Checking Cap Electrodes for Noise

To troubleshoot electrodes, there are three items to check before contacting EGI:

• Visual inspection of the net (are wires broken, electrode caps loose, or sponges torn)
• Seeing evidence of a bad channel in the bucket tests (see below)
• Visual identification of the impact of a bad reference on data quality (impedance checks and observing data)

Performing a bucket test

• Make up a bucket of the electrolyte solution, as if you were making a normal recording.
• Place the net that you wish to test in the solution and soak for 10 minutes. Agitate the net to make sure all the sponges are properly soaked and that all sensors are completely submerged.
• Plug the net into the amplifier.
• Open a simple acquisition setup and turn it on, or start a session template.
• Got to the Panels pull-down menu and select Net Noise. Click on "Measure Net Noise" to check the level of noise on each of the sensors.
• A bad electrode will be consistently out of spec (the green shaded area) within each of the tests.