- Email: [email protected]
P13. Childhood narcolepsy with cataplexy: Clinical characteristics of 4 cases
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Abstracts / Clinical Neurophysiology 125 (2014) e43–e48
Conclusions: As described previously lack of NMDAR antibodies in serum does not exclude anti-NMDAR encephalitis, and necessitates testing of CSF. Rising awareness for the disease is important as recognition of milder variants and early diagnosis will result in earlier treatment and most probably better outcome. doi:10.1016/j.clinph.2014.06.017
P15. Measures of autonomic dysfunction in early-motor Parkinson’s disease—S.R. Schreglmann a, L. Epprecht b, O. Götze c, L. Zimmerli d, D. Waldvogel a, C.R. Baumann a (a Department of Neurology, University Hospital Zurich, Zurich, Switzerland, b Department of Neurosurgery, KantonSpital St.Gallen, St. Gallen, Switzerland, c Department of Gastroenterology, University Hospital Zurich, Zurich, Switzerland, d Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland) Aims: Symptoms of autonomic dysfunction are increasingly recognized as part of the clinical spectrum in Parkinson’s disease (PD), often causing considerable distress. The extent and disease burden of autonomic nervous system (ANS) dysfunction in PD patients has been studied extensively, however the relationship between ANS and motor symptoms as well as their pathoaetiology is not well understood. This cross-sectional study is aimed at investigating the extent of ANS dysfunction in the early-motor phase of PD by comparing patients to control (Ctrl) subjects in the absence of potentially interfering medication. Methods: 16 PD patients (Hoehn & Yahr 2) and 11 sex- and age-matched Ctrl subjects without history of gastrointestinal (GI) disease, diabetes mellitus and antihypertensive treatment were examined in the morning of a single study visit after an overnightfast in the strict absence of medication influencing GI motility or blood-pressure (bp) regulation. Long-acting dopaminergic medication (dopamine agonists, extended release L-Dopa) was stopped 36 h, standard L-Dopa 12 h prior to testing. Objective Schellong test, Finapres heart rate (HR) variability assessment, 7d-blood pressure recording and C13-octanoate gastric emptying breath test were performed and subjective symptoms assessed using questionnaires. Results: Groups were well matched for age (PD 66.3 ± 8.5 vs. Ctrl 61.7 ± 7.1), sex (10/6 vs. 7/4) and BMI (25.4 ± vs. 24.1). Mean duration of motor symptoms in the patient group was 5.5 ± 4.5 years, mean L-dopa equivalent dose 694 ± 340 mg/d. Objective measures for gastric emptying and subjective GI function did not differ between both groups OFF medication. Patients reported significantly more subjective orthostatic hypotension (OH) symptoms prior to testing (whilst on dopaminergic medication) than Ctrl subjects (8.9 ± 6.2 vs. 1.8 ± 3.0, p = 0.001), although Schellong measurements did not differ significantly in the absence of medication. Patients had a significantly higher HR (70.1 ± 11.7 vs. 60.5 ± 8.5, p = 0.02) than controls. Conclusion: In the absence of medication interfering with GI function and cardiovascular control we did not see OH or delayed gastric emptying in early-motor PD patients. The significantly higher subjective OH symptom-score whilst on dopaminergic medication might reflect its known influence on bp regulation. Ongoing HR variability analysis might clarify in how far a parasympathetic deficit might explain the HR difference. doi:10.1016/j.clinph.2014.06.013
P16. Neurologic-psychiatric disease patterns in Niemann-Pick type C disease: A cohort study on 14 Suisse patients—L. Abela a, B. Plecko a, A. Palla b, J.M. Nuoffer c, D. Ballhausen d, P. Burda e,
