Clinical and EEG features of ischemic stroke patients with abnormal discharges

Abstract

Objective To investigate the clinical and EEG features of ischemic stroke patients with abnormal discharges.  Methods Clinical data and 24-hour EEG monitoring of 162 ischemic stroke patients were analyzed retrospectively. One-year follow-up was carried out and post-ischemic epilepsy was diagnosed.  Results Among 162 ischemic stroke patients, 24-hour EEG was abnormal in 87 cases (53.70%). According to the correspondence of site of infarcts and abnormal discharges, these 87 cases were classified into 2 groups: matched group (N = 24, 27.59%) and unmatched group (N = 63, 72.41%). There was no significant difference between 2 groups in terms of Oxfordshire Community Stroke Project (OCSP) and TOAST classification (P = 0.792, 0.111), while there was significant difference between 2 groups on the site of infarcts (P = 0.000). In matched group, the infarcts were mainly located in cortex (N = 23, 95.83%). However, in unmatched group, the infarcts were mainly located in cortex and basal ganglia (N = 27, 42.86%), or in basal ganglia only (N = 24, 38.10%). In matched group, 24-hour EEG showed slowing of background activities, and sharp waves and sharp and slow wave complex which were corresponding to the infarct sites. The abnormal discharges could only be recorded around the infarct unilaterally. In unmatched group, the epileptiform discharges were recorded in both contralateral and ipsilateral ischemic hemispheres, usually with widespread slow waves and asymmetric background. The infarcts were limited, but abnormal discharges were widespread. For example, the infarct was located in deep brain, while scalp abnormal discharges were recorded. Although there was no significant difference in terms of epilepsy incidence between 2 groups (P = 0.908), the types of epilepsy were statistically different between 2 groups (P = 0.000). In matched group, the main type was partial seizure. But in unmatched group, the main types of epilepsy were secondary generalized seizure and generalized seizure.  Conclusions Infract site has an influence on the abnormal EEG pattern, and the unmatched location of ischemic region and abnormal EEG may be indicative for the seizure type of post-ischemic epilepsy.

DOI: 10.3969/j.issn.1672-6731.2016.05.008