However, there is a difference between ‘lapses’ and the development of a serious cognitive problem. Cognitive abilities include memory, sense of time, place and person, attention, making and understanding language, judgment, problem solving and decision-making.
At the extreme end of changes in brain functioning is the brain disease called dementia. In Canada, over 500,000 people suffer from this disabling disease. Five per cent of people over age 65 are affected. Over age 80, the number grows greatly to at least twenty per cent. Over 90 per cent of dementias are of the Alzheimer’s type. The rest are related to circulatory system causes like strokes, and other diseases where the health of the nervous system declines.
Alzheimer’s type dementia usually starts with significant disruption of the connections between nerve cells, where abnormal proteins have formed in the brain. This disables the nerve transmission networks. Usually, an increasing struggle with short-term memory results. There are also episodes of confusion, difficulty following directions, problems with speech and appreciating subtle differences, and inappropriate behavior. Dementias cannot be reversed. People may live for many years with the disorder.
At a certain stage, a person is considered to have mild cognitive impairment. This is seen as a transition between the cognitive changes of normal aging and Alzheimer’s disease. Typically the memory loss is not consistent with normal aging, but does not confirm a diagnosis of Alzheimer’s disease. The concern is that more people with this condition progress to Alzheimer’s dementia. It is hoped that current research will develop drugs to prevent that progress.
The working memory is an important cognitive process vulnerable to aging. Working memory is particularly concerned with long-term memory, our ability to remember past events, solve problems, make decisions, and manipulate information to complete a task. It tends to become less stable as we age. The frontal and parietal lobes of the brain and the hippocampus play a role in this type of memory.
The hippocampus is key to encoding our memories. Disease affecting this area of the brain puts us at risk of serious memory problems. An extreme example in 1953 involved a man who had surgery for a serious convulsion disorder. Both of his hippocampal lobes were removed to stop the seizures. After the surgery, he was unable to recall recent events. He could no longer transfer new memories into long-term recollections. Events in his life were so fleeting that he could not recall from moment to moment to whom he had spoken.
Some people have extraordinary trained memories that appear to be present from birth. Brain scans show that they usually have hippocampal lobes that appear to grow rather than shrink with age. Ben Pridmore, who is about seventy years of age, is one example. He works hard to maintain his memory by routinely doing memory exercises. He is able to memorize, in a precise order, about fifteen hundred random digits in an hour. He can memorize a poem within minutes. He can remember a shuffled deck of playing cards in thirty-two seconds. Ben says anyone can do it. Stan Lee, who at age 90 is the coordinator of the Marvel Comic books, is another example. He writes, edits, and continues to do very well in the cognitive areas.
Twelve people in the world have been described as having super autobiographical memories. One of these is actress Marilu Henner. She is able to recall up to twenty occurrences that happened on any given day since she was 12. She is now 60 years of age.
Neurotransmitters are chemicals that transmit signals. Certain ones, such as serotonin and acetylcholine, are involved in memory. With age, and especially with brain damage, the tissues containing these necessary chemicals may disappear. This leaves fewer connections to transmit and maintain memory.
Our understanding of the genetics of dementias like Alzheimer’s disease is still developing. One type of Alzheimer’s disease is an inherited genetic disorder. It may begin to appear as early as in one’s thirties. If one parent has had a diagnosis of an Alzheimer’s dementia or there is a family history, the risk is greatly increased.
People who have died with Alzheimer’s disease have been found to have large numbers of protein amyloid plaques in their brains. These plaques are protein fragments that have gathered together to form hard clumps. Neurofibrillary tangles, or twisted insoluble fibres, were also found. However, some people have had these plaques in their brains, but lived into old age with no mental difficulties.
No test can diagnose Alzheimer’s disease. Although brain scans may show shrinking of areas like the hippocampus, this does not diagnose Alzheimer’s. The spinal fluid may change to include abnormal protein like tau.
An Alzheimer’s diagnosis primarily depends on evidence of significant memory loss, and progressive changes in:
A group of drugs called acetylcholinesterase inhibitors may stabilize the disease for a few years. These drugs, which include Aricept® and Reminyl®, work to maintain levels of acetylcholine. However, they eventually lose their effect. Other drugs, used for depression and to stabilize mood, may improve quality of life. All can have side effects that may require their use be stopped.
Dementias related to circulatory system causes are usually treated with medication that manages cardiovascular issues like high blood pressure.
While there is no silver bullet, extensive research suggests some strategies may help maintain our memory networks as we age. They may even help to prevent developing dementia.
Diet plays a significant role. We know that omega-3 fats and antioxidants found in various amounts in fresh produce can prevent cell damage. Foods like blueberries, salmon, tuna, walnuts and flaxseeds are particularly helpful. Lifestyle approaches such as moderate use of alcohol, not smoking, and reducing stress are also key. Regular aerobic exercise like walking, bicycling, and physical activity around the home may help protect memory.
Stay intellectually active. Activities like reading, learning a new language, using a computer, and playing games like bridge, or any other activities that stimulate the intellect, are important.
Be sure to treat any medical problem like a lack of certain vitamins, depression, or thyroid problems. Side effects of medication that cause people to act like they have dementia when they do not must be addressed.
The good news is that what we learn over a lifetime typically is remembered as we age. Our habits, once established, remain fairly stable. Vocabulary may actually improve with age. The recollection of emotional events in our own biographies may very well be maintained. Dementias do not reflect the normal aging process. There is much we can do to preserve our memories throughout our lifetime.