Common Sleep Disorders Tied to Unseen Brain Structure Changes, Study Finds

Sleep problems may do more than leave people tired. New research from Florida International University (FIU) has found that several sleep disorders are associated with physical changes in brain regions involved in attention, motivation, and decision-making. The results point to a possible connection between disrupted sleep and important differences in brain structure.

Published in the journal Scientific Reports, the study provides one of the widest looks yet at brain changes linked to a range of sleep disorders. The findings could one day help researchers spot sleep problems earlier and design treatments that better match the brain systems affected.

What 57 Brain Imaging Studies Reveal About Sleep Disorders

Sleep disorders affect an estimated 50 million to 70 million Americans, making them a major public health issue. To understand their impact on the brain, scientists at FIU's Center for Children and Families combined and reviewed results from 57 brain imaging studies involving adults.

Instead of examining only one condition, the team compared multiple sleep disorders to see whether they shared similar structural brain changes. That approach, still relatively uncommon in sleep research, also helped the researchers identify differences tied to specific disorders.

The analysis focused on two broad categories. Dyssomnias include insomnia and sleep apnea, which make it harder to fall asleep, stay asleep, or get enough restorative rest. Parasomnias include sleepwalking, nightmare disorder, and sleep terrors, all of which involve unusual events or behaviors that interrupt normal sleep cycles.

"As more people recognize how important sleep is, there's growing urgency to understand what's happening in the brain," said Matthew Sutherland, a cognitive neuroscientist at FIU and senior author of the study. "By bringing together results from many studies, this research gives us a clearer picture of how sleep disorders affect brain structure and function and where we need to focus next."

Sleep Disorders Share Changes in a Critical Brain Region

One of the clearest findings was that both groups of sleep disorders were linked to reductions in the thalamus, a deep brain structure that helps process information, sustain attention, and support complex thinking.

The researchers found changes in a specific thalamic area known as the pulvinar. This region helps direct attention toward important information and supports cognitive control, which allows people to regulate their thoughts and actions while carrying out tasks.

These affected areas connect to broader brain networks that support concentration, decision-making, and reactions to the environment. Differences in these systems may help explain why people with sleep disorders often have slower reaction times, trouble making decisions, and a higher risk of errors or accidents.

"Most research looks at sleep disorders one at a time," said Katharine Crooks, a recent FIU cognitive neuroscience doctoral graduate and lead author of the study. "By looking across many studies, we found shared patterns in the brain that help explain why sleep problems can impact focus, decision-making and everyday functioning. With so many people struggling with sleep, understanding what is happening in the brain is key to finding better interventions, diagnostic tools and personalized treatments."

Sleepwalking and Nightmares Show Additional Brain Differences

While the study uncovered common structural patterns across sleep disorders, it also found differences that appeared specific to parasomnias.

People with these conditions showed changes in the posterior cingulate cortex, a region involved in motivation, decision-making, and emotional regulation. That may help explain why disorders such as sleepwalking, recurring nightmares, and sleep terrors can sometimes be linked to problems with mood, behavior, or emotional control.

By contrast, the analysis did not find a consistent pattern of structural changes seen only in dyssomnias, the category that includes insomnia and sleep apnea.

Overall, the findings suggest that different forms of disrupted sleep may be associated with both shared and distinct changes in the brain. The specific regions involved may vary depending on the type of sleep disorder.

Could Brain Imaging Lead to Better Sleep Disorder Treatments?

The results offer researchers fresh clues about how sleep disorders relate to the brain systems that shape everyday thinking and behavior.

By identifying which regions are associated with particular sleep problems, scientists hope to improve diagnosis and create more personalized interventions. Future treatments may aim not only to improve sleep quality, but also to protect the brain networks involved in attention, decision-making, and emotional regulation.

Still, one major question remains unresolved. The study found links between sleep disorders and brain structure differences, but it did not show whether disrupted sleep causes those changes, whether existing brain differences contribute to sleep disorders, or whether both are true.

To explore that relationship further, the FIU team plans to examine individual parasomnias in more detail, including sleepwalking and REM sleep behavior disorder.

Learning how these conditions relate to brain changes could help researchers develop better ways to identify, manage, and potentially prevent some of the cognitive and emotional difficulties tied to disrupted sleep.