Brain mapping in comparison to EEG and CT in transient ischemic attacks

ABSTRACT

This study was carried out on 68 patients suffering from TIA either of carotid or vertebro basilar origin with the aim of investigating the role of brain mapping in diagnosis of TIAs. In addition to the clinical assessment, brain mapping was carried out simultaneously with a 16 channel EEG recording, being done within 12 hours from the disappearance of symptoms, or sometimes could be done during the attack. Also, CT was done 48 to 72 hours following the attack. The patients were 47 males and 21 females with age ranged between 42 - 82 years. According to clinical presentation and results of neuro examination, patients could be classified into 2 main groups Patients with TIA of carotid origin [44] and those of TIA affecting VB system [24]. The clinical presentation within each group was rather variable with most of the patients showing combinations of relevant neuro symptoms and signs. CT showed relevant infarctions [mostly lacunar] in 20% of patients, EEG was positive in 57%, while brain mapping gave positive figures in about 85% of patients. The most commonly encountered map findings were decrease in alpha power and increase in the power of delta and theta bands. Also, it could differentiate well between TIAs of carotid origin [main abnormality is asymmetry] and those of VB origin [main abnormality is the increase of power of slow bands posteriorly]. Both EEG and mapping gave higher positive figure with increased duration of the attack