- Email: [email protected]
P36.33 Brain activity in a timing control task
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Posters / Clinical Neurophysiology 117 (2006) S121–S336
2 with neuropathic facial pain. EEG was recorded from a 128 electrodes cap. Beta ERS (13–25 Hz) was computed with respect to the end of right and left self-paced finger extensions. Each patient was recorded before and after implantation of an extradural electrode for MCS. Results: Patient 1 with peripheral neuropathic pain of right superior limb presented an abnormal pattern of beta ERS mainly ipsilateral to his painful arm after right movements. Left MCS restored a contro-lateral beta ERS, predominant over left fronto-central areas. Patient 2 with central neuropathic left superior limb pain presented a small beta ERS contro-lateral to his painful arm and only a small ipsilateral beta ERS after right movement. Right MCS restored normal patterns of contro and ipsilateral beta ERS after left movements. It also restored a controlateral beta ERS after right movements. Right MCS in patient 3 with left central neuropathic facial pain increased ipsi and contro-lateral beta ERS after left movement. Left MCS in patient 4 with right peripheral neuropathic facial pain decreased dramatically contro-lateral beta ERS during right and left finger movement. Conclusion: Motor cortex stimulation was able to restore beta ERS patterns in cases of neuropathic pains. The abnormalities in beta ERS would be greater in case of peripheric pain. Moreover, recovery of beta ERS would have a somatotopic organization since beta ERS following finger movement was not restored in patient 4. doi:10.1016/j.clinph.2006.06.640
P36.32 Diagnostic properties of P300 analysis techniques in head injury patients: Comparison with imaging data and neuropsychological data J. Elting, N. Maurits, W. van Weerden, J. Spikman, J. De Keyser, J. van der Nallt University Medical Center Groningen, The Netherlands Objectives: In this study, we evaluated diagnostic accuracy of conventional P300 analysis and source analysis in head injury patients. We compared P300 results with neuropsychological test data and imaging data. Methods: In total, 21 healthy control subjects and 33 patients with head injury were included. Latency and amplitude parameters were obtained for both analysis methods. Neuropsychological evaluation included the Stroop test, the Paced Auditory Serial Addition Test (PASAT) and Rey’s Verbal Learing Test (VLT). Diagnostic accuracy was evaluated with ROC analysis using the neuropsychological test results as the golden standard. Magnetic Resonance Imaging (MRI) was performed between 3 and 9 months after the injury. Results: For both P300 analysis methods, only amplitude parameters were correlated with neuropsychological test data. Diagnostic accuracy was better with source analysis when compared to the VLT (p = 0.03) and the PASAT
(p = 0.04, only for those patients with imaging abnormalities). Correlation with MRI data showed a non-linear trend between contusional severity and P3A amplitude. Patients with normal MRI results and patients with severe diffuse MRI abnormalities had decreased mean P3A amplitude compared to controls. ERP task performance was worse in patients with normal MRI results when compared to controls and patients with MRI abnormalities. In patients with focal frontal or temporal injury, the presence of medio-frontal lesions was associated with P3A amplitude reduction, while orbito-frontal lesions tended to increase P3A amplitude. Conclusions: Source analysis of P300 resulted in improved diagnostic accuracy in head injury patients. In view of the non-linear trend between contusional severity and P3A abnormalities, it is advisable to analyze P300 results in conjunction with imaging results. This approach may further facilitate the interpretation and diagnostic applicability of source analysis P300 results in head injury patients. doi:10.1016/j.clinph.2006.06.641
P36.33 Brain activity in a timing control task T. Ozawa 1, A. Mori 2, M. Takayose 1 1
Nihon University of Graduate School of Literature and Society Sciences, Japan 2 Nihon University, Japan Various adjustments are necessary for smooth execution of movements in human being. Above all, adjustment of output that adapts movement to external phenomenon, which is called timing, is an element indispensable for smooth movement. Timing of movement is believed to be controlled by the brain, but the brain activity during timing control movement by humans has not been studied. In the present study, focusing on timing which is the element necessary for smooth movement, we examined the brain activity by electroencephalogram (EEG) monitoring in human subjects during movements of timing control. Five healthy adult subjects were studied. All subjects were right-handed. We used two tasks (a control task and a coincident timing task) to examine information processing in the brain during the timing control movement. Both tasks were conducted with computer display placed approximately 1.5 m away from the subject. EEGs were recorded from electrodes placed at 128 sites on the scalp. The frequency band of beta wave (13–30 Hz) was isolated from the EEG and analyzed. The beta waves generated during task execution were superimposed on three-dimensional models produced from MRI images and analyzed at 2-ms intervals. From the result of analysis of chronological transition, we observed characteristic transition patterns in the activity region, which were different in the two tasks. In the comparison of electric potential amplitudes calculated by FFT in the regions that correspond to F3, P7, and O1 according to
