Theta power is reduced in healthy cognitive aging

The effects of healthy cognitive aging on electroencephalographic (EEG) theta (4.9–6.8 Hz) power were examined during performance of a modified Sternberg, S., 1966. High-speed scanning in human memory. Science 153, 652–654.) word recognition task. In a sample of fourteen young (mean age 21.9 years, range = 18–27) and fourteen older (mean age 68.4 years, range = 60–80) participants, theta power was found to be significantly lower in older adults during both the retention and recognition intervals. This theta power difference was greatest at the fronto-central midline electrode and occurred in parallel with a small, non-significant decrease in recognition accuracy in the older sample. A significant decrease in older adults' mean theta power was also observed in resting EEG, however, it was of substantially smaller magnitude than the task-related theta difference. It is proposed that a neurophysiological measure(s), such as task-specific frontal midline theta (fmθ) power, may be a more sensitive marker of cognitive aging than task performance measures. Furthermore, as recent research indicates that fmθ is generated primarily in the anterior cingulate cortex, the current findings support evidence that the function of brain networks incorporating this structure may be affected in cognitive aging.