Eighteen older adults and 18 younger adults were compared on two quantitative measures describing changes over time in the spatial distribution of running EEG. EEG was collected from 128 electrodes under resting eyes-open and eyes-closed conditions and during performance of a 13 minute sustained attention task. One EEG measure, the recrudescence rate, represented the number of changes in the location of the highest squared voltage per second. A second EEG measure consisted of the algorithmic complexity of changes in the location of the highest squared voltage over time. Regardless of the task condition, older adults had significantly higher scores than younger adults on both the recrudescence rate and the measure of algorithmic complexity. The implications of the results for neurologically-based theories of performance declines in older adults are discussed.