Absence Seizures Induce a Decrease in Cerebral Blood Flow: Human and Animal Data

Nehlig, Astrid; Vergnes, Marguerite; Waydelich, Rosita; Hirsch, Édouard; Charbonne, R.; Marescaux, Christian; Seylaz, Jacques

doi:10.1097/00004647-199601000-00017

Cited by 61 publications

(44 citation statements)

References 31 publications

(20 reference statements)

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“…In GSW however we have little prior anatomical hypothosis regarding the spatial extent of BOLD changes. We propose that thalamic activation seen here represents subcortical activity , 1988,Klingelhofer et al, 1991,Bode, 1992,Nehlig et al, 1996,De Simone et al, 1998 Although the majority of our cases showed cortical negative response a number of cases showed activation or biphasic time courses in the same areas. These did not differ significantly (2-sample t-tests, all p > 0.8) from those with negative response in terms of the frequency of GSW, the number of events, their median duration or total duration during the scan session.…”

Section: Discussionmentioning

confidence: 64%

EEG–fMRI of idiopathic and secondarily generalized epilepsies

Hamandi¹,

Salek‐Haddadi²,

Laufs³

et al. 2006

NeuroImage

252

188

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We used simultaneous EEG and functional MRI (EEG-fMRI) to study generalized spike wave activity (GSW) in idiopathic and secondary generalized epilepsy (SGE). Recent studies have demonstrated thalamic and cortical fMRI signal changes in association with GSW in idiopathic generalized epilepsy (IGE). We report on a large cohort of patients that included both IGE and SGE, and give a functional interpretation of our findings. Forty six patients with GSW were studied with EEG-fMRI; 30 with IGE and 16 with SGE. GSWrelated BOLD signal changes were seen in 25 of 36 individual patients who had GSW during EEG-fMRI. This was seen in thalamus (60%) and symmetrically in frontal cortex (92%), parietal cortex (76%) and posterior cingulate cortex / precuneus (80%). Thalamic BOLD changes were predominantly positive and cortical changes predominantly negative.Group analysis showed a negative BOLD response in the cortex in the IGE group and to a lesser extent a positive response in thalamus. Thalamic activation was consistent with its known role in GSW, and its detection with EEG-fMRI may in part be related to the frequency and duration of GSW epochs recorded. The spatial distribution of the cortical fMRI response to GSW in both IGE and SGE involved areas of association cortex that are most active during conscious rest. Reduction of activity in these regions during GSW is consistent with the clinical manifestation of absence seizures. EEG-fMRI of GSWHamandi K 3

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Section: Discussionmentioning

confidence: 64%

EEG–fMRI of idiopathic and secondarily generalized epilepsies

Hamandi¹,

Salek‐Haddadi²,

Laufs³

et al. 2006

NeuroImage

252

188

View full text Add to dashboard Cite

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“…In four children with absences, Nehlig et al (15) documented an average CBFV decrease of 24% with a latency of 5 s during 31s gSW (two to nine paroxysms each). Most investigators (12,13,15) did not use heart-cycle integration to account for systolic and diastolic fluctuation of CBFV. By applying heart-cycle integration, a higher temporal resolution of CBFV changes can be achieved than by low-pass filtering.…”

Section: Discussionmentioning

confidence: 97%

“…In genetic absence rats of Strasbourg, petit mal status was provoked by injection of haldol; 5-10 min later, Pco, decreased. But the authors also observed a decrease in PCO, after administration of ESM, which suppressed the SW discharges (15) and therefore considered it unlikely that the reduction in perfusion during gSW was due to Pco, decrease. However, in the patient monitored for end-expiratory Pco,, we demonstrated an increase in respiratory frequency with a subsequent decrease in Pco, during gSW.…”

Section: Discussionmentioning

confidence: 98%

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Cerebral Hemodynamic Response to Generalized Spike‐Wave Discharges

