Mental Capacity Determination-Could the Physicians be Wrong?

Decision Making Capacity describes a person’s ability to make a clear decision such as a financial or a health care one. An individual who has decision making capacity can demonstrate the ability to understand the risks and benefits of a proposed intervention and communicate a choice. For example, in a medical context, capacity refers to the ability to utilize information about an illness and proposed treatment options to make a choice that is congruent with one’s own values and preferences. While decision making capacity is a clinical assessment, competency is a legal term and can only be determined by the court of law.

       As the number of people suffering from dementia grows each year (5.1 million Americans were affected by dementia in 2015 and this number will triple by year 2050), determination of mental capacity will continue to be a challenge for physicians, families and lawyers. Patients with mild to moderate dementia pose the biggest challenge since in these patients cognitive impairment fluctuates over time. One of the most common mistake physicians often make for such patients is that they only assess the patient’s cognitive ability while ignoring his/her decision making capacity. Cognitive tests should not be used as a substitute for capacity assessment in patients who suffer from mild to moderate degree of dementia.

         For these patients mental capacity is best determined by a face-to-face interview using a series of open-ended questions that relate to the medical decision at hand. The goal of the interview is to evaluate four decision-making abilities: the ability to Understand information about treatment; the ability to Appreciate how that information applies to their situation; the ability to Reason with that information; and the ability to make a Choice.

         These abilities can be determined by different tests, the most common being MacCAT-T (MacArthur Competency Assessment Tool for Treatment) and ACED (Assessment of Capacity for Everyday Decision). When conducting the test the interviewer scores the patient’s answer as adequate (2 points), marginal (1 point), or inadequate (0 points). A summary score is then generated for each decisional ability. A skilled physician should then be able to interpret the scores on an individual basis keeping in mind factors such as the patient’s medical history and judgment status and not solely based on the scores attained.

         Recently, one of my colleagues conducted a formal cognitive evaluation test called a Mini Mental Status exam (MMSE) on a patient who was supposed to be evaluated for mental capacity. Unfortunately, she did not perform a mental capacity test on the patient and based on the patient’s score of 27/30 on the MMSE test concluded the patient did not suffer from dementia (any score higher than 24) and had intact mental capacity. The patient’s care givers, however, did not agree with the physician’s conclusions based on the patient’s health and judgment status and contested the results. One thing the physician overlooked was that the patient had lost 3 scores in the recall part of the MMSE test, indicating significant impairment in short term memory. It is imperative to note that while some patients lack decision-making capacity they can have high scores on MMSE (or cognitive evaluation tests) while patients who perform poorly on MMSE may be able to make health care decisions. Therefore, the correct test and the right interpretation of the results by the physician are of essence when determining mental capacity.