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Assessing decisional capacity

A person’s decisional capacity, or lack thereof, should not be judged simply on the basis of age, appearance, condition or any aspect of his/her behaviour. If a patient’s decisional capacity is in doubt, an assessment should be carried out. In general, this means conveying information to the patient, discussing it to gauge his/her understanding and then asking questions about the salient points to see if the patient has grasped them. The focus should be on the reasoning the patient employs to arrive at a decision, rather than on the choice the patient makes – ie, not what the patient decides, but how he or she decides.

There is limited advice available in the medical literature on how to make such an assessment, and it is difficult to find agreed standards and criteria to apply – a problem that a few authors (eg, Applebaum4) have tried to address.

Patients with cognitive impairment should be supported and encouraged as much as possible to exercise their decisional capacity. This means delivering information in a form that they can understand and using visual and other aids to assist them if necessary. A speech and language therapist, a translator, or other professionals with special skills or knowledge might be needed to help with communication.

Avoid asking questions inviting “Yes” or “No” answers – for example, “Do you understand?” Instead, frame your questions in such a way that the patient will need to give a fuller response – for example, the above question could be re-phrased as “Tell me what you understand by…” Words like “What”, “How”, "Why”, and “Tell me” are good for framing open-ended questions.

Other aspects to consider are the timing and location of an assessment. A patient’s mental state may fluctuate in the course of a day, so choosing the best time to assess someone is important. It is also important to be aware of the possible impact of the environment – if it is strange or intimidating, it may inhibit the patient or make him/her tense and agitated.

Even if a patient lacks decisional capacity, they should still be involved, as far as possible, in decisions that affect their lives. Patients who lack the decisional capacity to consent to treatment may still be able to assent (ie, indicate their willingness to go along with the proposed treatment).

The process of assessing a patient’s decisional capacity should be carefully documented, including all the evidence gathered to inform the judgment about the patient’s decision-making abilities – eg, past decisions made by the patient, the views of family and carers, and the results of formal functional tests.