Fluid intelligence, memory and blood pressure in cognitive aging

Predictors of performance on Ravenʹs Progressive Matrices (RPM) and Wechsler Logical Memory (LM) were examined in a longitudinal study of initially healthy old people in the HOPE (Healthy Old People in Edinburgh) study. In total, 387 subjects were tested twice, first (wave 1) when their mean age was 75.1 years and again (wave 2) when the mean age was 79.3 years. Multivariate regression models were constructed for all subjects and for only those subjects who remained healthy over the four year gap between the test sessions (n = 195). RPM and LM were significantly correlated (r = 0.44, P< 0.001). Demographic, premorbid intelligence and blood pressure data collected at wave 1 accounted for up to 39% of the reliable variance in RPM at wave 2, but only 12% of LM variance. Blood pressure was related prospectively to fluid intelligence but not memory differences. It is suggested: 1. (i) that the concept of fluid intelligence might be given more emphasis in studies of cognitive aging2. (ii) that there are likely to be individual differences in brain reserve capacity for different mental abilities.