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| Author(s): |
Fabricio Oliveira Lima
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas |
| Defense date: | 2015-00-00 |
| Examining board members: |
Fernando Cendes;
Antonio Luis Eiras Falcão;
Anelyssa Cysne Frota D'Abreu;
Jamary Oliveira Filho;
Marino Muxfeldt Bianchin
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| Advisor: | Li Li Min |
| Abstract | |
Seizures are associated with a worse prognosis in acute ischemic stroke (AIS). The prognostic significance of interictal epileptiform discharges (IED) and periodic patterns (PP) after ischemic stroke has not been assessed. Although electroencephalography (EEG) has been widely used to monitor cerebral ischemia, its prognostic value in AIS has been infrequently studied. We sought to test whether IED and PP, detected on standard EEG performed during the acute phase of ischemic stroke are associated with a worse functional outcome and whether quantitative EEG (qEEG) indexes add prognostic information independent of clinical parameters. We also assessed the hemodynamic consequences of interictal epileptiform activity by using a combined EEG-fMRI methodology. One-hundred-fifty-seven patients 18 years or older with a diagnosis of AIS presenting within 72 hours from stroke onset were enrolled and prospectively followed. EEG interpretation was performed by a blinded board certified neurophysiologist. IED and PP (grouped as epileptiform activity ¿ EA) were defined according to proposed guidelines. Univariable and multivariable analysis were used to identify predictors of outcome (modified Rankin Scale dichotomized ? 2 versus. ? 3) at 3 months. For the qEEG analysis, power spectral density was calculated for the first 60 seconds of artifact free EEG. Three qEEG indexes were analyzed: a symmetry index, pdBSI (pairwise-derived brain symmetry index) and a sum index. Spearman¿s correlation was used to assess the association among qEEG indexes and between them and the admission NIHSS. ROC curves and multivariable logistic regression were used to assess the effect of qEEG indexes on the main outcome. In the univariable analysis, admission NIHSS (OR 1.20, IC 95% 1.12-1.28, p=0.001), age (OR 1.03, IC 95%1.01-1.05, p=0.02) and presence of EA (OR 2.94, IC 95% 1.51-5.88, p=0.001) were significantly associated with the outcome at 3 months. In the multivariable analysis, only admission NIHSS (OR 1.19, IC 95% 1.11-1.28, p<0.001) and the presence of EA (OR 2.27, IC 95% 1.04-5.00, p=0.04) were independently associated with the prognosis. For the quantitative analysis, 4 patients were excluded (use of sedative medication). All indexes showed a similar weak correlation with the admission NIHSS with rho=0.32, p<0.001 for pdBSI and the symmetry index; and rho=0.30, p<0.001 for the sum index. The sum index showed a slightly larger AUC (0.702, p<0.001). On multivariable analysis, only admission NIHSS (OR 1.19; 95% CI 1.12-1.27; p<0.001) and the sum index (OR 1.12; 95% CI 1.02-1.24; p=0.02) were independently associated with the outcome. Four patients were eligible for the EEG-fMRI combined analysis. In 3 patients, positive BOLD areas were observed in the vicinity of the ischemic area. Slow waves were associated with negative BOLD responses. qEEG analysis seems to be a promising tool in acute neurological monitoring beyond the detection of epileptic activity. Interictal epileptiform activity might be associated with important hemodynamic changes in the peri-infarct area as well as in remote brain areas. Additional research examining the role of medication therapy on the outcome and the occurrence of seizures for those patients with specific EEG patterns is warranted (AU) | |