Two complementary studies led by researchers from the Institute of Neurosciences of the University of Barcelona (UBneuro) provide new insights into the brain mechanisms underlying juvenile fibromyalgia, a chronic pain condition affecting 2-6% of children and adolescents. Using neuroimaging and detailed sensory assessments, the research shows that hypersensitivity to non-painful sensory stimuli, such as sounds, bright lights or light touch, is a key feature of the disease and is closely linked to symptom severity and brain function.
Juvenile fibromyalgia is a complex and often misunderstood condition, with symptoms that can persist into adulthood and have a major impact on daily life. While pain is its most visible manifestation, many patients also report strong discomfort in response to everyday sensory inputs. Until now, the neural mechanisms behind these experiences and their clinical relevance early in life were poorly understood.
Non-painful sensory hypersensitivity is linked to symptom severity and brain responses in adolescents with chronic pain
In the first study, published in Pain, the researchers investigated whether adolescents with juvenile fibromyalgia show augmented sensitivity to non-painful sensory stimuli in daily life and how this relates to alterations in brain responses during sensory stimulation. The results show that affected adolescents report significantly higher sensitivity to visual, auditory and tactile stimuli, as well as greater unpleasantness during multisensory stimulation, compared to healthy peers.
Importantly, the study found no evidence of deficits in hearing or basic auditory attentional processes, indicating that sensory hypersensitivity is not due to peripheral sensory impairment. Instead, brain imaging revealed that, in patients, stronger activation in brain regions involved in sensory integration and cognitive–emotional regulation, particularly prefrontal areas, was closely associated with the severity of pain, functional disability and overall symptom burden. These findings suggest that altered brain processing of non-painful sensory input plays a central role in the clinical expression of the disease already at a young age, before pain has chronified for decades.
“Even everyday sounds can feel stronger for adolescents with fibromyalgia, not due to any hearing impairments, but as a result of their brains amplifying and coordinating sensory signals. This heightened neural processing helps explain why the condition can be so disabling, affecting pain levels and daily functioning from an early age.”, highlights Laura Martín-Herrero, first author of the study.
Identifying patient subtypes through sensory profiles
The second study, published in the Journal of Pediatric Psychology, builds on these findings by showing that sensory hypersensitivity is not uniform across patients. Using data-driven clustering methods, the researchers identified two distinct subgroups of adolescents with juvenile fibromyalgia: one with pronounced multisensory hypersensitivity and another with sensory profiles similar to those of healthy adolescents
Patients in the hypersensitive subgroup showed more severe core symptoms, including greater functional disability and fatigue. Remarkably, however, this group did not differ in levels of anxiety, depression, or psychological coping, suggesting that their sensory hypersensitivity is primarily associated with sensory symptoms rather than affective symptoms. At the brain level, this subgroup showed increased activation in regions such as the primary motor cortex and the amygdala during multisensory stimulation, suggesting heightened motor-level response and emotional responses to otherwise non-painful inputs.
Together, these results highlight multisensory hypersensitivity as a key factor for understanding the heterogeneity of juvenile fibromyalgia and support the idea that different neurobiological mechanisms may underlie different clinical profiles.
“Our findings suggest that in adolescents with fibromyalgia, the brain may ‘turn up the volume’ on everyday sensory experiences. This can make daily life -social settings, the classrooms, sports,…- feel overstimulating and sometimes overwhelming. It points to the importance of therapies that help young people handle sensory overload and its impact in their day-to-day activities and experiences”, remarks Prof. Marina López-Solà, principal investigator and senior author of the studies.
Toward more personalized approaches in pediatric chronic pain
By combining detailed behavioral assessments with advanced brain imaging, these two studies provide a more nuanced picture of juvenile fibromyalgia. They show that non-painful sensory processing is deeply intertwined with disease severity and that identifying sensory-based patient subtypes may help explain why some patients experience a more disabling course than others.
These findings open new avenues for improving diagnosis and for developing more personalized therapeutic strategies, particularly in a pediatric condition that remains difficult to characterize and manage. Understanding how the brain processes everyday sensory information in juvenile fibromyalgia could ultimately help reduce symptom burden and improve quality of life for affected young people.
