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S42-2 Automatic EEG interpretation
29th International Congress of Clinical Neurophysiology patients with cerebral and cerebellar lesions due to stroke and degenerative diseases, gait disturbance such as hemiparetic gait and ataxic gait was characterized by the combination of asymmetrical activities in the medial motor related areas, recruitment of premotor cortex and prefrontal cortex, and abnormal time-course of oxygenated hemoglobin signals during sustained gait. Improved gait performance after rehabilitative intervention was related to improvement of these abnormal signal patterns and/or augmented signals in the motor related areas. Cortical activities during postural control were also modified by these diseases. Recent data have suggested that the prefrontal cortex plays an important role in controlling balance in healthy subjects and patients with cerebral and cerebellar lesions. Supported by Grant-in-Aid for “the Research Committee for Ataxic Diseases” of Research on Measures for Intractable Diseases & Research Grant (21B-9) for Nervous and Mental Disorders. Reference(s) Miyai et al. NeuroImage 2001;14:1186 1192. Miyai et al. Stroke 2003;34:2866 2870. Suzuki M et al. NeuroImage 2004;23:1020 26. Miyai et al. Exp Brain Res 2006;169:85 91. Mihara M et al. NeuroImage 2007;37:1338 45. Suzuki et al. NeuroImage 2008;39:600 607. Mihara et al. NeuroImage, 2008:43(2)329 336. S41-4 Post-stroke gait disturbances: innovative rehabilitation approaches A. Lamontagne1 1 School of Physical and Occupational Therapy, McGill University, and Jewish Rehabilitation Hospital (CRIR), Montreal, Canada Stroke commonly leads to gait disturbances that can alter a person’s capacity to navigate in the environment while adapting to its constraints. Most gait rehabilitation paradigms recognize the importance of repetitive, intensive, task-specific and varied practice to enhance locomotor abilities post-stroke. The advances of virtual reality and robotics in rehabilitation research have brought new opportunities for the assessment and treatment of post-stroke locomotor disturbances. Such technology allows for systematic and purposeful manipulation of sensory, biomechanical or environmental parameters to better understand or treat specific aspects of locomotor disturbances. It also allows training and participation in simulated daily living environments of varying levels of complexity, potentially maximizing the patient’s functional recovery. This presentation focuses on some of the virtual reality applications to locomotor rehabilitation. The first part will address a series of studies in which real-time manipulation of visual motion information was used to not only perturb but also to adapt the speed and steering control behaviors of stroke survivors during walking. The second part of this presentation will demonstrate how virtual environments of varying levels of complexity can be used to enhance different aspects of locomotor functions after stroke. Projects are funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Canada and the Canadian Stroke Network. S42. Digital EEG and EEG standards S42-1 Digital EEG and EEG Standards M.R. Nuwer1 Department of Neurology, UCLA, Los Angeles, California, USA
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The field of digital EEG has advanced since publication of the IFCN digital EEG standards 12 years ago (Electroencephalogr Clin Neurophysiol 106:259 261, 1998). Some problems remain. Electronic file sharing and archiving is easier. However, some vendors make this difficult by software constraints on digital files. Digital sampling rates, sample resolution, noise limits, display characteristics, and filter setting now are routinely well within acceptable ranges. Internet access makes technologically easy the review of EEG, video-EEG monitoring, ICU-EEG monitoring, and intraoperative monitoring at a distance. With easy access to digital data, protecting privacy of patient information is a current topic of concern. The recording medium durability remains problematic. Any current medium, and software to read it, is likely to become obsolete within the desired archiving lifetime of clinical EEG records. Older
S61 files now can no longer be read due to obsolescence and long-term deterioration of digital data. Technological advances are needed in this area. Other digital EEG topics include automated techniques to assist in EEG interpretation. S42-2 Automatic EEG interpretation M. Nakamura1 , T. Sugi2 , A. Ikeda3 , T. Nagamine4 , H. Shibasaki5 Research Institute of Systems Control, Saga, Japan, 2 Department of Advanced Systems Control Engineering, Saga University, Saga, Japan, 3 Department of Neurology, Kyoto University School of Medicine, Kyoto, Japan, 4 Department of System Neuroscience, Sapporo Medical University, Sapporo, Japan, 5 Takeda General Hospital, Kyoto, Japan 1
