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Clin Neurophysiol. 2012 Feb;123(2):252-60. doi: 10.1016/j.clinph.2011.06.030. Epub 2011 Jul 28.

Cortical excitability varies upon ictal onset patterns in neocortical epilepsy: a cortico-cortical evoked potential study.

Author information

1
Epilepsy Center, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.

Abstract

OBJECTIVE:

To better understand pathological neuronal excitation in epilepsy by comparing cortico-cortical evoked potential (CCEP) responses in regions with different ictal onset patterns: focal paroxysmal fast (PF) and repetitive spiking (RS).

METHODS:

Fourteen patients undergoing invasive monitoring (six patients with PF and eight with RS) were studied with CCEPs. A repetitive 1 Hz bipolar electrical stimulus was applied to both the ictal onset region (iCCEP) and to a control region (nCCEP) and CCEPs were recorded from the surrounding electrodes. The two groups were compared by subtracting the amplitude of nCCEP from that of iCCEP (CCEP(ictal-control)) at each stimulus intensity, and then normalizing the amplitudes of iCCEP at maximum stimulus intensity by dividing by nCCEP (CCEP(ictal/control)).

RESULTS:

The CCEP response to stimulation in the ictal onset region was significantly larger than to control stimulation for both ictal patterns (paroxysmal fast: P=0.02, repetitive spiking: P<0.01), with repetitive spiking group amplitudes higher than the paroxysmal fast group (CCEP(ictal-control): P<0.01 and CCEP(ictal/control): P=0.04).

CONCLUSIONS:

Pro-epileptic excitability is more accentuated in regions showing an ictal repetitive spiking pattern than a paroxysmal fast pattern.

SIGNIFICANCE:

These findings confirm in a new way that cortical excitability varies depending on the ictal onset pattern.

PMID:
21802356
DOI:
10.1016/j.clinph.2011.06.030
[Indexed for MEDLINE]

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