- Email: [email protected]
P905: Spreading depression detection by different methods of imaging
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
dysphasia. The pathophysiology of these subgroups of common forms of migraine with aura has been studied rarely. Methods: Forty-seven migraine with aura patients were subgrouped in migraine with pure visual aura (MA, N=27) and migraine with complex aura (MA+, N=20), i.e. those who had visual aura associated with paraesthesia and/or dysphasia. We recorded visual evoked potentials (VEPs, 15 min of arc cheques, 3.1 reversal rate, 600 sweeps) amplitude and habituation (slope of the linear regression line for N1-P1 amplitude from the 1st to 6th block of 100 sweeps) in patients and in 30 healthy volunteers (HV) of comparable age and gender distribution. Results: Habituation (i.e. response decrement), which could be observed in most HVs (slope -0.54), was deficient in both MA (slope +0.01, p=0.001) and MA+ (+0.14, p<0.001) patients. However, VEP amplitudes across the blocks generally tended to be lower in MA patients, while were significantly higher in MA+ patients, than in HVs. Conclusions: We found different patterns of visual responses in subgroups of MA patients. We hypothesize that a different genetic load and energetic metabolism may characterize migraine with aura patients with more severe focal symptoms.
P903 Assessment of course of tension-type headache in adolescents based on nonlinear multidimensional analysis (deterministic chaos) EEG K. Stepanchenko Kharkiv Medical Academy of Postgraduate Education, Department of Neurology, Kharkiv, Ukraine The life prevalence of tension-type headache in the general population by various studies ranged from 30 to 78%, and in the children – 28.7–72.8%. Question: Examine the condition of nonspecific cerebral regulatory systems based on the study of bioelectrical brain activity using the method of nonlinear multidimensional analysis (deterministic chaos) EEG in adolescents with episodic and chronic tension-type headache. Methods: We observed 43 adolescents with tension-type headache at the age of 13–18. Two groups: 1st (23 pers.) – patients with episodic tension-type headache, 2nd (20 pers.) – patients with chronic tension-type headache. Registration the electroencephalogram (EEG) was performed at rest with eyes closed and intellectual load (countdown in mind in 1000, 993, 986, etc.). We conducted nonlinear multidimensional analysis (deterministic chaos) EEG and calculated Kolmogorov-Sinai entropy. Results: Decrease in the value Kolmogorov-Sinai entropy is observed with increasing frequency of episodes of tension-type headache, i.e. the transition to the chronic form of the disease. This means reducing the number of active parallel functional processes in the brain, the possibilities for self-organization, the ability to form ranked adaptive dissipative structures, reducing neuroplasticity of the brain and, consequently, the capacity to adapt. Conclusions: Study of nonlinear parameter - the Kolmogorov-Sinai entropy of EEG signal is an objective quantitative measure of the dynamic characteristics of cortical and limbic - reticular structures of the brain that are involved in the formation of adaptive processes in patients with episodic and chronic tension-type headache.
