Brain shrinkage is normal as we age — it happens to us all. It sometimes correlates with reduced mental faculties — but not always. Despite that, some doctors, hospitals, and attorneys can (and have!) used this normal shrinkage as “proof” of mental deterioration. Here’s how to protect yourself from both the shrinkage and from those who would use it against you.
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How much is your brain shrinking?
The volume and/or weight of human brains shrinks about 5% per decade, starting at age 40. There are a tiny number of studies which suggest this normal rate of shrinkage may increase after the age of 70. What we do know is that by age 75, our brain is an average of 15% smaller than it was at 25.
Most knowledge of aging brains comes from insufficient studies and participants, and with complicating factors not properly controlled for. For example, scientists are unsure whether the actual number of brain cells decline, or if it is more the volume of each neuronal cell that declines. White matter in our brains also declines and lesions start forming in it. This starts at the age of 40, but it happens in normal aging as well as aging which brings reduced mental capacity.
Why I’m refusing to let any hospital take a MRI of my brain(!)
My Medical Power of Attorney document threatens a lawsuit against any hospital which conducts an MRI on my brain — for any reason — without my written permission. Why? Because a hospital treating my mother did exactly that to her — then told me they would support me if I wanted to legally take over my mother’s affairs because they had proof (the MRI) of her mental incapacity (her shrunken brain).
Mother went in the hospital because she had been non-responsive when one of her visiting helpers arrived. Once mother woke up, she was refusing several of the the medications the doctors wanted to give her and demanding to go home. The hospital did an MRI on her brain without telling her why, then told me these results.
I was stunned, because mother at 89 had shown no signs whatsoever of dementia or Alzheimers. She was still running her life as she saw fit, still completely lucid in our weekly talks. Still smart as a whip. I told the hospital that while they (and I!) might not like mother’s choices, she was still completely capable of making her own decisions.
Then I researched this idea of a brain shrinkage and found out it happens to EVERYONE. The idea that they would support me taking away her independence for something that happens to everyone — I see it as incredibly evil.
Which parts of your brain are most affected?
If you look at brain volume, the prefrontal cortex is most affected and the occipital lobe (involved in visual processing) is the least affected. Interestingly, men and women seem to differ on which brain areas show the most shrinkage.
- For men, the frontal and temporal lobes are most affected.
- The frontal lobe (red in the drawing), has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior. It also plays a large role in voluntary movement and houses the primary motor cortex which regulates activities like walking.
- The temporal lobe (purple/black in the drawing) is involved in processing sensory input into derived meanings for the appropriate retention of visual memory, language comprehension, and emotion association.
- For women, it’s the hippocampus and parietal lobes that are most affected.
- The hippocampus (the purple worm between the corpus callosum and the thalamus in the drawing) plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation.
- The parietal lobe (teal in the drawing) is involved with a huge number of functions (click on this link to see which).
How your brain compensates for this shrinkage(!)
Your brain doesn’t just take this shrinkage lying down. No, it has two active methods to compensate and keep us mentally healthy:
- Dendritic Sprouting. Brain function isn’t only a matter of how many cells we have, it’s also how good the connections (synapses) are between them. While some studies show a decrease in synapses or loss of synaptic plasticity, other studies show “dendritic sprouting” where the brain sprouts more dendrites in order to maintain the same number of synapses we had before — thus compensating for any cell death. (Go brain!)
- HAROLD. Our brains also compensate by “HAROLD” (Hemispheric Asymmetry Reduction in Older Adults). Our right and left brain hemispheres normally specialize in functions. However, if there is damage in one hemisphere, our brain can change the other hemisphere to try to compensate. Older adults show less specialization in the two hemispheres. Thus electrodes in older brains will show activity in the right hemisphere as well as the left for language, whereas for younger adults language resides solely in the left hemisphere. (I LOVE picturing Harold (one of my brothers’ names) looking out for me from on high by expanding my brain into new areas to compensate for any shrinkage problems!)
How you can help your brain compensate
There are seven factors that we control that can help our brains to compensate.
- Alcohol. Remember when we learned that alcohol kills brain cells? And we laughed about it? Well, that party should be mostly over. However, not all alcohol need be off the table. Studies show a “U” shaped curve that is bad news for teetotalers and for heavy drinkers, while no more than one drink a day (women) or two (men) shows reduced brain problems — even reduced dementia(!) (Instead of that one drink/day, we could replace it with some added polyphenols in our diets. They can come from grapes or supplements.)
- Exercise. Our reduced prefrontal cortex hurts “executive function,” but exercise increases it. Exercise also slows reduction in white and grey tissue density. AND it lowers our cardiovascular risk (see number 5).
- Diabetes. People with diabetes had faster shrinkage in the brain region called the hippocampus, which is involved with memory.
- Smoking. Smokers had more rapid overall brain shrinkage than nonsmokers, and also showed faster white matter changes.
- Cardiovascular and stroke risk factors. Anything that reduces our risk of heart attack or stroke will help slow brain shrinkage. High blood pressure is especially likely to create lesions in our white matter — which can (but may not) lead to dementia. Studies also show raised systolic blood pressure was related to grey matter volume loss.
- Being overweight or obese. People who were overweight or obese in middle age were more likely to be among the top quartile of those with the fastest rates of decrease in brain volume and the most rapid declines in executive function.
- Increased cognitive effort in the form of education or occupational attainment. Environmental factors such as schooling and occupation appear to contribute to a “cognitive reserve” that protects us against mental decline. This does not mean playing mental games will protect us (studies have not shown it), but instead finds a benefit to higher level schooling and occupations that use our minds. However, all that didn’t prevent my attorney father from getting Alzheimers.
(Note on references: While I researched a number of articles for this post, the best, clearest source, complete with its own references can be found here. Another excellent source is this Time article.)
Author bio
Marlene Jensen is a 71-year-old full-time marketing professor. Previously she was a VP at CBS and ABC and spent decades as an entrepreneur and pricing author/consultant. Sadly, none of these prepared her for the onslaught of marketers who now think her daily interests/needs consist solely of hearing aids, wheel chairs, adult diapers, medi-alert buttons, medications, and bath tubs you walk into.