A High Density EEG Comparison of Sleep Patterns in Insomnia

Recent advances in electroencephalographic recording techniques have produced new ways to probe the process and function of sleep. Through the use of high-density EEG (hdEEG, up to 256 channels), it is possible to approach the spatial resolution of other brain imaging modalities while affording the millisecond temporal resolution of EEG and providing a direct measure of the underlying brain activity, unlike the indirect and/or secondary biophysical signals of brain hemodynamics/metabolism obtained with PET or SPECT that are suboptimal for exploring the short-lived spatio-temporal dynamics of many brain processes. Here we used hdEEG to try to characterize topographic changes in sleep EEG expression in individuals with insomnia compared to normal controls. We further used serial awakenings to determine if individuals with insomnia were more likely to subjectively report being awake when they were sleeping, and study instances where a direct confirmation of sleep was followed by a subjective report of wakefulness to see if they are characterized by changes in EEG oscillations.