Posters / Clinical Neurophysiology 117 (2006) S121–S336
the international 10/20 system, significant differences were observed between the two tasks. These results suggest that in human subjects, the timing movement by visual stimulus is controlled by the premotor area, posterior temporal area, visual area and their interacting network. doi:10.1016/j.clinph.2006.06.642
P36.34 Developmental changes of N400 ERP of a semantic category decision task and modality specific findings in patients with developmental dyslexia M. Inagaki, S. Oana, S. Suzuki, M. Kaga National Institute of Mental Health, NCNP, Department of Developmental Disorders, Japan Background: N400 event-related potential (ERP) is known to be a sensitive indicator of semantic processing, and the amplitude reflects the extent to which a word is unpredictable or unexpected. Objectives: To clarify age- and modality-specific changes in N400 in control subjects and patients with developmental dyslexia (DD). Methods: Eight patients with DD and 38 control subjects were investigated electrophysiologically during a semantic category decision task in auditory(A), visual (V) and auditory–visual (AV) condition. Results: There was a prominent difference between younger children and adults in the general ERP waveforms. In control children under 10 years old, auditory N400 showed a remarkably large negative deflection over the fronto-centro-parietal areas with a mean peak latency of 511 ± 47 ms at Fz. Elder control children and adult had localized auditory N400 distribution around frontocentral areas, demonstrating dual-peak negative waveforms at Fz with latencies of 300 and 430, 290, and 410 ms, respectively. Control children over 10 years old showed a similar pattern of N400 waves in V and AV conditions, suggesting that the visual modality becomes dominant in the late teens. Adult had small N400 with predominant late positive component at centro-parietal areas in V and AV conditions. Dyslexic children showed more errors on a visual than auditory modality task with poorer N400 wave formation for visual stimuli. However, peak latencies of N400 in an auditory-visual modality were almost the same for auditory stimuli in control children. The scalp topography of auditory N400 in dyslexic children was almost the same pattern as in elder children; however, negative component was diminished in visual condition. Conclusions: Differences in the N400 pattern in control and dyslexic children might reflect the fragility and reversibility of the semantic processes through stimulus modalities. doi:10.1016/j.clinph.2006.06.643
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P36.35 Auditory evoked visually awareness in a late blind patient – An electrophysiological investigation A. Rao, A.C. Nobre, I. Alexander, A. Cowey University of Oxford, Department of Experimental Psychology, UK Background: Neurophysiological and neuroanatomical studies have provoked controversy about whether the visual cortex may be more modifiable than previously believed. Objectives: Auditory processing is enhanced in blind compared to sighted people, and the enhancement might reflect encroachment of auditory transmission on to visual cortex. Methods: We recorded the auditory event-related potentials (ERPs) correlated with auditory-related paradoxical visual awareness and transcranial magnetic stimulation (TMS) in a patient (PS) with traumatic total late-onset blindness and 8 normally sighted control participants. In two ERP sessions, PS listened to pure tones or meaningful stimuli and indicated the presence or absence of associated visual awareness. In the TMS session, PS described and drew his visual sensations of phosphenes when TMS was delivered to his caudal occipital cortex. Results: We found that (1) there was auditory-related brain activity over the occipital visual scalp regions starting from a very early stage (<80 ms), and (2) this occipital activity was significantly different between ‘‘visually aware’’ and ‘‘visually unaware’’ responses in the P1 (40–80 ms) component following meaningful stimuli. There was also a significant difference between responses with and without visual awareness in the N1 (100–120 ms) component following either tones or meaningful stimuli. The phosphenes accompanying auditory stimuli in the ERP experiment were always perceived to be directly in front of the subject and this was reproduced by transcranial magnetic stimulation over the blind primary visual cortex and by sudden sounds delivered to the side or behind the subject. The TMS induced phosphenes were restricted to the central part of space and were, at least qualitatively, the same as those induced by sounds. Discussion: The results are clear evidence that human perceptual functions can be reorganized after sudden, late-onset, total ocular blindness. doi:10.1016/j.clinph.2006.06.644
P36.36 Cholinesterase inhibitors have modulating effect on frontal theta oscillations in Alzheimer’s disease ¨ niz 3, E. Ba·ar 3 G.G. Yener 1, B. Gu¨ntekin 2, A. O 1
Dokuz Eylu¨l University, Neurology and Neurosciences, Turkey 2 ¨ BY´TAK-BAYG, ¨ BY´TAK TU TU Brain Dynamics Research Center, Turkey 3 DEU Multidisciplinary Brain Dynamics Research Center, ¨ BY´TAK Brain Dynamics Research Center, Turkey TU