M. Rohrbach e (a Division of Neurology, Children’s Hospital Zurich, University of Zurich, Zurich, Switzerland, b Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland, c Division of Metabolic Diseases, Department of Pediatrics, University Hospital Bern, Bern, Switzerland d Division of Metabolic Diseases, Department of Pediatrics, University of Lausanne, Lausanne, Switzerland, e Division of Metabolic Diseases, Children’s Hospital Zurich, University of Zurich, Zurich, Switzerland) Objective: Niemann-Pick disease type C (NP-C) is a rare autosomal recessive disorder of lysosomal cholesterol transport. The diagnosis of NP-C disease still poses a considerable challenge to clinicians, hampered by the lack of specific biomarkers and a remarkable clinical heterogeneity. The objective of this study was to critically analyze the onset and time course of symptoms, and the clinical diagnostic work-up of NP-C disease in a national Swiss cohort. Methods: Clinical, biochemical and genetic data were collected from 14 patients diagnosed with NP-C between 1994 and 2013. Diagnostic delays were calculated for neurological, psychiatric and visceral symptoms associated with NP-C disease. We further retrospectively evaluated prevalence rates of clinical symptoms during the observation period ending in September 2013. Results: In our cohort, neurological symptoms showed a median diagnostic delay of 5 years. Among these, vertical supranuclear gaze palsy, dysphagia and seizures had the shortest median diagnostic delays of 2 years and 3 years for the latter. Neurological symptoms such as ataxia, dysarthria, spasticity and cataplexy displayed a median diagnostic delay of 4–5 years, similar to psychiatric symptoms such as cognitive decline.Visceral symptoms, in particular hepatosplenomegaly, were associated with the longest median diagnostic delay of 13 years. Highest prevalence rates were noted for ataxia, dysarthria, VSGP and cognitive decline. All of these symptoms showed an early onset within the first and second decade, respectively. Conclusion: A neurologic-psychiatric disease pattern may represent the most characteristic clinical manifestation of NP-C and occurs early in the disease course. Patients with neurological & psychiatric disorders of unclear etiology should be investigated for accompanying organomegaly. doi:10.1016/j.clinph.2014.06.018
P17. Isolated effective coherence (iCoh) based on estimated electric neuronal activity using exact low resolution brain electromagnetic tomography (eLORETA)—R.D. Pascual-Marqui a,f, R.J. Biscay b,f, J. Bosch-Bayard c,f, D. Lehmann a,f, K. Kochi a,f, N. Yamada e,f, T. Kinoshita d,f, N. Sadato a,f (a The KEY Institute for BrainMind Research, Zurich, Switzerland, b Universidad de Valparaiso, Valparaiso, Chile, c Cuban Neuroscience Center, Havana, Cuba, d Kansai Medical University, Osaka, Japan, e Shiga University of Medical Science, Shiga, Japan, f National Institute for Physiological Science, Okazaki, Japan) A problem of great interest in real world systems, where multiple time series measurements are available, is the estimation of the intra-system casual relations. For instance, electric cortical signals are used for studying functional connectivity between different brain areas, the directionality, the direct or indirect nature of the connections, and the spectral characteristics such as which frequencies are transmitted. The earliest spectral measure of causality was Akaike’s (1968) seminal work on the noise contribution ratio (NCR), reflecting direct and indirect connections. Later, the partial directed coherence (PDC) of Baccala and Sameshima (2001) was proposed for direct connections. In this study, the partial coherence is estimated under a
Abstracts / Clinical Neurophysiology 125 (2014) e43–e48
stable, stationary multivariate auto-regressive model with stable isolated self-auto-regressions. The new measure of direct causal coherence, namely the isolated causal coherence (iCC), is defined under the a posteriori assumption that all irrelevant connections are zero. It is shown that when these assumptions are applied to the NCR, it produces the iCC, thus enriching its interpretability. In comparison with the iCC, it is shown that the PDC is affected by irrelevant connections to such an extent that it can misrepresent the frequency response. Toy examples are included to demonstrate these properties. Analysis of real EEG data is also included. doi:10.1016/j.clinph.2014.06.014
