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Spatial coherence of EEG activity: Results on healthy subjects and in cerebral vascular disease
s137 EATON-LAMBERT MYASTHENIC SYNDROME (ELMS): STAGING ‘OF SINGLE MUSCLE INVOLVEMENT BY EMC STUDY OF WEAKNESS, FATICABILITY AND FACILITATION. C. Scoppetta, C. Casali, Restuccia (La Sapienza
University,
S. D’Agostini,
I. La Cesa
and
R.
Rome, Italy)
In ELMS each affected muscle has its own degree of involvement at each moment owing to the varying combination of the situation at rest with the effects of synaptic fatigue (SyFatig) and synaptic facilitation (SyFacil). We performed serial repetitive stimulation tests (RS) on the abductor pollicis brevis muscle in four ELMS patients and identified four patterns of muscle involvement. Stage 0 (normal or remission): all junctions normally work and the CMAP has a normal amplitude. SyFatig and SyFacil do not modify this amplitude. Stage 1: at rest all junctions work; but the safety factor SF is reduced and, because of SyFatig, during low frequency RS (LFRS) a decrement is recorded. As the 1st CMAP is normal, during high frequency RS (HFRS) SyFacil has no effect on the CMAP amplitude. Stage 2: some junctions are already blocked at rest and therefore the first CMAP is low. Some other junctions work at rest but they have a reduced SF: therefore during LFRS a decrementing response is recorded. During HFRS, because of SyFacil, many junctions become reactivated and an increase occurs of the CMAP amplitude. Stage 3: the first CMAP is low; owing to SyFatig during LFRS a decrement is recorded. But presynaptic damage is so marked that the SyFacil is inadequate and during HFRS no facilitation occurs.
SPATIAL COHERENCE OF EEG ACTIVITY: RESULTS ON HEALTHY SUBJEXTS AND IN CEREBRAL VASCULAR DISEASE. C. S&ban, (Hopital
C. Debouzy Charles
and R. Leguen
Foix, Ivry-sur-Seine,
France)
Coherence function analysis of EEG signals provides a new topographic representation of EEG activity. With this method the power of one component or of a frequency band is divided into one part coherent with the cortical site chosen as the time origin and a second part non-coherent with this site. In this study the time origin chosen was 01-02. Dissociation of total power in coherent (C/01-02) and non-coherent (NC/Ol-02) power was studied in 12 young, healthy subjects. Recordings of 1 min were at 8.30 a.m., 11.45 a.m. and 4.15 p.m. in 2 classical states (eyes open, eyes closed). The stability of C/01-02, NC/Ol-02 and total power both between and within subjects will be discussed.
In normal subjects with eyes closed C/01-02 power appeared essentially in the left and right parietotemporal regions. Moreover, the NC/Ol-02 power appeared independent between these two areas. With opening of the eyes a blocking reaction was significant for nearly all the EEG components and for both C/01-02 and NC/Ol-02 powers. On the contrary observations in cerebra-vascular disease frequently showed an opposite power variation with opening of the eyes for the C/01-02 and NC/Ol-02. EEG activity related to the cerebral infarct always appeared on the NC/Ol-02 power. This method could thus give a better quantitative evaluation of disease-related EEG impairment.
ARE THE DRUG RELATED EEG EFFECTS DEPENDENT ON VASCULAR PATHOLOGY IN DEMENTIA? EFFECTS OF DUXIL@ (ALMITRINERAUBASINE COMBINATION) IN 2 STUDIES. C. Sebban, M. Malbezin,
(Hopital
Charles
D. Guez and R. Moulias
Foix, Ivry-sur-Seine,
France)
In view of some controversy regarding the importance of vascular disorders in dementia 2 double-blind randomized parallel group trials were carried out with quantitative electroencephalography (q EEG). The first study (I) was performed in 2 groups of 12 patients, one receiving Duxil” (80 mg daily) and the other a placebo during 3 months. These out-patients, mean age 66.7 years, had complained about memory loss and had abnormal performances at the backward visual masking test, but none of them had a history of vascular disease. The second study (II) was performed in 14 in-patients, mean age 78 years, with an ischemic stroke in the area of the middle cerebral artery 30-45 days before. The patients were randomized into 2 groups and received a single oral dose of either Duxil” (80 mg) or placebo. q EEG on 16 leads was performed in study 1 before and after treatment period and in study II before and 30, 60 and 120 min after treatment. When compared to the placebo group in study I Duxil’ induced a decrease in delta and theta power (P i 0.01) and an increase in the high frequency components of the alpha band (P < 0.01). These results are in agreement with those of previous trials with nootropics in such aged patients. In study II, apart from a significant and time related increase in beta power (P < 0.001) classically related to an increase in brain 0, consumption, we have observed a surprising significant increase in the theta power (P < 0.001). Indeed for the low and middle frequencies, the EEG profile of changes induced by Duxil” seemed to be reversed. Moreover in study II, this profile was identical in normal and lesioned hemispheres. The physiopathological basis of these differences will be discussed but already these results stress that it is important to separate vascular and non-vascular dementia in therapeutic studies.
