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phase reversal
EEG phenomenon where waveforms change polarity across adjacent electrodes, indicating the location of electrical activity source.
Full Definition
Phase reversal is a key concept in EEG interpretation where electrical waveforms appear inverted or opposite in polarity when comparing adjacent electrode positions. This phenomenon occurs when the recording electrodes are positioned on opposite sides of an electrical dipole source in the brain. Phase reversals are crucial for localizing abnormal electrical activity, such as epileptiform discharges, and are fundamental to understanding EEG montage interpretation and source localization.
Usage
Usage note: Essential concept for accurate EEG localization and interpretation.
In Context
- "The sharp wave showed clear phase reversal at electrode F4, indicating a right frontal focus." — EEG interpretation report
- "Phase reversal analysis confirmed the seizure onset zone in the left temporal region." — Epilepsy evaluation
Also known as
polarity inversion
dipole localization
Contrasted with
phase synchrony
in-phase activity
Don't confuse with
phase lag
amplitude reversal