- Email: [email protected]
ERD mapping in healthy subjects
Society Proceedings in different pharmacological conditions, using an experimental model of quantified EEG in the rabbit. Drug-induced changes of the target variables were evaluated during baseline and after administration of 2 peptides with opposite EEG and behavioural effects: corticotropin releasing factor (CRF), an activating peptide, and dermorphin, a mu receptor agonist opioid with long-lasting sedative properties. By means of regression techniques we found that absolute power was the best predictor of both effects. Drug-induced changes of frequency bands and dominant frequenties need more detailed comments. 80. ERD mapping in healthy subjects. - G. Magnani, T. Locatelli, M. Cursi, L. Leocani, A. Elia and G. Comi (Dept. of Neurophysiopathology, Hosp. S. Raffaele, Milan) activity following activation, such on centra1 areas after motor activity, are wel1 known (Gastaut, 1952). The event-related desynchronization (ERD; Pfurtscheller, 19771 allows to quantify and follow over time the modifications of alpha and beta band activity. In this study we evaluated 10 normal subjects aged 18-70 years, using topographic ERD representation obtained with Pfurtscheller’s method. Al1 subjects underwent 19Channel EEG recording, using the 10-20 International System, with biauricular reference. Each subject had to keep the eyes closed and press a button switch following a “go” verba1 command (preceded 2 sec before by an “attention” command) in separate trials for each limb. For each recording 40 artifact free epochs of 6 sec each were selected (2 sec at rest, 2 sec of “attention” and 2 sec after movement). Topographic ERD distribution was reconstructed by maps at time intervals of 62 msec each. Methodological, technical and interpretation problems are discussed. Changes of electroencephalographic
as the mu rhythm desynchronization
81. Spectra1 analysis and topographic mapping of EEG in normal aging and dementia. - C. Lia, E. Bottacchi, C. Degioz and L. Carenini (Dept. of Neurology and Neurophysiology, Osp. Regionale di Aosta, Aosta) The aim of our study was to investigate EEG changes in normal aging, and the differences between normal elderly and patients with dementia of Alzheimer type (DAT). We applied EEG mapping to 63 healthy subjects, aged 20-84 years, and 20 patients with DAT. EEG data were recorded from 16 electrodes referred to linked ears. Spectra1 analysis and topographic mapping were performed. In the healthy subjects there was no significant correlation between age and posterior alpha frequency. Slow activity was decreased whereas beta relative power was significantly increased in old healthy subjects. In contrast in demented patients we observed slowing of posterior alpha frequency and a diffuse increase of delta and theta relative powers. In conclusion, our preliminary data confirm that EEG mapping is a non-invasive and practicable method for a first screening of demented patients. 82. Conventional and digital EEG: an investigation concerning national operators. - F. De Carli, M. Gabarra, M. Gambaro, G. Rodriguez, W.G. Sannita and G. Rosadini (Department of Motor Science, Neurophysiopathology, University of Genoa, Genoa, and Center for Cerebral Neurophysiology, National Research Countil, Genoa) The widespread availability and continuing development of computer-assisted systems for the acquisition, storage and processing of electrophysiological data may become a potential source of problems relating to the potentialities, strategies of application and final impact of this approach. A questionnaire was produced and addressed to 500 members of the Italian Society of Clinical Neurophysiology to obtain a genera1 outline of the field in this country. One hundred and twelve questionnaires from 98 different units (hospita1 units in 56% of cases) were returned with the requested information. Computer-assisted systems
57P
