Concurrent optical and EEG recordings on the human brain during sleep
We report optical measurements aimed at monitoring the variations in the cerebral metabolic activity during whole night sleep in human subjects. The metabolic rate, blood flow, and oxygen consumption are all minimized during deep sleep (stages III and IV), while they are maximal during REM (rapid eye movement) stage. The sleep staging was assessed by EEG (electro-encephalography), EOG (electro-oculography) and EMG (electromyography). The cerebral hemodynamics and oxygenation were measured with an 80 ms temporal resolution using a multi-channel tissue spectrometer. In this talk, we will describe the optical instrumentation, the EEG/optical experimental setup for the sleep study, and the initial results collected on healthy human volunteers.