02 November 2007

How impairment is measured

There are no good practical tests available for the measurement of decision-making ability. Memory tests and other cognitive tests can to some extent assist.

It is sometimes difficult to determine loss of decision-making abilities in a patient with Alzheimer’s disease. Even young and healthy adults make wrong decisions. We only have to look at the divorce rates and business insolvency rates to comprehend that incorrect decisions are made by even the healthiest of persons.

There are no good practical tests available for the measurement of decision-making ability. Memory tests and other cognitive tests can to some extent assist. A very low Mini-Mental Status Examination score (less than 12) indicates severe impairment of cognitive functioning and an inability to make decisions. Scores above 12 require further evaluation to determine judgement, insight and planning abilities. The Mini-Mental Status Examination is not a good test of planning ability and supplemental tests are required.

Judgement is defined as making the correct decision for a particular situation. In a clinical setting it is measured by asking the patient about his plans for the future. Does he have any investment or business decisions? Is he planning relocation? Responses are probed and then evaluated for appropriateness. Alternatively, the patient may be provided with a hypothetical scenario and requested to indicate a decision. An example is: If you walk in the street and pick up an envelope with a stamp and address on it, what will you do? The correct answer would be to put the envelope in the nearest postbox because obviously somebody has dropped it. Incorrect answers would include opening the envelope or throwing it into a dustbin.

Insight is defined as the ability to fully comprehend the extent of your illness, to understand the treatment options available, and to be able to comply with treatment requirements. Additionally, it also includes the ability to comprehend the extent of social and occupational impairment caused by the illness. In practical terms this means that a patient with Alzheimer’s disease and memory difficulties should comprehend that the memory difficulties will impair his ability to engage in financial transactions. In a clinical setting insight is measured by asking the patient questions about his deficits and comparing his replies with objective evidence. The patient will also be asked if he would comply with treatment.

After a careful clinical evaluation the clinician is able to form an opinion on the patient’s cognitive abilities and decision-making ability. Below follows a discussion of different issues that are involved with impaired decision-making ability.

Written by Dr Frans Hugo, MBChB, M.Med Psychiatry and Dr L. Van Wyk, MBChB, M. Med (Psych) from the Panorama Memory Clinic.

Read more:
Mini Mental Status Examination (MMSE)
Does Alzheimer's only cause memory impairment or are other brain functions also involved?

For more information visit: Dementia SA: or Alzheimer’s South Africa:


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