Estimation of the Correlation Dimension of All-Night Sleep EEG Data with a Personal Super Computer
Peter Achermann, Rolf Hartmann, A. Gunzinger, W. Guggenbühl, Alexander A. Borbély · Birkhäuser Basel eBooks · 1994
The correlation dimension (CD) is a gauge of the complexity of the recorded signal. An algorithm proposed by ( 1985 ) was implemented on the personal super computer MUSIC (multi processor system with intelligent communication) which allowed to analyze for the first time the data of entire sleep episodes. The all-night sleep EEG of a subject recorded under three different conditions (baseline (BL), sleep in a sitting condition after intake of placebo (PL) or triazolam (TR)) served as the data base. The CD of the EEG was modulated by the sleep cycle. Median values decreased from nonREM (non rapid eye movement) sleep stage 1 to 4. For REM (rapid eye movement) sleep the values were between those of stage 1 and 2. For sleep in a sitting position, the CD in REM sleep (PL and TR) and stage 2 (PL) was increased compared with BL. In stage 4 the CD was lower for TR than for BL and PL, and higher for PL than BL. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.