Memory loss: When should you worry?

AS you read this, you will probably be able to relate to at least one of these moments: suddenly not remembering a word, a book or a movie's name (and finding you have to Google it), or forgetting a friend's name (I regularly cycle through all my brothers' names before I hit on the right one). Or having that word on the tip of your tongue but not being able to recall it for love of life or money.  

“Some people simply have a less organised mind, and people also have different observational capacities," says John Wilkinson, a Cape Town clinical psychologist with extensive experience working with Alzheimer's patients.

“So being unable to find your car keys is usually just a scattiness. You come into the house and your mind is already going on to the next thing, so your memory bank is not filing the information of where you put your keys. That is entirely normal. And so is forgetting a name or a word. Some form of age-related memory loss is also entirely normal. The time to start worrying is when your memory loss starts affecting your ability to function normally."

Memory

Memory is less like a filing cabinet and more like a set of processes that work together.

Our long-term memory works like an archive system for storing, managing, and retrieving information. And in dementia patients, this memory usually stays intact. 

Short-term memory is different. It holds small amounts of information — related to what our brains are processing at that specific time — and retains it only for short periods. That's why it's often compared to a computer's RAM (or Random Access Memory). Short-term memory is essential for making decisions and mental calculations, and in dementia patients it is the short-term memory that becomes impaired, weakening someone's ability to complete everyday tasks.

Normal problems

Because of how our short-term memory works, many kinds of forgetfulness fall within the normal range and should be no cause for concern. Harvard Medical School outlines seven types of memory lapses.

The three most prevalent everyday issues are absent-mindedness, transience and memory blocks.

Absent-mindedness is the where-did-I-put-my-keys or did-I-take-my-pills type of forgetfulness and happens when you don't pay close enough attention, so your brain doesn't encode the information.

Transience relates to bits of information that get lost if not used. Memory has a use-it-or-lose-it quality, and brain scientists regard this as beneficial because it clears the brain of unused memories, making way for newer, more useful ones.

Then there is the at-the-tip-of-your-tongue temporary inability to retrieve a memory. This is blocking, which happens when a memory similar to the one you're looking for intrudes and stops you finding the one you really want. Memory blocks are believed to become more common as you get older because the ageing brain becomes less agile.

Misattribution is another form of forgetfulness that becomes more common with age but is entirely normal in younger people. This is when you get a small detail in a memory wrong — like the time, place or person involved. Or when you think something you previously heard or read is something original you came up with.

Misattribution becomes more common with age because the ageing brain often becomes less adept at rapidly concentrating and processing information and absorbs fewer details. As you grow older, your memories grow older as well, and old memories are especially prone to misattribution.

Two other interesting features of how our memory works, suggestibility and bias, can lead you to believe that you might have a cognitive issue. Suggestibility is not about forgetfulness per se, but when information you learn after an event somehow shows up in your memory of the incident. Bias, which “includes experiences, beliefs, prior knowledge" according to Harvard Medical School, can affect the memory because it is encoded in your brain, influencing the information you recall. This explains why different people recollect the same event differently.  

Finally, there is the opposite of forgetting. Persistence is when people are tormented by memories they wish they could forget, such as fears, traumatic events or negative feelings. Some memories can accurately reflect horrible events, while others can distort events.

None of these memory problems is an indication of dementia.

Sleep, nutrition and medication

Scientists have established that Rapid Eye Movement (REM) sleep is vital for storing memories. This study provides the most direct evidence to date that REM sleep may play a role in how the brain decides which memories to store.

Getting enough sleep, which has been found to be critical for so many areas of physical health, is increasingly seen as a critical protection against dementia.

This (small) study found that just one night of bad sleep led to increased beta-amyloid, a protein in the brain that is associated with impaired brain function and Alzheimer’s disease. 

Nutritional deficiencies can also play a role: vitamin B12, for example, is essential for normal nerve functioning and memory. 

Sometimes, memory loss is caused by other age-related physical changes such as menopause, which can produce the dreaded brain fog (been there, done that).

Some medical issues also raise their ugly head in relation to memory loss. Some diabetes and cholesterol medications can cause memory loss, as can chemotherapy.

What is average age-related memory loss?

Studies suggest our brains peak between the ages of 35 and 44. As we get older, neurons slow down, certain areas shrink and blood flow decreases, which can slow down our ability to solve problems or remember information.

Some form of age-related memory loss is expected. About 40% of people older than 65 will have a diminishing memory, but only 1% will progress to dementia. This is according to the US National Institutes of Health. But this is only cheering news if you don't fall into the 1% who will forget how to dress themselves or recognise their children, and who live in a parallel universe of disconnected reality.

Other research found memory lapses in highly educated people could point to undetected silent strokes that change brain function and deplete memory. (OK, this one worries me. I saw it in my father.)

If your memory lapses are minor and occasional, it’s considered normal age-related memory loss.

John Wilkinson says one of the first indications that age-related memory loss could become diagnostic — and point to dementia — is when someone's vocabulary starts decreasing. They have to pause frequently to try to retrieve words or memories. Or they keep repeating themselves.

Another is when basic functions start being affected. Such as suddenly not being able to do routine tasks like buttoning a shirt or paying bills without having to think. Or suddenly not knowing where you are. A deterioration in basic hygiene is usually the most apparent indicator of dementia.

“Over time, Alzheimer's, the umbrella term we use for various forms of dementia, affects long-term memory, so the person keeps losing more and more of their old self. The last to go are the youngest memories, usually from childhood.”

Dementia is not a normal part of ageing. Memory loss, though common, is also not the only sign of dementia. It includes a broad-spectrum loss of cognitive functioning — thinking, remembering, learning and reasoning. People with dementia may also have problems with language skills, visual perception or paying attention. 

The brain is a muscle

It’s not a foregone conclusion that you’ll slip into a permanent mental fog the older you get. The brain is like a muscle, and you have to exercise it.

Our brains have around 100-billion nerve cells that work together to keep our brains sharp and functional. 

A recent paper in the journal Brain Sciences brings together much of what we know from previous research in brain health. The researchers went to great lengths to be thorough in their theoretical perspective paper and offered 101 references to articles on keeping our grey and white matter in shape.

“The keys to our nervous system are the grey and white matter,” says Hermundur Sigmundsson, the study leader and a professor in psychology at the Norwegian University of Science and Technology.

Roughly speaking, the grey matter consists of the nerve cells — or neurons — and dendrites. The white matter provides the contacts between the cells (myelinated axons) and contributes to transmission speed and signal distribution.

Sigmundsson says three factors stand out if you want to keep your brain at its best.

“An active lifestyle has been shown to contribute to the development of the central nervous system and to combat brain ageing. Interpersonal relationships and interactions have been shown to contribute to complex biological factors that benefit the cognitive resilience to decline. Furthermore, the current scientific literature suggests that passion and strong interest could be the driving factor motivating individuals to learn new things, thus influencing the development and maintenance of the neural functional network over time."

♦ VWB ♦

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