Gottfries’ Cognitive Scale for Staff Proxy Rating of Cognitive Function Among Nursing Home Residents

Article type: Research Article

Authors: Lövheim, Hugo^{a; *} | Gustafsson, Maria^{a; b} | Isaksson, Ulf^{c; d} | Karlsson, Stig^c | Sandman, Per-Olof^{c; e}

Affiliations: [a] Department of Community Medicine and Rehabilitation, Geriatric Medicine, Umeå University, Umeå, Sweden | [b] Department of Pharmacology and Clinical Neuroscience, Clinical Pharmacology, Umeå University, Umeå, Sweden | [c] Department of Nursing, Umeå University, Umeå, Sweden | [d] Arctic Research Centre, Umeå University, Umeå, Sweden | [e] Department of Neurobiology, Care Sciences and Society, Division of Nursing, Karolinska Institute, Stockholm, Sweden

Correspondence: [*] Correspondence to: Hugo Lövheim, MD, PhD, Department of Geriatric Medicine, Umeå University, SE-901 85 Umeå, Sweden. Tel.: +46 70 297 94 99, +46 90 785 88 59; E-mail: hugo.lovheim@umu.se.

Abstract: Background:For research purposes, there is a need for tools to assess an individual’s level of cognitive function. For survey-based investigations in nursing home contexts, proxy ratings allow the assessment also of individuals with severe cognitive impairment. Objective:The aim of this study was to describe the feasibility and psychometric properties of Gottfries’ cognitive scale when used in a nursing home context for proxy rating of cognitive function. Method:The psychometric properties of Gottfries’ cognitive scale were investigated in a sample of 8,492 nursing home residents in Västerbotten County, Sweden, using item response theory and classic scale theory-based approaches. Results:Cognitive function could be scored in 97.1% of the assessed individuals. The scale had a negligible floor effect, it had items with a large spread in difficulties, it appeared linear, and it distributed the assessed individuals equally over the scale. Internal consistency (Cronbach’s alpha) was 0.967, and an exploratory factor analysis revealed three factors of the scale – interpreted to represent orientation to time, to place, and to person. Conclusion:Gottfries’ cognitive scale is a feasible tool for grading cognitive function among nursing home residents using staff proxy ratings. The scale has excellent psychometric properties with a very high internal consistency, a favorable distribution of item difficulties producing an almost rectangular distribution of scores, and a negligible floor effect. The scale thus can be recommended for use in survey-based investigations in nursing home contexts.

Keywords: Assessment, cognitive function, cognitive impairment, dementia, measurement, nursing home, scale, survey

DOI: 10.3233/JAD-190599

Journal: Journal of Alzheimer's Disease, vol. 72, no. 4, pp. 1251-1260, 2019