Normative data are quantitative measures are used to compare an individual’s performance to that of a relevant population. A comparison to a normative baseline is essential to interpret an individual test score and ideally accounts for differences related to age, education and sex. In fact, not comparing to normative data will often result in missing subtle signs of cognitive impairment. The cognitive assessment in ISC features well-established neuropsychological tests, each with its specific normative corrections but based on the same representative group of the US population. These normed outcome measures are validated against the traditional paper versions of each test. In 2019, Philips collected the normative data and test validation data through a study that was performed in accordance with the ISO14155 standard for Good Clinical Practice.1 It involved collecting data across four different states (NY, FL, PA, CA) from a group of 450 healthy participants enrolled using stratified sampling such that distributions of age (50-80y), sex, education level, and racial/ethnic background reflect the US Census.
For test validation we used data from this study to compare the psychometric properties of the digital ISC tests to their paper counterparts. Two-hundred fifty participants in the study completed either the digital ISC tests or the paper tests versions, once or twice in repeated visits about 2-3 weeks apart. Two hundred of the participants visited twice to perform both the digital ISC tests and the paper versions. The data from this specific subgroup allows a direct comparison between the ISC tests and the traditional paper while eliminating inter-individual differences that could otherwise obscure subtle differences.