[R] ERP software

[Mark M. Span]

----- Original Message -----
From: "Bill Simpson" <wsi at gcal.ac.uk>
To: "Mark M. Span" <span at psy.uva.nl>
Sent: Thursday, July 05, 2001 4:02 PM
Subject: Re: [R] ERP software


> No I haven't written any package to do EEG analysis. However I just
> started some expts with a colleague who uses Matlab for analysis. I will
> probably convert some of these into R so I can fool around with the data.
>
> I know that you can use Matlab to read the incoming data (from
> the A/D board) directly in realtime. Is that what R-streams is for??
> It would be handy to be able to use R both for the data collection phase
> and for the data analysis phase.
>
Rstreams reads in binary data (in the non-text meaning of binary). I guess
most of us (???) have dedicated software for data collection though..
We use a dataformat that is simple: all the data are written as two-byte
integers, channelwise.

reading in the data for analysis is a simple

 s <- openstream("U:/d1x001.eeg", "read")
 dat<-matrix(readint(s, n=33*3000000, size = 2, signed = F, swapbytes =
FALSE), ncol=33, byrow=T)   # for 33 channel eeg, 3000000 datapoints (R
complaints about memory here)
 closestream(s)
 plot(dat[1:1000,31])  # plot the 31'th channel

The additional software would then cut up the matrix into (a list) of
trials...

almost looks too easy doesn't it...
> Cheers,
> Bill



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