Poster P37. Decreased functional electrophysiological cortical connectivity in first episode medication-naive schizophrenics: A threecenter study—D. Lehmann a, R.D. Pascual-Marqui a, P.L. Faber a, P. Milz a, W.M. Herrmann b, M. Koukkou a, N. Saito c, G. Winterer d, K. Kochi a (a The KEY Institute for Brain-Mind Research, Dept. of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry, Zurich, Switzerland, b Laboratory of Clinical Psychophysiology, Dept. of Psychiatry, University Hospital Benjamin Franklin, Free University, Berlin, Switzerland, c Saito Mental Clinic, Osaka, Switzerland, d Charité – University Medicine Berlin, Experimental and Clinical Research Center, Campus Buch, Berlin, Switzerland) Aims: Abnormality of thought and emotion in schizophrenic patients is widely hypothesized to be caused by functional dissociation between brain processes. Analyses of the typically small groups of schizophrenic patients yielded different neurophysiological findings, because small patient groups are likely to comprise different schizophrenia subtypes. We wanted to see whether there are identical deteriorated cortical functional EEG connectivities in different patient groups. Methods: Multichannel no-task resting eyes-closed EEG from three small groups of acutely ill, first episode productive schizophrenic patients before start of medication (from three centers: Bern N = 9; Osaka N = 9; Berlin N = 12) and their controls was analyzed. Using LORETA (low resolution brain electromagnetic tomography), we computed intracortical source model-based lagged functional connectivity (not biased by volume conduction effects) between 19 cortical regions of interest (ROIs). The connectivities were compared between controls and patients of each group. The results across groups were combined using conjunction analysis. Results: Six aberrant cortical functional connectivities were identical in the three patient groups as determined by conjunction analysis. Four of these occurred in the facilitating EEG alpha 1 frequency band; they were decreased in the patients. Another two of these occurred in the inhibiting EEG delta frequency band; they were increased in the patients. Thus, all six reduced the functional interactions between the concerned brain regions. The principal spatial orientation of the six aberrant cortical functional connectivities was sagittal; five of them involved both hemispheres. Conclusions: The study shows that, common across schizophrenia subtypes in the three patient groups, a core set of functional connections between the preprocessing functions in posterior brain areas and the evaluation and behavior control functions in anterior brain areas is compromised. The results also support the concept of functional dissociation in schizophrenia. doi:10.1016/j.clinph.2014.06.019
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P38. Effect of anaesthetic agents on the prognosis of refractory status epilepticus—N.A. Marchi a, J. Novy a, M. Faouzi b, C. Stähli a, B. Burnand b, A.O. Rossetti a (a Department of Clinical Neurosciences, CHUV-Lausanne University Hospital, Lausanne, Switzerland, b Institute of Social and Preventive Medicine, CHUV-Lausanne University Hospital, Lausanne, Switzerland) Aim: Anaesthetic agents (AAs) are advocated in guidelines for management of refractory status epilepticus (SE), although their effect on prognosis has not been established. The aim of this study was to determine their impact on clinical outcome, after adjustment for all relevant prognostic factors. Methods: We included consecutive adults with incident SE lasting 30 min, admitted between 2006 and 2013. Demographics, clinical SE features, treatment type and functional outcome at discharge were prospectively recorded, while medical comorbidities were retrospectively retrieved. The association between potential predictors and clinical outcome was analyzed using multinomial logistic regressions. Results: We identified 467 episodes of SE; 238 (51.1%) patients returned to baseline, 162 (34.6%) had new disability, and 67 (14.3%) died. Of 50 subjects managed with AAs, 14 presented with non-convulsive SE (NCSE) without coma (mostly complex partial SE) (28%), and 36 with generalized convulsive SE (GCSE) or NCSE in coma (72%). Multinomial logistic regression showed that AAs were independently associated with poorer outcome at discharge [risk ratio (RR) for new disability: 6.9, 95% CI 2.8–16.6; RR for mortality: 9.1, 95% CI 3.2–26.2]. The effect was higher in the group of patients with NCSE without coma, especially for mortality [RR for new disability: 8.6, 95% CI 1.4–52.0; RR for mortality: 26.6, 95% CI 3.4–205.4]. Conclusions: Management with AAs is independently associated with poorer outcome in SE. This study suggests caution in the indiscriminate use of this approach, especially in patients with complex partial SE. doi:10.1016/j.clinph.2014.06.020