P904 Normalization of EEG power spectrum in patients with migraine during peri-ictal periods K.-L. Lai 1,2,3,4 , F.-J. Hsiao 5 , K.-K. Liao 2,3 , J.-L. Fuh 2,3 , S.-J. Wang 2,3,5 Taipei Municipal Gandau Hospital, Neurology, Taipei, Taiwan; 2 Taipei Veterans General Hospital, Neurology, Taipei, Taiwan; 3 National Yang-Ming University School of Medicine, Faculty of Medicine, Taipei, Taiwan; 4 National Yang-Ming University School of Medicine, Institute of Clinical Medicine, Taipei, Taiwan; 5 National Yang-Ming University School of Medicine, Institute of Brain Science, Taipei, Taiwan 1
Question: Previous resting EEG spectral analyses in patients with migraine showed inconsistent results. The inconsistency might be related to the spontaneous fluctuation of electrophysiological activity in a headache state-dependent manner in patients with migraine. In this study, we aimed to investigate the resting EEG power spectrum and its relation to migraine state. Methods: Resting EEG data (30 seconds for 3 times) was recorded with 256 Hz sampling rate, and 19 electrodes positioned according to the interna-
S287
tional 10-20 system, while the subjects kept awake and alert. After artifacts rejection, independent component analysis was applied to remove noises. Minimum norm estimate analysis was then used to transform the original electrode-based EEG signal into region-of-interest (ROI)-based EEG activity. Then, normalization of spectral power was done by normalizing the power at each frequency band with total power to reduce the inter-individual variability. We then compared the relative power of each band across all ROIs in patients with migraine and control subjects. Statistical significance was defined as a p-value of <0.05. All tests were two-tailed. Results: One hundred and twenty-seven episodic migraine patients were recruited (M/F: 29/98, age: 35.1±10.3, headache frequency: 4.3±2.6 days/m). Compared to age- and gender-matched controls (n=20, M/F: 8/12, age: 36.4±6.8), patients during inter-ictal period (n=75) showed decreased alpha and theta power over most of all brain regions and increased delta power over bilateral frontal regions. These spectral abnormalities were less obvious or normalized during pre-ictal (n=21), ictal (n=19) or post-ictal (n=12) periods. Of note, compared with controls, patients with migraine had a consistent increment of beta- and gamma-band powers regardless of their clinical headache state. Conclusions: Resting EEG spectral analysis in patients with migraine showed a state-dependent fluctuation at delta-, theta- and alpha-band range, which tended to be normalized during peri-ictal periods. Besides, we found that gamma-band power, and beta-band power to a lesser extent, were consistently increased in patients with migraine, which deserves further studies to evaluate its potential as a non-invasive biomarker.
P905 Spreading depression detection by different methods of imaging M. Lotfinia 1,2 , A.A. Lotfinia 1 , B. Khodaie 1 , M. Ahmadi 1 1 Shefa Neuroscience Research Center, Tehran, Islamic Republic of Iran; 2 Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran Neurosurgical diagnosis has been widely based on using neuroradiology methods such as Computed tomography (CT), Magnetic resonance imaging (MRI) and Positron emission tomography (PET). Cortical Spreading Depression (CSD) is a well-known pathophysiological phenomena, which is associated with propagation of electrophysiological hyperactivity followed by a wave of inhibition. CSD which mostly located in the visual cortex of the brain can spread as wave of depolarization, vasoconstriction and ischemia. In this study we aimed to have a review on the way of influence of CSD on most frequent imaging method.
P906 Central mechanisms of migraine improvement with ketogenic diet G. Coppola 1 , C. Di Lorenzo 2 , M. Bracaglia 2 , D. Di Lenola 2 , V. Parisi 1 , F. Pierelli 2 1 G.B.Bietti Foundation, Neurophysiology of Vision and Neurophthalmology, Rome, Italy; 2 Sapienza University of Rome Polo Pontino, Department of Medical and Surgical Sciences and Biotechnologies, Latina, Italy Question: Ketogenic diet (KD) is a dietetic regimen that mimics fasting in producing ketone bodies, which seems to have a potential role in treating migraine. From animal and human models emerges that KD might affects CNS at multiple levels: it is able to normalize cortical dysexcitability and to reduce cortical spreading depression velocity of propagation, which mechanisms are potentially of interest in migraine pathophysiology. Here, with the aim of identifying cortical electrofunctional correlates of responsiveness to short-lasting preventive intervention with KD in migraine, we investigated visual evoked potentials (VEPs) before and after KD. Methods: To find out whether ketogenic diet alters VEP habituation, we recorded VEPs (3.1Hz reversal rate, 15 min of arc checkerboard visual pattern) before and during ketogenesis, as confirmed by urinary sticks, in 12 migraine patients. We measured VEP N75-P100 amplitudes in 6 sequential blocks of 100 sweeps and habituation as the percentage change in N1-P1 amplitude between the 6th and the 1st block. Results: After a mean of 1-month period of KD, a significant reduction of migraine frequency (from a mean of 6.4 to 1.9 attacks/month, p=0.02) and duration (from 50.6 to 17.0 hours/month, p<0.01) was observed. KD tended to increase VEP amplitude in block 1 and induced normalization of the interictally reduced VEP habituation (from +3.2% to -10.8%, p=0.01). Conclusions: These findings suggest that ketogenic diet may exert its prophylactic effect in migraine by influencing the processing of information at
dysphasia. The pathophysiology of these subgroups of common forms of migraine with aura has been studied rarely. Methods: Forty-seven migraine with aura patients were subgrouped in migraine with pure visual aura (MA, N=27) and migraine with complex aura (MA+, N=20), i.e. those who had visual aura associated with paraesthesia and/or dysphasia. We recorded visual evoked potentials (VEPs, 15 min of arc cheques, 3.1 reversal rate, 600 sweeps) amplitude and habituation (slope of the linear regression line for N1-P1 amplitude from the 1st to 6th block of 100 sweeps) in patients and in 30 healthy volunteers (HV) of comparable age and gender distribution. Results: Habituation (i.e. response decrement), which could be observed in most HVs (slope -0.54), was deficient in both MA (slope +0.01, p=0.001) and MA+ (+0.14, p<0.001) patients. However, VEP amplitudes across the blocks generally tended to be lower in MA patients, while were significantly higher in MA+ patients, than in HVs. Conclusions: We found different patterns of visual responses in subgroups of MA patients. We hypothesize that a different genetic load and energetic metabolism may characterize migraine with aura patients with more severe focal symptoms.