University,
S. D’Agostini,
I. La Cesa
and
R.
Rome, Italy)
In ELMS each affected muscle has its own degree of involvement at each moment owing to the varying combination of the situation at rest with the effects of synaptic fatigue (SyFatig) and synaptic facilitation (SyFacil). We performed serial repetitive stimulation tests (RS) on the abductor pollicis brevis muscle in four ELMS patients and identified four patterns of muscle involvement. Stage 0 (normal or remission): all junctions normally work and the CMAP has a normal amplitude. SyFatig and SyFacil do not modify this amplitude. Stage 1: at rest all junctions work; but the safety factor SF is reduced and, because of SyFatig, during low frequency RS (LFRS) a decrement is recorded. As the 1st CMAP is normal, during high frequency RS (HFRS) SyFacil has no effect on the CMAP amplitude. Stage 2: some junctions are already blocked at rest and therefore the first CMAP is low. Some other junctions work at rest but they have a reduced SF: therefore during LFRS a decrementing response is recorded. During HFRS, because of SyFacil, many junctions become reactivated and an increase occurs of the CMAP amplitude. Stage 3: the first CMAP is low; owing to SyFatig during LFRS a decrement is recorded. But presynaptic damage is so marked that the SyFacil is inadequate and during HFRS no facilitation occurs.
SPATIAL COHERENCE OF EEG ACTIVITY: RESULTS ON HEALTHY SUBJEXTS AND IN CEREBRAL VASCULAR DISEASE. C. S&ban, (Hopital
C. Debouzy Charles
and R. Leguen
Foix, Ivry-sur-Seine,
France)
Coherence function analysis of EEG signals provides a new topographic representation of EEG activity. With this method the power of one component or of a frequency band is divided into one part coherent with the cortical site chosen as the time origin and a second part non-coherent with this site. In this study the time origin chosen was 01-02. Dissociation of total power in coherent (C/01-02) and non-coherent (NC/Ol-02) power was studied in 12 young, healthy subjects. Recordings of 1 min were at 8.30 a.m., 11.45 a.m. and 4.15 p.m. in 2 classical states (eyes open, eyes closed). The stability of C/01-02, NC/Ol-02 and total power both between and within subjects will be discussed.
In normal subjects with eyes closed C/01-02 power appeared essentially in the left and right parietotemporal regions. Moreover, the NC/Ol-02 power appeared independent between these two areas. With opening of the eyes a blocking reaction was significant for nearly all the EEG components and for both C/01-02 and NC/Ol-02 powers. On the contrary observations in cerebra-vascular disease frequently showed an opposite power variation with opening of the eyes for the C/01-02 and NC/Ol-02. EEG activity related to the cerebral infarct always appeared on the NC/Ol-02 power. This method could thus give a better quantitative evaluation of disease-related EEG impairment.
ARE THE DRUG RELATED EEG EFFECTS DEPENDENT ON VASCULAR PATHOLOGY IN DEMENTIA? EFFECTS OF DUXIL@ (ALMITRINERAUBASINE COMBINATION) IN 2 STUDIES. C. Sebban, M. Malbezin,
(Hopital
Charles
D. Guez and R. Moulias
Foix, Ivry-sur-Seine,
France)
In view of some controversy regarding the importance of vascular disorders in dementia 2 double-blind randomized parallel group trials were carried out with quantitative electroencephalography (q EEG). The first study (I) was performed in 2 groups of 12 patients, one receiving Duxil” (80 mg daily) and the other a placebo during 3 months. These out-patients, mean age 66.7 years, had complained about memory loss and had abnormal performances at the backward visual masking test, but none of them had a history of vascular disease. The second study (II) was performed in 14 in-patients, mean age 78 years, with an ischemic stroke in the area of the middle cerebral artery 30-45 days before. The patients were randomized into 2 groups and received a single oral dose of either Duxil” (80 mg) or placebo. q EEG on 16 leads was performed in study 1 before and after treatment period and in study II before and 30, 60 and 120 min after treatment. When compared to the placebo group in study I Duxil’ induced a decrease in delta and theta power (P i 0.01) and an increase in the high frequency components of the alpha band (P < 0.01). These results are in agreement with those of previous trials with nootropics in such aged patients. In study II, apart from a significant and time related increase in beta power (P < 0.001) classically related to an increase in brain 0, consumption, we have observed a surprising significant increase in the theta power (P < 0.001). Indeed for the low and middle frequencies, the EEG profile of changes induced by Duxil” seemed to be reversed. Moreover in study II, this profile was identical in normal and lesioned hemispheres. The physiopathological basis of these differences will be discussed but already these results stress that it is important to separate vascular and non-vascular dementia in therapeutic studies.