A fully automatic integrative interpretation system of awaked EEG was developed by some of the authors over 10 years ago. The system has been used at over 200 hospitals and institutes in Japan. Through clinical usage of the system and continuous discussion of the automatic EEG interpretation within the authors, we found several requirements for further developments: (a) real time evaluation of each EEG segment, (b) montage selection to find out correct topographical distribution of EEG rhythms, (c) selection of EEG segments of high vigilance level to exclude drowsy ones, (d) selection of appropriate EEG segments to make final integrated EEG judgment and report making. Equations and algorithm of the automatic EEG interpretation system was formulated so as to imitate the procedure, which qualified electroencephalographers (EEGers) are making visual inspection. The method has been modified so that the automatic EEG interpretation brings the same results of visual EEG interpretation. The EEG data, recorded at Kyoto University for patients and Saga University for healthy persons, was used for the system development. By use of real time evaluation of EEG (a), technicians can record high quality of EEG, contaminated with few artifacts, keeping subjects in high vigilance level, by taking into account the information from the system. The results by use of developed automatic EEG interpretation (b) fits to automatic EEG interpretation results in more precisely close. Item of (c) and (d) are underdeveloped and can show some merits of automatic EEG interpretation. Developed automatic EEG interpretation system can be usable to record high quality EEG in real time, and can be usable for useful assistant tool for EEGers. The development of the automatic EEG interpretation should be endless, because the requirements form EEGers and technicians are increasing for many purposes, such as digital EEG recording, monitoring, etc. S42-3 Utility of digital EEG analysis in childhood epilepsy K. Kobayashi1 , H. Yoshinaga1 1 Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, and Okayama University Hospital, Department of Child Neurology, Japan Computer analysis of digitally recorded EEG data allows for the clear identification of clinically important information of brain function that is often obscured in ordinary traces. It has been suggested that gamma and higher frequency activities have a particular relationship to epileptogenicity as well as to higher brain functions. Moreover, gamma activity can be detected to some extent from scalp recordings in children with certain types of epilepsy using sophisticated techniques, such as time-frequency power spectral analysis. In West syndrome and related disorders, we found gamma rhythms with a frequency of 50 100 Hz in the ictal scalp EEGs of epileptic spasms, and we suspect that these gamma rhythms represent a slower part of the cortically generated high-frequency oscillations (HFOs). Similar gamma rhythms were detected from the bursts of suppression-burst pattern in early infantile epileptic encephalopathies and also from the ictal EEGs of a proportion of tonic seizures in Lennox-Gastaut syndrome. Therefore, epileptic gamma rhythms are suggested to have a close relationship to the pathophysiological mechanisms of these epileptic encephalopathies. HFOs with a frequency of about 120 Hz (ripples) were observed in association with spikes in patients with epilepsy with continuous spikewave during sleep (CSWS). Generation of pathological HFOs is suspected to interfere with physiological high-frequency brain activity, resulting in neuropsychological abnormalities related to CSWS. The detection of HFOs may open a novel window for the investigation of the relationship
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The field of digital EEG has advanced since publication of the IFCN digital EEG standards 12 years ago (Electroencephalogr Clin Neurophysiol 106:259 261, 1998). Some problems remain. Electronic file sharing and archiving is easier. However, some vendors make this difficult by software constraints on digital files. Digital sampling rates, sample resolution, noise limits, display characteristics, and filter setting now are routinely well within acceptable ranges. Internet access makes technologically easy the review of EEG, video-EEG monitoring, ICU-EEG monitoring, and intraoperative monitoring at a distance. With easy access to digital data, protecting privacy of patient information is a current topic of concern. The recording medium durability remains problematic. Any current medium, and software to read it, is likely to become obsolete within the desired archiving lifetime of clinical EEG records. Older
