Forgetfulness or cognitive decline: what is the difference?

Everyone forgets things

You go upstairs and cannot think why. A name you know perfectly well will not come. You hunt for your keys and they turn out to be in your coat pocket.

These moments are part of life, and they happen more often as you get older. Your brain takes longer to process what comes in than it did at thirty, and you need more time to store something new. That is not an illness. It is ageing, in the way your eyes become less sharp.

What stays with people is the question underneath: how do I know whether mine is ordinary ageing too?

What we call ordinary forgetfulness

Ordinary forgetfulness tends to be about small, everyday things. You forget where you put something, you search for a word, you miss an appointment that comes back to you later in the day.

Two things are typical of it. It is temporary: the information is still there, you simply cannot reach it straight away. And it does not stop you. You do your shopping, you drive, you handle your affairs the way you always did.

What cognitive decline means

Cognitive decline is broader than memory alone. It is about brain functions working less well, and memory is one of them. It also covers:

• holding attention and concentration
• planning and organising
• solving problems you never had to think about before
• knowing where you are or what day it is
• language: finding the right word, following a conversation

Decline also means it has a direction. It is not about a bad week, but about something that changes gradually over months or years.

Where the difference lies

No single incident settles it. What does give you something to hold on to are four questions.

Does it happen more often than it used to? Not more often than for someone else, but more often than for you a year or two ago. You are your own reference point.

What does it affect? Losing a name is not the same as losing your way in a neighbourhood you know. The more automatic something used to be, the more it says when it now takes effort.

Do other people notice it too? This may be the most useful signal of all. People who see you daily often spot changes before you do, because you do not notice the adjustments you make.

Is it getting in your way? As long as you are doing what you always did, something different is going on than when you start avoiding things or leaving them undone.

Why one moment says little

Everyone has off days. Poor sleep, stress, a cold, medication, too much to drink the night before: all of it affects how well your head works. Test yourself on a day like that and the result will alarm you, while nothing has changed.

That is why a single measurement is not an answer. What does say something is a series: the same measurement, repeated over months, in which you can see what is usual for you and whether there is a direction in it. An outlier then stands out as an outlier, rather than as a verdict.

What you can do yourself

This is the part that tends to get lost. A considerable share of dementia cases is connected to factors you can influence. Researchers at Maastricht University brought these together in the LIBRA score: fifteen factors, among them blood pressure, exercise, smoking, sleep, hearing, mood and seeing people.

That is not a guarantee, and nobody can promise that living well will keep everything at bay. It is the opposite of waiting helplessly, though, and it works at any age.

Read about the fifteen lifestyle factors

When it is time to do something with it

If several of the four questions above ring true, and it persists, it is wise not to carry it on your own. Talk it over with someone you trust and who knows you well enough to look with you. Two sets of observations are more reliable than one, and it saves you from turning it over alone.