Can I get an fMRI scan to show that my daughter has dyslexia?

Unfortunately, brain scans can’t be used yet to “prove” that a child has dyslexia. The same is true for other learning and thinking differences, like ADHD.

Scientists use functional magnetic resonance imaging (fMRI) and other technologies like EEG to study how the brain works when it does complex tasks like reading. They're using these tools to create better maps of the brain.

But everyone’s brains look different. If you pick two random people off the street, their brain anatomy and brain function will not be identical, just as their faces aren't identical. We need to better understand this kind of variation before it becomes clear how the dyslexic brain is truly different.

Another challenge with fMRI research is that the differences between the brain scans of people with and without dyslexia are small. That’s why research studies need to look at groups of people to see which differences reliably occur in people with dyslexia. Typically in a research study, 15 or more people who have reading issues are compared to roughly the same size group of people who don’t have reading issues. Then the study looks for statistically significant differences between the two groups.

In other words, it takes a lot of brains (literally!) to reliably identify which features look different in people with dyslexia. A single brain is not enough.

Some researchers are starting to look into using a brain scan to identify people with dyslexia. But this is still just a concept. For this to become a reality, researchers need to develop techniques that allow them to pinpoint differences in an individual that can be identified reliably in most people with dyslexia.

Your child’s doctor may have heard of something called a “clinical fMRI.” For example, fMRI can help map out critical language areas of the brain so they can be avoided when a surgeon removes a tumor that is causing seizures. But before this became acceptable practice, researchers had to provide sufficient evidence to show that fMRI was helpful and reliable in this process.

We haven’t reached the point where fMRI can be used in clinical settings to identify dyslexia. When children participate in one of our research studies, we always let their parents know that we can share with them the results of the behavioral testing in the study. For example, some parents want to know their child’s scores on the reading tests that are given as part of the study. These tests take place separately from the fMRI session.

But we never provide families with an interpretation based on the scans. And we can’t comment on any individual differences (unless we make an incidental observation, such as a tumor). We give the kids a picture of their brain, which they think is very cool. But the brain of a child with dyslexia doesn’t look different to the naked eye.

Perhaps one day imaging will play a role in identifying individuals with dyslexia. Until then, parents need to continue to use traditional options, such as a neuropsychological evaluation. This process can provide useful insights into your daughter’s strengths and weaknesses. It can also inform decisions about what kinds of services and support she needs in school.