P39. Fast versus slow charge cortical stimulation for motor evoked potential—E. Pralong, R.T. Daniel, M. Levivier, J.M. Duff (CHUV, Lausanne, Switzerland) Aim: Fast charge (FC) and slow charge (SC) stimulation protocols are both available on modern neuromonitoring machines in order to induce motor evoked potentials (MEP). In order to define the best strategy for MEP recording, we have compared the efficiency and the feasibility of both stimulation protocols for the induction of motor evoked potential in neurosurgical patients that present without myelopathy. Methods: Fifteen consecutive adult patients (13 arthrodesis and 2 kyphoplasties) without clinical motor deficit undergoing spine surgery under neuromonitoring were included in this study. Fast (50 ls) and slow (500 ms) charge biphasic cortical stimulation was applied between C3 and C4 electrodes in trains of 5 at 500 Hz. Muscular response was quantified as the area under the curve between the MEP start and end time. Results: We were able to deliver FC and SC in all patients. SC induced always-measurable MEP response up to 140 V. On the contrary, in some patients FC induced large recording artefacts that precluded measurement. Current delivery saturated between 100 (129 ± 32 mA) and 140 (117 ± 62 mA) V for SC while this was not the case for FC up to 450 V (660 ± 123 mA). In the same way MEP area under the curve value reached a plateau between 120 and 140 V for SC (96% of maximal response) while FC induced MEP area under the curve varied linearly with stimulation current
Abstracts / Clinical Neurophysiology 125 (2014) e43–e48
Conclusions: As described previously lack of NMDAR antibodies in serum does not exclude anti-NMDAR encephalitis, and necessitates testing of CSF. Rising awareness for the disease is important as recognition of milder variants and early diagnosis will result in earlier treatment and most probably better outcome. doi:10.1016/j.clinph.2014.06.017
P15. Measures of autonomic dysfunction in early-motor Parkinson’s disease—S.R. Schreglmann a, L. Epprecht b, O. Götze c, L. Zimmerli d, D. Waldvogel a, C.R. Baumann a (a Department of Neurology, University Hospital Zurich, Zurich, Switzerland, b Department of Neurosurgery, KantonSpital St.Gallen, St. Gallen, Switzerland, c Department of Gastroenterology, University Hospital Zurich, Zurich, Switzerland, d Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland) Aims: Symptoms of autonomic dysfunction are increasingly recognized as part of the clinical spectrum in Parkinson’s disease (PD), often causing considerable distress. The extent and disease burden of autonomic nervous system (ANS) dysfunction in PD patients has been studied extensively, however the relationship between ANS and motor symptoms as well as their pathoaetiology is not well understood. This cross-sectional study is aimed at investigating the extent of ANS dysfunction in the early-motor phase of PD by comparing patients to control (Ctrl) subjects in the absence of potentially interfering medication. Methods: 16 PD patients (Hoehn & Yahr 2) and 11 sex- and age-matched Ctrl subjects without history of gastrointestinal (GI) disease, diabetes mellitus and antihypertensive treatment were examined in the morning of a single study visit after an overnightfast in the strict absence of medication influencing GI motility or blood-pressure (bp) regulation. Long-acting dopaminergic medication (dopamine agonists, extended release L-Dopa) was stopped 36 h, standard L-Dopa 12 h prior to testing. Objective Schellong test, Finapres