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P529: Abnormal auditory synchronization in stuttering: a magnetoencephalographic study
S192
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
in PWS while controls did not show such difference. Phase locking factors (PLFs) for local phase synchronization in the right hemisphere in PWS were significantly higher than those of left hemisphere, and greater than those of controls. In addition, the right PLFs in PWS were positively correlated with stuttering severity. Phase locking values (PLVs) representing the synchronizations between right and left auditory cortices were significantly higher in PWS than in controls. Increased right hemispheric local phase synchronization with increased inter-hemispheric phase synchronization could underlie the impaired function of left auditory cortex in PWS. Therefore, we suggest that one of compensatory mechanisms in PWS is abnormal synchronization even in basic auditory processing.
Figure 1
operate. Although the number of patients is low, since this is an ongoing project, we argue that MEG should be considered for epilepsy surgery candidates. References: [1] Stufflebeam et al. Hum Brain Mapp. 2009; 30(6):1813-1823. [2] De Tiege et al. J Neurol Neurosurg Psychiatry. 2012; 83(4):417-423.
P528 Modulation of the 20-Hz motor cortex rhythm to passive movement and tactile stimulation 1,2
1,2,3
1,4
1,2,3
E. Parkkonen , K. Laaksonen , L. Parkkonen , N. Forss 1 Aalto University, Brain Research Unit/O.V. Lounasmaa Laboratory, Espoo, Finland; 2 Helsinki University Central Hospital, Department of Neurology, Helsinki, Finland; 3 University of Helsinki, Department of Neurological Sciences, Helsinki, Finland; 4 Aalto University, Biomedical Engineering and Computational Science, Espoo, Finland Question: Modulation of the 20-Hz rolandic rhythm to somatosensory input has been proposed to reflect alterations in the motor cortex excitability. In stroke patients, the strength of this modulation is associated with recovery of hand function. In this study we compared the suppression and rebound amplitudes of the 20-Hz (15-25 Hz) rhythm to tactile stimulation and passive movement. Methods: We recorded rhythmic brain activity in 22 healthy subjects (11 males, mean 59 years) with a 306-channel MEG system during tactile stimulation and passive movement. Tactile stimuli were delivered using pneumatic diaphragms to both index fingers alternately with an interstimulus interval of 1.5 s. For passive movements, the subjects’ index fingers were lifted by a nurse every 3 s. Suppression and rebound of the 20-Hz rhythm were analyzed using Temporal Spectral Evolution (TSE) and their amplitudes were quantified from the MEG channel displaying the strongest rebound/suppression. Results: The peak amplitudes of the rebound in both ipsi- and contralateral hemispheres were significantly (p<0.05) stronger after passive movement than after tactile stimulation. In contrast, the peak amplitudes of the suppression did not significantly differ between the stimuli. Conclusions: According to our results, passive movements are strong modulators of the motor cortex excitability. Thus, passive movement might be a more robust and feasible tool than tactile stimulation to study motor cortex alterations in stroke patients.
P529 Abnormal auditory synchronization in stuttering: a magnetoencephalographic study Y. Kikuchi 1 , T. Okamoto 2 , K. Ogata 3 , K. Hagiwara 3 , T. Umesaki 1 , M. Kenjo 4 , S. Komune 1 , S. Tobimatsu 3 1 Kyushu University, Otolaryngology, Fukuoka-shi, Hakata-ku, Japan; 2 Kyushu University, Faculty of Medical Sciences, Fukuoka-shi, Japan; 3 Kyushu University, Clinical Neurophysiology, Fukuoka-shi, Japan; 4 Department of Special Education, Fukuoka University of Education, Fukuoka-shi, Japan Our previous magnetoencephalographic study (Kikuchi et al., NeuroImage 2011) demonstrated that people who stutter (PWS) had both functional and structural reorganization of right auditory cortex with impaired left auditory cortex function. However, it is unclear how right and left auditory cortices interact to compensate stuttering. We re-analyzed previous MEG data in healthy controls and PWS through N100m responses of auditory cortex to pure tone. Their latencies and related hemispheric local and interhemispheric phase synchronizations were further evaluated. The results showed that left N100m latency was significantly longer than that of right
P530 Functional and directed coherence on simultaneous recorded EEG and MEG data during resting state M. Siniatchkin 1 , M. Muthuraman 2 , A.R. Anwar 2 , K.G. Medeksa 2 , V. Moliadze 1 1 Goethe-University of Frankfurt, Department of Child and Adolescents Psychiatry, Frankfurt, Germany; 2 Christian-Albrechts-University of Kiel, Department of Neurology, Kiel, Germany Question: In the last years, more and more attempts have been done to increase validity and sensitivity of different methods of neuroimaging using a combination/fusion of methods. This study focuses on the combination of EEG and MEG and tries to describe advantages of each particular method and their fusion. Methods: Ten healthy adults were investigated using simultaneous recordings of EEG (60 channels, VSM MedTech system) and MEG (256 channel, VSM MedTech) in two resting state condition: with 5 min eyes closed (EC) and 5 min eyes open (EO). Each recording was segmented into a number of 1s-long epochs. The data were analyzed across the following frequency bands: delta (1-3 Hz), theta (4-7 Hz), alpha (8-13 Hz), and beta (14-30 Hz) for each condition. Analysis of power