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The electroencephalogram (EEG) is a noninvasive technique for measuring neurophysiological activity. This diagnostic tool provides valuable insights into brain function by detecting electrical activity. The EEG has numerous applications, including differentiating epileptic seizures from nonepileptic events, such as psychogenic nonepileptic seizures, syncope, subcortical movement disorders, and migraine variants. However, a normal EEG does not exclude epilepsy, as its sensitivity for detecting the condition is less than 50%. Additionally, interictal discharges and other abnormalities can occur in healthy individuals. Unnecessary EEG testing may lead to misdiagnosis and inappropriate treatment if findings are not interpreted correctly. This activity for healthcare professionals is designed to enhance learners' proficiency in identifying abnormal EEG waveforms. Participants will deepen their understanding of the differences between ictal and interictal discharges and their significance. This activity will also discuss the indications of this diagnostic modality, including applications beyond epilepsy assessment, such as degenerative disease, infection, cerebrovascular disease, and brain death evaluation, as well as prognostication. Improved skills will enable interprofessional team members to collaborate effectively to optimize health outcomes for individuals monitored by EEG. Objectives: Differentiate nonepileptiform abnormalities from epileptiform discharges noted on electroencephalogram recordings. Identify patients with indications for further diagnostic workup, including neuroimaging and metabolic testing, based on electroencephalogram findings. Evaluate treatment effectiveness or futility using clinical and electroencephalogram findings. Collaborate with other healthcare professionals to manage abnormal electroencephalogram waveforms and coordinate a comprehensive neurologic care plan. Access free multiple choice questions on this topic.

The electroencephalogram (EEG) is a noninvasive technique for measuring neurophysiological activity. This evaluation modality serves as a valuable tool for analyzing the brain's complex functions by detecting electrical activity. EEG signals reflect the brain’s electrical function and are recorded by placing electrodes on the scalp to measure cortical neuron activity.[1] Hans Berger first used EEG in humans in 1924, publishing his findings in 1929. EEG records voltage fluctuations over time from multiple scalp electrodes arranged in a specific pattern to sample different cortical regions. These signals represent fluctuating dendritic potentials from superficial cortical layers, requiring voltage amplification for proper recording. However, extracranial electrodes do not effectively capture deep brain activity. EEG waveforms result from the summation of excitatory (EPSPs) and inhibitory postsynaptic potentials (IPSPs) in cortical neurons. Some benign EEG variants appear normal but may be mistaken for epileptiform activity.[2] Abnormal EEG waveforms include both epileptiform and nonepileptiform abnormalities. Recognizing the differences requires understanding normal EEG patterns across different physiological states in children and adults. Electroencephalographers must also distinguish artifacts from true abnormalities and identify benign variants. This article reviews abnormal EEG waveforms and their clinical significance.

An interprofessional team involving EEG technicians, nurses, and physicians enhances the care of individuals with abnormal EEG findings. Educating healthcare professionals on EEG interpretation and abnormal waveforms is essential for accurate diagnosis and management. Proper training in EEG report analysis supports clinical decision-making and improves patient outcomes. A recent study highlighted the role of abnormal EEG findings in assessing seizure risk in hospitalized patients alongside factors such as age, focal seizures, and low protein levels. EEG may play a crucial role in inpatient evaluation by guiding clinical management and supporting a comprehensive approach to patient care.[70]