We are delighted that Sandra McDonald is doing a guest blog for us for dementia awareness week. After 14 years as Public Guardian for Scotland, Sandra now provides independent training and advice on mental capacity issues.She is currently supporting Scottish Government with the AWI reforms.

The knowledge that any one interacting, in any way, with a person with cognitive or volitional impairment must support that person in the exercise of their legal capacity (known colloquially as supported decision making) is gaining increased recognition. But where has this come from and how do we achieve this?

The requirement comes from the United Nations Convention on the Rights of Persons with Disabilities, which the UK ratified in 2009. Specifically, the requirement arises from Article 12(3), which requires 'States Parties to take appropriate measures to provide access by persons with disabilities to the support they may require in exercising their legal capacity'. The UN have clarified that "disability" includes intellectual disability, thus, the requirement to support the exercise of legal capacity extends to us providing this support to adults with incapacity.

A discussion of how one achieves this must start with a consideration of the factors which influence decision making, which are the same for any of us. These are many and varied - for example our confidence with decision making per se, our previous experience, the information we have, our mood, the views of our peers or loved ones, even down to whether we are in pain, are hungry, or tired.

A short blog cannot hope to do justice to how one supports decision making for persons with cognitive impairment but many people will say it is a matter of common sense - ensure all of the factors which may negatively impact on one's ability to make a decision are, as far as is possible, removed - so is the person at their best, pain free, comfortable, etc, i.e. are conditions optimal; take time; maintain eye contact; adopt a non defensive body positioning; remain patient; talk in short sentences; talk quietly and calmly; provide options if required.

The antithesis of supported decision making is substituted decision making. There is a school of thought, including the United Nations themselves, which believes we should never make substituted decisions, that we must always support an individual to make autonomous decisions. Is this possible? Of course providing support for decision making must always be the start point but what of those people who have no decision making capacity, for example those in end stage dementia.

Well we first have to challenge an assumption that such a person doesn't have capacity. Capacity is decision specific and should be assessed against, and at the time, that the decision needs to be made. But what if we have done our absolute best to support the individual to make an autonomous decision and, with the best will in the world, it isn't going to be possible to get them to a supported outcome.

We have then to turn to best interpretation decision making - what would the person's previous decisions tell us, is there any statement of wishes or advance statement that would give us guidance, would a review of their Will (if there is one) assist? What is their behaviour indicating? Is their mood, their tone or pitch of voice, their attitude, even their physiological responses telling us anything about a preference?

Even then, sometimes it's just not possible to interpret, or discern, the individual's view. Are we then in a position of having to make a substituted decision? There are occasions when another person, assuming they have due authority, has to make a decision on behalf of another individual. In this situation the decision maker is an alternative, a substitute, but the decision itself does not have to be a substituted decision. Contrast the following approaches - the proxy decision maker decides what should happen, versus, the proxy decision maker decides what the individual would have wished to happen; both are decisions made by a substitute, the former is also a substituted decision, the latter is not.

Longer term, supporting the exercise of legal capacity is likely to be incorporated into primary legislation but we need not, indeed should not, wait for this, given it is already required by the Convention, ratified 10 years ago, this very week; so I challenge you to think is your practice compliant, does it truly support a person with cognitive impairment to exercise their legal capacity?

Sandra can be contacted via email on sandra@ex-pg.com.