Cognitive Functioning in Obstructive Lung Disease

SupplementaRY DATA

cognitive functioning in Obstructive Lung Disease:

RESULTS FROM THE UK BIOBANK

Fiona A.H.M. Cleutjens, Martijn A. Spruit, Rudolf W.H.M. Ponds, Jeanette B. Dijkstra, Frits M.E. Franssen, Emiel F.M. Wouters, Daisy J.A. Janssen

Cognitive functioning tests

Prospective memory test. The participant was shown the message ‘At the end of the games we will show you four colored shapes and ask you to touch the Blue Square. However, to test your memory, we want you to actually touch the Orange Circle instead’. This test assesses prospective memory, which refers to the ability to carry out future intentions at a specific time or in response to a specific event. Successful prospective remembering requires that an intention to be remembered is encoded and recalled some time later in response to a cue so that accurate prospective memory task performance has both a prospective component (remembering to remember) and a retrospective component (remembering the content of what is to be remembered).(1)

Fluid intelligence test. The participant had 2 minutes to complete as many questions as possible from the test. This test assesses fluid cognitive functioning, which can be thought of as the capacity to solve problems that require logic and reasoning ability, independent of acquired knowledge.(2)

Pairs matching test. This visual spatial ability test provides data on two 'pairs' matching tests. Participants were asked to memorize the position of as many matching pairs of cards as possible. The cards are then turned face down on the screen and the participant is asked to touch as many pairs as possible in the fewest tries. The first test includes 3 pairs of cards, the second 6 pairs of cards.(3)

Numeric memory test. The participant was shown a 2-digit number to remember. The number then disappeared and after a short while they were asked to enter the number onto the screen. The number became 1-digit longer each time they remembered correctly (up to a maximum of 12 digits). This test is used to measure numeric short-term memory and assesses the ability to recollect a series of digits. The length of the longest list a person can remember is called the digit span of this person.(4)

Reaction time test. The participant was shown two cards at a time. If both cards are the same, they press a button-box that is on the table in front of them as quickly as possible. During 12 rounds, this test measures the reaction time which is the elapsed time between presentation of two cards (a sensory stimulus) and pressing the button-box (the subsequent behavioral response). It gives an indirect index of the cognitive processing speed of a participant.(5)

Statistics

Analysis included correction for the following confounders, which have been associated with cognitive functioning in previous studies: sex,(6-9) age,(9-12) race,(13-15) education,(9, 10, 16) employment,(17, 18) current tobacco smoking,(19, 20) alcohol intake,(21-23) depressed mood in the last two weeks,(24, 25) vascular/heart problems diagnosed by doctor,(26-28) and diabetes diagnosed by doctor.(27, 29, 30)

Additional tables

Table S1. Prospective memory test: association with OLD using logistic regression analysis

Standardized Coefficient Beta (95% CI) / p-value
Primary predictor
OLD versus non-OLD (ref: non-OLD) / -0.15 (-0.22 to -0.09) / <0.005
Possible confounders
Sex (ref: female) / 0.10 (0.05 to 0.14) / <0.005
Age / -0.04 (-0.04 to -0.03) / <0.005
Race (ref: non-Caucasian) / 1.20 (1.10 to 1.29) / <0.005
Education (ref: less than college or University degree) / 0.51 (0.45 to 0.56) / <0.005
Employment (non employed) / 0.16 (0.11 to 0.22) / <0.005
Current tobacco smoking (ref: non-smoking) / -0.16 (-0.24 to -0.08) / <0.005
Alcohol intake (ref: none) / 0.33 (0.25 to 0.41) / <0.005
Depressed mood in last 2 weeks (ref: no) / 0.04 (-0.02 to 0.09) / 0.210
Vascular/heart problems diagnosed by doctor / -0.07 (-0.13 to -0.02) / 0.006
Diabetes diagnosed by doctor / -0.14 (-0.25 to -0.04) / 0.007