Cognitive Tests: A battery of cognitive tests was used because of the interest in examining the differential influence of the physiologic and psychological parameters on tasks that differ in their cognitive demands. Fluid intelligence, reaction time, and working memory span were examined because of the past evidence that COPD subjects are deficient in the capability to perform these types of tasks. Additionally, a measure of inhibition was incorporated because there is substantial evidence that suggests that inhibition ability declines as a function of aging.
Fluid Intelligence: Fluid intelligence is the basic power of reasoning and problem solving. Form A of Scale 3 of the Culture Fair Intelligence Test (Institute for Personality and Ability Testing; Champaign, IL) was administered because it is designed for use with an educated adult population. To reduce test anxiety and to minimize the effects of speed of performance on fluid intelligence, the recommended time limit for each subtest was doubled. Validity of the Culture Fair Intelligence Test as a measure of fluid intelligence ranges between 0.71 and 0.84 reliability of the test ranges from 0.71 to 0.92 when administered as a power test as opposed to a speed test. Instructions were read to participants from the manual. Breaks and verbal encouragement were provided between subtests. buy ventolin
Processing Speed: This test was developed by Salthouse and is patterned after the Wechsler Adult Intelligence Scale-Digit Symbol Subtest. The participant’s task was to determine whether or not a number and symbol pair presented as a stimulus were properly matched, as determined by the display bar, and then to depress the appropriate key on the keyboard. Equal emphasis was placed on speed and accuracy. Participants were given 20 practice trials and 90 measured presentations. Stimulus presentation and response time collection routines were computed using appropriate software (Micro Experimental Lab [MEL] software; Psychology Software Tools; Pittsburgh, PA), allowing millisecond accuracy for both. The Wechsler Adult Intelligence Scale digit-symbol test has a validity of 0.91 and a reliability of 0.92.