[Eeglablist] EGI Net Station Offset Integration

[Arild Hestvik]

Hi Alyssa, EGI told us in the past that data collected with 250ms sampling
rate on a NetAmps 300 should use an offset value of 8ms, due to Nyquist
anti-aliasing filter.The numbers depended on the specific amp and sampling
rate, ask EGI for specifics! In addition to this comes any delay measured
in the delivery in sound stimuli, adding up to the total offset value you
should use.
-Arild

On Mon, Sep 9, 2024 at 4:01 PM Arnaud Delorme via eeglablist <
eeglablist at sccn.ucsd.edu> wrote:

> Dear Alyssa,
>
> The EGI documentation indicates that the latencies of the data are
> different from the events due to filtering during acquisition.
> In EEGLAB, you can use the following call to adjust the latency of the
> events and realign them with the data.
>
> EEG = pop_adjustevents(EEG);
>
> Best wishes,
>
> Arno
>
> > On Aug 26, 2024, at 06:46, Alyssa Dawne Nicole Janes via eeglablist <
> eeglablist at sccn.ucsd.edu> wrote:
> >
> > Hi all,
> >
> > We are currently trying to re-process some old EGI/Net Station data in
> EEGLab, specifically focusing on averaged AEPs. However, I am encountering
> some challenges with latency alignment that I am hoping to get some advice
> on.
> >
> > The primary issue that I am facing is that the latencies for the AEPs
> seem to be off, and I am unsure whether I should manually account for the
> anti-alias filter delay and the stimulus delay in my data. When I try to
> integrate these offsets, the data shifts accordingly, yet the latencies
> become even more unexpected.
> >
> > I am struggling to pinpoint where the AEPs should be ideally located
> within the average epoch and whether these delays should be integrated, or
> if there might be another factor that I am overlooking?
> >
> > Here are some further specifics:
> >
> >  *
> > The original data was collected using Net Station V4.5.6
> >  *
> > Loaded into EEGLab 2024.0 using MFFMatlabIO5.0 plugin
> >
> > Any guidance or insights greatly appreciated!
> >
> > Thanks,
> > Alyssa
> >
> > Alyssa Janes, MSc (she/her)
> > MClSc/PhD student
> > Health and Rehabilitation Science
> > Autism Spectrum & Language Disorders Lab, Western University
> >
> > Lab webpage:
> https://urldefense.com/v3/__http://www.uwo.ca/fhs/ASLD/__;!!Mih3wA!HMh3qQrhONHPp2edhHXdbGbYYRj_0Qsp0FVa_OiqpOsybGTZHsQny8FEBkfjeWME0nwsH7---BUcVWEbuejhCw$
> <
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> >
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