Some effects of aging on event-related potentials during a linguistic monitoring task.

Two groups of adults, one young and one elderly, were compared on a dichotic task in which continuous speech was monitored for grammatically and semantically anomalous words. Event-related potentials (ERPs) elicited by these anomalies were analyzed in terms of peak amplitude and peak latency of the evoked late-positive component (LPC). Results showed that while LPC peak amplitudes were overall reduced for the group of seniors, LPC peak latencies were similar between both groups of listeners. These findings are consistent with the hypothesis that elderly persons can offset declines in memory, perceptual processes, and speed of mental processing by taking advantage of contextual and prosodic cues in running speech. Additionally, an apparently asymmetric processing negativity was observed in the waveforms of young adults but not seniors. Possible mechanisms include the N400 response to semantic incongruity and a processing negativity component associated with attentional bias toward right hemispace.