[Eeglablist] ERP analyses across groups with different latencies

Mate Gyurkovics mgyurkovics1 at sheffield.ac.uk
Wed Mar 20 05:25:38 PDT 2019

Hi all,

I am looking for "best practice" suggestions on how to deal with analyzing
group differences in component magnitude when the two groups have different
latencies and probably different latency jitter.

I have EEG data from two age groups (kids and adults), and I would like to
look at the magnitude of the frontocentral N2 component across the two
groups. I have a within-subject condition (conflict vs. no conflict trial)
too, so what I'm mostly interested in is a Trial Type by Age Group
interaction. I was originally planning on using mean amplitude but I ran
into a problem, namely that the latency of the component is different
between the two groups, so using the same time window to capture the N2 in
mean amplitude in both groups seems difficult or impossible because if the
window is broad enough to capture the wider peak of the younger group, it's
too wide for the adults, and if it suits the adults, it's too narrow for
the kids. I am reluctant to switch to peak amplitude because trial numbers
are slightly different across conditions thus noise level differs too.

One option I considered is to create multiple shorter time windows and get
the mean from each of those, and then add "Time" as a variable to my
analyses, however the choice of time window lengths and number of time
windows feels very arbitrary. I was also considering using an adaptive mean
approach as that hopefully would be more robust to slight differences in
noise level than a simple peak amplitude measure, but I'm not sure. What do
you think? Any suggestions are welcome.

Thank you.

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