Cerebral hemodynamic response to generalized spike-wave discharges.
OBJECTIVE
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 pco2 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 decrease in pco2 (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.
Diehl
B
B
Department of Neurology, University Hospital, Münster, Germany.
Knecht
S
S
Deppe
M
M
Young
C
C
Stodieck
S R
SR
D000328:Adult; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D012039:Regional Blood Flow; D017585:Ultrasonography, Doppler, Transcranial / Q000706:statistics & numerical data