A short form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): development and cross-validation

TLDR

The authors used data from four studies to evaluate 26 IQCODE items, selected 16 items with strong psychometric properties, and cross‑validated the resulting short form against dementia/delirium diagnoses. The short form performed comparably to the full 26‑item version.

Abstract

Synopsis Data from four studies were used to assess the psychometric properties of the 26 IQCODE items. The items were assessed in terms of item–total correlations, test–retest reliabilities, correlations with indicators of current cognitive functioning and correlations with indicators of pre-morbid cognitive functioning. These data were used to develop a 16-item short form. The short form was cross-validated in a new sample using dementia/delirium diagnosis as the validity standard. It was found to perform as well as the long form.