heart rate (HR) variability assessment, 7d-blood pressure recording and C13-octanoate gastric emptying breath test were performed and subjective symptoms assessed using questionnaires. Results: Groups were well matched for age (PD 66.3 ± 8.5 vs. Ctrl 61.7 ± 7.1), sex (10/6 vs. 7/4) and BMI (25.4 ± vs. 24.1). Mean duration of motor symptoms in the patient group was 5.5 ± 4.5 years, mean L-dopa equivalent dose 694 ± 340 mg/d. Objective measures for gastric emptying and subjective GI function did not differ between both groups OFF medication. Patients reported significantly more subjective orthostatic hypotension (OH) symptoms prior to testing (whilst on dopaminergic medication) than Ctrl subjects (8.9 ± 6.2 vs. 1.8 ± 3.0, p = 0.001), although Schellong measurements did not differ significantly in the absence of medication. Patients had a significantly higher HR (70.1 ± 11.7 vs. 60.5 ± 8.5, p = 0.02) than controls. Conclusion: In the absence of medication interfering with GI function and cardiovascular control we did not see OH or delayed gastric emptying in early-motor PD patients. The significantly higher subjective OH symptom-score whilst on dopaminergic medication might reflect its known influence on bp regulation. Ongoing HR variability analysis might clarify in how far a parasympathetic deficit might explain the HR difference. doi:10.1016/j.clinph.2014.06.013
P16. Neurologic-psychiatric disease patterns in Niemann-Pick type C disease: A cohort study on 14 Suisse patients—L. Abela a, B. Plecko a, A. Palla b, J.M. Nuoffer c, D. Ballhausen d, P. Burda e,
M. Rohrbach e (a Division of Neurology, Children’s Hospital Zurich, University of Zurich, Zurich, Switzerland, b Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland, c Division of Metabolic Diseases, Department of Pediatrics, University Hospital Bern, Bern, Switzerland d Division of Metabolic Diseases, Department of Pediatrics, University of Lausanne, Lausanne, Switzerland, e Division of Metabolic Diseases, Children’s Hospital Zurich, University of Zurich, Zurich, Switzerland) Objective: Niemann-Pick disease type C (NP-C) is a rare autosomal recessive disorder of lysosomal cholesterol transport. The diagnosis of NP-C disease still poses a considerable challenge to clinicians, hampered by the lack of specific biomarkers and a remarkable clinical heterogeneity. The objective of this study was to critically analyze the onset and time course of symptoms, and the clinical diagnostic work-up of NP-C disease in a national Swiss cohort. Methods: Clinical, biochemical and genetic data were collected from 14 patients diagnosed with NP-C between 1994 and 2013. Diagnostic delays were calculated for neurological, psychiatric and visceral symptoms associated with NP-C disease. We further retrospectively evaluated prevalence rates of clinical symptoms during the observation period ending in September 2013. Results: In our cohort, neurological symptoms showed a median diagnostic delay of 5 years. Among these, vertical supranuclear gaze palsy, dysphagia and seizures had the shortest median diagnostic delays of 2 years and 3 years for the latter. Neurological symptoms such as ataxia, dysarthria, spasticity and cataplexy displayed a median diagnostic delay of 4–5 years, similar to psychiatric symptoms such as cognitive decline.Visceral symptoms, in particular hepatosplenomegaly, were associated with the longest median diagnostic delay of 13 years. Highest prevalence rates were noted for ataxia, dysarthria, VSGP and cognitive decline. All of these symptoms showed an early onset within the first and second decade, respectively. Conclusion: A neurologic-psychiatric disease pattern may represent the most characteristic clinical manifestation of NP-C and occurs early in the disease course. Patients with neurological & psychiatric disorders of unclear etiology should be investigated for accompanying organomegaly. doi:10.1016/j.clinph.2014.06.018
