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Lambda waves: incidence and relationship to photic driving
ELSEVIER
Electroencephalography and clinical Neurophysiology 99 (1996) 2OP-22P
Society Proceedings
Western EEG Society Newport Beach, February 15-17, 1996
Secretary-Treasurer:
Donald Olson, M.D.
Children’s Hospital, 747 Fijiy-Second Street, Oakland, CA 94609, USA
Accepted for publication: 20 May 1996
1.
Lambda waves: incidence and relationship to pbotic driving. J. J. Shih and S.W. Thompson (University of New Mexico, Neurology Department, Albuquerque, NM)
The objective was to determine the incidence of lambda waves according to age and sex, and to evaluate for any correlation to photic driving and epileptiform discharges. The incidence of lambda waves in the conventional EEGs of adults and adolescents ranged from 2 to 88%. A relationship between lambda waves and the occipital photic driving response was presumed by Gastaut and Evans, but could not be confirmed by later workers. Three hundred sixty-seven records from different unselected patients obtaining an EEG from the University neurodiagnostic laboratory were prospectively collected over a 5 month period. Each record was interpreted independently by two electroencephalographers for the presence of lambda waves, photic driving and epileptiform discharges. The presence of lambda waves was based on the criterion of Chatrian. The incidence of lambda waves, photic stimulation and epileptiform discharges was 76%, 85% and 23%, respectively. A strong correlation existed between the presence of lambda waves and photic driving (P < 0.001). No significant correlation existed between epileptiform discharges and either lambda waves or photic driving. Inter-rater agreement was 93% for lambda waves and 94% for photic driving. The strong correlation between the presence of lambda waves and photic driving suggests the possibility of similar cerebral generatars
2.
Three-dimensional visualization of EEG topographic mapping for power PC-based personal computers. - Sh. Baatar, Sh. Tani, F. Suzuki, M. Kimura and T. Kanno (School of Medicine, Hamamatsu, Japan)
We have developed software for 3-dimensional EEG topographic mapping, using Code Warrior C on a Power Macintosh which can download patient data from UNIX, PC and Macintosh computers and then moves topographic maps on a virtual head-model. We propose a new approach to 3D topographic mapping in the virtual world. This technique is divided into three parts: converting the position of a 2D topographic map into 3D coordinates; showing moving topographic maps on the virtual head-model; rotating a selected topographic mapcovered virtual head-model. In this paper, the program has the following merits: the animation of topographic maps on a rotatable virtual head-model demonstrates the potential of high-speed performance in the latest personal computers; inexpensive yet powerful computers have
0013-4694/96/$15.00
become commonplace in hospitals and they have become necessary to develop more virtual simulation software for practical usage by medical personnel; the program utilizes a virtual reality visual simulation system for EEG topography. This EEG virtual model is proposed as an aid to physicians in making more accurate diagnoses and in finding more practical methods and more effective treatment of neurological disorders. 3.
Interictal epileptlform abnormalities in patients with bilateral independent temporal lobe epilepsy (BITLE). - P. Garcia and K. Laxer (University of California, San Francisco, CA)
In order to confirm bilateral independent temporal lobe seizure onsets, patients must often be monitored for several days after their first seizure type is recorded. We wished to determine whether interictal EEG findings would help to distinguish patients with BITLE prior to monitoring. We reviewed telemetry records from 1986 to 1995 at UCSF and selected 27 patients with BITLE based on the following criteria: (1) ictal EEG onsets from each temporal lobe, and (2) different clinical patterns for each EEG pattern. We reviewed a single, sleepinduced EEG obtained on these patients prior to inpatient monitoring. Additionally, we reviewed interictal data acquired during inpatient monitoring. EEG findings were classified as either bilateral, unilateral or normal. Sleep-induced EEG revealed epileptiform abnormalities in 16/27 patients. The transients were bilateral in 6 patients and unilateral in 10. During inpatient monitoring, prolonged recording demonstrated epileptiform interictal EEG abnormalities in all patients and these transients were bilateral in all but 5 patients. We conclude that routine EEG is not a sensitive screen for BITLE. Even prolonged interictal recordings may fail to demonstrate bilateral epileptiform activity in these patients. 4.
Subregional localization of focal epileptiform discharges in polygraphic EEG. - F. Matsuo, C. Jones, M. Johnson, C. Me&an and L. Webster (EEG Laboratory, University of Utah Medical Center, Salt Lake City, UT)
Localization of EEG focal epileptiform discharges (FEDS) can be made more geometrically realistic by adding head-surface electrodes over the basal hemisphere. We demonstrated in a recent study that FED peaks thus evaluated were localized over the basal hemisphere in more than half of the patients with FEDS. We compared geometric localization of the FED peak from serial bipolar derivations among 5 clinical
0 1996 Elsevier Science Ireland Ltd. All rights reserved
PII SO921-884X(96)96069-9
EEG 96069
Electroencephalography and clinical Neurophysiology 99 (1996) 2OP-22P
Society Proceedings
Western EEG Society Newport Beach, February 15-17, 1996
Secretary-Treasurer:
Donald Olson, M.D.
