:10.1016/j.clinph.2015.11.375
ID 284 – Abnormal delta cortical sources of resting state eyes closed EEG rhythms correlate with cerebrospinal fluid (CSF)Ò amyloid (AÒ) level in amnesic MCI subjects—G. Noce a, C. Del Percio b,c, N. Marzano a, S. Cordone b, C. Bagnoli d, P.M. Rossini e, A. Soricelli a, F.M. Nobili f, D. Bartres Faz g, O. Blin h, P. Payoux i, R. Bordet j, B.W. Müller k, M. Tsolaki l, L. Parnetti m, U. Hegerl n, T. Hensch n, J. Dukar o, A. Bertolino o, G. Forloni p, J.C. Richardson q, G. Frisoni d, C. Babiloni c,r (a IRCCS SDN, Naples, Italy, b University of Foggia, Foggia, Italy, c IRCSS San Raffaele Pisana, Rome, Italy, d IRCCS Fatebenefratelli, Brescia, Italy, e Catholic University, Rome, Italy, f University of Genoa, Genoa, Italy, g University of Barcelona, Barcelona, Spain, h Marseille University, Marseille, France, i University of Toulouse, Toulouse, France, j Lille 2 University, Lille, France, k University of Duisburg-Essen, Essen, Germany, l University of Thessaloniki, Thessaloniki, Greece, m University of Perugia, Perugia, Italy, n University of Leipzig Leipzig, Germany, o Roche, Basel, Switzerland, p Mario Negri Institute, Milan, Italy, q Neurosciences Therapeutic Area U.K., United Kingdom, r University of Rome ‘‘La Sapienza”, Rome, Italy) Aim: In the framework of IMI PharmaCog project (Grant Agreement no. 115009), this study evaluated whether abnormal cortical sources of resting state electroencephalographic (EEG) rhythms are correlated to cerebrospinal fluid (CSF)Ò amyloid (AÒ) level in amnesic Mild Cognitive Impairment (MCI) subjects. Methods: Artifact-free resting state eyes-closed EEG rhythms (19 electrodes) were recorded. Individual datasets were divided into those with high CSF AÒ level (81 AÒ-negative, CSF AÒ > 550 pg=ml) and those with low CSF AÒ level (46 AÒ-positive, CSF AÒ < 550 pg=ml). Regional normalized cortical sources of EEG rhythms at frequency bands of interest were estimated by LORETA package. ANOVA compared these sources between the two MCI groups (p < 0.05, corrected) and 50 cognitively normal elderly (Nold) subjects. Results: Statistical results showed: (1) source pattern Nold < AÒ-negative < AÒ-positive at frontal, temporal and limbic delta sources level; (2) significant negative correlation (Pearson test, p < 0.05) between temporal delta sources and CSF AÒ level (r = 0.26; p = 0.003) across all MCI subjects. Conclusions: These results suggest a relationship between the brain amyloid charge, as revealed by CSF AÒ level, and pathological delta cortical sources indicating cortical disconnection in amnesic
followed chronologically by other muscular segments of limbs or axial musculature we classified the event as propagated or generalized (NM GEN). Results: SNNM was observed in REM and NREM sleep phases. Conclusions: NM occurred more often during REM sleep than during NREM sleep. More studies are needed to demonstrate if a relation exists between the frequency of NM and medical conditions. doi:10.1016/j.clinph.2015.11.373
ID 202 – Characterising seizures in anti-NMDA-receptor encephalitis with Dynamic Causal Modelling—G.K. Cooray a,b, B. Sengupta a, P. Douglas a, M. Englund b, R. Wickstrom c, K. Friston a (a Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK, b Clinical Neurophysiology, Karolinska University Hospital, Stockholm, Sweden, c Neuropediatric Unit, Department of Women’s and Children’s Karolinska Institutet, Sweden) Objective: To characterise the pathophysiology of seizures in terms of slow fluctuations in synaptic efficacy in patients with anti-N-methyl-D-aspartate Receptor (NMDA-R) encephalitis. Method: Non-invasive clinical EEG recordings were obtained from two patients with anti-NMDA-R encephalitis with recurrent partial seizures (both females of age 19 and 33) using nine scalp electrodes positioned according to the 10–20 system. Electrographic seizure activity was localised using a Beamformer inversion. A virtual electrode at this position was used to estimate the underlying dynamics of the cortex using a Dynamic Causal Model (DCM). Results: The DCM generated activity with a close fit to measured seizure activity which allowed us to confidently track changes in both excitatory and inhibitory connectivity. Seizure initiation was induced with a disruption in both excitatory and inhibitory connectivity resulting in excitatory–inhibitory imbalance, with an increasing weight on excitation as the seizure progressed. Conclusion: Our findings suggest that seizures in anti-NMDA-R encephalitis are due to disruption in both inhibitory, GABA dependent, and excitatory, partly NMDA dependent, connectivity. Key message: This study illustrates the inversion of dynamic causal models of seizure activity – recorded from the scalp in a clinical setting – to identify the underlying pathophysiological mechanisms. doi:10.1016/j.clinph.2015.11.374
ID 247 – Cortical modulation of thermal detection and pain thresholds in migraineurs—M. Uglem a, P.M. Omland a, T. Sand a,b (a Department of Neuroscience, Norwegian University of Technology and Science, Trondheim, Norway, b Department of Neurology and Clinical Neurophysiology, St. Olavs Hospital, Trondheim, Norway) Objective: To explore the effect of 10 Hz repetitive transcranial magnetic stimulation (rTMS) of secondary somatosensory cortex (S2) on thermal perception and pain in migraineurs. Methods: We measured thermal detection and pain thresholds on the hand and forehead before and after real and placebo rTMS in 26 interictal, 7 preictal migraineurs and 31 headache-free controls.
