The image shows areas of the brain that can be affected by sensory processing disorders. Using an advanced form of MRI, researchers at UCSF have identified abnormalities in the brain structure of children with SPD primarily in the back of the brain.
Pratik Mukherjee, MD, PhD
One of the reasons SPD has been overlooked until now is that it often occurs in children who also have ADHD or autism, and the disorders have not been listed in the Diagnostic and Statistical Manual used by psychiatrists and psychologists.
“Until now, SPD hasn’t had a known biological underpinning,” said senior author Pratik Mukherjee, MD, PhD, a professor of radiology and biomedical imaging and bioengineering at UCSF. “Our findings point the way to establishing a biological basis for the disease that can be easily measured and used as a diagnostic tool,” Mukherjee said.
The work is published in the open access online journal NeuroImage:Clinical.
‘Out of Sync’ KidsSensory processing disorders affect 5 to 16 percent of school-aged children.
Elysa Marco, MD
“Sometimes they are called the ‘out of sync’ kids. Their language is good, but they seem to have trouble with just about everything else, especially emotional regulation and distraction. In the real world, they’re just less able to process information efficiently, and they get left out and bullied,” said Marco, who treats affected children in her cognitive and behavioral neurology clinic.
“If we can better understand these kids who are falling through the cracks, we will not only help a whole lot of families, but we will better understand sensory processing in general. This work is laying the foundation for expanding our research and clinical evaluation of children with a wide range of neurodevelopmental challenges – stretching beyond autism and ADHD,” she said.
Imaging the Brain’s White MatterIn the study, researchers used an advanced form of MRI called diffusion tensor imaging (DTI), which measures the microscopic movement of water molecules within the brain in order to give information about the brain’s white matter tracts. DTI shows the direction of the white matter fibers and the integrity of the white matter. The brain’s white matter is essential for perceiving, thinking and learning.
These brain images, taken with DTI, show water diffusion within the white matter of children with sensory processing disorders. Row FA: The blue areas show white matter where water diffusion was less directional than in typical children, indicating impaired white matter microstructure. Row MD: The red areas show white matter where the overall rate of water diffusion was higher than in typical children, also indicating abnormal white matter. Row RD: The red areas show white matter where SPD children have higher rates of water diffusion perpendicular to the axonal fibers, indicating a loss of integrity of the fiber bundles comprising the white matter tracts.
The imaging detected abnormal white matter tracts in the SPD subjects, primarily involving areas in the back of the brain, that serve as connections for the auditory, visual and somatosensory (tactile) systems involved in sensory processing, including their connections between the left and right halves of the brain.
“These are tracts that are emblematic of someone with problems with sensory processing,” said Mukherjee. “More frontal anterior white matter tracts are typically involved in children with only ADHD or autistic spectrum disorders. The abnormalities we found are focused in a different region of the brain, indicating SPD may be neuroanatomically distinct.”
The researchers found a strong correlation between the micro-structural abnormalities in the white matter of the posterior cerebral tracts focused on sensory processing and the auditory, multisensory and inattention scores reported by parents in the Sensory Profile. The strongest correlation was for auditory processing, with other correlations observed for multi-sensory integration, vision, tactile and inattention.
The abnormal microstructure of sensory white matter tracts shown by DTI in kids with SPD likely alters the timing of sensory transmission so that processing of sensory stimuli and integrating information across multiple senses becomes difficult or impossible.
“We are just at the beginning, because people didn’t believe this existed,” said Marco. “This is absolutely the first structural imaging comparison of kids with research diagnosed sensory processing disorder and typically developing kids. It shows it is a brain-based disorder and gives us a way to evaluate them in clinic.”
Support SPD ResearchThanks to groundbreaking work from UCSF Benioff Children’s Hospital San Francisco, a biological basis for SPD has been discovered. There is much work to be done and a funding gap. We still need to:
- Understand the genetic causes of sensory processing differences
- Uncover risk factors for SPD
- Measure the neurologic brain differences in affected individuals
- Determine if current interventions are truly effective for brain plasticity
- Develop new therapies based on scientific evidence
Learn how you can help.
The study’s co-authors are Shivani Desai, BS, Emily Fourie, BS, Julia Harris, BS, and Susanna Hill, BS, all of UCSF, and Anne Arnett, MA, of the University of Denver.
The research was supported by the Wallace Research Foundation. The authors have reported that they have no conflicts of interest relevant to the contents of this paper to disclose.
UCSF Benioff Children’s Hospital creates an environment where children and their families find compassionate care at the forefront of scientific discovery, with more than 150 experts in 50 medical specialties serving patients throughout Northern California and beyond. The hospital admits about 5,000 children each year, including 2,000 babies born in the hospital. For more information, visit www.ucsfbenioffchildrens.org.
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