Loef EEG Setup

Setup for EEG at Loeffler

Notes:

• CMS and DRL are ground. If they're not conductive, will get bad signal everywhere

• over 40 bad!

From Smith 2025-03-25 (correspondence with NR) with emphasis added

Unplugging, turning off, and turning back on cannot fix the CM out of range problem. Handling the cables may affect whether a partially broken cable works or does not. When you perform a bucket test, it is important to manipulate the cables, especially near the electrode end and the cable end, to see if manipulating these weak areas reveals an intermittent fault. Also, as time passes, gel may make its way from on top of the hair to the scalp at the critical CMS and DRL sites. Contact quality tends to improve with time as gel gets down to the scalp, but also as it wets the skin. With a participant who has very dry skin on the scalp, you might see a flashing blue light simply because of insufficient contact quality at CMS and DRL.
When the blue light flashes with electrodes connected, unplug everything but CMS/DRL at the AD box to see if the problem persists with only those electrodes. If so, either CMS or DRL is broken or one or both lacks the quality of contact needed for the system to operate.

If a faulty electrode is connected to the system but not touching the body, the blue CM in Range light could be on if everything else was connected well. I am actually not certain whether a faulty EXG electrode being connected to the system but not the body would cause the CM in Range light to flicker. But, when that faulty electrode is connected to the body, it would cause the CM in Range light to flicker if it was already burning solid blue. If the CM in Range light was not already burning solid blue, then there could be a different reason, namely whether CMS and DRL were well connected to the body..