What are common hardware setup mistakes that lead to signal problems?
Signal quality problems during an EEG recording are often caused by incorrect connections, poor electrode contact, device interference, reference electrode issues, or patient movement. Identifying and correcting these issues can help restore stable EEG recordings.
Common Hardware Setup Mistakes
Poor Electrode Contact
- Electrodes are not properly prepared or attached to the scalp or skin.
- Poor electrode contact can result in high artifacts and low signal quality indicators.
Loose or Incorrect Cable Connections
- Electrode cables are not firmly connected to the snap connectors.
- Connectors are partially attached or move during the session.
- Unstable connections can cause intermittent signal loss or increased noise.
Damaged or Stressed Cables
- Cables are bent, kinked, or previously pulled.
- Cable damage is not visible but affects signal stability.
- Improper cable handling can degrade EEG signal quality.
Incorrect Amplifier Handling
- The SAM amplifier is not fully powered on or not properly connected.
- The amplifier is placed in an unstable position during recording.
- Incorrect amplifier setup can prevent stable signal transmission.
Environmental Interference
- Cables are routed close to power supplies or other electronic devices.
- The setup is exposed to sources of electromagnetic interference.
- Such conditions can increase noise and artifacts in the EEG signal.
Patient Movement
Movement can change electrode contact and introduce artifacts into the EEG signal.
Common examples include:
- Head movement.
- Shifting position in the chair.
- Sudden body movements.
- Excessive facial or jaw movement.
To reduce movement-related artifacts:
- Ensure the patient is seated comfortably.
- Encourage the patient to remain relaxed and still throughout the recording.
- Minimize unnecessary head and body movement.
Notes and Limitations
- Signal problems may also be caused by user movement or insufficient preparation, not only hardware setup.
- Always check electrode placement and signal quality indicators before starting a session.