Most of us use one of the available brief mental status tests with individuals we think may have a dementia. But our goals in using these tests and the way we use them will influence the information we obtain.
"When I gave her the MMSE she didn't know where she was, but she read the name of the hospital on my coat. I figured if she was smart enough to do that I should give her the points. "
"She couldn't do the drawing, but she said she had always been poor at art, so I didn't count it."
When we begin to make allowances for people on these tests, we limit the tests' usefulness. These tests can be used to determine whether or not a person has a dementia. When this is the purpose of the test, the test must be used precisely as its creator designed it. Mixing items from different tests or making judgment calls on answers means that your patient's score will not compare to the scores of other patients whose cognitive status, extent of neurological damage, or ability to function was known.
But often we are fairly sure our patient is demented. And these brief tests are not very good at discriminating between those patients who are mildly demented and those who are not. Mental status scores can be very useful to us for other things.
Mental status tests, accurately given, can chart a patient's course. A sudden drop in score can mean that the patient is delirious. A decline helps families understand why a person can no longer do something.
Not all mental function declines at the same rate. The MMSE tests several different kinds of mental function which is useful for caregivers who need to be able to predict what a person might be able to do. It also helps to explain to families why a person can do one thing but not another. Being able to read the name of the hospital on a lab coat is a somewhat different skill from knowing where one is. It indicates an ability to cover up an impairment (and the person may be covering up a lot more problems), but it does not indicate that she knows where she is and will not wander away.
The design on the MMSE is simple enough for people who cannot draw or who have a tremor. It. tests the ability to perceive things as a whole - a whole diagram with sides and corners in the proper relationship. People often get some of the sides and then put the interlocking corners in a different place. These people are likely to have trouble setting the table, doing a craft project, or paying attention to several visitors because they can focus on only fragments and are unable to perceive all of something.
People who are still fairly intact are often able to bluff their way out of being asked to remember three words for a few minutes. This question identifies people who seem to be doing very well but who will not remember leaving a pan on the stove or taking medicine or a promise made or a question answered. Knowing this helps families understand the difference between "she looks ok" and "why does she do these things?"
The MMSE shows a patient a written message, "CLOSE YOUR EYES," and asks that the patient act on it. Some patients can read the note but do not close their eyes. These are the people who will not obey a note left on the refrigerator door or use a schedule put in their pocket. People who cannot follow this instruction often are unable to follow other instructions, such as "stand still," "take off your blouse," or "brush your teeth."
You can use the scores on mental status tests to educate families and staff and to estimate what patients can and cannot still do. Thinking about the errors a person makes can help you to understand the problems he is having in function so that you can devise ways to support him.
Of course such a brief test is not a substitute for thorough neurological testing and, of course, patients will always surprise you, but a mental status test can be a useful tool far beyond the simple score you obtain.