P903 Assessment of course of tension-type headache in adolescents based on nonlinear multidimensional analysis (deterministic chaos) EEG K. Stepanchenko Kharkiv Medical Academy of Postgraduate Education, Department of Neurology, Kharkiv, Ukraine The life prevalence of tension-type headache in the general population by various studies ranged from 30 to 78%, and in the children – 28.7–72.8%. Question: Examine the condition of nonspecific cerebral regulatory systems based on the study of bioelectrical brain activity using the method of nonlinear multidimensional analysis (deterministic chaos) EEG in adolescents with episodic and chronic tension-type headache. Methods: We observed 43 adolescents with tension-type headache at the age of 13–18. Two groups: 1st (23 pers.) – patients with episodic tension-type headache, 2nd (20 pers.) – patients with chronic tension-type headache. Registration the electroencephalogram (EEG) was performed at rest with eyes closed and intellectual load (countdown in mind in 1000, 993, 986, etc.). We conducted nonlinear multidimensional analysis (deterministic chaos) EEG and calculated Kolmogorov-Sinai entropy. Results: Decrease in the value Kolmogorov-Sinai entropy is observed with increasing frequency of episodes of tension-type headache, i.e. the transition to the chronic form of the disease. This means reducing the number of active parallel functional processes in the brain, the possibilities for self-organization, the ability to form ranked adaptive dissipative structures, reducing neuroplasticity of the brain and, consequently, the capacity to adapt. Conclusions: Study of nonlinear parameter - the Kolmogorov-Sinai entropy of EEG signal is an objective quantitative measure of the dynamic characteristics of cortical and limbic - reticular structures of the brain that are involved in the formation of adaptive processes in patients with episodic and chronic tension-type headache.
P904 Normalization of EEG power spectrum in patients with migraine during peri-ictal periods K.-L. Lai 1,2,3,4 , F.-J. Hsiao 5 , K.-K. Liao 2,3 , J.-L. Fuh 2,3 , S.-J. Wang 2,3,5 Taipei Municipal Gandau Hospital, Neurology, Taipei, Taiwan; 2 Taipei Veterans General Hospital, Neurology, Taipei, Taiwan; 3 National Yang-Ming University School of Medicine, Faculty of Medicine, Taipei, Taiwan; 4 National Yang-Ming University School of Medicine, Institute of Clinical Medicine, Taipei, Taiwan; 5 National Yang-Ming University School of Medicine, Institute of Brain Science, Taipei, Taiwan 1
Question: Previous resting EEG spectral analyses in patients with migraine showed inconsistent results. The inconsistency might be related to the spontaneous fluctuation of electrophysiological activity in a headache state-dependent manner in patients with migraine. In this study, we aimed to investigate the resting EEG power spectrum and its relation to migraine state. Methods: Resting EEG data (30 seconds for 3 times) was recorded with 256 Hz sampling rate, and 19 electrodes positioned according to the interna-
S287
tional 10-20 system, while the subjects kept awake and alert. After artifacts rejection, independent component analysis was applied to remove noises. Minimum norm estimate analysis was then used to transform the original electrode-based EEG signal into region-of-interest (ROI)-based EEG activity. Then, normalization of spectral power was done by normalizing the power at each frequency band with total power to reduce the inter-individual variability. We then compared the relative power of each band across all ROIs in patients with migraine and control subjects. Statistical significance was defined as a p-value of <0.05. All tests were two-tailed. Results: One hundred and twenty-seven episodic migraine patients were recruited (M/F: 29/98, age: 