How to perform some basic preprocessing on EEG signal and extract important feature using wavelet toolbox?

Hi everyone,

I am a undergraduate student of Electronic Engineer currently working on a project regarding EEG signal analysis. Basically it is to extract feature to tell whether a person is concentrating or not. However, so far in my study I have very little exposure to Matlab and signal analysis.

Thus, I would like to ask anyone who are experienced in this field to enlight me. I had recorded raw signal of data using neurosky mindwave and the data was saved in excel file. The x-axis being the sample and y-axis being the volt.

The following are the problems I am having now :

1. I performed FFT on my data but the transformed data is quite messed up in circular shape. Can anyone share a proper way of performing FFT on EEG signal?

2. Do I need to convert my data to frequency domain before I perform wavelet transform on it?

3. How can I extract feature using wavelet toolbox available in Matlab?

I really hope someone can enlight me and help me through my project. Apart from that, I would like to apologize for my long post. Thank you very much.