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Abortive generalized spike-and-wave bursts: an electroclinical entity
Society proceedings
6P that inter-electrode ECoG coherence reflects gyral and may indicate the macroscopic organization of some functions.
anatomy cognitive
E133. The phenomena of time coincidence of change-point periods in different derivations of EEG. - A.Ya. Kaplan, B.E. Brodsky, B.S. Darkhovsky, A.A. Fingelcurtz, A.An. Fingelcurtz, S.L. Shishkin (Moscow State University, 119899, Moscow, Russia) Twelve young male volunteers were instructed to look on the screen during each of 10-12 1 min trial period with registration of EEG and try to remember the matricidal visual image. Four hundred and seventy-three EEG records for every 8 EEG standard derivations were analyzed for calculations of change-point moments by original nonparametric method. It was shown that elaborated methodology of nonparametric quest of change-points is quite effective for short duration change periods (CP) search in EEG. The time distribution of CP was not uniform during 1 min EEG records: CP quantity statistically increased in compact period of time when subjects switched from one type of cognitive activity to another. The valuation of cases of coincidence frequency of CP in each of the two possible paired coincidences was taken from derivations of EEG. It was discovered that 3 different periods of human cognitive activity sharply differ on patterns of paired coincidences (PPC). Thus, the spatial map of CP coincidence in pairs of EEG derivations reflect the specific features of brain cognitive activity. E134.
Hemispheric dominancy of color isoluminant VEP during hemifield stimulation. - S. Kawashima, M. Yeh, T. Yamada, M. Wall (Department of Neurology, Division of Clinical Electrophysiology, College of Medicine, University of Iowa, Iowa City, IA 52240)
Isoluminant pattern-reversal color stimulation elicits a PlOO response having ‘W’-wave-form pattern consisting of PlOOa, NIOO and PlOOb complexes. NlOO appears to correspond to the PI00 of conventional VEP from black-white pattern reversal stimulation. In this study, we evaluated the field distribution of VEP components during black-white and isoluminant color pattern reversal stimulations. We used a high resolution monitor screen and a computerized pattern generator devised for stimulation. The hemifield stimulation was obtained by eccentric gaze at the right or left side of the screen. The isoluminant level between two colors was determined by psychophysical flicker-fusion using 19 Hz stimulation. Ten eyes of 5 healthy volunteers were measured. As expected, black and white pattern VEP showed paradoxically lateralized PlOO. In contrast, the color pattern reversal VEP at isoluminance produced an NlOO component that was always lateralized to the hemisphere contralateral to the side of the stimulated field. The findings suggest that field distributions in response to blackwhite contrast and isoluminent color perceptions are different and that conical color receiving areas may be located on the occipital hemispheric surface rather than on the mesial surface of the calcarine fissure. E135. Changes of spectral EEG variables in patients with hemispheric stroke. - C. Juh&z and I. Szirmai (Department of Neurology, Semmelweis University Medical School, Budapest, Hungary) Spectral EEG parameters correlate with cerebral blood flow and metabolism and provide information about the functional state of postischemic brain tissue. Spectral EEG allows to estimate the degree of ipsi- and contralateral brain dysfunction in hemispheric ischemia. EEG of 40 stroke patients was recorded within 48 h of stroke onset and after 2 weeks. Alpha peak frequency (APF), alpha (AP) and theta band power were calculated. Hemispheric APF and power asymmetries and
changes of band power were statistically evaluated. Localization of brain infarction was determined by CT. More than 0.5 Hz asymmetry of APF in the acute stage was detected in 16 cases. Most patients with small subcortical infarction (.5/6) were in this group, while more extended parieto-occipital lesions caused bilateral symmetric decrease of APF (11115). AP significantly increased more frequently over both hemispheres in patients with asymmetric compared to those with symmetric APF. In conclusion, (1) the used parameters are good indicators of ischemic brain injury in hemispheric stroke; (2) functional involvement of contralateral hemisphere estimated by spectral EEG analysis may have prognostic value and correlates with the localization of infarction. E137. Abortive generalized spike-and-wave bursts: an electroclinical entity. - Peter Kellaway (Department of Neurology, Baylor College of Medicine, Houston, TX 77030) Abortive generalized spike-and-wave bursts (AGSW) are here defined as bursts having a duration of no more than 1.5 s, in spite of sleep, hyperventilation or photic stimulation. The findings in 629 untreated individuals showing AGSW were as follows: AGSW occurred predominantly in children with a peak incidence between 2 and 10 years. After 16 years, the incidence drops rapidly to a low asymptomatic level. Sixty-three percent had seizures and 37% had no seizures. Of the individuals with seizures, 93.4% had generalized tonic-clonic seizures, 5% had partial or secondarily generalized seizures, and 1.6% had myoclonic seizures. None had absence seizures. The 5% with partial seizures had benign centrotemporal focal epilepsy of childhood. Of another 1781 patients with complex partial seizures monitored as possible candidates for surgery, 41 (2.3%) had AGSW. It is suggested that in the 37% of patients with no seizures, and in the patients with simple or complex partial seizures, AGSW is simply a genetic marker. Supponed by NIH Grant NS I 1535. E138.
