BioProfile analysis · brain scan

Your head is full of cotton wool and nobody tells you whether that matters. Four questions put a number on it.

Your result in 3 minutes

The result screen of the BioProfile brain scan on a phone, with a focus score of 50 and the reading band noticeable

Your focus score over the past two weeks, with the reading band it falls into and, for each question, the number that pulled your score down or up. All on your own screen, in your dashboard.

Four questions about the past two weeks: fog, focus, forgetting and the effort thinking costs you. You get a focus score from 0 to 100 with the reading band alongside it. An analysis of how you experience your thinking, never a diagnosis.

Free

4 questions

About 3 minutes

Score from 0 to 100

Fill in your first name and email address, and your focus score is in your dashboard.

Four questions that lay bare why your head will not keep up, while the rest of you is healthy

(and the scientifically grounded reason why it is exactly these four)

You read a paragraph three times and still do not know what it said. You walk into the room and have lost what you came for. Following a conversation takes effort, making a decision takes more, and by three in the afternoon your head is a radio between two stations. You are not ill. Your head is just not joining in.

The awkward thing about brain fog is that no measurement for it exists. There is no thermometer for your head, and usually no test at your GP either, so it stays a word you chose yourself for something you feel yourself. Researchers who did try to capture it kept arriving at the same list: slow thinking, trouble concentrating, confusion, forgetfulness, a haze over your thoughts. Recognisable, and still not a number.

What you can do is measure the pattern instead of the feeling: how often the fog is there, how well you hold your attention, how often you forget everyday things, and how much effort thinking costs you. Four questions about two weeks, added up into a score from 0 to 100. Not a diagnosis. But a number. And in two weeks you can lay that number next to a new one.

The first two questions of the BioProfile brain scan, about mental fog and holding your focus, each with five answer options
Questions 1 and 2 of 4. For each question you pick the answer that comes closest to your past two weeks.

Most people start at the solution

A jar of fish oil. An app with brain training. Less coffee, more coffee, a supplement from a podcast, a weekend without a screen. All understandable, and they all begin in the same place: with what you are going to do about it.

So after a month you still do not know whether it did anything. You have not recorded anywhere how foggy it was when you started, and with your own thinking your memory is a poor witness: you remember a clear day, a foggy week fades. Without a baseline, every improvement is a feeling about a feeling.

We analyse the real cause first

At BioProfile we turn the order around. First measure what is there now, with questions that follow the research into perceived thinking, and put that score next to your sleep and your mood, because that is usually where it points. Only then talk about what you do with it. Analyse first, advise after.

The brain scan is the first step of that analysis, and the shortest of them all: four questions.

The question about what you would most like to improve, in the BioProfile scan, with sharper focus ticked
The scan starts with what you want to improve.

What you get back in about three minutes

You start with eight short questions about yourself. They do not count towards your score; they make sure we can read the rest properly. One of them you may skip.

Then come the four brain questions, about the past two weeks: how often your head feels foggy, how well you hold your attention, how often you forget everyday things, and how much effort thinking takes you. Each question has five answers, from rarely to almost always.

You fill in your first name and email address. You see a first picture straight away, and with one tap on your dashboard your focus score is on your screen, with the reading band alongside it. Your email holds a login link, so you can find your result again later and expand your scan into your full BioProfile.

Start screen of the BioProfile brain scan with the button to begin
Where you land when you click the button on this page.

This is what is on your screen after about three minutes:

  • Your focus score from 0 to 100, over the past two weeks
  • The reading band your score falls into, from a lot of fog to clear
  • For each question, how heavily it weighed on your score, from low to high, so you can see where the trouble lies
  • An honest limit: what a questionnaire about your thinking can and cannot say
  • A login link in your email, so you can keep your result and repeat it in two weeks
The screen where you fill in your first name and email address to see your result
First name and email address, and your first picture is on your screen.

Repeat the scan in two weeks and you no longer have a feeling about your head, you have two numbers.

Fill in your first name and email address, and your focus score is in your dashboard.