P17. Isolated effective coherence (iCoh) based on estimated electric neuronal activity using exact low resolution brain electromagnetic tomography (eLORETA)—R.D. Pascual-Marqui a,f, R.J. Biscay b,f, J. Bosch-Bayard c,f, D. Lehmann a,f, K. Kochi a,f, N. Yamada e,f, T. Kinoshita d,f, N. Sadato a,f (a The KEY Institute for BrainMind Research, Zurich, Switzerland, b Universidad de Valparaiso, Valparaiso, Chile, c Cuban Neuroscience Center, Havana, Cuba, d Kansai Medical University, Osaka, Japan, e Shiga University of Medical Science, Shiga, Japan, f National Institute for Physiological Science, Okazaki, Japan) A problem of great interest in real world systems, where multiple time series measurements are available, is the estimation of the intra-system casual relations. For instance, electric cortical signals are used for studying functional connectivity between different brain areas, the directionality, the direct or indirect nature of the connections, and the spectral characteristics such as which frequencies are transmitted. The earliest spectral measure of causality was Akaike’s (1968) seminal work on the noise contribution ratio (NCR), reflecting direct and indirect connections. Later, the partial directed coherence (PDC) of Baccala and Sameshima (2001) was proposed for direct connections. In this study, the partial coherence is estimated under a
Abstracts / Clinical Neurophysiology 125 (2014) e43–e48
stable, stationary multivariate auto-regressive model with stable isolated self-auto-regressions. The new measure of direct causal coherence, namely the isolated causal coherence (iCC), is defined under the a posteriori assumption that all irrelevant connections are zero. It is shown that when these assumptions are applied to the NCR, it produces the iCC, thus enriching its interpretability. In comparison with the iCC, it is shown that the PDC is affected by irrelevant connections to such an extent that it can misrepresent the frequency response. Toy examples are included to demonstrate these properties. Analysis of real EEG data is also included. doi:10.1016/j.clinph.2014.06.014
Poster P37. Decreased functional electrophysiological cortical connectivity in first episode medication-naive schizophrenics: A threecenter study—D. Lehmann a, R.D. Pascual-Marqui a, P.L. Faber a, P. Milz a, W.M. Herrmann b, M. Koukkou a, N. Saito c, G. Winterer d, K. Kochi a (a The KEY Institute for Brain-Mind Research, Dept. of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry, Zurich, Switzerland, b Laboratory of Clinical Psychophysiology, Dept. of Psychiatry, University Hospital Benjamin Franklin, Free University, Berlin, Switzerland, c Saito Mental Clinic, Osaka, Switzerland, d Charité – University Medicine Berlin, Experimental and Clinical Research Center, Campus Buch, Berlin, Switzerland) Aims: Abnormality of thought and emotion in schizophrenic patients is widely hypothesized to be caused by functional dissociation between brain processes. Analyses of the typically small groups of schizophrenic patients yielded different neurophysiological findings, because small patient groups are likely to comprise different schizophrenia subtypes. We wanted to see whether there are identical deteriorated cortical functional EEG connectivities in different patient groups. Methods: Multichannel no-task resting eyes-closed EEG from three small groups of acutely ill, first episode productive schizophrenic patients before start of medication (from three centers: Bern N = 9; Osaka N = 9; Berlin N = 12) and their controls was analyzed. Using LORETA (low resolution brain electromagnetic tomography), we computed intracortical source model-based lagged functional connectivity (not biased by volume conduction effects) between 19 cortical regions of interest (ROIs). The connectivities were compared between controls and patients of each group. The results across groups were combined using conjunction analysis. Results: Six aberrant cortical functional connectivities were identical in the three patient groups as determined by conjunction analysis. Four of these occurred in the facilitating EEG alpha 1 frequency band; they were decreased in the patients. Another two of these occurred in the inhibiting EEG delta frequency band; they were increased in the patients. Thus, all six reduced the functional interactions between the concerned brain regions. The principal spatial orientation of the six aberrant cortical functional connectivities was sagittal; five of them involved both hemispheres. Conclusions: The study shows that, common across schizophrenia subtypes in the three patient groups, a core set of functional connections between the preprocessing functions in posterior brain areas and the evaluation and behavior control functions in anterior brain areas is compromised. The results also support the concept of functional dissociation in schizophrenia. doi:10.1016/j.clinph.2014.06.019
