A comparison of univariate, vector, bilinear autoregressive, and band power features for brain–computer interfacesReport as inadecuate

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Medical and Biological Engineering and Computing

, Volume 49, Issue 11, pp 1337–1346

First Online: 25 September 2011Received: 04 March 2011Accepted: 08 September 2011


Selecting suitable feature types is crucial to obtain good overall brain–computer interface performance. Popular feature types include logarithmic band power logBP, autoregressive AR parameters, time-domain parameters, and wavelet-based methods. In this study, we focused on different variants of AR models and compare performance with logBP features. In particular, we analyzed univariate, vector, and bilinear AR models. We used four-class motor imagery data from nine healthy users over two sessions. We used the first session to optimize parameters such as model order and frequency bands. We then evaluated optimized feature extraction methods on the unseen second session. We found that band power yields significantly higher classification accuracies than AR methods. However, we did not update the bias of the classifiers for the second session in our analysis procedure. When updating the bias at the beginning of a new session, we found no significant differences between all methods anymore. Furthermore, our results indicate that subject-specific optimization is not better than globally optimized parameters. The comparison within the AR methods showed that the vector model is significantly better than both univariate and bilinear variants. Finally, adding the prediction error variance to the feature space significantly improved classification results.

KeywordsBrain–computer interface Autoregressive model Logarithmic band power Feature extraction Motor imagery  Download fulltext PDF

Author: Clemens Brunner - Martin Billinger - Carmen Vidaurre - Christa Neuper

Source: https://link.springer.com/

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