Posters / Clinical Neurophysiology 117 (2006) S121–S336
2 with neuropathic facial pain. EEG was recorded from a 128 electrodes cap. Beta ERS (13–25 Hz) was computed with respect to the end of right and left self-paced finger extensions. Each patient was recorded before and after implantation of an extradural electrode for MCS. Results: Patient 1 with peripheral neuropathic pain of right superior limb presented an abnormal pattern of beta ERS mainly ipsilateral to his painful arm after right movements. Left MCS restored a contro-lateral beta ERS, predominant over left fronto-central areas. Patient 2 with central neuropathic left superior limb pain presented a small beta ERS contro-lateral to his painful arm and only a small ipsilateral beta ERS after right movement. Right MCS restored normal patterns of contro and ipsilateral beta ERS after left movements. It also restored a controlateral beta ERS after right movements. Right MCS in patient 3 with left central neuropathic facial pain increased ipsi and contro-lateral beta ERS after left movement. Left MCS in patient 4 with right peripheral neuropathic facial pain decreased dramatically contro-lateral beta ERS during right and left finger movement. Conclusion: Motor cortex stimulation was able to restore beta ERS patterns in cases of neuropathic pains. The abnormalities in beta ERS would be greater in case of peripheric pain. Moreover, recovery of beta ERS would have a somatotopic organization since beta ERS following finger movement was not restored in patient 4. doi:10.1016/j.clinph.2006.06.640
P36.32 Diagnostic properties of P300 analysis techniques in head injury patients: Comparison with imaging data and neuropsychological data J. Elting, N. Maurits, W. van Weerden, J. Spikman, J. De Keyser, J. van der Nallt University Medical Center Groningen, The Netherlands Objectives: In this study, we evaluated diagnostic accuracy of conventional P300 analysis and source analysis in head injury patients. We compared P300 results with neuropsychological test data and imaging data. Methods: In total, 21 healthy control subjects and 33 patients with head injury were included. Latency and amplitude parameters were obtained for both analysis methods. Neuropsychological evaluation included the Stroop test, the Paced Auditory Serial Addition Test (PASAT) and Rey’s Verbal Learing Test (VLT). Diagnostic accuracy was evaluated with ROC analysis using the neuropsychological test results as the golden standard. Magnetic Resonance Imaging (MRI) was performed between 3 and 9 months after the injury. Results: For both P300 analysis methods, only amplitude parameters were correlated with neuropsychological test data. Diagnostic accuracy was better with source analysis when compared to the VLT (p = 0.03) and the PASAT
(p = 0.04, only for those patients with imaging abnormalities). Correlation with MRI data showed a non-linear trend between contusional severity and P3A amplitude. Patients with normal MRI results and patients with severe diffuse MRI abnormalities had decreased mean P3A amplitude compared to controls. ERP task performance was worse in patients with normal MRI results when compared to controls and patients with MRI abnormalities. In patients with focal frontal or temporal injury, the presence of medio-frontal lesions was associated with P3A amplitude reduction, while orbito-frontal lesions tended to increase P3A amplitude. Conclusions: Source analysis of P300 resulted in improved diagnostic accuracy in head injury patients. In view of the non-linear trend between contusional severity and P3A abnormalities, it is advisable to analyze P300 results in conjunction with imaging results. This approach may further facilitate the interpretation and diagnostic applicability of source analysis P300 results in head injury patients. doi:10.1016/j.clinph.2006.06.641
P36.33 Brain activity in a timing control task T. Ozawa 1, A. Mori 2, M. Takayose 1 1
Nihon University of Graduate School of Literature and Society Sciences, Japan 2 Nihon University, Japan Various adjustments are necessary for smooth execution of movements in human being. Above all, adjustment of output that adapts movement to external phenomenon, which is called timing, is an element indispensable for smooth movement. Timing of movement is believed to be controlled by the brain, but the brain activity during timing control movement by humans has not been studied. In the present study, focusing on timing which is the element necessary for smooth movement, we examined the brain activity by electroencephalogram (EEG) monitoring in human subjects during movements of timing control. Five healthy adult subjects were studied. All subjects were right-handed. We used two tasks (a control task and a coincident timing task) to examine information processing in the brain during the timing control movement. Both tasks were conducted with computer display placed approximately 1.5 m away from the subject. EEGs were recorded from electrodes placed at 128 sites on the scalp. The frequency band of beta wave (13–30 Hz) was isolated from the EEG and analyzed. The beta waves generated during task execution were superimposed on three-dimensional models produced from MRI images and analyzed at 2-ms intervals. From the result of analysis of chronological transition, we observed characteristic transition patterns in the activity region, which were different in the two tasks. In the comparison of electric potential amplitudes calculated by FFT in the regions that correspond to F3, P7, and O1 according to