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P38. Effect of anaesthetic agents on the prognosis of refractory status epilepticus—N.A. Marchi a, J. Novy a, M. Faouzi b, C. Stähli a, B. Burnand b, A.O. Rossetti a (a Department of Clinical Neurosciences, CHUV-Lausanne University Hospital, Lausanne, Switzerland, b Institute of Social and Preventive Medicine, CHUV-Lausanne University Hospital, Lausanne, Switzerland) Aim: Anaesthetic agents (AAs) are advocated in guidelines for management of refractory status epilepticus (SE), although their effect on prognosis has not been established. The aim of this study was to determine their impact on clinical outcome, after adjustment for all relevant prognostic factors. Methods: We included consecutive adults with incident SE lasting 30 min, admitted between 2006 and 2013. Demographics, clinical SE features, treatment type and functional outcome at discharge were prospectively recorded, while medical comorbidities were retrospectively retrieved. The association between potential predictors and clinical outcome was analyzed using multinomial logistic regressions. Results: We identified 467 episodes of SE; 238 (51.1%) patients returned to baseline, 162 (34.6%) had new disability, and 67 (14.3%) died. Of 50 subjects managed with AAs, 14 presented with non-convulsive SE (NCSE) without coma (mostly complex partial SE) (28%), and 36 with generalized convulsive SE (GCSE) or NCSE in coma (72%). Multinomial logistic regression showed that AAs were independently associated with poorer outcome at discharge [risk ratio (RR) for new disability: 6.9, 95% CI 2.8–16.6; RR for mortality: 9.1, 95% CI 3.2–26.2]. The effect was higher in the group of patients with NCSE without coma, especially for mortality [RR for new disability: 8.6, 95% CI 1.4–52.0; RR for mortality: 26.6, 95% CI 3.4–205.4]. Conclusions: Management with AAs is independently associated with poorer outcome in SE. This study suggests caution in the indiscriminate use of this approach, especially in patients with complex partial SE. doi:10.1016/j.clinph.2014.06.020
P39. Fast versus slow charge cortical stimulation for motor evoked potential—E. Pralong, R.T. Daniel, M. Levivier, J.M. Duff (CHUV, Lausanne, Switzerland) Aim: Fast charge (FC) and slow charge (SC) stimulation protocols are both available on modern neuromonitoring machines in order to induce motor evoked potentials (MEP). In order to define the best strategy for MEP recording, we have compared the efficiency and the feasibility of both stimulation protocols for the induction of motor evoked potential in neurosurgical patients that present without myelopathy. Methods: Fifteen consecutive adult patients (13 arthrodesis and 2 kyphoplasties) without clinical motor deficit undergoing spine surgery under neuromonitoring were included in this study. Fast (50 ls) and slow (500 ms) charge biphasic cortical stimulation was applied between C3 and C4 electrodes in trains of 5 at 500 Hz. Muscular response was quantified as the area under the curve between the MEP start and end time. Results: We were able to deliver FC and SC in all patients. SC induced always-measurable MEP response up to 140 V. On the contrary, in some patients FC induced large recording artefacts that precluded measurement. Current delivery saturated between 100 (129 ± 32 mA) and 140 (117 ± 62 mA) V for SC while this was not the case for FC up to 450 V (660 ± 123 mA). In the same way MEP area under the curve value reached a plateau between 120 and 140 V for SC (96% of maximal response) while FC induced MEP area under the curve varied linearly with stimulation current