Detection of TAAs and extracting the features of a TAA group.
(A) For each channel, we calculate the normalized log-power in the θ − α band and determine the period of growth (in blue) from the baseline to full seizure activity. We then test if the growth is roughly close to linear (R2 > 0.75). If so, we check whether the largest peak of the normalized spectral density lies in the θ − α band and whether all other peaks are its harmonics. (B) When the TAA pattern is detected on four or more consecutive contacts on a single electrode, three features are extracted: the slope and coefficient of determination of the TAA onsets (in red) and average duration of the TAA patterns (in blue). The figure shows an example on five contacts of the electrode TB’ implanted in the left temporo-basal cortex. (C) In the TAA interval, the principal component analysis of the SEEG signals is done to extract two more features: the variance explained by the first one and first two components.
