An efficient method for quantifying the multichannel EEG spatial-temporal complexity

The complexity index (δ) quantifies the intrinsic dimensionality of the global complexity of a point set, and was shown to be able to characterize electroencephalogram spatial-temporal features. The complexity index is conceptually comprehensible and easily implemented, yet, it is time consuming. Here, the authors present an efficient computational method based an the projection of the high-dimensional state-space points onto a one dimensional axis. The computational time decreases by at least 50%, without affecting the measure accuracy.