Age trends in the sleep EEG of healthy older men and women.

The all-night sleep EEGs of 314 (191 women, 123 men) healthy older subjects between the ages of 45 and 90 were studied for age trends in the power spectra of the all-night NREM sleep EEG. Power spectra of the unnormalized EEG of the women show a power loss in the delta band and a power increase in the beta band with increasing age. For the men no significant trends in the power spectra of the unnormalized EEG were in evidence. A normalization of the power spectra was performed by referencing each logarithmically expressed spectra to its area between 2 Hz and 30 Hz. For both genders the normalized spectra show significant decreases in power at many frequencies below 16 Hz and significant increases in power at frequencies above 18 Hz with increasing age. The age trends observed in the spectra of this population (45-90 y age group) are about a third of the magnitude of those reported in the literature for subjects between the ages of 20 y and 40 y.