Development and validation of the Observation List for early signs of Dementia (OLD)

Objective Development and validation of a short Observation List of possibl e early signs of Dementia (OLD) for use in general practice. Design Stepwise development using reviews of publications and expert consen sus. Field study for evaluation of reliability. Validation study (interview s, family forms) using existing valid and reliable measures. Use of data re duction techniques to construct a short version. Setting of field study Twenty-two GPs in 19 Dutch practices. Participants The first two patients seen on 15 working days (n=470) were ob served. Inclusion: age > 75, without a known diagnosis of dementia. Exclusi on: psychiatric treatment, severe depression, acute illness with confusion. Division of patients into three groups with no, intermediate, and the most signs (total of interviewed patients, n = 60; family forms, n = 39). Outcome measures Reliability (Cronbach's alpha and factor-analysis). Conver gent validity using the Cognitive Screening Test (CST), the Word Learning T est (WLT, total and retention), the Informant Questionnaire on Cognitive De cline in the Elderly(IQCODE), the Groningen Activities Restriction Scale (G ARS), and an IADL scale. Discriminant validity using the geriatric depressi on scale (GDS). Construct validity using a Principal Component Analysis (PR INCALS). Incremental validity using the intuitive opinion of the GP (McNema r test). Results Reliability in the total group 0.88, first factor explained varianc e 42.5%. Convergent validity (two-way ANOVA) results: CST (p=0.00), WLT-tot al (p=0.001), WLT retention (p=0.00), IQCODE (p=0.09). No statistically sig nificant differences for CARS and IADL. GDS (p=0.30) not different. PRINCAL S first factor explained 48% of variance. The OLD added to the GP opinion ( McNemar p = 0.00). Reliability short version 0.89 (interviewed group), 0.86 (total group). Conclusion The OLD is a valid and reliable method to detect early signs of dementia in general practice that can indicate when it may be useful to employ existing screening instruments. Copyright (C) 2001 John Wiley & Sons, Ltd.