electrode impedance
The electrical resistance between an electrode and the scalp, measured to ensure optimal signal quality in EEG recordings.
Full Definition
Electrode impedance refers to the opposition to electrical current flow between an EEG electrode and the patient's scalp. Measured in ohms, impedance values must typically be below 5,000 ohms (5 kΩ) for diagnostic EEG studies and below 10,000 ohms for routine monitoring. High impedance can result from poor skin preparation, inadequate electrode gel application, or loose electrode contacts, leading to artifacts and reduced signal quality. Impedance checking is a critical quality control step performed before and during EEG recordings.
Usage
Usage note: Always express impedance values with appropriate units (ohms or kΩ) for clarity.
In Context
- "Electrode impedance values exceeded 10 kΩ on the frontal leads, requiring skin preparation to be repeated." — Technical quality report
- "The technologist verified that all electrode impedance measurements were within acceptable limits before starting the recording." — Procedure documentation