Diehl¹,

Knecht²,

Deppe³

et al. 1998

Epilepsia

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Summary: Purpose: Data in the literature concerning metabolic demand during generalized spike-wave activity (gSW) are conflicting. We investigated instantaneous changes in cerebral blood flow velocities (CBFV) in both middle cerebral arteries (MCAs) by transcranial Doppler sonography (TCD) during gSW paroxysms recorded by scalp EEG.Methods: In 13 patients, CBFVs in both MCAs were averaged, time-locked to the occurrence of the gSW; respiratory rate (RR) and end-expiratory pco, were measured in one patient.Results: Nine patients showed significant changes in CBFV during gSW. Four had biphasic flow changes with an initial increase (p < 0.05) and a subsequent decrease (p < 0.01). This was partially paralleled by an increase in RR (p < 0.01) and a Functional imaging is steadily moving toward a larger role in neurologic practice. In the evaluation of epilepsy, it is being used for determination of epileptic foci and for the presurgical mapping of higher cortical functions (1,2). However, several biologic phenomena can affect functional imaging results and interpretation. One such potentially confounding factor in the evaluation of patients with epilepsy is the incidental occurrence of generalized spike-wave activity (gSW). There are conflicting reports on increased and decreased metabolic demands associated with gSW. In several studies, spontaneous and provoked generalized seizures were studied by means of positron emission tomography (PET) and single-photon-emission tomography (SPECT). decrease in pco, (p < 0.01). In three patients, an increase in CBFV that preceded the onset of gSW by several seconds was observed, followed by a decrease in CBFV. Two patients showed a significant decrease only of CBFV. Only gSWs of a median duration of >0.8 s were associated with significant changes in CBFV. Conclusions:We were able to demonstrate that gSWs of several seconds duration lead to cortical perfusion changes. We suggest that the initial increase of CBFV demonstrated in some patients reflects neuronal activation, whereas the subsequent decrease might in part be due to hyperventilation-induced hypocapnia. Key Words: Cerebral blood flow velocitiesTranscranial Doppler sonography-Generalized spike-wave. fusely increased metabolic rates. This discrepancy might be related to the technical constraints of the autoradiographic techniques that measure a metabolic window of -30 min (6) and therefore reflect a mixture a ictal and interictal (i.e., activity without gSW) activity. Moreover, the model for metabolic-rate calculations is based on steady-state conditions whose applicability to rapidly changing physiologic states such as periods of spikewave' discharges is uncertain (7).Flow responses to various stimulations such as hypocapnia as measured by intravenous xenon-133 have shown direct correlation with cerebral blood flow velocity (CBFV) changes as measured by transcranial Doppler sonography (TCD) in the major cerebral arteries (8). Thus TCD allows non-invasive, on-line monitoring of cerebral perfusion changes with a high tempo...

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“…Human and animal studies have shown large increases in neuronal activity, CBF, and metabolism during GTCS (reviewed in . However, some investigators have shown increases in CBF during SWD (Prevett et al, 1995;Yeni et al, 2000), whereas others have shown the opposite (Bode, 1992;Nehlig et al, 1996;Sanada et al, 1988;Sperling and Skolnick, 1995).…”

mentioning

confidence: 98%

Relative Changes in Cerebral Blood Flow and Neuronal Activity in Local Microdomains during Generalized Seizures

Nersesyan

Hermán

Erdogan³

et al. 2004

J Cereb Blood Flow Metab

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Summary:There is broad agreement that generalized tonicclonic seizures (GTCS) and normal somatosensory stimulation are associated with increases in regional CBF. However, the data regarding CBF changes during absence seizures are controversial. Electrophysiologic studies in WAG/Rij rats, an established animal model of absence seizures, have shown spikewave discharges (SWD) that are largest in the perioral somatosensory cortex while sparing the visual cortex. Recent functional magnetic resonance imaging (fMRI) studies in the same model have also shown localized increases in fMRI signals in the perioral somatosensory cortex during SWD. Because fMRI signals are only indirectly related to neuronal activity, the authors directly measured CBF and neuronal activity from specific microdomains of the WAG/Rij cortex using a specially designed probe combining laser-Doppler flowmetry and extracellular microelectrode recordings under fentanyl/haloperidol anesthesia. Using this approach, parallel increases in neuronal activity and CBF were observed during SWD in the whisker somatosensory (barrel) cortex, whereas the visual cortex showed no significant changes. For comparison, these measurements were repeated during somatosensory (whisker) stimulation, and bicuculline-induced GTCS in the same animals. Interestingly, whisker stimulation increased neuronal activity and CBF in the barrel cortex more than during SWD. During GTCS, much larger increases that included both the somatosensory and visual cortex were observed. Thus, SWD in this model produce parallel localized increases in neuronal activity and CBF with similar distribution to somatosensory stimulation, whereas GTCS produce larger and more widespread changes. The normal response to somatosensory stimulation appears to be poised between two abnormal responses produced by two physiologically different types of seizures.

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Absence Seizures Induce a Decrease in Cerebral Blood Flow: Human and Animal Data

Cited by 61 publications

References 31 publications

EEG–fMRI of idiopathic and secondarily generalized epilepsies

EEG–fMRI of idiopathic and secondarily generalized epilepsies

Cerebral Hemodynamic Response to Generalized Spike‐Wave Discharges

Relative Changes in Cerebral Blood Flow and Neuronal Activity in Local Microdomains during Generalized Seizures

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