PREDICTING EPISODIC MEMORY PERFORMANCE OF VERY OLD MEN AND WOMEN - CONTRIBUTIONS FROM AGE, DEPRESSION, ACTIVITY, COGNITIVE-ABILITY, AND SPEED

Regression models were developed to explain age-related and total vari ance in memory and to determine the independent contribution from gene ral processing speed, having taken into account cognitive and noncogni tive individual differences. Episodic memory was assessed for 3 tasks in a population-based sample of 951 adults comprising 515 men and 436 women (aged 70-96, M = 77.6, SD = 5.5). Correlations between age and m emory accounted for 6%-9% of the variance, Hierarchical multiple regre ssions showed a reduction in this age-related variance by up to 94%, a fter entering gender, depression, health, cognitive status, activities , and speed. General processing speed was the major mediator of age-re lated variance in memory. Although both the age-related variance and t he speed-related variance in memory were significantly reduced by prio r entry of ether individual differences variables for all 3 tasks, spe ed remained a significant mediator of remembering, and negligible diff erences in the residual age-related variance were observed by inclusio n of other background variables.