Intraoperative electrocochleography during stapedectomy and ossicular reconstruction. - Ronald G. Emerson, Jack J. Wazen, David Foyt, Edward Gallo, and Katherine Dowling (Departments of Neurology and Otolaryngology, Columbia University College of Physicians and Surgeons)
We performed transtympanic eiectrocochleograms (ECOG) in I9 patients, aged 27-73 years, with otosclerosis undergoing stapedectomy and prosthetic ossicular reconstruction. For each patient. the NI threshold to click stimulation was measured intraoperatively, before and after reconstruction. Post-reconstruction ECOGs demonstrated improvements in the Nl threshold in 16 cases, and were unchanged in one case. Technical failures occurred in two cases. In all but one case, improvement in the intraoperative NI threshold corresponded with improvement in audiograms obtained postoperatively, compared with preoperative studies. Intraoperative ECOG appears to be an effective tool for verifying the functional integrity of ossicular reconstruction. We speculate that intraoperative ECOG may allow the surgeon to ‘fine tune’ the reconstruction to optimize hearing. E139. Digital telephonic EEG transmission and receiving system. Harley E. Schear, Larry L. Woodard and Land B. Wilson (Neurological Institute, San Francisco) Analog 8 or 10 channel telephonic EEG transmission is a technology which has been in widespread use for over 20 years. Quantitative EEG (QEEG) (brain mapping) requires 16-20 or more channels. A new state-of-the-science system using high-speed modem, digital data transmission/compression has been developed which transmits 24 channels of data in real time via standard voice line. This new system interfaces directly to computers for QEEG and also allows improved monitoring of patients in intensive care units, emergency rooms and epilepsy centers. EEG receiving centers can increase their routine clini-
6P that inter-electrode ECoG coherence reflects gyral and may indicate the macroscopic organization of some functions.
anatomy cognitive
E133. The phenomena of time coincidence of change-point periods in different derivations of EEG. - A.Ya. Kaplan, B.E. Brodsky, B.S. Darkhovsky, A.A. Fingelcurtz, A.An. Fingelcurtz, S.L. Shishkin (Moscow State University, 119899, Moscow, Russia) Twelve young male volunteers were instructed to look on the screen during each of 10-12 1 min trial period with registration of EEG and try to remember the matricidal visual image. Four hundred and seventy-three EEG records for every 8 EEG standard derivations were analyzed for calculations of change-point moments by original nonparametric method. It was shown that elaborated methodology of nonparametric quest of change-points is quite effective for short duration change periods (CP) search in EEG. The time distribution of CP was not uniform during 1 min EEG records: CP quantity statistically increased in compact period of time when subjects switched from one type of cognitive activity to another. The valuation of cases of coincidence frequency of CP in each of the two possible paired coincidences was taken from derivations of EEG. It was discovered that 3 different periods of human cognitive activity sharply differ on patterns of paired coincidences (PPC). Thus, the spatial map of CP coincidence in pairs of EEG derivations reflect the specific features of brain cognitive activity. E134.
