UD Interference Test: creation and validation of a new instrument of resistance to interference. Normalisation and standardisation for Spanish population

Abstract

IntroductionThe UD Interference Test measures processing speed and attention, and is based on the concept of interference of the Stroop Color and Word Test. The main purpose of the study is to provide an alternative version of the Stroop Color and Word Test that overcomes some of the limitations of previous versions in assessing individuals with daltonism or age-related reading difficulties, and to obtain normative and standardised data for the Spanish population. MethodsThis study is part of the Normacog project. We evaluated 905 individuals (age range, 18–93 years) to analyse the test’s reliability and concurrent and construct validity. We evaluated the effect of age, sex, and level of education on UD Interference Test performance and calculated percentiles and age- and education-adjusted scaled scores. ResultsThe test has good reliability (α = 0.875) and concurrent (r = 0.443−0.725; P < .001) and construct validity (r = 0.472–0.737; P < .001). We observed age and educational level to have a significant effect on UD Interference Test scores, explaining 12% to 40% of variance. Sex only had a significant effect on the resistance to interference index. ConclusionsWe present an alternative version of the Stroop Color and Word Test with some advantages over previous versions. We provide standardised and normalised data for the Spanish population to correct the test according to the subject’s age and level of education.