Re-assessing the dimensional structure of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): empirical evidence for a shortened Brazilian version

Abstract

BackgroundThe dimensional structure, effective number of item responses and item redundancies are controversial features of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) requiring more light. The aims of the present study are to revisit the dimensional structure and propose a shorter version of the instrument.MethodsThe sample comprised 652 elderly and their informants, either attending a geriatric service of a public university clinic or enrolled in a health care provider database in Rio de Janeiro, Brazil. A Confirmatory Factor Analysis (CFA) first tested the originally proposed one-dimensional structure comprised of 26 items. This was followed by sequential Exploratory Structural Equation Model (ESEM) to evaluate alternative models, in particular a bi-dimensional solution. The identification of residual correlations (RC) lead to a shortened 20-item model, which was tested further via CFA.ResultsThe original model fitted poorly (RMSEA = 0.073; 90 % CI: 0.069-0.077). Regarding the two-dimensional model, the exploratory procedure (ESEM) indicated several RCs and a lack of factor-based discriminant validity. The ensuing CFA on the one-dimensional model with freely estimated RCs showed an adequate fit (RMSEA = 0.051; 90 % CI: 0.047-0.055). Addressing the identified RCs, the CFA on the abridged 20-item version also showed an adequate fit (RMSEA = 0.058; 90 % CI: 0.053-0.064) and no further RCs.ConclusionA one-factor dimensional structure and a reduced version with 20 locally independent items were the most tenable solution. However, although promising, this simpler structure requires further examination before it may be fully supported and recommended.

Accuracy of the Informant Questionnaire on Cognitive Decline in the Elderly for Detecting Preexisting Dementia in Transient Ischemic Attack and Stroke

“…Studies in non-stroke populations rarely found low scores since aging is usually associated with stable or declining cognition. 27 Mistakenly scoring early recovery after stroke as improvement might explain these low scores. Patients with low scores were younger and young patients are more likely to improve after stroke.…”

Fragilidade em Idosos Brasileiros - Fibra-RJ: metodologia de pesquisa dos estudos de fragilidade, distúrbios cognitivos e sarcopenia

“…O estudo FIBRA-RJ, deu origem a uma série de artigos, dissertações de mestrado e teses de doutorado. 3,12,[28][29][30][31][32][33][34][35][36] Discussão O estudo FIBRA-BR, por seu delineamento multicêntrico, provavelmente representou um dos esforços mais abrangentes de pesquisadores brasileiros, para a compreensão da dimensão da fragilidade e seus fatores associados, em território nacional. O segmento Rio de Janeiro desse estudo, o FIBRA-RJ, representou uma tentativa de ir além dos objetivos inicialmente traçados, e dar continuidade ao acompanhamento da amostra examinada, investigando outros aspectos de acometimento de saúde, bastante comuns entre a população idosa, e ainda carentes de estudos populacionais com um número substancial de indivíduos.…”

“…Além disso, alguns instrumentos de avaliação geriátrica foram abordados do ponto de vista da sua adaptação transcultural para o Brasil. 12,35,36 Se tais estudos têm conhecida limitação, associada à causalidade reversa, que impede conclusões seguras acerca da ordem cronológica dos fenômenos, no entanto, eram necessários, uma vez que, até então, poucos trabalhos descreviam tais condições na população brasileira.…”