What we ask you

This scan is about the past two weeks. You get four questions about how your thinking feels and for each question you choose the answer that comes closest to your days.

  • Mental fog
  • Holding your focus
  • Everyday forgetfulness
  • Thinking takes effort

Every question counts equally. The software then reads your answers back question by question, from low to high, so you can see which of the four pulled your score down the most.

Questions 3 and 4 of the BioProfile brain scan: everyday forgetfulness and how much effort thinking takes
Questions 3 and 4. The same two weeks, two other sides of your head.

What this scan is based on

used descriptively only

Umbrella review of subjective versus objective cognition

An umbrella review of ten meta-analyses covering roughly 92,600 people found that how people rate their own thinking correlates only around 0.14 with their measured cognitive performance. That is why we call this score experienced, why we never call it a cognitive test, and why we read it alongside your sleep and wellbeing instead of on its own.

Used only descriptively. We do not apply the diagnostic rule behind it here.

Validated for: the relationship between self-rated and measured cognition.

Umbrella review, Clinical Psychology Review, 2025.

used descriptively only

Subjective cognitive complaints and mood

Self-reported complaints about memory and concentration go together more strongly with mood and fatigue than with measured ability. Read the other way round, that is exactly what makes them useful: if this score is low, it usually points to sleep, stress or mood, and those are things you can do something about.

Used only descriptively. We do not apply the diagnostic rule behind it here.

Validated for: the link between self-reported cognition and mood.

Review of subjective cognitive complaints, PubMed Central.

What this scan cannot tell you

Experienced thinking is not measured thinking

There is no honest way to measure cognitive performance with a questionnaire. What self-report captures is experienced daily cognition, which correlates around 0.14 with measured performance and correlates far more strongly with mood and fatigue. That is why we call this score experienced, why we never call it a cognitive test, and why we read it alongside your sleep and wellbeing instead of on its own. It is also why this area is capped at average reliability and can never become high on answers alone.

BioProfile scoring rules, measurement class C, labelled as perceived, reliability capped at average.

How your score is built up

Each of the four questions gets 0 to 4 points, from rarely to almost always. The points are added up and converted into a focus score from 0 to 100. Higher is better.

0 to 39

a lot of fog

40 to 59

noticeable

60 to 79

mild

80 to 100

clear

Reading bands, not clinical cut-off values. Your questions about brain performance are written in house and modelled on validated instruments, so no published cut-off value applies to precisely this score. Higher is always healthier.

This scan falls into measurement class C: what a questionnaire measures here is experienced thinking, so the reliability of your score stays capped at average, even if you add blood values or a wearable later. What does sharpen the score is reading it alongside your sleep and your wellbeing, and that is exactly what your full BioProfile does.

On your result screen that reliability stands as a label beside your score: average reliability, experienced. That label is not an aside; it says exactly how much weight you may hang on the number.

The brain questions read back on the result screen of the BioProfile scan, each with your answer and a score from 0 to 100
This is how the software builds your score: each question gets its own number from 0 to 100, the lowest at the top.

What the science says about this

This page describes a measuring instrument, so below you can read where that instrument comes from and what has been studied about it. Every claim points to the source it appears in.

Brain fog exists, and science has no thermometer for it

In 2013 Ocon described what people mean when they use the word: slow thinking, trouble focusing, confusion, a lack of concentration, forgetfulness, a haze over your thoughts.⁠1 In 2013 Ross and colleagues put the question to 138 young adults with a condition in which the heart rate rises too steeply on standing up: 132 of them recognised the fog, and the more often and the more heavily it came, the higher they scored on a validated scale for mental fatigue.⁠2

In 2022 Callan and colleagues had fifty people with fog after COVID-19 describe in their own words what it is; the title of their study is a quote from one of them: I can’t cope with multiple inputs.⁠3 In 2015 Theoharides summed it up as reduced thinking ability, not being able to concentrate or multitask, and loss of short-term and long-term memory, and listed the conditions in which it occurs.⁠4

Four descriptions, the same list, and nowhere a number. That is why this scan exists: not to say what it is, but to measure how much of it there is.

