How good are we are diagnosing declines in our own mental abilities?
Suppose we take a group of individuals who are over 70 years of age. We test their cognitive abilities with the best tests we have. We believe that they are completely normal. They are showing no signs of decline with age. We ask them whether they feel that their cognitive abilities have declined. Anywhere between 50% and 80% will say “yes”.
Why? Clearly the “Enemy Within” is hard at work (Newsletter #017 “The Enemy Within”. Throughout our youth we absorb the negative stereotypes of ageing. We have no resistance to this “infection” since age means nothing to us when we are young. Only when it is too late, when we age, do we realize the stereotype is embedded. If you are over 70, you will think you are having “senior moments” even if there is nothing wrong.
SCD’s as a Predictor of Dementia
Doctors and scientists have become interested in these “Subjective Cognitive Declines” (SCD’s). Self perceptions of cognitive decline when objective tests would show otherwise. Everyone is looking for tools to diagnose dementia and Alzheimer’s as early as possible. The two drugs that finally offer a potential treatment are wonderful news. One was only announced this week and they have been a long time coming. Both drugs work best with the earliest possible diagnosis. The researchers speculate that SCD’s might be the “leading indicator” they desire. That of course assumes that we understand better what is happening to our ability than the tests can measure.
Early studies suggested that might be the case . In 1984 researchers were running a longitudinal study. They were testing different parts of cognitive ability. They used multiple tests for each ability and tested the same individuals every 7 years. After one administration they added a self-assessment of decline. They asked respondents whether they felt their performance had improved, declined or stayed the same, compared to seven years earlier. They expected an emotional reaction - an overall feeling. They thought that people would not separate the different abilities.
Instead they got separate and thoughtful answers for each. What they did find was an overlay of pessimism or optimism. Many people were realistic in their assessment of their changing performance. Others were consistently pessimistic and understated any improvement and over stated any decline. Others were consistently optimistic. It is importasnt to put those studies into context. They were not looking at memory specifically. They may have preceded the inclusion of Alzheimer’s within the stereotype.
The Good News and the Bad News
The good news is that a “Senior Moment” is not related to cognitive decline for most individuals. At least according to a working group who published a piece in the Lancet recently. Most of us will experience at least an occasional SCD’s. There is no wonder that, when given a questionnaire, we will tick a box saying our mind may be in decline.
The news is not all good. Individuals who get dementia are likely to have had SCD’s earlier. Doctors have come up with additional diagnostics. Perceived loss of memory rather than other mental ability losses seems to be a better predictor. There is not much evidence about other declines. If we suddenly cannot read maps or give directions, no one is sure whether it means anything. Worry about SCD’s seems to make the odds of dementia worse. Consistency of SCD’s over time increases the chances of dementia. If we sense SCD’s all the time we should be more concerned. The occasional senior moment is less of an issue. If someone else notices the decline then it is definitely time to consult a doctor.
There are many other reasons why people can suffer cognitive impairment. It has been shown that hypertension and diabetes can impact mental ability. Thyroid problems and even vitamin difficiency can cause the same symptoms. So too can medication side effects and recreational drug use. Unlike Alzheimer's these kind of declines can be reversed. They can be mitigated with medication, a healthy diet, quality sleep and the reduction of stress. Many people have mild cognitive impairment and still live a normal independent life.
The Ogre of Dementia.
For whatever reason the media likes a crisis. They have focused on the strain on the care system caused by the increasing numbers of dementia patients. There are close to 1m people in the UK now suffering from dementia. I fear when we reach the “magic number” the news will be full of it. The number is big enough that we are all know someone impacted by dementia in some way.
No one likes to think of “losing our minds”. The result of the media crisis and our fears is that dementia has become an ogre. It stalks the backwaters of our mind and frightens us. Until recently there had been no progress on a cure which made matters worse. The reality is somewhat different.
Prevalence is significantly related to age. Below the age of 80 the prevalence is less than 10%. You have less than a 10% chance of getting dementia. Below 65 it is even lower. For men this rises to 15% for those above 90. Women across the board suffer more than men. For women above the age of 90 it can rise to just over 20%.
The good news is that the global data shows that the prevalence is declining. It has been going down by about 10% per decade. One of the reasons is that we are treating and preventing cardio vascular disease. There are over 200 types of dementia. Two thirds of cases are Alzheimer’s. Twenty percent of all cases are caused by Vascular Dementia. This is caused by shortage of blood to the brain and often results from strokes.
Going forward the incidence will fall further. Within the past year there have been two successful drug trials. These drugs can slow the decline that comes with Alzheimer’s.
The ageing of the population disguises most progress. It seems that dementia is exploding. This has everything to with the fact we are all living longer. There are a lot more people over ninety. It has nothing to do with our chances of getting dementia, which is going down. Governments around the world are developing policy initiatives. These included dementia friendly communities. They are building awareness within the care system of the needs of dementia patients. Grants have been poured into research.
We should not be so afraid of “Senior Moments”. Nor can we ignore them. If you are worried don’t be afraid to see a doctor.