Adding markers to AEP waveforms?

Discussions
1

Hi there BST community,

I think this will be more of a "request" post rather than a general discussion post but I will categorise it as a general discussion in case anyone in the community has any ideas.

Right now I am trying to determine the peaks and troughs of auditory evoked potentials (AEPs); cortical auditory evoked potentials (CAEPS) and auditory brainstem responses (ABRs).

I used to use BioSigRZ software (a TDT software) to do this where I open up an ABR trace, double click on a particular location on the waveform to add a marker, and export the ABR trace with the markers in an Excel form from BioSigRZ. The exported Excel file will have the ABR trace in the time domain as well as the latency and voltage value of the markers so that calculations of amplitudes and latencies of the ABR waves can be easy.

The below diagram shows an example of that showing several ABR traces with markers on their peaks and troughs.

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My question is, can something similar be done within Brainstorm and if not, is it possible to add this as a feature?

Right now I am selecting a portion of the ABR trace to include the peak and trough (seen below) and manually typing the values down in an Excel file which I deem inefficient.

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2

Hi @mcp0228,

There are event markers in Brainstorm, they can be set by placing the cursor and pressing the key E
https://neuroimage.usc.edu/brainstorm/Tutorials/EventMarkers

AFAIK, there is not a way in the GUI to export the recordings values at given markers.
Once the markers are placed, two potential ways to get the signals values at those points could be:

  1. Export the signals as (timeseries in xls file), then export the marker locations (exported as number of sample), get the value from the exported signals

  2. With a Matlab script: get the events in a file, use that information to index the signals, and save the signal values at the event locations

Best,
Raymundo

3

Thanks for that Raymundo - is this something that I can kindly request the BST team to implement?

4

@Raymundo.Cassani @Francois ?

5

Hi @mcp0228,

I think a good approach for this would be to have a process to extract the signals values at a given event, then the user will be able to export them to Matlab, Excel, etc. Something similar to the process Extract > Extract values

What do you think?

6

Hi @Raymundo.Cassani

That sounds good to me.

  1. If by extracting the event markers you can extract BOTH the time and voltage values that would be ideal.
  2. It would also be great to extract the signal values (time and voltage) between two event markers. As in this example (event window)

Thanks.

7

Hi @Raymundo.Cassani any updates on this?