EEG alpha power and intelligence

The hypothesis was tested whether alpha power in different subbands (lower-1, lower-2, and upper alpha) is selectively related to intelligence. For 74 subjects, the EEG was recorded during a resting session. Two different intelligence tests (LGT-3 and IST-70) were performed. We found a strong positive correlation between intelligence and alpha power. Large differences between the two intelligence tests and alpha power subbands were obtained. Whereas the upper alpha band shows the strongest correlation with the IST-70, power in the two lower alpha bands tend to show a more consistent relationship with the LGT-3. Considering the fact that the IST-70 has a strong emphasis on semantic memory demands, whereas the LGT-3 focuses more on the ability to learn new material, we conclude that upper alpha is related to the ability to process semantic information, whereas the two lower alpha bands are associated with attentional demands that dominate during the encoding of new information.