Background: Heightened public awareness about Alzheimer's disease and dementia increases the need for at-home cognitive self-testing. We offered Cognitive Online Self-Test Amsterdam (COST-A) to independent groups of cognitively normal adults and investigated the robustness of a norm-score formula and cutoff.
Methods: Three thousand eighty-eight participants (mean age ± standard deviation = 61 ± 12 years, 70% female) completed COST-A and evaluated it. Demographically adjusted norm scores were the difference between expected COST-A scores, based on age, gender, and education, and actual scores. We applied the resulting norm-score formula to two independent cohorts.
Results: Participants evaluated COST-A to be of adequate difficulty and duration. Our norm-score formula was shown to be robust: ≈8% of participants in two cognitively normal cohorts had abnormal scores. A cutoff of -1.5 standard deviations proved optimal for distinguishing normal from impaired cognition.
Conclusion: With robust norm scores, COST-A is a promising new tool for research and clinical practice, providing low cost and minimally invasive remote assessment of cognitive functioning.
Keywords: Alzheimer's disease; cognition; normative data; remote assessment; screener; self‐testing.
© 2021 The Authors. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.