Which of the following are the recommended impedance levels for the EEG electrodes?

Which of the following are the recommended impedance levels for the EEG electrodes?

• A. Less than 20,000 ohms
• B. Less than 5 ohms
• C. Less then 5k ohms
• D. At least 20,000 ohms

Answer: (C)

Low electrode impedance is crucial for clean EEG recordings because the signals are extremely small and any impedance at the electrode–skin interface adds noise and can mask neural activity. Keeping impedance under 5 kΩ provides a good, stable electrical contact with minimal noise, allowing the amplifier to accurately capture the brain signal. Impedance higher than this—tens of kilo-ohms or more—introduces more noise, artifacts, and baseline drift, degrading data quality. Therefore, the recommended impedance level is less than 5 kΩ.

Low electrode impedance is crucial for clean EEG recordings because the signals are extremely small and any impedance at the electrode–skin interface adds noise and can mask neural activity. Keeping impedance under 5 kΩ provides a good, stable electrical contact with minimal noise, allowing the amplifier to accurately capture the brain signal. Impedance higher than this—tens of kilo-ohms or more—introduces more noise, artifacts, and baseline drift, degrading data quality. Therefore, the recommended impedance level is less than 5 kΩ.