Ictal EEG and its tensor decompositions in patient 3. (a) A segment of the seizure. The whole 10 s window was used to model the spatial spread of the seizure. (b) CPD decomposition of the seizure of patient 3. The first component corresponds to seizure activity, showing a clear right temporal localisation and a 4-Hz oscillatory pattern. (c) CWT-BTD of the seizure. The first block term captures the same seizure source (compare S1a and T1a with S1 and T1), however, also captures a source with the same frequency characteristics located frontally. While T1b increases in amplitude after 900 samples, T1a decreases in amplitude after 700 samples. This can be interpreted as the seizure spreading from the temporal to the frontal region, in accordance with the visual assessment of the ictal EEG pattern.