In medical practice, a patient’s loss of competency is a major obstacle when choosing a treatment and a starting treatment program smoothly. A large number of studies have revealed the lack of medical competency in patients with dementia. However, there have been only a few reports focusing on the capacity of patients with mild cognitive impairment (MCI) to make a medical choice.

In this study, we evaluated the competency of 40 patients with amnestic MCI (aMCI) and 33 normal subjects to make a medical choice using the MacArthur Competence Assessment Tool-Treatment (MacCAT-T). We compared the judgement of a team conference using the recorded semi-structured interview with the clinical judgement of a chief clinician.

A team conference concluded that 12 aMCI patients had no competency, and the clinical judgement, without any special interview, judged that five aMCI patients had no competency. All subjects in the control groups were judged to be competent to consent to treatment by both clinicians and the team conference.

Without supplementary tools such as explanatory documents, not a few patients with aMCI were judged by a team conference to have no competency to consent to therapy even in a relatively simple and easy case. In contrast, clinical physicians tended to evaluate the competency of aMCI patients in a generous manner.