What is the IQCODE?

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) is a proxy-rated tool used to assess potential cognitive decline. Instead of asking patients directly, it asks someone who knows them well (e.g., a family member) to compare current cognitive abilities to those from 10 years ago.

What It Measures

The IQCODE covers memory, practical skills, and other cognitive functions using questions like “Does the person have more difficulty remembering recent events?” Every item is rated on a 5-point scale, where 1 = much improved and 5 = much worse.

Scoring and Interpretation

Scores are averaged across all items, with higher averages indicating more significant decline. A threshold of ~3.6–3.8 is often used to flag cognitive impairment, depending on the version. When administered through Creyos Health, scores are automatically generated and flagged if elevated.

How It Relates to Cognition

The IQCODE captures subjective change from an informant perspective—complementing objective cognitive task data and helping detect early decline that patients may not notice themselves.

Psychometric Properties

Extensively validated, the IQCODE shows strong reliability and sensitivity to changes in cognition, especially for dementia screening.

Clinical Considerations

Useful in cases where patients lack insight or ability to self-report. It should supplement—not replace—direct cognitive testing and clinical evaluation.

To explore all behavioral and cognitive health tools available in the Creyos platform, refer to the Creyos Standardized Questionnaires Guide.