Wednesday, February 24, 2010

Calibration signal

For those interested,

"The calibration signal is a 14Hz 250uVp-p squarewave, so your signal
is correct. Your Y-axis unit for an eeg signal should be in
microvolts. A typical eeg signal is within 20uVp-p range. (can
actually vary from 0 - 100 uV according to the literature)."

A quote from one of the senior members of openEEG forum

Thursday, February 11, 2010

Cursor control

This cursor control paper looks interested. Note it identifies just c3 and c4 positions (2 electrodes)
EEG-based online two-dimensional cursor control

Dandan Huang; Lin, P.; Ding-Yu Fei; Xuedong Chen; Ou Bai;
Engineering in Medicine and Biology Society, 2009. EMBC 2009. Annual International Conference of the IEEE
3-6 Sept. 2009 Page(s):4547 - 4550
Digital Object Identifier 10.1109/IEMBS.2009.5332722

Abstract
This study aims to explore whether human intentions to move or cease to move right and left hands can provide four spatiotemporal patterns in single-trial non-invasive EEG signals to achieve a two-dimensional cursor control. Subjects performed motor tasks by either physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored to support accurate computer pattern recognition. The performance was evaluated by both offline classification and online two-dimensional cursor control. Event-related desynchronization (ERD) and post-movement event-related synchronization (ERS) were observed on the contralateral hemisphere to the moving hand for both physical movement and motor imagery. The offline classification of four motor tasks provided 10-fold cross-validation accuracy as high as 88% for physical movement and 73% for motor imagery. Subjects participating in experiments with physical movement were able to complete the online game with the average accuracy of 85.5plusmn4.65%; Subjects participating in motor imagery study also completed the game successfully. The proposed brain-computer interface (BCI) provided a new practical multi-dimensional method by noninvasive EEG signal associated with human natural behavior, which does not need long-term training.

I will put the pdf in dropbox.

This is a link to IEEEXPLORE results for a search on "cursor" and "eeg" - there look to be some other interesting papers.