EEG Overview & Refresher

Electroencephalography (EEG) remains one of the most widely used—and most frequently misunderstood—diagnostic tools in neurology. While EEG can provide critical insights into cerebral function, seizure risk, and encephalopathy, misinterpretation and over-reading continue to contribute to diagnostic error, unnecessary treatment, and patient anxiety. An effective EEG reader must balance pattern recognition with clinical judgment, understanding not only what abnormalities look like but also when findings are clinically meaningful.

This CME activity provides a high-yield overview and refresher to reinforce foundational EEG principles for practicing clinicians. Participants will revisit essential concepts, including electrode placement, montages, waveform morphology, frequency bands, and normal variants that are commonly mistaken for pathology. The course emphasizes a systematic, conservative approach to EEG interpretation—encouraging clinicians to recognize artifacts, benign patterns, and age-related changes before labeling findings as epileptiform.

The activity also reviews EEG findings associated with typical clinical scenarios such as diffuse encephalopathy, focal cerebral dysfunction, and seizure disorders. Through practical examples, learners will understand how EEG should be integrated with history, examination, and imaging rather than interpreted in isolation. Special attention is given to avoiding overdiagnosis of epilepsy, recognizing nonspecific slowing, and appreciating the limitations of EEG in both outpatient and inpatient settings.

By the end of this refresher, participants will be better equipped to interpret EEG reports, communicate findings accurately with patients and colleagues, and apply EEG data appropriately in clinical decision-making.

Educational Objectives

After completing this activity, learners will be able to:

• Describe fundamental EEG principles, including waveform characteristics, electrode placement, and montage selection.
• Differentiate normal EEG patterns, normal variants, and everyday artifacts from epileptiform abnormalities.
• Recognize EEG patterns associated with encephalopathy, focal cerebral dysfunction, and seizure risk.
• Apply a structured, conservative approach to EEG interpretation to reduce over-reading and misdiagnosis.

Who Should Do This Course?

• Clinicians who routinely order or review EEGs and want a structured refresher on interpretation.
• Neurologists seeking to reduce EEG over-reading and improve diagnostic accuracy.
• Providers managing patients with seizures, altered mental status, or suspected encephalopathy.
• Trainees preparing for neurology, epilepsy, or clinical neurophysiology examinations.
• Healthcare professionals are aiming to integrate EEG findings more effectively with the clinical context.

Did You Know?

• Routine EEG has limited sensitivity, detecting interictal epileptiform discharges in only about 30–50% of patients with epilepsy after a single study. (Epilepsia. 2017)
• Overinterpretation of EEG is a major contributor to epilepsy misdiagnosis, accounting for up to 20–30% of incorrect epilepsy diagnoses in referral centers. (Neurology. 2018)
• Diffuse background slowing on EEG is a nonspecific finding most commonly associated with metabolic or toxic encephalopathy rather than epilepsy. (Clin Neurophysiol. 2020)
• Normal variants such as wicket spikes and small sharp spikes can closely mimic epileptiform activity but have no pathological significance. (J Clin Neurophysiol. 2019)
• EEG should always be interpreted in a clinical context, as normal EEGs do not exclude epilepsy and abnormal EEGs do not confirm it in isolation. (Lancet Neurol. 2016)

The estimated time to complete this activity is 0.75 hour.