Abstract

EEG interpretation: common problems

Author(s): William O Tatum*

An EEG that contains epileptiform discharges has a high specificity in supporting the clinical diagnosis of epilepsy. The ability to correctly identify and distinguish a pathological epileptiform discharge is a skill based upon the subjective and qualitative nature of EEG. There are common pitfalls that exist when interpreting the EEG. Physiological aspects noted during drowsiness, normal variants and artifact can mimic interictal epileptiform activity and challenge the EEG interpreter. A clinician that lacks exposure to EEG during residency training or interprets with a known clinical bias is at risk for overinterpreting the EEG. The ramifications of this may be enormous. The incorrect identification of interictal epileptiform activity may lead to a misdiagnosis of epilepsy and subsequently to the risks of antiepileptic drug treatment. Recognizing and understanding the common traps and pitfalls associated with misinterpretation will underscore the importance of a conservative approach to reading EEG and serve as a means of reducing error that may impair correct interpretation.