Posters / Clinical Neurophysiology 117 (2006) S121–S336
the international 10/20 system, significant differences were observed between the two tasks. These results suggest that in human subjects, the timing movement by visual stimulus is controlled by the premotor area, posterior temporal area, visual area and their interacting network. doi:10.1016/j.clinph.2006.06.642
P36.34 Developmental changes of N400 ERP of a semantic category decision task and modality specific findings in patients with developmental dyslexia M. Inagaki, S. Oana, S. Suzuki, M. Kaga National Institute of Mental Health, NCNP, Department of Developmental Disorders, Japan Background: N400 event-related potential (ERP) is known to be a sensitive indicator of semantic processing, and the amplitude reflects the extent to which a word is unpredictable or unexpected. Objectives: To clarify age- and modality-specific changes in N400 in control subjects and patients with developmental dyslexia (DD). Methods: Eight patients with DD and 38 control subjects were investigated electrophysiologically during a semantic category decision task in auditory(A), visual (V) and auditory–visual (AV) condition. Results: There was a prominent difference between younger children and adults in the general ERP waveforms. In control children under 10 years old, auditory N400 showed a remarkably large negative deflection over the fronto-centro-parietal areas with a mean peak latency of 511 ± 47 ms at Fz. Elder control children and adult had localized auditory N400 distribution around frontocentral areas, demonstrating dual-peak negative waveforms at Fz with latencies of 300 and 430, 290, and 410 ms, respectively. Control children over 10 years old showed a similar pattern of N400 waves in V and AV conditions, suggesting that the visual modality becomes dominant in the late teens. Adult had small N400 with predominant late positive component at centro-parietal areas in V and AV conditions. Dyslexic children showed more errors on a visual than auditory modality task with poorer N400 wave formation for visual stimuli. However, peak latencies of N400 in an auditory-visual modality were almost the same for auditory stimuli in control children. The scalp topography of auditory N400 in dyslexic children was almost the same pattern as in elder children; however, negative component was diminished in visual condition. Conclusions: Differences in the N400 pattern in control and dyslexic children might reflect the fragility and reversibility of the semantic processes through stimulus modalities. doi:10.1016/j.clinph.2006.06.643
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P36.35 Auditory evoked visually awareness in a late blind patient – An electrophysiological investigation A. Rao, A.C. Nobre, I. Alexander, A. Cowey University of Oxford, Department of Experimental Psychology, UK Background: Neurophysiological and neuroanatomical studies have provoked controversy about whether the visual cortex may be more modifiable than previously believed. Objectives: Auditory processing is enhanced in blind compared to sighted people, and the enhancement might reflect encroachment of auditory transmission on to visual cortex. Methods: We recorded the auditory event-related potentials (ERPs) correlated with auditory-related paradoxical visual awareness and transcranial magnetic stimulation (TMS) in a patient (PS) with traumatic total late-onset blindness and 8 normally sighted control participants. In two ERP sessions, PS listened to pure tones or meaningful stimuli and indicated the presence or absence of associated visual awareness. In the TMS session, PS described and drew his visual sensations of phosphenes when TMS was delivered to his caudal occipital cortex. Results: We found that (1) there was auditory-related brain activity over the occipital visual scalp regions starting from a very early stage (<80 ms), and (2) this occipital activity was significantly different between ‘‘visually aware’’ and ‘‘visually unaware’’ responses in the P1 (40–80 ms) component following meaningful stimuli. There was also a significant difference between responses with and without visual awareness in the N1 (100–120 ms) component following either tones or meaningful stimuli. The phosphenes accompanying auditory stimuli in the ERP experiment were always perceived to be directly in front of the subject and this was reproduced by transcranial magnetic stimulation over the blind primary visual cortex and by sudden sounds delivered to the side or behind the subject. The TMS induced phosphenes were restricted to the central part of space and were, at least qualitatively, the same as those induced by sounds. Discussion: The results are clear evidence that human perceptual functions can be reorganized after sudden, late-onset, total ocular blindness. doi:10.1016/j.clinph.2006.06.644
P36.36 Cholinesterase inhibitors have modulating effect on frontal theta oscillations in Alzheimer’s disease ¨ niz 3, E. Ba·ar 3 G.G. Yener 1, B. Gu¨ntekin 2, A. O 1
Dokuz Eylu¨l University, Neurology and Neurosciences, Turkey 2 ¨ BY´TAK-BAYG, ¨ BY´TAK TU TU Brain Dynamics Research Center, Turkey 3 DEU Multidisciplinary Brain Dynamics Research Center, ¨ BY´TAK Brain Dynamics Research Center, Turkey TU