e111
Thresholds, defined as difference from baseline (32 °C), were analysed with repeated measures ANOVA. Results: rTMS of S2 increased hand heat pain thresholds in controls, but not in migraineurs (p = 0.042). The effect was not significant when compared to placebo stimulation. rTMS increased hand cold detection thresholds in both groups (p < 0.001). The effect of rTMS did not differ between interictal and preictal migraineurs. Conclusions: rTMS of S2 had an analgesic effect on heat pain in controls compared to migraineurs. The effect-size was not large, however, i.e. of similar magnitude as the effects caused by placebo. Stimulation of S2 seems to alter detection thresholds primarily, possibly because pain is modulated by deeper brain structures, namely the medial operculum and insula. Key message: rTMS of S2 had greater analgesic effect in controls compared to migraineurs, although not distinguishable from the placebo effect. doi:10.1016/j.clinph.2015.11.375
ID 284 – Abnormal delta cortical sources of resting state eyes closed EEG rhythms correlate with cerebrospinal fluid (CSF)Ò amyloid (AÒ) level in amnesic MCI subjects—G. Noce a, C. Del Percio b,c, N. Marzano a, S. Cordone b, C. Bagnoli d, P.M. Rossini e, A. Soricelli a, F.M. Nobili f, D. Bartres Faz g, O. Blin h, P. Payoux i, R. Bordet j, B.W. Müller k, M. Tsolaki l, L. Parnetti m, U. Hegerl n, T. Hensch n, J. Dukar o, A. Bertolino o, G. Forloni p, J.C. Richardson q, G. Frisoni d, C. Babiloni c,r (a IRCCS SDN, Naples, Italy, b University of Foggia, Foggia, Italy, c IRCSS San Raffaele Pisana, Rome, Italy, d IRCCS Fatebenefratelli, Brescia, Italy, e Catholic University, Rome, Italy, f University of Genoa, Genoa, Italy, g University of Barcelona, Barcelona, Spain, h Marseille University, Marseille, France, i University of Toulouse, Toulouse, France, j Lille 2 University, Lille, France, k University of Duisburg-Essen, Essen, Germany, l University of Thessaloniki, Thessaloniki, Greece, m University of Perugia, Perugia, Italy, n University of Leipzig Leipzig, Germany, o Roche, Basel, Switzerland, p Mario Negri Institute, Milan, Italy, q Neurosciences Therapeutic Area U.K., United Kingdom, r University of Rome ‘‘La Sapienza”, Rome, Italy) Aim: In the framework of IMI PharmaCog project (Grant Agreement no. 115009), this study evaluated whether abnormal cortical sources of resting state electroencephalographic (EEG) rhythms are correlated to cerebrospinal fluid (CSF)Ò amyloid (AÒ) level in amnesic Mild Cognitive Impairment (MCI) subjects. Methods: Artifact-free resting state eyes-closed EEG rhythms (19 electrodes) were recorded. Individual datasets were divided into those with high CSF AÒ level (81 AÒ-negative, CSF AÒ > 550 pg=ml) and those with low CSF AÒ level (46 AÒ-positive, CSF AÒ < 550 pg=ml). Regional normalized cortical sources of EEG rhythms at frequency bands of interest were estimated by LORETA package. ANOVA compared these sources between the two MCI groups (p < 0.05, corrected) and 50 cognitively normal elderly (Nold) subjects. Results: Statistical results showed: (1) source pattern Nold < AÒ-negative < AÒ-positive at frontal, temporal and limbic delta sources level; (2) significant negative correlation (Pearson test, p < 0.05) between temporal delta sources and CSF AÒ level (r = 0.26; p = 0.003) across all MCI subjects. Conclusions: These results suggest a relationship between the brain amyloid charge, as revealed by CSF AÒ level, and pathological delta cortical sources indicating cortical disconnection in amnesic