spectrum, Dynamic Imaging of Coherent Sources (DICS) for source analysis, Renormalized Partial Directed Coherence (RPDC) for information flow between sources, and the signalto-noise ratio (SNR) analysis were performed using FIELDTRIP. All analyses were carried out for EEG and MEG separately and for combined EEG-MEG data sets. Results: 1) Spectral mean power was significantly higher in EEG than in MEG data for all frequency bands; 2) For the source absolute mean power the combined approach had significantly higher power compared to EEG and MEG alone; 3) For comparison between EEG and MEG for both the cortical and sub-cortical sources, there was no significant difference for the number of voxels in sources (p=0.45). However, the combined approach (EEG+MEG) had significantly lower number of voxels activated for both cortical and sub-cortical sources (EEG vs. MEG+EEG: p=0.006; MEG vs. MEG+EEG: p=0.009); 4) During both conditions with EO and EC the direction of information flow for EEG and MEG was not different between the sources. However, the combined approach detected some additional interactions in each of the frequency bands. The RPDC values in all the four frequency bands showed a similar pattern (p=0.004; MEG+EEG>EEG>MEG); 5) On the scalp and source levels, the relative SNR showed significant difference between the three modalities. In all frequency bands the pattern remained similar (p=0.006; MEG+EEG > EEG > MEG). Conclusion: The combined approach of EEG and MEG fusion may increase validity of results leading to the more focused source reconstruction, better modeling of information flow and higher SNR.
P531 Correlation between impulsivity and auditory sustained field strength measured by magnetoencephalography R. Han 1 , A. Miyazaki 2 , T. Kadoya 3 , T. Takahashi 4 , K. Yokosawa 5 1 Hokkaido University, Graduate school of letters, Sapporo, Japan; 2 Hokkaido University, Graduate school of medicine, Sapporo, Japan; 3 Hokkaido University, Graduate school of health sciences, Sapporo, Japan; 4 Hokkaido University, Faculty of letters, Sapporo, Japan; 5 Hokkaido University, Faculty of Health Sciences, Sapporo, Japan Question: How is impulsivity reflected in brain activities? This question is important for establishing neurotechnological diagnosis of addiction and ADHD. In this study, we examined the relationship between impulsivity (operationalized as “temporal discount rate (k)”, the degree of preference
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
in PWS while controls did not show such difference. Phase locking factors (PLFs) for local phase synchronization in the right hemisphere in PWS were significantly higher than those of left hemisphere, and greater than those of controls. In addition, the right PLFs in PWS were positively correlated with stuttering severity. Phase locking values (PLVs) representing the synchronizations between right and left auditory cortices were significantly higher in PWS than in controls. Increased right hemispheric local phase synchronization with increased inter-hemispheric phase synchronization could underlie the impaired function of left auditory cortex in PWS. Therefore, we suggest that one of compensatory mechanisms in PWS is abnormal synchronization even in basic auditory processing.
Figure 1
operate. Although the number of patients is low, since this is an ongoing project, we argue that MEG should be considered for epilepsy surgery candidates. References: [1] Stufflebeam et al. Hum Brain Mapp. 2009; 30(6):1813-1823. [2] De Tiege et al. J Neurol Neurosurg Psychiatry. 2012; 83(4):417-423.
P528 Modulation of the 20-Hz motor cortex rhythm to passive movement and tactile stimulation 1,2
1,2,3
1,4
1,2,3
E. Parkkonen , K. Laaksonen , L. Parkkonen , N. Forss 1 Aalto University, Brain Research Unit/O.V. Lounasmaa Laboratory, Espoo, Finland; 2 Helsinki University Central Hospital, Department of Neurology, Helsinki, Finland; 3 University of Helsinki, Department of Neurological Sciences, Helsinki, Finland; 4 Aalto University, Biomedical Engineering and Computational Science, Espoo, Finland Question: Modulation of the 20-Hz rolandic rhythm to somatosensory input has been proposed to reflect alterations in the motor cortex excitability. In stroke patients, the strength of this modulation is associated with recovery of hand function. In this study we compared the suppression and rebound amplitudes of the 20-Hz (15-25 Hz) rhythm to tactile stimulation and passive movement. Methods: We recorded rhythmic brain activity in 22 healthy subjects (11 males, mean 59 years) with a 306-channel MEG system during tactile stimulation and passive movement. Tactile stimuli were delivered using pneumatic diaphragms to both index fingers alternately with an interstimulus interval of 1.5 s. For passive movements, the subjects’ index fingers were lifted by a nurse every 3 s. Suppression and rebound of the 20-Hz rhythm were analyzed using Temporal Spectral Evolution (TSE) and their amplitudes were quantified from the MEG channel displaying the strongest rebound/suppression. Results: The peak amplitudes of the rebound in both ipsi- and contralateral hemispheres were significantly (p<0.05) stronger after passive movement than after tactile stimulation. In contrast, the peak amplitudes of the suppression did not significantly differ between the stimuli. Conclusions: According to our results, passive movements are strong modulators of the motor cortex excitability. Thus, passive movement might be a more robust and feasible tool than tactile stimulation to study motor cortex alterations in stroke patients.
