Chapter 9 - Approach to EEG Reading

Summary

Confirm the patient’s identity, age, state(s) of recording, and the presence of any skull defects. Confirm the technical parameters of including the filter settings, sensitivity, paper speed, and time base. Note the montage you are reading in and the calibration signal. Identify the background from the foreground. Describe the background based on symmetry, continuity, voltage, organization, variability-reactivity, and sleep architecture. Categorize the foreground components as cerebral activity or artifact. Describe cerebral activity based on its location (general or lateral), occurrence (sporadic or repetitive), and morphology (slow or sharp). Then categorize the activity as normal (normal variant) or abnormal. Decide if the abnormality is epileptogenic (associated with seizures) or ictal (ongoing seizure). Evolution is the hallmark of electrographic seizure activity. Remember that isolated changes in amplitude are not evolution. Look for the use of any provocation methods, such as hyperventilation and photic stimulation, and their effect on the EEG. Before you finish up, make sure you’ve looked at the single-channel EKG and the technologist’s log.