The effect of aging on movement related cortical potentials during a face naming task

In the present study a face naming reaction time task was employed in order to evaluate the effect of age on performance and on movement related cortical potentials (MRCPs). In addition, the effect of three response categories with different cognitive demands (DON'T KNOW–don't know the name–, KNOW–correct naming– and TOT—tip-of the-tongue state) on performance and on MRCPs in a sample of older adults was evaluated. The same MRCPs found in a previous study in a sample of young adults were identified in older adults. The results indicated that older participants were generally slower at providing responses than young adults, and that both age groups showed longer reaction time in TOT than in DON'T KNOW and KNOW categories. The first component of readiness potential (1st-RP) showed larger amplitude and longer duration in older than in young adults, especially in the TOT category, which would explain the generally slower responses provided by older participants. In addition, in older adults, the 1st-RP was larger in TOT than in the DON'T KNOW category, but a slope reduction and stabilization were observed in TOT from the more demanding stages of stimulus processing. These results may reflect a lengthening in the preparation period in the TOT category, which probably explains the behavioural slowing in this category. The data of the present study suggest differences in the allocation of processing resources between groups, indicating that the sensoriomotor performance should be compromised more in older than in young adults in tasks with high cognitive load.

Research Highlights
► The readiness potential showed longer duration in older than in young adults.
► The longer duration of the preparation period may explain the aging-behavioural slowing.
► Processing resource allocation strategies differed between age groups.
► Aging-related difficulties with conflict management were observed in the TOT category.
► Sensoriomotor performance is compromised more in older than in young adults.