P529 Abnormal auditory synchronization in stuttering: a magnetoencephalographic study Y. Kikuchi 1 , T. Okamoto 2 , K. Ogata 3 , K. Hagiwara 3 , T. Umesaki 1 , M. Kenjo 4 , S. Komune 1 , S. Tobimatsu 3 1 Kyushu University, Otolaryngology, Fukuoka-shi, Hakata-ku, Japan; 2 Kyushu University, Faculty of Medical Sciences, Fukuoka-shi, Japan; 3 Kyushu University, Clinical Neurophysiology, Fukuoka-shi, Japan; 4 Department of Special Education, Fukuoka University of Education, Fukuoka-shi, Japan Our previous magnetoencephalographic study (Kikuchi et al., NeuroImage 2011) demonstrated that people who stutter (PWS) had both functional and structural reorganization of right auditory cortex with impaired left auditory cortex function. However, it is unclear how right and left auditory cortices interact to compensate stuttering. We re-analyzed previous MEG data in healthy controls and PWS through N100m responses of auditory cortex to pure tone. Their latencies and related hemispheric local and interhemispheric phase synchronizations were further evaluated. The results showed that left N100m latency was significantly longer than that of right
P530 Functional and directed coherence on simultaneous recorded EEG and MEG data during resting state M. Siniatchkin 1 , M. Muthuraman 2 , A.R. Anwar 2 , K.G. Medeksa 2 , V. Moliadze 1 1 Goethe-University of Frankfurt, Department of Child and Adolescents Psychiatry, Frankfurt, Germany; 2 Christian-Albrechts-University of Kiel, Department of Neurology, Kiel, Germany Question: In the last years, more and more attempts have been done to increase validity and sensitivity of different methods of neuroimaging using a combination/fusion of methods. This study focuses on the combination of EEG and MEG and tries to describe advantages of each particular method and their fusion. Methods: Ten healthy adults were investigated using simultaneous recordings of EEG (60 channels, VSM MedTech system) and MEG (256 channel, VSM MedTech) in two resting state condition: with 5 min eyes closed (EC) and 5 min eyes open (EO). Each recording was segmented into a number of 1s-long epochs. The data were analyzed across the following frequency bands: delta (1-3 Hz), theta (4-7 Hz), alpha (8-13 Hz), and beta (14-30 Hz) for each condition. Analysis of power spectrum, Dynamic Imaging of Coherent Sources (DICS) for source analysis, Renormalized Partial Directed Coherence (RPDC) for information flow between sources, and the signalto-noise ratio (SNR) analysis were performed using FIELDTRIP. All analyses were carried out for EEG and MEG separately and for combined EEG-MEG data sets. Results: 1) Spectral mean power was significantly higher in EEG than in MEG data for all frequency bands; 2) For the source absolute mean power the combined approach had significantly higher power compared to EEG and MEG alone; 3) For comparison between EEG and MEG for both the cortical and sub-cortical sources, there was no significant difference for the number of voxels in sources (p=0.45). However, the combined approach (EEG+MEG) had significantly lower number of voxels activated for both cortical and sub-cortical sources (EEG vs. MEG+EEG: p=0.006; MEG vs. MEG+EEG: p=0.009); 4) During both conditions with EO and EC the direction of information flow for EEG and MEG was not different between the sources. However, the combined approach detected some additional interactions in each of the frequency bands. The RPDC values in all the four frequency bands showed a similar pattern (p=0.004; MEG+EEG>EEG>MEG); 5) On the scalp and source levels, the relative SNR showed significant difference between the three modalities. In all frequency bands the pattern remained similar (p=0.006; MEG+EEG > EEG > MEG). Conclusion: The combined approach of EEG and MEG fusion may increase validity of results leading to the more focused source reconstruction, better modeling of information flow and higher SNR.
P531 Correlation between impulsivity and auditory sustained field strength measured by magnetoencephalography R. Han 1 , A. Miyazaki 2 , T. Kadoya 3 , T. Takahashi 4 , K. Yokosawa 5 1 Hokkaido University, Graduate school of letters, Sapporo, Japan; 2 Hokkaido University, Graduate school of medicine, Sapporo, Japan; 3 Hokkaido University, Graduate school of health sciences, Sapporo, Japan; 4 Hokkaido University, Faculty of letters, Sapporo, Japan; 5 Hokkaido University, Faculty of Health Sciences, Sapporo, Japan Question: How is impulsivity reflected in brain activities? This question is important for establishing neurotechnological diagnosis of addiction and ADHD. In this study, we examined the relationship between impulsivity (operationalized as “temporal discount rate (k)”, the degree of preference