Complex question, particularly regarding your use of "dementia" rather than "cognitive impairment". If you are interested in understanding the current testing for "cognitive impairment", I would recommend reviewing Gilbert et al.

Their conclusions are as follows regarding the "testing of cognitive impairment":

"The MacCAT-CR is currently the most used and the best validated questionnaire. However, it appears difficult to use and time-consuming. A more recent tool, the University of California Brief Assessment of Capacity to Consent (UBACC), seems interesting for routine practice because of its simplicity, relevance, and applicability in older patients."

Reference:

Assessing capacity to consent for research in cognitively impaired older patients."

Gilbert T, Bosquet A, Thomas-Antérion C, Bonnefoy M, Le Saux O.

Clin Interv Aging. 2017 Sep 26;12:1553-1563. doi: 10.2147/CIA.S141905. eCollection 2017. Review.

PMID: 29026293 Free PMC Article

Dennis

Dennis Mazur

Thanks Dennis. The reason I say dementia rather than cognitive impairment is because of the requirement to consider fluctuating capacity. Cognitive impairment scoring is not recommended as it's of no relevence. The issue is that the person has the capacity - limited or full to make the decision at the time.

There is no test, form, legislation nor science.

This is an individual by individual, specific decision by specific decision process based upon the complexity of the issue, the capabilities of the person to "understand" and then a subjective decision made by the clinician.

It is easy to do with a systematic approach but challenging if not clearly defined paramaeters.

In the UK, The Mental Capacity Act provides the legal framework for decision making in dementia. It does emphasise the need to adequately inform and support the decision making process. As you say, capacity may be retained in dementia and is decision-specific. I don't agree that cognitive testing is irrelevant; it's part of a full assessment and can be informative when assessing capacity, which tends to be quite a subjective judgement and legally made only on the balance of probabilities.

Cognitive testing, while not irrelevant, needs to not be seen as a substitute for capacity assessment. Someone who is 11/30 on the MMSE may be competent while someone else who is 30/30 may be incompetent for the same domain dependent upon other issues (eg delusions, complexity of situation).

Whilst Barry is technically correct, in my clinical experience, it's unusual for a patient with MMSE 11/30 to have capacity for most decisions. One of the requirements of capacity is the ability to retain information long enough to come to a reasoned decision. Hence evidence of poor short term memory on cognitive testing may be quite informative when assessing capacity.

Thanks everyone for your replies. Yes it may be unusual for someone with an MMSE of 11/30 to be able to retain the information required to make a decision at the time the decision is requred which is why fluctuating capacity needs to be recognised. The legal position under the ADMCA (2015) is that there must be presumption of capacity to consent. Carrying out an MMSE will prejudice that process. The capacity decision making tool is the most appropriate action. I see that British Columbia is now - 20 years after the introduction of their assisted decision making act carrying out a research project on how the rights to autonomous decision making with people with dementia are protected. If we don't learn from the other States we in Ireland risk failure of this right before we even get started. Comments anyone ?

Can someone at 11/30 consent to sugar in their coffee? What if they are diabetic? What if when they were 30/30 they put sugar in their coffee? What if their substitute consent provider values lower glucose levels than pleasure of sweet coffee?

No scale can determine if this person is competent as the decision is not entirely based on measureable values.

Without consideration of the person (their values, memory, executive function, psychosis, depression) , the specific decision, the complexity and risk of the decision and the need for enduring vs momentary capacity there Is no way to determine if there is understanding.