60% of laboratories active in clinical neuroare used in approximately physiology, with their application focussed in most cases on sleep analysis and epilepsy. The use of techniques for digital processing (mostly power spectra1 analysis and brain mapping) is restricted to 36% and 46% of cases in clinical routine and in research programs respectively. Most responders to the questionnaire are explicitly interested, and willing to collaborate in future multicenter research protocols and normative studies. 83. The FFT approximation technique in Alzheimer’s disease patients. - C. Fornara, M. Cursi, L. Roveri, T. Locatelli, L. Leocani and G. Comi (Dept. of Neurophysiology, Hosp. S. Raffaele, Milan) Previous EEG quantified (EEGq) studies described in Alzheimer’s disease (AD) patients an abnormal topographic power distribution of different frequency bands as compared to controls. In this study we used the FFr approximation technique (D. Lehmann) to evidente the equivalent dipole source localizations of the following frequency bands: delta, theta, alpha,, alpha,, beta, and betaz. We analyzed 15 AD patients and 15 normal age matched subjects. For each subject 1 min of EEG at rest and artifact free was analyzed. Statistical comparison between the 2 groups showed in AD patients a significant shift on the Y axis high of dipole source localization. This modification, which is present in 14 out of 15 subjects (93.3%), concerns al1 frequency bands although it is more evident in low bands (7 subjects presented a shift on high of delta, 11 of theta, 8 of alpha,, 7 of alpha,, 6 of beta, and 4 of beta?). The alpha, band, moreover, showed a significant shift on Z axis (anterior) of dipole source. In no band are there modifications on X axis (lateralizationl of dipolar source. The dipole orientation and magnitude of different frequency bands did not present abnormalities. 84. Spectra1 analysis of suhclinical rhythmic EEG discharge of adults (SREDPL). - A. Cerullo, M. Crisci, P. De Carolis, C. Marini, F. Provini, G. Plazzi and P. Tinuper (Neurological Institute, Bologna University, Bologna, and ’ Neurological Service, Maggiore Hospital, Bologna) Subclinical rhythmic EEG discharge of adults (SREDA) is considered an unusual benign EEG pattern which may resemble an EEG seizure. Three patients (2 females and 1 male), 52, 56 and 59 years old respectively, underwent neurological examination; two had “ vertigo” and one had a short aphasic episode without loss of consciousness. EEG tracings were normal apart from SREDA activity. We performed computerized EEG spectra1 analysis (Rhythm Programme Stellate System) of background and SREDA activity. EEG was recorded on a Nihon Kohden 16 channels with monopolar referential montage. EEG was digitized at 128 samples/sec/channel. Amplitude spectra in al1 patients showed a main peak at the frequency of their alpha activity and a second or a third peak at harmonie tor multiple) of their frequency. Therefore SREDA is a rhythmic activity probably constituting a physiological variant of background activity. 8.5. Acoustic hrain-stem evoked potential (BAEP) investigation in Bell’s palsy. - M. Danni, P. Bellucci, F. Lognllo, G. Lagalla and P. Di Bella (Institute of Nervous Disease, Univ. of Ancona, Ancona) Some authors suggest that idiopathic facial palsy (Bell’s palsyl is a polyneuritis, where the frequent association with hyperacusis represents a cochlear news involvement (Adour, 1982). In order to detect the acoustic pathway and/or brain-stem involvement in Bell’s palsy, BAEPs were studied in 24 patients (mean age: 50.42 years, range: 15-77 years) within 72 h from the onset of facial palsy. BAEPs were performed with Cz-ipsiand contralateral ear recording montage and monoaural alternating click stimulation. A series of 2000 records were averaged for each side and
as the mu rhythm desynchronization
81. Spectra1 analysis and topographic mapping of EEG in normal aging and dementia. - C. Lia, E. Bottacchi, C. Degioz and L. Carenini (Dept. of Neurology and Neurophysiology, Osp. Regionale di Aosta, Aosta) The aim of our study was to investigate EEG changes in normal aging, and the differences between normal elderly and patients with dementia of Alzheimer type (DAT). We applied EEG mapping to 63 healthy subjects, aged 20-84 years, and 20 patients with DAT. EEG data were recorded from 16 electrodes referred to linked ears. Spectra1 analysis and topographic mapping were performed. In the healthy subjects there was no significant correlation between age and posterior alpha frequency. Slow activity was decreased whereas beta relative power was significantly increased in old healthy subjects. In contrast in demented patients we observed slowing of posterior alpha frequency and a diffuse increase of delta and theta relative powers. In conclusion, our preliminary data confirm that EEG mapping is a non-invasive and practicable method for a first screening of demented patients. 