Can the Mini-Mental State Examination Predict Capacity to Consent to Treatment?

Abstract

This study examines the relationship between capacity to consent to treatment as measured by the MacArthur Competence Assessment Tool for Treatment (MacCAT-T) and severity of cognitive impairment as measured with the Mini-Mental State Examination (MMSE). It also looks at the role of verbal retrieval in this relationship. We hypothesized that the often-quoted correlation between the MacCAT-T and the MMSE lies mainly in the joint dependence on verbal retrieval ability. Potential subjects were recruited from memory clinics, senior citizen meeting places, and a university program for seniors. Data of 149 people over 54 years, 49 of whom had been diagnosed with Alzheimer’s disease or mixed dementia, were used. The relationship between capacity to consent to treatment, verbal retrieval, and MMSE was examined using a structural equation modeling framework. The findings suggest that verbal retrieval is a confounding method factor. In the informed consent process for people with dementia, verbal memory loads should be minimized to provide a more valid measure of their capacity to consent to treatment.