Sensitivity of the informant questionnaire on cognitive decline: An application of item response theory

Zeeshan Butt*

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

The Informant Questionnaire on Cognitive Decline (IQCODE) is a formal informant report instrument, originally developed by Jorm and Jacomb (1989; Psychological Medicine, 19(4), 1015). The goal of the present study was to evaluate the range of cognitive decline in which the IQCODE is most sensitive, using item response theory (IRT). Existing data (N = 740) from a sample of community-dwelling older adults was used for this purpose. A 2-parameter model estimating item difficulty and discrimination fit the data best. Additionally, the IQCODE provided the most psychometric information in the range of -0.5 < θ < 1.5, with peak information obtained at approximately θ = 0.4. Based on individuals' latent score (θ) estimates, items on the IQCODE are adequate for use as a screening tool for dementia. Results of the item calibration may be useful for targeted assessment needs, such as the development of short forms.

Original languageEnglish (US)
Pages (from-to)642-655
Number of pages14
JournalAging, Neuropsychology, and Cognition
Volume15
Issue number5
DOIs
StatePublished - Mar 1 2008

Keywords

  • Assessment
  • Cognitive decline
  • Informant
  • Informant Questionnaire on Cognitive Decline
  • Item response theory

ASJC Scopus subject areas

  • Psychology(all)
  • Developmental and Educational Psychology
  • Experimental and Cognitive Psychology

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