Clinical Usefulness of the Electroencephalogram in Acute Stroke – A Preliminary Study
2Department of Neurology and Neurophysiology, Hospital Pedro Hispano - Local Health Unit of Matosinhos, Portugal
3PhD Program in Neuroscience, Faculty of Medicine - University of Porto, Portugal
Received Date: September 06, 2018; Published Date: October 17, 2018
Introduction: Stroke is the main cause of disability worldwide, being the first cause of death in Portugal. In the first hours of the event, the cranioencephalic CT scan (CT Scan) does not show the lesion in about 74% of cases, making validation of alternative diagnostic approaches of utmost importance. The electroencephalogram (EEG) may provide useful information for the diagnosis and prognosis of stroke.
Objective: To study the potential usefulness of the EEG for the early diagnosis of acute stroke in patients with initial negative CT Scan, and for the evaluation of the functional status and risk of epilepsy.
Methods: Retrospective analysis of patients with ischemic stroke who underwent EEG and acute phase CT scan between January 2014 and February 2018. Patient characteristics and stroke were classified according to the Oxfordshire Community Stroke Project (OCSP) criteria. The patients were functionally evaluated at 12 months post-stroke by the modified Rankin Scale (mRS) and the existence of post-stroke epilepsy was determined by telephone interview on February 2018.
Results: Thirty patients (25 females and 5 males, mean age 70.5 years) were included. According to the OCSP were identified: 40% TACS, 37% PACS, 10% LACS and 13% POCS. 50% with acute vascular injury visible on the initial CT Scan performed with 7 hours of evolution in median. All patients underwent EEG with a median of 3 days of evolution, and slow focal activity was observed in all patients, and focal paroxysmal activity (PA) was seen in 17% of the participants. 17 patients (58% of patients) developed post-stroke epilepsy (PSE) with 4 of these having PA evidence in the initial EEG (24%). One of the patients with PA in the initial EEG did not develop epilepsy during a 4 years follow-up period. In patients without PA, the average of mRs at follow-up was 3.8 and the mortality was 24%, whereas in patients with PA, the mean of the mRs was 5.0 and the mortality was 40%.
Conclusion: In this study, unlike CT Scan, the acute-phase EEG presented with abnormal features in all patients with acute stroke, therefore the EEG may potentially provide significant diagnostic information, estimates of risk for developing future epilepsy and also overall risk stratification. Further studies are needed to validate this hypothesis.
Keywords: Eletroencephalogram; Stroke; Epilepsy; CT scan