bucket testing new electrode sets
Posted: Fri Jun 17, 2016 4:08 pm
Hello,
we have just bucket tested our 2 full sets of electrodes for a 64 system.
I am not sure what to expect therefore I calculated few quantities from 5 min of data:
- single-channel histogram: should I expect a Gaussian histogram (white noise?) or something more uniform?
- single-channel PDS: i see very low power with some power line contamination, is this what I should expect in healthy electrodes?
- single-channel mean over time: I would expect a stable mean or slowly changing (in case of drift)?
- single-channel standard deviation over time: I would expect a stable value over time and no sudden changes
Is there any other sensible measure I should include (we would like to define a set of measures to run periodically on the system for maintenance)?
If everything I said above makes sense I have few problems with my electrodes.
FIRST 64 set: the PSD of electrodes bundle 1 doesn't show any power line contamination, while bundle 2 is clearly contaminated. Why differetn bundles in the same conditions show different PSD content? How would this affect my data when half of the electrodes are collected with one bundle and the other half with another bundle? Also some spikes in the standard deviation over time in both bundles. Is this something to expect? Quite strange histogram distributions for both bundles.
SECOND 64 SET: a strangely oscillating PSD in TP8, a noisy electrode and a huge artefact on another one.
Any thoughts?
I have figures and screenshot but I would appreciate some feedback first, so that I could be more specific.
Thank you in advance
Best regards
Sara
we have just bucket tested our 2 full sets of electrodes for a 64 system.
I am not sure what to expect therefore I calculated few quantities from 5 min of data:
- single-channel histogram: should I expect a Gaussian histogram (white noise?) or something more uniform?
- single-channel PDS: i see very low power with some power line contamination, is this what I should expect in healthy electrodes?
- single-channel mean over time: I would expect a stable mean or slowly changing (in case of drift)?
- single-channel standard deviation over time: I would expect a stable value over time and no sudden changes
Is there any other sensible measure I should include (we would like to define a set of measures to run periodically on the system for maintenance)?
If everything I said above makes sense I have few problems with my electrodes.
FIRST 64 set: the PSD of electrodes bundle 1 doesn't show any power line contamination, while bundle 2 is clearly contaminated. Why differetn bundles in the same conditions show different PSD content? How would this affect my data when half of the electrodes are collected with one bundle and the other half with another bundle? Also some spikes in the standard deviation over time in both bundles. Is this something to expect? Quite strange histogram distributions for both bundles.
SECOND 64 SET: a strangely oscillating PSD in TP8, a noisy electrode and a huge artefact on another one.
Any thoughts?
I have figures and screenshot but I would appreciate some feedback first, so that I could be more specific.
Thank you in advance
Best regards
Sara