Short term vs long term memory loss: What’s the difference?
When memories are made, they are saved in either your short term memory or long term memory, and understanding how they differ is vital for helping to understand dementia symptoms
In a nutshell
Your brain is taking in and processing thousands of facts, thoughts and experiences every single day. Some of these will be stored in the brain for a few seconds or minutes and then forgotten, others remain there for a few days, while some will be ingrained for many years or even a lifetime.
Our ability to recall these thoughts are what form the basis for memory, and it can be defined as either short term memory, or long term memory.
What is short term memory?
Remembering what you ate for breakfast this morning, or the TV show you watched last night are what constitutes short term memory. It is sometimes called primary or active memory.
In most cases, these short term memories will remain there for anywhere between 30 seconds and several days. Many will be forgotten (nobody can remember what they ate for breakfast for the last 10 years) – effectively pushed out of the brain to make way for new facts and memories.
However, some things will remain, especially if we make a conscious effort to remember them. They are transferred to an area of the brain that stores long term memories. This area is called the frontal lobe.
What is long term memory?
Long term memory refers to events, facts or experiences that were laid down weeks, months or even years ago.
Your brain makes millions of ‘decisions’ every day about whether to store facts and experiences and in what part – short term or long term memory. If you decide that you have to remember something – for example, when studying for a test – the brain makes connections between the cells, which alters their structure, and is what allows us to retain memories.
Sometimes things that you may not have intended to remember are stored in your long term memory. For example, a fun day out at the fair when you were a child or the death of a much-loved pet. The reason you remember these is because they are often very strongly linked to a particular emotion or sensory experience. You remember the day at the fair because you had fun, laughed or were even scared on the rides. You remember the death of your dog because it was a particularly sad experience.
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Fact worth knowing
Long-term memory can be divided into other types including declarative memory (memory of facts) and procedural (unconscious memory of skills such as tying a shoe lace).
What does all this mean for someone with dementia?
People living with dementia can often remember events that happened when they were very young – stored in their long-term memory – but struggle to remember what they did yesterday or last week.
This is because changes in the brain caused by diseases such as Alzheimer’s and vascular dementia affect the short term memory first. Learned long-term memories may eventually be affected, but not until much later.
Good to know
The sooner you recognise issues surrounding short term memory loss, the sooner you can see a doctor for a proper diagnosis. The doctor will be able to assess, in quite some detail, exactly how serious your memory loss is and suggest ways to help.