4.4.2016 How Your Body, Brain and Memory Change with Alzheimer’s by Mary Yamin-Garone
Good Afternoon. Welcome to Demystifying Alzheimer’s. I’m your hostess Mary Yamin-Garone.
Today’s topic is “The New Normal: How Your Body, Brain and Memory Change with Age.”
It wasn’t that long ago that physical frailty and chronic memory loss were considered natural signs of old age. Doctors knew very little about normal, healthy aging because relatively few people lived past age 65. In 1990, the average life expectancy in the United States was 47. In 2013, it had risen to 76 for men and 81 for women.
In 2004, 12 percent of all Americans were 65 years of age and over. By 2050, there will be 86.7 million people over 65, accounting for 21 percent of the U.S. population.
Until recently, doctors repeatedly diagnosed seniors with a blanket condition known as senile dementia. Senility, as defined in the dictionary, means old age. Physical and mental deterioration were presumed to be part and parcel of the illness. Some of that thinking was based on scientific beliefs about our brains that have only recently changed.
Until the late 20th century, scientists believed we were born with all our brain cells already formed. They also believed that deterioration of the brain was a normal part of aging as cells died off in large numbers.
In the 1990s, impressive scientific discoveries were made that showed that neurons can divide, propagate and develop into functional new nerve cells in the brain. This process, known as neurogenesis, occurs in the hippocampus (a center of learning and memory) and in the part of the brain that regulates our sense of smell. This discovery led to radical rethinking of the function—and dysfunction—of the human brain.
Did you know your brain reaches it maximum weight when you’re about 20 years old and slowly loses about 10 percent of its weight over your lifetime? That’s because neurons shrink and synapses—the connections between the neurons—gradually deteriorate. Your brain’s supply of neurotransmitters, or chemical messengers, diminishes and communication slows. This impedes your ability to think, remember and calculate quickly. In most cases, these changes are just a nuisance that don’t interfere with your ability to perform activities of daily living.
Like the rest of our bodies, our brains go through predictable changes over time. Memory experts at John Hopkins University Medical School have developed a timeline of how the normal brain ages.
Between the ages of 20 and 30, you’re normally at the top of your mental game. Your memory is sharp, whether you’re recalling details of your childhood, an intricate project or what you and your friends talked about last weekend. Your reasoning skills are strong and your creativity may be at its peak. Normal neuron shrinkage causes minor physical changes in your brain.
In your 30s, a series of cognitive tests might show declines from the previous decade but most of those changes are so minor that neither you or anyone else will notice. Normal neuron shrinkage continues as your brain slowly loses its volume.
In your 40s, you may sense some slowing of your mental processing, especially when it comes to your short-term memory. The slow loss of brain volume continues and may start to accelerate. Recalling phone numbers may get a little fuzzy and calculating tips or playing challenging card games may not be as easy as they used to be.
You cross a threshold in the years between 50 and 60. It’s a time of accelerated brain volume loss and there are more noticeable changes in your memory, thinking and learning. Most of us need more time to remember names and words and to learn something new. Multitasking gets more difficult and your attention to detail wanes. You also may find that placing an event in time and place becomes harder. You might remember a phone conversation but not when or where you were when you had it. Visual-spatial processing, such as how easily you can finish a jigsaw puzzleor retrace your steps in an unfamiliar place—may get harder.
The cognitive changes that start in your 50s become more noticeable. You might find it harder to concentrate, learn new information or master complex mental tasks. Your brain has to work harder to form new memories and to recall names, dates and words. Loss of brain volume continues. Brain structures critical to memory and other cognitive abilities may have shrunk by as much as 25 percent.
Cognitive abilities of individuals in their 70s and 80s vary widely. You might stay sharp during these years, gaining perspective, even wisdom. This also is the time when body stressors, such as high blood pressure, diabetes, smoking and heavy drinking, will have taken a toll on your memory and general cognitive ability. Individuals who develop dementia usually begin to exhibit signs of the disorder in their mid-to late seventies. Normal memory loss is frustrating but doesn’t diminish your ability to perform activities of daily living. With Alzheimer’s, memory loss is incapacitating.
Now that you have an idea of how a normal brain ages, this is what happens to a brain with Alzheimer’s.
Alzheimer’s leads to nerve cell death and tissue loss throughout the brain. Over time, your brain shrinks dramatically, affecting nearly all of its functions.
In an Alzheimer’s brain:
· The cortex shrivels up, damaging areas involved in thinking, planning and remembering.
· Shrinkage is especially severe in the hippocampus and
· Ventricles (fluid-filled spaces within the brain) grow larger.
Scientists can also see the terrible effects of Alzheimer’s disease when they look at brain tissue under the microscope
· Alzheimer’s tissue has many fewer nerve cells and synapses than a healthy brain.
· Plaques, abnormal clusters of protein fragments, build up between nerve cells and
· Dead and dying nerve cells contain tangles, which are made up of twisted strands of another protein.
Scientists are not absolutely sure what causes cell death and tissue loss in the Alzheimer’s brain but plaques and tangles are the prime suspects.
Researchers have discovered so much about how the brain works that it can be tempting to think of someone just in terms of their brain and that changes in their behavior are caused entirely by damage to their brain.
This is a mistake.
Our behavior does reflect changes in our brain. But it also depends on our attitude, life experiences, environment and how others relate to us—whether we have dementia or not. It’ s important to focus on what a person with dementia can still do or feel, not just on what they might have lost. This will help support them to live well with the condition.
That’s all for today. Thanks for listening. I hope this information was helpful.
Join me at 1 pm Saturday when I’ll discuss the stages of Alzheimer’s.