Hemispheric dominancy of color isoluminant VEP during hemifield stimulation. - S. Kawashima, M. Yeh, T. Yamada, M. Wall (Department of Neurology, Division of Clinical Electrophysiology, College of Medicine, University of Iowa, Iowa City, IA 52240)
Isoluminant pattern-reversal color stimulation elicits a PlOO response having ‘W’-wave-form pattern consisting of PlOOa, NIOO and PlOOb complexes. NlOO appears to correspond to the PI00 of conventional VEP from black-white pattern reversal stimulation. In this study, we evaluated the field distribution of VEP components during black-white and isoluminant color pattern reversal stimulations. We used a high resolution monitor screen and a computerized pattern generator devised for stimulation. The hemifield stimulation was obtained by eccentric gaze at the right or left side of the screen. The isoluminant level between two colors was determined by psychophysical flicker-fusion using 19 Hz stimulation. Ten eyes of 5 healthy volunteers were measured. As expected, black and white pattern VEP showed paradoxically lateralized PlOO. In contrast, the color pattern reversal VEP at isoluminance produced an NlOO component that was always lateralized to the hemisphere contralateral to the side of the stimulated field. The findings suggest that field distributions in response to blackwhite contrast and isoluminent color perceptions are different and that conical color receiving areas may be located on the occipital hemispheric surface rather than on the mesial surface of the calcarine fissure. E135. Changes of spectral EEG variables in patients with hemispheric stroke. - C. Juh&z and I. Szirmai (Department of Neurology, Semmelweis University Medical School, Budapest, Hungary) Spectral EEG parameters correlate with cerebral blood flow and metabolism and provide information about the functional state of postischemic brain tissue. Spectral EEG allows to estimate the degree of ipsi- and contralateral brain dysfunction in hemispheric ischemia. EEG of 40 stroke patients was recorded within 48 h of stroke onset and after 2 weeks. Alpha peak frequency (APF), alpha (AP) and theta band power were calculated. Hemispheric APF and power asymmetries and
changes of band power were statistically evaluated. Localization of brain infarction was determined by CT. More than 0.5 Hz asymmetry of APF in the acute stage was detected in 16 cases. Most patients with small subcortical infarction (.5/6) were in this group, while more extended parieto-occipital lesions caused bilateral symmetric decrease of APF (11115). AP significantly increased more frequently over both hemispheres in patients with asymmetric compared to those with symmetric APF. In conclusion, (1) the used parameters are good indicators of ischemic brain injury in hemispheric stroke; (2) functional involvement of contralateral hemisphere estimated by spectral EEG analysis may have prognostic value and correlates with the localization of infarction. E137. Abortive generalized spike-and-wave bursts: an electroclinical entity. - Peter Kellaway (Department of Neurology, Baylor College of Medicine, Houston, TX 77030) Abortive generalized spike-and-wave bursts (AGSW) are here defined as bursts having a duration of no more than 1.5 s, in spite of sleep, hyperventilation or photic stimulation. The findings in 629 untreated individuals showing AGSW were as follows: AGSW occurred predominantly in children with a peak incidence between 2 and 10 years. After 16 years, the incidence drops rapidly to a low asymptomatic level. Sixty-three percent had seizures and 37% had no seizures. Of the individuals with seizures, 93.4% had generalized tonic-clonic seizures, 5% had partial or secondarily generalized seizures, and 1.6% had myoclonic seizures. None had absence seizures. The 5% with partial seizures had benign centrotemporal focal epilepsy of childhood. Of another 1781 patients with complex partial seizures monitored as possible candidates for surgery, 41 (2.3%) had AGSW. It is suggested that in the 37% of patients with no seizures, and in the patients with simple or complex partial seizures, AGSW is simply a genetic marker. Supponed by NIH Grant NS I 1535. E138.
Intraoperative electrocochleography during stapedectomy and ossicular reconstruction. - Ronald G. Emerson, Jack J. Wazen, David Foyt, Edward Gallo, and Katherine Dowling (Departments of Neurology and Otolaryngology, Columbia University College of Physicians and Surgeons)
We performed transtympanic eiectrocochleograms (ECOG) in I9 patients, aged 27-73 years, with otosclerosis undergoing stapedectomy and prosthetic ossicular reconstruction. For each patient. the NI threshold to click stimulation was measured intraoperatively, before and after reconstruction. Post-reconstruction ECOGs demonstrated improvements in the Nl threshold in 16 cases, and were unchanged in one case. Technical failures occurred in two cases. In all but one case, improvement in the intraoperative NI threshold corresponded with improvement in audiograms obtained postoperatively, compared with preoperative studies. Intraoperative ECOG appears to be an effective tool for verifying the functional integrity of ossicular reconstruction. We speculate that intraoperative ECOG may allow the surgeon to ‘fine tune’ the reconstruction to optimize hearing. E139. Digital telephonic EEG transmission and receiving system. Harley E. Schear, Larry L. Woodard and Land B. Wilson (Neurological Institute, San Francisco) Analog 8 or 10 channel telephonic EEG transmission is a technology which has been in widespread use for over 20 years. Quantitative EEG (QEEG) (brain mapping) requires 16-20 or more channels. A new state-of-the-science system using high-speed modem, digital data transmission/compression has been developed which transmits 24 channels of data in real time via standard voice line. This new system interfaces directly to computers for QEEG and also allows improved monitoring of patients in intensive care units, emergency rooms and epilepsy centers. EEG receiving centers can increase their routine clini-