Summary: It is presumed that the EEG records only cerebral activity. However, frequently it can include other electrical activities, referred to as noise or artifact, which are not of cerebral origin. In the last few decades, evolution in digital technology has greatly improved the ability to record and display interpretable EEG. With the widespread availability of prolonged EEG recording, new artifacts have been described. The addition of concomitant video with audio during recordings has allowed in most instances to determine the source of certain artifacts. One of the challenges of interpreting EEGs consists of identifying artifacts correctly. Some of the EEG artifacts are so distinctive in appearance that the experienced reader can readily identify them. It is not uncommon for normal EEGs to be overinterpreted, especially by inexperienced readers. Failing to identify artifacts correctly can lead to “over reading” a study and doing so can result in misdiagnosis of epilepsy. This in turn can result in inappropriate treatments that ultimately can have serious clinical implications. This review will provide a description of the most commonly encountered artifacts that mimic spike or sharp waves, also referred to as interictal epileptiform discharges. In addition, we will describe troubleshooting approaches to eliminate these artifacts whenever possible. Artifacts that mimic ictal discharges will be reviewed in a different section.

There is concern that bluish skin discoloration associated with ezogabine treatment could be permanent. We present a case of ezogabine-induced skin discoloration that resolved completely after discontinuation. A 55-year-old woman started ezogabine 400 mg three times a day at age 41. Bluish pigmentation over the toe nails, finger nails, around eyes and over and around lips was first noted after 5 years of treatment. Ezogabine was discontinued eight years after initiation. Skin discoloration improved within 6 months and completely resolved within 6 years of discontinuation. This case suggests that ezogabine-induced discoloration is reversible after discontinuation of treatment.