Sensory processing disorders (SPD) are usually diagnosed as a part of another disorder like autism or ADHD. They affect anywhere from 5% to 16% of children, but until now, there was no tangible evidence that SPDs were a distinct disorder. However, new research from the University of California San Francisco has found that children with sensory processing disorders have marked differences in brain structure.

The study used diffusion tensor imaging (DTI), a type of MRI that yields data about the paths of the brain’s white matter, which is a component of the central nervous system that transmits information and is essential to learning and thinking. Researchers scanned 16 boys, aged eight to 11 who had SPD, but who were not diagnosed with autism or other disorders. They also studied 24 boys who did not have SPD, but who were matched to the experimental group in age, handedness, gender, and IQ.

The scans revealed that the white matter in the SPD subjects takes an abnormal route through the back of the brain. These circuitous connections were involved in tactile, auditory, and visual processing, as well as linking the hemispheres of the brain. In contrast, white matter tracks through the frontal region of the brain in children with autism or ADHD.

This research not only provides concrete evidence that sensory processing disorders are a discrete neurological problem, but also uncovers a few hints as to why people with the disorder have processing issues. The abnormal path that the white matter takes may alter the timing of sensory transmission, which could make integrating sensory input from several senses challenging, if not impossible.

Dr. Elysa Marco, one of the study leaders and cognitive behavioral child neurologist at the UCSF Benioff Children’s Hospital, commented, “We are just at the beginning, because people didn’t believe this existed. 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.”

This research is published in the open access journal NeuroImage: Clinical.

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