Most participants in the UK biobank underwent web-based cognitive testing when they enrolled. The baseline test was only five minutes, consisting of Pairs Memory test, a test of visual memory, and the Reaction Time test. A subset underwent tests of working memory (Numeric Memory test), prospective memory (Prospective Memory), and verbal and numerical reasoning (Fluid Intelligence). Some years later the tests minus Numeric Memory were repeated on a much smaller subset of 20,000 people.
Several new tests were introduced in the second round that were not included in the baseline assessment. These included; tests of verbal declarative memory, executive function, and non-verbal reasoning. Prior cognitive functioning was estimated with a vocabulary test, as this normally does not have much variance in the age group that predominates the UK biobank.
Normally such tests are supervised by a trained psychological tester, however in the interests of processing a large cohort, the tests were administered via a computer interface in a self-directed manner. It is not clear if such methods are reliable or valid. Chloe Fawns-Ritchie and Ian J. Deary of the University of Edinburgh, UK, investigated the reliability and validity of the tests and published the results in the journal PLoS One.
An independent cohort of 160 middle-aged and older adults that did not take part in the UK Biobank study was recruited. They were given the enhanced UK Biobank cognitive assessment plus all baseline tests as well as the more detailed tests introduced since baseline. These tests were paired with validated, standard cognitive tests, which were used as reference standards.
Increasing age was generally associated with poorer performance. Reporting poor memory was associated with more errors. Three main findings were that: 1) = broadly, the UK Biobank tests correlated moderately-to-strongly with well-validated, standard tests; 2) a measure of general
cognitive ability can be created; 3) the majority of the UK Biobank tests showed moderate to high test-retest reliability, but these tended to be lower than for the reference tests.
“The present study found that [the cognitive tests] showed a range of concurrent validity coefficients with well-validated, standard tests of cognitive ability, and most tests tended to have moderate-to-good test-retest reliability. UK Biobank is one of the largest and most detailed health resources available worldwide. This paper provides currently-lacking information on the psychometric properties of the UK Biobank cognitive tests,” concluded the authors.