Aim of this preliminary study was to examine and compare topographic distribution of
Higuchi's fractal dimension (FD, measure of signal complexity) of EEG signals between
states of relaxed wakefulness and drowsiness, as well as their FD differences. The
experiments were performed on 10 healthy individuals using a fourteen-channel montage.
An explanation is offered on the causes of the detected FD changes. FD values of 60s
records belonging to wake (Hori's stage 1) and drowsy (Hori's stages 2–4) states were …