82. Conventional and digital EEG: an investigation concerning national operators. - F. De Carli, M. Gabarra, M. Gambaro, G. Rodriguez, W.G. Sannita and G. Rosadini (Department of Motor Science, Neurophysiopathology, University of Genoa, Genoa, and Center for Cerebral Neurophysiology, National Research Countil, Genoa) The widespread availability and continuing development of computer-assisted systems for the acquisition, storage and processing of electrophysiological data may become a potential source of problems relating to the potentialities, strategies of application and final impact of this approach. A questionnaire was produced and addressed to 500 members of the Italian Society of Clinical Neurophysiology to obtain a genera1 outline of the field in this country. One hundred and twelve questionnaires from 98 different units (hospita1 units in 56% of cases) were returned with the requested information. Computer-assisted systems
57P
60% of laboratories active in clinical neuroare used in approximately physiology, with their application focussed in most cases on sleep analysis and epilepsy. The use of techniques for digital processing (mostly power spectra1 analysis and brain mapping) is restricted to 36% and 46% of cases in clinical routine and in research programs respectively. Most responders to the questionnaire are explicitly interested, and willing to collaborate in future multicenter research protocols and normative studies. 83. The FFT approximation technique in Alzheimer’s disease patients. - C. Fornara, M. Cursi, L. Roveri, T. Locatelli, L. Leocani and G. Comi (Dept. of Neurophysiology, Hosp. S. Raffaele, Milan) Previous EEG quantified (EEGq) studies described in Alzheimer’s disease (AD) patients an abnormal topographic power distribution of different frequency bands as compared to controls. In this study we used the FFr approximation technique (D. Lehmann) to evidente the equivalent dipole source localizations of the following frequency bands: delta, theta, alpha,, alpha,, beta, and betaz. We analyzed 15 AD patients and 15 normal age matched subjects. For each subject 1 min of EEG at rest and artifact free was analyzed. Statistical comparison between the 2 groups showed in AD patients a significant shift on the Y axis high of dipole source localization. This modification, which is present in 14 out of 15 subjects (93.3%), concerns al1 frequency bands although it is more evident in low bands (7 subjects presented a shift on high of delta, 11 of theta, 8 of alpha,, 7 of alpha,, 6 of beta, and 4 of beta?). The alpha, band, moreover, showed a significant shift on Z axis (anterior) of dipole source. In no band are there modifications on X axis (lateralizationl of dipolar source. The dipole orientation and magnitude of different frequency bands did not present abnormalities. 84. Spectra1 analysis of suhclinical rhythmic EEG discharge of adults (SREDPL). - A. Cerullo, M. Crisci, P. De Carolis, C. Marini, F. Provini, G. Plazzi and P. Tinuper (Neurological Institute, Bologna University, Bologna, and ’ Neurological Service, Maggiore Hospital, Bologna) Subclinical rhythmic EEG discharge of adults (SREDA) is considered an unusual benign EEG pattern which may resemble an EEG seizure. Three patients (2 females and 1 male), 52, 56 and 59 years old respectively, underwent neurological examination; two had “ vertigo” and one had a short aphasic episode without loss of consciousness. EEG tracings were normal apart from SREDA activity. We performed computerized EEG spectra1 analysis (Rhythm Programme Stellate System) of background and SREDA activity. EEG was recorded on a Nihon Kohden 16 channels with monopolar referential montage. EEG was digitized at 128 samples/sec/channel. Amplitude spectra in al1 patients showed a main peak at the frequency of their alpha activity and a second or a third peak at harmonie tor multiple) of their frequency. Therefore SREDA is a rhythmic activity probably constituting a physiological variant of background activity. 8.5. Acoustic hrain-stem evoked potential (BAEP) investigation in Bell’s palsy. - M. Danni, P. Bellucci, F. Lognllo, G. Lagalla and P. Di Bella (Institute of Nervous Disease, Univ. of Ancona, Ancona) Some authors suggest that idiopathic facial palsy (Bell’s palsyl is a polyneuritis, where the frequent association with hyperacusis represents a cochlear news involvement (Adour, 1982). In order to detect the acoustic pathway and/or brain-stem involvement in Bell’s palsy, BAEPs were studied in 24 patients (mean age: 50.42 years, range: 15-77 years) within 72 h from the onset of facial palsy. BAEPs were performed with Cz-ipsiand contralateral ear recording montage and monoaural alternating click stimulation. A series of 2000 records were averaged for each side and