Overnight recordings of sleep EEG contained standard polysomnographic
channels, 21 channels of EEG according to the 10-20 standard (see
Table 2) and A1 and A2 derivations (ears). Silver
electrodes were applied with collodion. Maximal accepted resistance
was less than 5 Kohms. 12 bit analog-digital converter was used and
conversion rate was 128 Hz (in some cases 102.4 Hz). Results
described below were obtained from recordings of second nights of
healthy volunteers, usually about 7 hours of EEG. Analysis was
performed on signals referenced to the A1/A2 electrodes (linked ears).
Subsequent segments of 20s length were subjected to MP decomposition.
Table 2:
Relative positions--and names--of electrodes in 10-20 system,
front of head towards the top of page
