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Page last reviewed: 13/07/2011

It's normal to become a bit forgetful as you get older. However, memory loss could be a symptom of something more serious and should be checked by a GP.

Memory loss, also called amnesia, occurs when a person loses the ability to remember events and information they would normally be able to recall. This could be something that happened only seconds or minutes ago, or a memorable event that happened in the past. The memory loss may have started suddenly or may have been getting worse over the last year or so.

Memory loss can be distressing, for the person affected as well as for their family. Relatives may fear the worst and assume it's causedby dementia, but this often isn't the case.

The following information will tell you:

  • what to do if you're worried about memory loss
  • how to tell if it could be caused by dementia
  • the most common causes of memory loss (but don't rely on this to self-diagnose a condition)
  • how to cope with a poor memory

What to do if you're worried about memory loss

If you're worried because you or someone you care for has lost their memory, see your GP. They'll do an initial assessment and ask questions about symptoms, family history and lifestyle. They may also order a blood test.

Memory loss has a wide range of possible causes, depending on the type of memory loss.

Doctors classify memories as either:

  • Immediate memories, such as sounds, which are only stored for a few seconds.
  • Short-term or recent memories, such as telephone numbers, which stay in your memory for 15-20 seconds. The brain can store about seven chunks of short-term information at any time.
  • Long-term or remote memories - more permanent memories, which have been reinforced because you've repeatedly gone over them in your mind.

If your GP thinks that you or your relative needs an assessment for dementia or that there may be another more serious underlying condition, such as brain damage, they'll refer you to a specialist.

Could it be dementia?

If you're reading this because you think your memory problems may be a sign of dementia, rest assured that they probably aren't. A person with dementia will not usually be aware of their memory loss or will deny it.

Your memory loss is likely to be caused by something a lot more common and treatable, such as depression (see below).

You may be worried that someone you care for has dementia. However, bear in mind that around 40% of people aged over 65 have some kind of memory difficulty, and only 15% will develop dementia each year.

Signs that someone has dementia

As a general guide:

  • Dementia usually occurs in people over the age of 65.
  • Someone with dementia will struggle to remember immediate or recent events, but can still recall events that happened a long time ago. Therefore, if their long-term memory is affected, it probably isn't dementia.
  • The memory loss doesn't happen suddenly but gets gradually worse over time.

Common causes of memory loss

Generally, GPs find that patients who see them about memory loss are most likely to have:

  • anxiety
  • stree
  • depression

Their memory loss is due to poor concentration and not noticing things in the first place because of a lack of interest. Sleeping problems make the memory loss worse.

Your GP may suggest trying antidepressant tablets. If their assumption is correct, these should improve the memory problems as the depression lifts.

An elderly person with memory loss is likely to have depression if they also experience changes in behaviour, such as hoarding or being bad tempered.

Other common causes of memory loss are:

  • a head injury, for example after a car accident
  • a stroke that cuts off some of the blood supply to the brain and causes brain tissue to die

These will cause sudden memory loss, where you either forget events that happened before the trauma (retrograde amnesia), or you forget everything that happened after the trauma (anterograde amnesia). 

Less common causes of memory loss

Less commonly, memory loss can be caused by:

  • an underactive thyroid, which means your thyroid gland (found in the neck) does not produce enough hormones
  • certain types of medication, such as sedatives and some treatments for Parkinson's disease
  • long-term alcohol misuse
  • bleeding in the brain, known as subarachnoid haemorrhage
  • vitamin B1 (thiamine) deficiency for example because of a digestive problem
  • problems with blood flow to part of the brain, which cause sudden episodes of memory loss that a person cannot recall afterwards (known as transient global amnesia) 
  • a stressful or traumatic event that causes someone to block out the memory, leaving them unable to remember important information (known as psychogenic amnesia)
  • a brain tumour

Tips for coping with a poor memory

  • Keep everyday items, such as car keys, in the same place and try to do things in the same order each time.
  • Write information down and keep paper and a pencil near the phone.
  • Keep a diary at home as well as at work to remind you to do daily tasks.
  • Use an alarm to help you remember to do something in the future, such as taking something out of the oven.
  • Repeat back to someone important information you need to remember.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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