Our analyses revealed that the interaction between age and slow wave power at temporal and central regions was a significant predictor of performance in the Trail Making Test. The presence of a significant interaction suggests that the effects of power on performance are conditional on the participants' age. Figure 3 illustrates the nature of this relation: scatterplots are presented, depicting associations between cognitive performance and spectral power separately for “younger” (<55 years old, n = 26) and “older” (n = 27) participants (based on a median split).