S61 files now can no longer be read due to obsolescence and long-term deterioration of digital data. Technological advances are needed in this area. Other digital EEG topics include automated techniques to assist in EEG interpretation. S42-2 Automatic EEG interpretation M. Nakamura1 , T. Sugi2 , A. Ikeda3 , T. Nagamine4 , H. Shibasaki5 Research Institute of Systems Control, Saga, Japan, 2 Department of Advanced Systems Control Engineering, Saga University, Saga, Japan, 3 Department of Neurology, Kyoto University School of Medicine, Kyoto, Japan, 4 Department of System Neuroscience, Sapporo Medical University, Sapporo, Japan, 5 Takeda General Hospital, Kyoto, Japan 1
A fully automatic integrative interpretation system of awaked EEG was developed by some of the authors over 10 years ago. The system has been used at over 200 hospitals and institutes in Japan. Through clinical usage of the system and continuous discussion of the automatic EEG interpretation within the authors, we found several requirements for further developments: (a) real time evaluation of each EEG segment, (b) montage selection to find out correct topographical distribution of EEG rhythms, (c) selection of EEG segments of high vigilance level to exclude drowsy ones, (d) selection of appropriate EEG segments to make final integrated EEG judgment and report making. Equations and algorithm of the automatic EEG interpretation system was formulated so as to imitate the procedure, which qualified electroencephalographers (EEGers) are making visual inspection. The method has been modified so that the automatic EEG interpretation brings the same results of visual EEG interpretation. The EEG data, recorded at Kyoto University for patients and Saga University for healthy persons, was used for the system development. By use of real time evaluation of EEG (a), technicians can record high quality of EEG, contaminated with few artifacts, keeping subjects in high vigilance level, by taking into account the information from the system. The results by use of developed automatic EEG interpretation (b) fits to automatic EEG interpretation results in more precisely close. Item of (c) and (d) are underdeveloped and can show some merits of automatic EEG interpretation. Developed automatic EEG interpretation system can be usable to record high quality EEG in real time, and can be usable for useful assistant tool for EEGers. The development of the automatic EEG interpretation should be endless, because the requirements form EEGers and technicians are increasing for many purposes, such as digital EEG recording, monitoring, etc. S42-3 Utility of digital EEG analysis in childhood epilepsy K. Kobayashi1 , H. Yoshinaga1 1 Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, and Okayama University Hospital, Department of Child Neurology, Japan Computer analysis of digitally recorded EEG data allows for the clear identification of clinically important information of brain function that is often obscured in ordinary traces. It has been suggested that gamma and higher frequency activities have a particular relationship to epileptogenicity as well as to higher brain functions. Moreover, gamma activity can be detected to some extent from scalp recordings in children with certain types of epilepsy using sophisticated techniques, such as time-frequency power spectral analysis. In West syndrome and related disorders, we found gamma rhythms with a frequency of 50 100 Hz in the ictal scalp EEGs of epileptic spasms, and we suspect that these gamma rhythms represent a slower part of the cortically generated high-frequency oscillations (HFOs). Similar gamma rhythms were detected from the bursts of suppression-burst pattern in early infantile epileptic encephalopathies and also from the ictal EEGs of a proportion of tonic seizures in Lennox-Gastaut syndrome. Therefore, epileptic gamma rhythms are suggested to have a close relationship to the pathophysiological mechanisms of these epileptic encephalopathies. HFOs with a frequency of about 120 Hz (ripples) were observed in association with spikes in patients with epilepsy with continuous spikewave during sleep (CSWS). Generation of pathological HFOs is suspected to interfere with physiological high-frequency brain activity, resulting in neuropsychological abnormalities related to CSWS. The detection of HFOs may open a novel window for the investigation of the relationship