title: Validity of the Katz Index to assess activities of daily living by informants in neuropathological studies.
abstract: OBJECTIVE
  To analyze the evidences of construct validity of the Katz Index for the retrospective assessment of activities of daily living (ADL) by informants, to assist neuropathological studies in the elderly.
  
  
  METHODS
  A cross-sectional study analyzed the functional ability of ADL measure by the Katz Index, of 650 cases randomly selected from the Brazilian Brain Bank of the Ageing Brain Study Group (BBBABSG) database. Sample was divided in two subsamples for the analysis (N=325, each) and then stratified according to cognitive decline assessed by the Clinical Dementia Rating Scale (CDR). Factor analyses with calculations of internal consistency and invariance were performed.
  
  
  RESULTS
  Factor analysis evidenced a unidimensional instrument with optimal internal consistency, in all subgroups. Goodness of fit indices were obtained after two treatments of covariance, indicating adequacy of the scale for assessing ADL by informants. The scale is invariant to cognitive decline meaning that it can be used for subjects with or without cognitive impairment.
  
  
  CONCLUSIONS
  Katz Index is valid for the retrospective assessment of basic ADL by informants, with optimal reliability.
authors.affiliation: Universidade de São Paulo, Escola de Enfermagem, Departamento de Enfermagem Médico-Cirúrgia, São Paulo, SP, Brazil.|University of Quebec in Trois-Rivières, Department of Psychology, Laboratory of Psychometric and Experimental Methods, Trois-Rivière, QC, Canada.
authors.forename: Renata Eloah de Lucena
authors.initials: RE
authors.lastname: Ferretti-Rebustini
authors.affiliation: University of Quebec in Trois-Rivières, Department of Psychology, Laboratory of Psychometric and Experimental Methods, Trois-Rivière, QC, Canada.
authors.forename: Marcos Alencar Abaide
authors.initials: MA
authors.lastname: Balbinotti
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.|Universidade de São Paulo, Faculdade de Medicina, Disciplina de Geriatria, São Paulo, SP, Brazil.
authors.forename: Wilson
authors.initials: W
authors.lastname: Jacob-Filho
authors.affiliation: University of Quebec in Trois-Rivières, Department of Psychology, Laboratory of Psychometric and Experimental Methods, Trois-Rivière, QC, Canada.|Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Biociências, Laboratório de Estudos e Pesquisas em Psicologia do Esporte, Rio Claro, SP, Brazil.
authors.forename: Flávio
authors.initials: F
authors.lastname: Rebustini
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.|Universidade de São Paulo, Faculdade de Medicina, Disciplina de Geriatria, São Paulo, SP, Brazil.
authors.forename: Claudia Kimie
authors.initials: CK
authors.lastname: Suemoto
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.|Serviço de Verificação de Óbitos da Capital, São Paulo, SP, Brazil.
authors.forename: Carlos Augusto Gonçalves
authors.initials: CA
authors.lastname: Pasqualucci
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.|Universidade de São Paulo, Faculdade de Medicina, Disciplina de Geriatria, São Paulo, SP, Brazil.
authors.forename: José Marcelo
authors.initials: JM
authors.lastname: Farfel
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.
authors.forename: Renata Elaine Paraizo
authors.initials: RE
authors.lastname: Leite
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.|University of California, Department of Neurology, Memory and Aging Center, San Francisco, California, USA.
authors.forename: Lea Tenenholz
authors.initials: LT
authors.lastname: Grinberg
authors.affiliation: Universidade de São Paulo, Faculdade de Medicina, Laboratório de Fisiopatologia no Envelhecimento, São Paulo, SP, Brazil.|Universidade de São Paulo, Faculdade de Medicina, Departamento de Neurologia, São Paulo, SP, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Nitrini
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009422:Nervous System Diseases / Q000175:diagnosis; D015203:Reproducibility of Results