Loading in an EEG file

Hi all,

I'm an absolute noob to Matlab, and I have a few files that I wish to look at which my local hospital has given me for an EEG they performed. They gave me files with the following file extensions: - eeg - ent - erd - epo - etc - snc - stc

I tried loading in the .eeg file using EEGLAB but it just blew up with the following error:

", 0: baseline: 8236  sensitivity: 4261158260372115100000000000000.000000  calibration: 250017424.000000
In an assignment  A(:) = B, the number of elements in A and B must be the same.

Error in loadeeg (line 145)
  calib(elec) = fread(fid, 1, 'float32');

Anyone have any idea what I can do?...

Thanks

[Star Strider]

This is what I would do:

Step #1: Find out what software created them.

Step #2: Look up that software on the Web and find out what the formats are, how to read them, and if the data you want can be saved to .mat files or some other format you can read.

[Suzan Aydin]

I think it must be Natus Xltek produced data. But there is no way to convert .erd or .eeg generated from the Neuroworks Xltek software to .mat, unless they convert it to .edf format then maybe convert to .mat somehow? Sounds like a whole load of faff tbh...

[Star Strider]

I share your frustration. See if the Neuroworks software can write it in a format that EEGLAB can read. At the very worst, see if you can write it to a spreadsheet format such as Excel. (When I worked with EEGs many years ago, the data were saved to text files.)

[Walter Roberson]

It looks like you might be trying to read a text file as if it is binary ?

Answer 1

[moez bechir]

hello do you have answer for this? [e-mail]

Answer 2

[Melinna]

Hi, I have confronted the same problems just as you described above, maybe a little bit better, because i was able to convert the data to EDF+ format, so it can be read in eeglab. However, another problem occurred that the EDF+ doesn't contain the event type, which makes it difficult for further analysis.

I was wondering whether the event information was stored in other file, such as in the .ent file. Could you tell us how you parse the data? Your reply is of great value. Thanks a lot.

Answer 3

[Melinna]

I have spent so much time on this problem, and my solution is that giving up to parse the raw data (mentioned above) but use the software named Natus Database to export the raw data as .edf format, so you can process it in eeglab or other software.

You can get access to the Natus Database software just on the computer where you copy the raw data.

[Xinyi Wang]

hello,I have tried your method,but there are some problems.If the software you use is EEG Viewer?if you download this from ..as follows?

Im not sure is it right?if not,could you offer a link to download the natus software,I will appreciate it very much~

Answer 4

[Diana]

If you are using Natus, then export as an .EDF file and you can use either of these functions to read your files.

https://www.mathworks.com/matlabcentral/fileexchange/42784-blockedfload

https://www.mathworks.com/help/signal/ref/edfread.html

.EDF does not contain the time markers but .EDF+ does. However, when natus export you do not get to choose between .EDF/EDF+. So, you can go to your original file, open it, right click on the notes, then export to text. Now you have a text file with all the information you need from the EEG.