Let's talk about dementia, memory loss, the most common kind being Alzheimer's. There are other kinds: multi-infarct dementia, Pick's, a few treatable dementias. I went to the big national family practice conference a few years ago and one talk radically changed how I follow memory loss and think about it. The first thing was the statistics they gave: 4% of 65 year olds have memory loss and then it increases by 2% a year. Do the math. At 85, it would be 2 times 20 plus 4 for a total of 44%. At 95 we are up to 64%. This changed my practice. I started recommending a screening baseline test for memory loss at 65 so that we could track it.
The second part of the lecture explained how a basic memory test correlated with three stages of memory loss. The test is the MMSE:Mini-Mental Status Exam. It consists of 30 questions which test different parts of the brain. I have done it with people so many times that I have it memorized. Short term memory, concentration, naming objects and stuff that we all hope should be simple: the first question is: what is the year, month, day, date and season? In the last three weeks in clinic I have had two people who scored 13/30. I also met a new woman. She has a caregiver who lives with her. This is a good thing, because she scored 4/30. She should not be left alone, use a stove, microwave, light candles and so forth. One of the people scoring 13 was brought to the emergency room because her car alarm was going off and she couldn't remember how to turn it off. She couldn't answer questions and could not tell the police where she lived. The ER physician, the police and I all filed forms to keep her from driving. I told her son she should not live alone any more. I have been doing MMSE tests on her since 2006: she has scored 26, 18, 19 and now 13.
How does the MMSE correlate with the stages of memory loss? The first stage is the loss of short axons in the brain, scores of about 26 down to 20. Short term memory loss and concentration are affected. The second stage is from 19 down to the low teens. This is the medium length axons in the brain and affects remembering people's names, how to get places, how to perform tasks even if one has been doing them for years. The final stage is the longest axons, scores dropping below 10 and this is when people lose executive function. They can't find words. They may no longer recognize family. They may think that a son is their brother. It is as if they travel back through their memories, losing them as they go. At last they lose any memory of a spouse, family, toilet training and eventually do not care about eating any more. The average lifespan from diagnosis is 7 years.
Once I learned about the different axons being destroyed I understood something that had puzzled me: why behavior may change radically as memory loss progresses, depending on what functions are currently being affected. People have trouble learning new information at one stage and at the next they start getting lost, even driving to very familiar places. I started to track scores on my patients so that I could help explain what was happening to their families. Most people are cared for at home for a very long time; behaviour or incontinence or not recognizing any family are the times when they are moved to a nursing home.
The MMSE is not perfect. Scores are affected by educational background. I think that I'll fool my future doctor for quite a while, because one of the questions is count backwards from 100 by 7s: 93, 86, 79, 72, 65. I have that down really solidly in the memory banks, so I'll get by for longer than I should. Still, the score will drop over time if the memory loss is Alzheimer's. The medicines do help slow the drop for a while.
After my lady with the car alarm was picked up, I called our local neurologist. I received no training in medical school or residency in determining someone's competence, so my question was about the MMSE: was there a score below which a person is probably not competent? That is, to make medical decisions. Our neurologist said he had not been trained in competency either, but he thought below 20. I did some reading: 18 and below is a fairly good measure. One study tested an MMSE and then gave people two medical scenarios. If they scored below 19, for the most part they could not make a medical decision.
The blessing of Alzheimer's or perhaps the irony, is that as it progresses, the person who is losing their memory does not usually seem to mind much. They do not like the MMSE, though I try to make it really gentle. Some people are amazing at covering up. One woman answered every question, saying, "Well, that's a very good question. I think that is an important thing to talk about. That is important." Family members are often in denial and automatically start answering questions for the loved one. Alzheimer's is hardest on the loved ones because they lose the person, bit by bit and axon by axon.
One couple recently asked if I would write a letter explaining the wife's memory loss to their children. The husband initially asked and I asked for the wife's permission. She agreed. They both came in to read the letter. I felt very sad as she read it. After she read it she got out of her chair. I asked her about her back, hoping to distract her a bit. She answered and then turned and looked at the chair. "There's nothing there that is going to help me," she said. I think that she was talking about the letter. Then she said, "You know we love you." So even though it felt terribly uncomfortable to give her the letter and watch her read it, it still was right.