The influence of diversity on the measurement of functional impairment: An international validation of the Amsterdam IADL Questionnaire in eight countries

Mark A Dubbelman (1) , Merike Verrijp (1) , David Facal (2) , Gonzalo Sánchez‐benavides (3) , Laura J E Brown (4) , Wiesje M Der Flier (3) , Hanna Jokinen (5) , Athene Lee (6) , Iracema Leroi (4) , Cristina Lojo‐seoane (2) , Vuk Milošević (7) , José Luís Molinuevo (3) , Arturo X Pereiro Rozas (2) , Craig Ritchie (8) , Stephen Salloway (6) , Gemma Stringer (4) , Stelios Zygouris (8) , Bruno Dubois (9) , Stéphane Epelbaum (9) , Philip Scheltens (1) , Sietske a M Sikkes (1)

1 Alzheimer Center Amsterdam
2 USC - Universidade de Santiago de Compostela [Spain]
3 Pasqual Maragall Foundation
4 University of Manchester [Manchester]
5 Helsingin yliopisto = Helsingfors universitet = University of Helsinki
6 Warren Alpert Medical School of Brown University
7 Clinical Center Niš
8 School of medicine [Thessaloniki]
9 ARAMIS - Algorithms, models and methods for images and signals of the human brain = Algorithmes, modèles et méthodes pour les images et les signaux du cerveau humain [ICM Paris]

Introduction: To understand the potential influence of diversity on the measurement of functional impairment in dementia, we aimed to investigate possible bias caused by age, gender, education, and cultural differences. Methods: A total of 3571 individuals (67.1 ± 9.5 years old, 44.7% female) from The Netherlands, Spain, France, United States, United Kingdom, Greece, Serbia, and Finland were included. Functional impairment was measured using the Amsterdam Instrumental Activities of Daily Living (IADL) Questionnaire. Item bias was assessed using differential item functioning (DIF) analysis. Results: There were some differences in activity endorsement. A few items showed statistically significant DIF. However, there was no evidence of meaningful item bias: Effect sizes were low (ΔR 2 range 0-0.03). Impact on total scores was minimal. Discussion: The results imply a limited bias for age, gender, education, and culture in the measurement of functional impairment. This study provides an important step in recognizing the potential influence of diversity on primary outcomes in dementia research.

Mots clés: Alzheimer's disease; Cross-cultural validation; Dementia; Differential item functioning; Diversity; Functional decline; Instrumental activities of daily living; Item response theory

Domaines: Neurosciences [q-bio.NC]

Mark A Dubbelman, Merike Verrijp, David Facal, Gonzalo Sánchez‐benavides, Laura J E Brown, et al.. The influence of diversity on the measurement of functional impairment: An international validation of the Amsterdam IADL Questionnaire in eight countries. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring, 2020, 12, ⟨10.1002/dad2.12021⟩. ⟨hal-03114813⟩