Concentration problems: what poor concentration looks like, where it comes from and what a brain fog scan measures

What poor concentration looks like

In this article you will read how concentration problems feel from the inside, which causes have really been measured, which options have been tested, and what a scan can and cannot show you. That matters, because these complaints are common and rising: in the first quarter of 2023, adults aged 25 and over went to the GP with memory and concentration problems 24% more often than in the same quarter of 2020, a figure from the seventh quarterly study by Netwerk GOR that rests on the GP registrations of Nivel Zorgregistraties Eerste Lijn.⁠¹ The brain fog scan from BioProfile measures how much of these complaints you notice, and gives you an indication of where you stand today in this area, as one of the 11 health areas the full scan assesses. This is not a diagnosis. It is self-insight, to see where you stand today, and to help you make better choices in your food and your daily life. What this scan does not do: point to a cause or name a condition. Only a doctor can do that.

In measurements, concentration problems first show up as lapses, the brief moments when attention simply drops away. A meta-analysis pooled 70 articles with 147 datasets, every participant an adult of 18 or over and the total sleep loss never more than 48 hours. Of six cognitive categories, lapses in simple attention showed the largest effect of short sleep loss: Hedges g = -0.776, 95% CI [-0.96, -0.60], p < .001. The accuracy of reasoning showed the smallest effect and was not significant: g = -0.125, 95% CI [-0.27, 0.02].⁠² In plain words: thinking a problem through slowly holds up reasonably well, and what gives way is the dull, continuous attention that a page of homework, a meeting or a drive home asks of you. That is the familiar description, that your head still works but nothing stays in it.

Causes of concentration problems: what has been measured

Stress is the second measured cause. Out of a final sample of 51 studies with 2,486 participants and 223 effect sizes, all without a known mental or psychiatric disorder and tested in a single laboratory session, 34 studies with 1,353 participants and 164 effect sizes were about working memory. A single moment of acute stress lowered performance there: g+ = -0.197, 95% CI [-0.330, -0.064], p = .005. The drop was larger when the task load was high (g+ = -0.303, p = .005) than when the load was not high (g+ = -0.049, p = .404).⁠³ What that means on a working day: a stressful morning does not flatten your whole head, but it takes the hardest work off your desk while the easy parts still run.

Water is the cause you can change within an hour. In a randomised controlled trial, 76 young adults aged 18 to 23 went 24 hours without water, and the score on the portrait memory test fell from 34 points at baseline to 27 points, p < 0.001. After water was given again, the groups that drank 1000 mL and 500 mL scored higher on the operation span test of working memory, p = 0.009 and p = 0.005.⁠⁴ So a day of drinking too little is not a small thing for your attention.

Thuisarts also names the causes of memory complaints that belong on your own list first: stress and major life events, certain medicines such as sleeping pills and medicines for the bladder or the prostate, alcohol and drugs.⁠⁵

Concentration problems with homework, screens and two things at once

The idea that heavy media use wears down your attention is weaker than it sounds. Two replication studies among students, one at Universitas Gadjah Mada and one at the Rijksuniversiteit Groningen, ran 14 tests with an average replication power of 0.81, and only 5 of those 14 gave a statistically significant effect in students with higher scores for media multitasking. A meta-analysis across 39 effect sizes from all studies published up to 2017 found a weak but significant link between media multitasking and distractibility, and that link became non-significant after correcting for small-study effects.⁠⁶ So it has not been shown that a phone next to your homework permanently wears down your attention. What a phone does do is split the hour you sit there, and the advice that has held up is simpler: do one task at a time, and write things down in a diary or planner.⁠⁵

What you can do

Exercise has the clearest effect in the short term. One Bayesian model pooled 651 effect sizes from 113 studies, together 4,390 participants aged 18 to 45, on single bouts of exercise. The benefit for cognition was small: Hedges g = 0.13 plus or minus 0.04, BF = 3.67. Reaction time on cognitive tasks was shorter after one bout of exercise (g = 0.27, HDI [0.18, 0.36]), while accuracy did not change (g = 0.04).⁠⁷ Read that as speed rather than correctness: a walk makes you faster at the task in front of you. Across the week, the Dutch physical activity guideline of 22 August 2017 asks adults for at least two and a half hours of exercise at moderate intensity, to keep moving more and sit still less, and names muscle and bone strengthening activities as recommended.⁠⁸

Caffeine does something small and limited. In a randomised, placebo controlled, double blind crossover test at home, 53 adults with a mean age of 36 years, standard deviation 14 years, completed all four sessions. One dose of 85 mg shortened reaction time on the Go-No Go attention test by about 10 ms, P = .02, while accuracy did not change, and the same dose gave no significant effect on reaction time in the coding and n-back tests.⁠⁹ For scale: a 125 ml cup of filter coffee contains about 60 mg of caffeine, a 125 ml cup of black tea about 30 mg, a 250 ml can of energy drink about 80 mg, the advice for adults is no more than 400 mg a day, and in people who are sensitive to caffeine 100 mg at once can affect sleep duration and sleep pattern, certainly a few hours or less before bedtime.⁠¹⁰ In short, one coffee earns you milliseconds on a simple task, and a late coffee can cost you the night your attention leans on.

What a brain fog scan measures, and what the scan does not measure

The scan asks a short set of questions about the past two weeks: how clear your head feels, how often you lose the thread, how much effort sustained attention takes. The answers are given points, the points are added up and converted into a score from 0 to 100, with the reading band the score falls into. Higher is better. What you get is a picture of how much of this you are carrying, and a baseline you can repeat in two weeks.

A questionnaire cannot attribute that picture to anything. Short sleep, one hard week, a medicine on your list, alcohol, a day of drinking too little: in a set of questions they all read the same.⁠⁵ It is not a diagnosis. Blood values, a look at your medicines and sleep data are the layers that take a picture of complaints to an explained picture, and you ask a doctor for those. Where a foggy head comes from in the wider sense is covered in brain fog: what it is and where it comes from.

Thuisarts names the moments to call your GP on a working day: the feeling that your memory is getting worse quickly, complaints that get in the way of the ordinary things in your day, complaints that keep getting worse and are no longer as they were, and the feeling that you have more trouble with your memory than other people do.⁠⁵

In summary

Concentration problems are among the complaints Dutch adults take to the GP more often than a few years ago. What drops out first is simple sustained attention, not slow reasoning, and the measured causes of concentration problems are close to home: short nights, a moment of acute stress during a demanding task, a day without water, medicines, alcohol. The tested options are modest and real: one bout of exercise and a week’s worth of it, caffeine early and in a known dose, one task at a time with the rest written down. A scan gives you a number for how much you are carrying today and a second number two weeks later. Naming what sits behind it remains work for a doctor.