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How do we compare cognitive performance?

I guess we've all been there; once again I've totally forgotten what I was actually searching for, after having been determined to find my pen on my desk. Gazing around a bit, returning to the living room, I realize that an empty letter can't be written without that pen I was looking for, and while cursing myself, I take another tour to my desk.

Sounds familiar? I guess so! It is completely natural to sometimes forget something, and it happens to all of us. Here we illustrated short-term memory, and it is part of a bigger concept called "cognition". Cognition is very important in our activities of daily living, enabling us for example to communicate and plan our activities.

If cognition is impaired, scenarios like the one I mentioned before will happen more often, which in turn has an impact on our activities of daily living. This impairment typically occurs in diseases such as Alzheimer and Multiple Sclerosis, affecting the brain. In order to counteract this, therapies like cognitive training or pharmaceutical treatment is available, but then we should first identify the ones suffering from cognitive problems!

To do so, we first have to quantify cognitive status. This is typically done with cognitive tests that measure how well someone does on a certain cognitive domain. But now we're in trouble: with what will we compare the test score in order to tell if it is good or bad? Ladies and gentlemen, we proudly present the work of one of our bright PhD students: Lars Costers! :) In 2017, he wrote a paper about exaclty this pain point. To enable you to optimally understand his work, another PhD student, Stijn Denissen, recently created an interactive web application about Lars' work.

Please enjoy this web application to understand how we compare cognitive scores, and declare whether it is impaired or not, in order to appropriately decide on any therapeutics to counteract the degenerative process. In short, we know that agegender and education level have an impact on your cognitive score. So, in order to assess someone's cognitive score, we should compare that person with what we would expect that person to score based on the aforementioned 3 influencing factors. We can do exactly this by transforming raw scores on the cognitive tests to z-scores, and this process is explained in the web application. Below this blog post, you will also find a small teaser video. Please play around with the values to see the impact on the normal distribution, the green/red figure you saw when entering this blog. What it's about? Unleash the adventurer in you and enter the web application!

Warm science-communication regards,

Stijn Denissen