Why your sense of your own thinking measures something different from a test

In 2014 Crumley and colleagues pooled fifty-three studies on the question of whether what older adults think about their memory matches what a memory test measures. The link was small: a correlation of 0.06.⁠5 The umbrella review that the BioProfile analysis cites arrives at around 0.14 across ten meta-analyses and about 92,600 people.⁠6 Perceived thinking and measured thinking are two different things.

That does not make the score worthless, it makes it something else. Self-reported complaints about memory and concentration are linked more strongly to mood and fatigue than to ability, and read the other way round that is exactly what makes it useful: a low score usually points to sleep, stress or mood, and those you can do something about.⁠7 That is why this number is called a focus score, and not a test.

Why these four in particular

In 2008 Mitchell lined up the studies in which people were asked about their memory: among people in whom cognitive decline had been established, 39.8 per cent reported complaints, against 17.4 per cent of healthy older people, more than twice as often.⁠8 In 2014 Jessen and an international working group set down how research into self-experienced decline ought to be carried out, precisely because that experience is sometimes there before a test sees anything.⁠9

Our four questions follow what that research asks about: the fog itself, your attention, your everyday memory and the effort thinking costs you. We worded them ourselves, after no licensed instrument, and the cards above say so in so many words.

What a low score means, and above all what it does not mean

In 2010 Lim and Dinges pooled seventy studies with 147 cognitive tests on what one night without sleep does: the largest effect was in attention slipping away, with an effect size of 0.78, the smallest in reasoning.⁠10 Van Dongen and colleagues had 48 healthy adults sleep 4, 6 or 8 hours for two weeks: at 6 hours or less the deficits in thinking performance stacked up day after day, to the level of two nights of no sleep at all, while the participants themselves said they were barely any sleepier.⁠11

Lo and colleagues found in 2016, across 35 samples and more than 97,000 older people, that both short and long sleep raised the chance of poorer thinking, by 1.40 and 1.58 times.⁠12 Rock and colleagues found in 2014, in people with symptoms of low mood, moderate shortfalls in executive functions, memory and attention, with effect sizes of 0.34 to 0.65, and part of that remained after the mood recovered.⁠13 Shields and colleagues showed in a meta-analysis in 2016 that acute stress too harms working memory and mental flexibility.⁠14

That is why this score is never read on its own: a low focus score is usually a sleep, stress or mood score in disguise. And a sudden, clear change in memory or language is not a score to follow, but a reason to see a doctor. Only a doctor can make a diagnosis.

Why your head is worth measuring

In 2010 Killingsworth and Gilbert had people report through the day, via a smartphone app, where their thoughts were: almost as often on something other than what they were doing, and that wandering generally left them less happy.⁠15

In 2018 Northey and colleagues pooled 39 randomised studies in people over fifty: exercise improved thinking ability with an effect size of 0.29, whatever cognitive level someone started from, and sessions of 45 to 60 minutes at moderate intensity or above went together with the greatest benefit.⁠16

That is correlation and effect from research and it promises nothing about your head. What it does say: perceived thinking moves along with sleep, stress and exercise, and what moves along can be followed.

This is what the scan rests on. Now your focus score.

Fill in your first name and email address, and your focus score is in your dashboard.

Written by

Jesse van der Velde

Founder of BioProfile

Jesse van der Velde

Since 2006 they have guided people towards a new body and optimal health, and have written or co-written fifteen books on nutrition and health. Forever Young (2012) and Superfood Recipes (2013) both reached number 1 in the Netherlands.

LinkedIn

Published on 27 August 2026 · Last updated on 27 August 2026

This page is written by BioProfile. BioProfile sells health products and this scan is free: no purchase comes with it. There is no validated questionnaire that measures thinking ability, and we say that out loud. Our four questions follow the research into perceived thinking and measure what you experience, never what a test would measure.

