Abstract
**Electroencephalography (EEG)** is a technique for recording the brain's electrical activity using a system of electrodes placed on the scalp according to a specific arrangement. The recorded brain wave activity represents the summation of excitatory and inhibitory postsynaptic potentials. The acquired signals are amplified and encoded into various waveforms displayed on the monitor. Additional channels such as electrocardiography (ECG), electromyography (EMG), respiratory monitoring, and simultaneous video recording during EEG acquisition can provide supplementary information to support diagnosis. Each recorded electrical activity must be described in detail with respect to its characteristics, including frequency, amplitude, morphology, quantity, distribution, symmetry, synchrony, pattern of occurrence (rhythmic, periodic, or continuous), evolution into a seizure pattern, responsiveness to activation procedures, and the context of occurrence (spontaneous or induced, during wakefulness or sleep), in order to determine whether the observed activity represents normal brain activity, abnormal activity, an uncommon pattern, or merely an artifact. To better analyze the characteristics of the electrical activity, during interpretation the electroencephalographer may adjust parameters such as sensitivity, high-frequency filter, low-frequency filter, and paper speed, as well as switch between different montages. The EEG report generally consists of three parts: general information, description of the recording, and interpretation of results. The first section covers general patient information, clinical indication, technical details of the recording, and the patient's state of alertness. The next section provides a detailed description of the recording, including background activity, interictal abnormalities, ictal abnormalities, any artifacts noted, and responsiveness to activation procedures. This is the most important part of the report and should be expressed using specific, clear terminology to provide objective information, facilitating re-review of the EEG at a later time or interpretation by another physician. Finally, the EEG findings are briefly summarized to indicate whether the recording is normal or abnormal, along with a list of specific abnormalities, before correlating these findings with the patient's clinical features to reach a conclusion. The conclusion should be expressed as clearly as possible and should attempt to specifically address the clinical question posed.
