BASE-LINE ASYMMETRIES IN BRAIN ELECTRICAL-ACTIVITY PREDICT DICHOTIC-LISTENING PERFORMANCE

Forty-four right-handed participants were assessed on 2 occasions 6 we eks apart on electrophysiological measures of activation asymmetry der ived from spectral estimates of electroencephalogram (EEG) alpha power in homologous scalp electrodes. Approximately 4 months following the final EEG assessment, participants were administered a dichotic listen ing CV-syllables task. Overall, participants exhibited a highly signif icant right-ear advantage. Differences among individuals in ear asymme try were predicted by the earlier recorded electrophysiological data. Participants with greater activation in left-sided posterior temporal and parietal regions showed a larger right-ear advantage. In addition, a larger right-ear advantage was predicted by right-sided prefrontal activation. These data indicate that some of the variance in dichotic listening performance can be explained by dispositional activation asy mmetries and is associated with a complex pattern of posterior and ant erior activation asymmetries.