Children’s Hospital, 747 Fijiy-Second Street, Oakland, CA 94609, USA
Accepted for publication: 20 May 1996
1.
Lambda waves: incidence and relationship to pbotic driving. J. J. Shih and S.W. Thompson (University of New Mexico, Neurology Department, Albuquerque, NM)
The objective was to determine the incidence of lambda waves according to age and sex, and to evaluate for any correlation to photic driving and epileptiform discharges. The incidence of lambda waves in the conventional EEGs of adults and adolescents ranged from 2 to 88%. A relationship between lambda waves and the occipital photic driving response was presumed by Gastaut and Evans, but could not be confirmed by later workers. Three hundred sixty-seven records from different unselected patients obtaining an EEG from the University neurodiagnostic laboratory were prospectively collected over a 5 month period. Each record was interpreted independently by two electroencephalographers for the presence of lambda waves, photic driving and epileptiform discharges. The presence of lambda waves was based on the criterion of Chatrian. The incidence of lambda waves, photic stimulation and epileptiform discharges was 76%, 85% and 23%, respectively. A strong correlation existed between the presence of lambda waves and photic driving (P < 0.001). No significant correlation existed between epileptiform discharges and either lambda waves or photic driving. Inter-rater agreement was 93% for lambda waves and 94% for photic driving. The strong correlation between the presence of lambda waves and photic driving suggests the possibility of similar cerebral generatars
2.
Three-dimensional visualization of EEG topographic mapping for power PC-based personal computers. - Sh. Baatar, Sh. Tani, F. Suzuki, M. Kimura and T. Kanno (School of Medicine, Hamamatsu, Japan)
We have developed software for 3-dimensional EEG topographic mapping, using Code Warrior C on a Power Macintosh which can download patient data from UNIX, PC and Macintosh computers and then moves topographic maps on a virtual head-model. We propose a new approach to 3D topographic mapping in the virtual world. This technique is divided into three parts: converting the position of a 2D topographic map into 3D coordinates; showing moving topographic maps on the virtual head-model; rotating a selected topographic mapcovered virtual head-model. In this paper, the program has the following merits: the animation of topographic maps on a rotatable virtual head-model demonstrates the potential of high-speed performance in the latest personal computers; inexpensive yet powerful computers have
0013-4694/96/$15.00
become commonplace in hospitals and they have become necessary to develop more virtual simulation software for practical usage by medical personnel; the program utilizes a virtual reality visual simulation system for EEG topography. This EEG virtual model is proposed as an aid to physicians in making more accurate diagnoses and in finding more practical methods and more effective treatment of neurological disorders. 3.
Interictal epileptlform abnormalities in patients with bilateral independent temporal lobe epilepsy (BITLE). - P. Garcia and K. Laxer (University of California, San Francisco, CA)
In order to confirm bilateral independent temporal lobe seizure onsets, patients must often be monitored for several days after their first seizure type is recorded. We wished to determine whether interictal EEG findings would help to distinguish patients with BITLE prior to monitoring. We reviewed telemetry records from 1986 to 1995 at UCSF and selected 27 patients with BITLE based on the following criteria: (1) ictal EEG onsets from each temporal lobe, and (2) different clinical patterns for each EEG pattern. We reviewed a single, sleepinduced EEG obtained on these patients prior to inpatient monitoring. Additionally, we reviewed interictal data acquired during inpatient monitoring. EEG findings were classified as either bilateral, unilateral or normal. Sleep-induced EEG revealed epileptiform abnormalities in 16/27 patients. The transients were bilateral in 6 patients and unilateral in 10. During inpatient monitoring, prolonged recording demonstrated epileptiform interictal EEG abnormalities in all patients and these transients were bilateral in all but 5 patients. We conclude that routine EEG is not a sensitive screen for BITLE. Even prolonged interictal recordings may fail to demonstrate bilateral epileptiform activity in these patients. 4.
Subregional localization of focal epileptiform discharges in polygraphic EEG. - F. Matsuo, C. Jones, M. Johnson, C. Me&an and L. Webster (EEG Laboratory, University of Utah Medical Center, Salt Lake City, UT)
Localization of EEG focal epileptiform discharges (FEDS) can be made more geometrically realistic by adding head-surface electrodes over the basal hemisphere. We demonstrated in a recent study that FED peaks thus evaluated were localized over the basal hemisphere in more than half of the patients with FEDS. We compared geometric localization of the FED peak from serial bipolar derivations among 5 clinical
0 1996 Elsevier Science Ireland Ltd. All rights reserved
PII SO921-884X(96)96069-9
EEG 96069