Long-term stability of frontal electroencephalogram alpha power and asymmetry at rest in adults born at extremely low or normal birth weight: A 10-year longitudinal study.

The idea that individual differences in resting frontal EEG alpha activity have "trait-like" features that are associated with stress vulnerabilities presumes that these physiological patterns should be stable across time. We know, however, relatively little regarding the very long-term (i.e., ≥10 years) stability of resting frontal EEG alpha power and asymmetry in typically or atypically developing populations. Here, we examined the long-term stability of regional electroencephalogram (EEG) alpha (8-13 Hz) power and asymmetry at rest across a decade in the oldest known prospectively followed cohort of extremely low birth weight (ELBW; <1000 g) adult survivors and normal birth weight (NBW; >2500 g) controls. Regional EEG was collected at rest from the left and right frontal (F3, F4) and parietal (P3, P4) scalp sites using a stretchable cap during baseline eyes-open and eyes-closed conditions in young adulthood (ages 21-25 years) and again in adulthood (ages 30-35 years). We found moderate stability in regional EEG absolute alpha spectral power measures across all scalp sites for each birth weight group between the young adulthood and adulthood assessments. As well, we found the frontal alpha asymmetry measure was stable, albeit weakly, between the two assessment periods only in the NBW group. However, parietal alpha asymmetry was weak-to-moderately stable for each birth weight group across the 10-year period. Findings are discussed in terms of their implications for understanding associations between individual differences in frontal and parietal brain activity at rest and long-term stress vulnerability in typical and atypical development.