35.1±10.3, headache frequency: 4.3±2.6 days/m). Compared to age- and gender-matched controls (n=20, M/F: 8/12, age: 36.4±6.8), patients during inter-ictal period (n=75) showed decreased alpha and theta power over most of all brain regions and increased delta power over bilateral frontal regions. These spectral abnormalities were less obvious or normalized during pre-ictal (n=21), ictal (n=19) or post-ictal (n=12) periods. Of note, compared with controls, patients with migraine had a consistent increment of beta- and gamma-band powers regardless of their clinical headache state. Conclusions: Resting EEG spectral analysis in patients with migraine showed a state-dependent fluctuation at delta-, theta- and alpha-band range, which tended to be normalized during peri-ictal periods. Besides, we found that gamma-band power, and beta-band power to a lesser extent, were consistently increased in patients with migraine, which deserves further studies to evaluate its potential as a non-invasive biomarker.
P905 Spreading depression detection by different methods of imaging M. Lotfinia 1,2 , A.A. Lotfinia 1 , B. Khodaie 1 , M. Ahmadi 1 1 Shefa Neuroscience Research Center, Tehran, Islamic Republic of Iran; 2 Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran Neurosurgical diagnosis has been widely based on using neuroradiology methods such as Computed tomography (CT), Magnetic resonance imaging (MRI) and Positron emission tomography (PET). Cortical Spreading Depression (CSD) is a well-known pathophysiological phenomena, which is associated with propagation of electrophysiological hyperactivity followed by a wave of inhibition. CSD which mostly located in the visual cortex of the brain can spread as wave of depolarization, vasoconstriction and ischemia. In this study we aimed to have a review on the way of influence of CSD on most frequent imaging method.
P906 Central mechanisms of migraine improvement with ketogenic diet G. Coppola 1 , C. Di Lorenzo 2 , M. Bracaglia 2 , D. Di Lenola 2 , V. Parisi 1 , F. Pierelli 2 1 G.B.Bietti Foundation, Neurophysiology of Vision and Neurophthalmology, Rome, Italy; 2 Sapienza University of Rome Polo Pontino, Department of Medical and Surgical Sciences and Biotechnologies, Latina, Italy Question: Ketogenic diet (KD) is a dietetic regimen that mimics fasting in producing ketone bodies, which seems to have a potential role in treating migraine. From animal and human models emerges that KD might affects CNS at multiple levels: it is able to normalize cortical dysexcitability and to reduce cortical spreading depression velocity of propagation, which mechanisms are potentially of interest in migraine pathophysiology. Here, with the aim of identifying cortical electrofunctional correlates of responsiveness to short-lasting preventive intervention with KD in migraine, we investigated visual evoked potentials (VEPs) before and after KD. Methods: To find out whether ketogenic diet alters VEP habituation, we recorded VEPs (3.1Hz reversal rate, 15 min of arc checkerboard visual pattern) before and during ketogenesis, as confirmed by urinary sticks, in 12 migraine patients. We measured VEP N75-P100 amplitudes in 6 sequential blocks of 100 sweeps and habituation as the percentage change in N1-P1 amplitude between the 6th and the 1st block. Results: After a mean of 1-month period of KD, a significant reduction of migraine frequency (from a mean of 6.4 to 1.9 attacks/month, p=0.02) and duration (from 50.6 to 17.0 hours/month, p<0.01) was observed. KD tended to increase VEP amplitude in block 1 and induced normalization of the interictally reduced VEP habituation (from +3.2% to -10.8%, p=0.01). Conclusions: These findings suggest that ketogenic diet may exert its prophylactic effect in migraine by influencing the processing of information at