Sources

Every source below was checked on the day this page was published. The numbering follows the text: source 1 is the first one the text refers to, and the two studies the analysis reads this score against sit among them at the point where they come up.

  1. Ocon AJ. Caught in the thickness of brain fog: exploring the cognitive symptoms of Chronic Fatigue Syndrome. Frontiers in Physiology, 2013. doi.org/10.3389/fphys.2013.00063
  2. Ross AJ, Medow MS, Rowe PC, Stewart JM. What is brain fog? An evaluation of the symptom in postural tachycardia syndrome. Clinical Autonomic Research, 2013. doi.org/10.1007/s10286-013-0212-z
  3. Callan C, Ladds E, Husain L, Pattinson K, Greenhalgh T. ‘I can’t cope with multiple inputs’: a qualitative study of the lived experience of ‘brain fog’ after COVID-19. BMJ Open, 2022. doi.org/10.1136/bmjopen-2021-056366
  4. Theoharides TC, Stewart JM, Hatziagelaki E, Kolaitis G. Brain ‘fog’, inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin. Frontiers in Neuroscience, 2015. doi.org/10.3389/fnins.2015.00225
  5. Crumley JJ, Stetler CA, Horhota M. Examining the relationship between subjective and objective memory performance in older adults: a meta-analysis. Psychology and Aging, 2014. doi.org/10.1037/a0035908
  6. Umbrella review, Clinical Psychology Review, 2025. sciencedirect.com
  7. Review of subjective cognitive complaints, PubMed Central. pmc.ncbi.nlm.nih.gov
  8. Mitchell AJ. The clinical significance of subjective memory complaints in the diagnosis of mild cognitive impairment and dementia: a meta-analysis. International Journal of Geriatric Psychiatry, 2008. doi.org/10.1002/gps.2053
  9. Jessen F, Amariglio RE, van Boxtel M, et al. A conceptual framework for research on subjective cognitive decline in preclinical Alzheimer’s disease. Alzheimer’s and Dementia, 2014. doi.org/10.1016/j.jalz.2014.01.001
  10. Lim J, Dinges DF. A meta-analysis of the impact of short-term sleep deprivation on cognitive variables. Psychological Bulletin, 2010. doi.org/10.1037/a0018883
  11. Van Dongen HPA, Maislin G, Mullington JM, Dinges DF. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep, 2003. doi.org/10.1093/sleep/26.2.117
  12. Lo JC, Groeger JA, Cheng GH, Dijk DJ, Chee MWL. Self-reported sleep duration and cognitive performance in older adults: a systematic review and meta-analysis. Sleep Medicine, 2016. doi.org/10.1016/j.sleep.2015.08.021
  13. Rock PL, Roiser JP, Riedel WJ, Blackwell AD. Cognitive impairment in depression: a systematic review and meta-analysis. Psychological Medicine, 2014. doi.org/10.1017/S0033291713002535
  14. Shields GS, Sazma MA, Yonelinas AP. The effects of acute stress on core executive functions: a meta-analysis and comparison with cortisol. Neuroscience and Biobehavioral Reviews, 2016. doi.org/10.1016/j.neubiorev.2016.06.038
  15. Killingsworth MA, Gilbert DT. A wandering mind is an unhappy mind. Science, 2010. doi.org/10.1126/science.1192439
  16. Northey JM, Cherbuin N, Pumpa KL, Smee DJ, Rattray B. Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. British Journal of Sports Medicine, 2018. doi.org/10.1136/bjsports-2016-096587

Start your brain scan

Four questions, about three minutes, and your focus score is in your dashboard. Your answers stay private (GDPR).

Fill in your first name and email address, and your focus score is in your dashboard.

Other scans

What this does not say. This is not a cognitive test and not a screening for progressive memory loss or attention disorders. How people judge their own thinking lines up only around 0.14 with measured performance, and self-reported complaints line up more strongly with mood than with ability. A sudden, clear change in memory or language, or fog that gets worse instead of coming and going, belongs with a doctor and not in a score.