PREDICTORS OF COGNITIVE FUNCTIONING IN COPD PATIENTS

Abstract

1898 It is well established that there are age-related declines in the cognitive functioning of older adults. A suggested mechanism underlying this effect is a decline in O2 availability to the brain. Presumably maintenance of aerobic fitness may ameliorate these declines. Because of the link to O2 availability, it is interesting to study this relationship in people with chronic obstructive pulmonary disease (COPD). Aerobic fitness (6-min walk, VO2 max test), blood O2 saturation levels, and pulmonary function were assessed in older adults (57-81 yrs) with COPD. Subjects were then randomly assigned to Study 1 ( n=60) or Study 2( n=39). Subjects in Study 1 completed a measure of fluid intelligence, the Culture Fair Intelligence Test (CF). Subjects in Study 2 completed tests of inhibition, processing speed, and memory. Preliminary data on a small subset were presented at ACSM in 1997; however, by doubling sample size, power has increased so that several hypothesized relationships are now interpretable. After controlling for education and depression, F(2,56)=8.85, r2=.21, 6-min walk, F(1,55)=18.63, r2=.19, and age, F(1,54)=8.80, r2=.08, were significant predictors of CF performance. On the speed of processing task, 6-min walk, F(1,32)=8.71, r2=.19, maximum voluntary ventilation, F(1,31)=6.08, r2=.11, and age, F(1,30)=5.62, r2=.09, were significant predictors of RT. Forced vital capacity was a significant predictor, F(1,27)=5.62, r2=.15, of memory, whereas age was a significant predictor of performance on the inhibition task as the stopping signal was presented increasingly further from the stimulus[75ms: p>.05; 150ms: F(1,33)=8.35, r2=.20; 225ms: F(1,33)=3.26, r2=.09; 300ms: F(1,33)=8.30, r2=.20]. Thus, in an older COPD sample, age, aerobic fitness, and pulmonary function are predictive of cognitive performance on a variety of tasks.