[Eeglablist] Subjects' sitting position and muscle-related noise

[Rotem Krispil]

Dear list members,

During data collection I help subjects find an optimal sitting position, so
that they will not tense their face, jaw, shoulder or neck muscles, which
would otherwise cause artifacts in the EEG signal. However, there are too
many variables for me to get a good understanding of what matters more for
muscle noise and what less: I can change the height of the chair, table,
and chinrest, plus guide subjects to sit in one way or another. Even when
certain actions will clearly help, it is difficult to guide subjects to
perform them, like relaxing one's jaw muscles. Some subjects seem to
understand how to do that, and some remain confused, tense, and their EEG
noisy.

Any of you have recommendations or tips picked up over time, and would be
kind enough to share them? For example, is there an optimal chair height?
Should subjects sit with their entire weight on the chinrest, or put only
some weight on it? What can help with frontal muscle noise, when subjects'
forehead is not tense, and they are not tired?

Thank you very much,
Rotem