Visual and computer-assisted assessment of the EEG in epilepsy of late onset

A study was made of 275 patients presenting with suspected epilepsy after the age of 20 years. In 122 it was concluded that the attacks were non-epileptic. In 60 others cerebral pathology was found. If the EEG was visibly abnormal the risk of cerebral pathology was 8 times greater than when the record was normal. The EEGs were also assessed by an automatic pattern recognition technique, which classified them as abnormal by reference to a control population of 300 volunteers. 90% of EEGs from patients with pathology were classified as abnormal and, conversely, 86% of patients with abnormal records (as assessed by the automatic analysis) had pathology.