Techniques for noise removal from EEG, EOG and air flow signals in sleep   patients
  Noise is present in the wide variety of signals obtained from sleep patients. This noise comes from a number of sources, from presence of extraneous signals to adjustments in signal amplification and shot noise in the circuits used for data collection. The noise needs to be removed in order to maximize the information gained about the patient using both manual and automatic analysis of the signals. Here we evaluate a number of new techniques for removal of that noise, and the associated problem of separating the original signal sources. 
Matthew J. Berryman, Sheila Messer, Andrew Allison and Derek Abbott