P1-459: informant- and participant-reported cognitive function using the iqcode measure is a robust indicator of cognitive health

There is an increasing need to understand cognitive trajectories in older adults in order to detect early stages of cognitive decline and support targeting of preventative interventions. Due to the subjective nature of cognition informant reporting is often a valuable means of detecting early changes. The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) provides a validated approach for capturing informant ratings of cognition over ten years. PROTECT is a 25-year innovative longitudinal online study in the UK (www.protect.org.uk) for cognitively healthy adults aged 50 and over. Participants complete a cognitive test battery in triplicate every year. During registration participants can opt to nominate an informant to complete the IQCODE. The participants also complete a self-report version of the scale, allowing direct comparison of reporting. This analysis compares the self-report and informant report on the IQCODE against cognitive performance on the cognitive test battery over three years. The self and informant IQCODE data were analysed separately with a repeated measures design that used the volunteers age, gender and education as covariates. Data was available for 7739 (61.9 (SD 7.0)) participants whose informants also completed the informant-IQCODE at baseline, one and two years and are included in this analysis. For both informants and participants a higher IQCODE score was associated with poorer cognitive performance in attention and working memory at each time point. IQCODE is a reliable method for capturing early decline in older adults who otherwise appear cognitively healthy. Further consideration should be given for the use of IQCODE in clinical practice to support early diagnosis of cognitive impairment