a boy eating a peachAutism encompasses a spectrum of symptoms—no two people with autism experience the world in exactly the same way. Despite these differences, new research suggests that the responses of people with autism to stimuli fall into several distinct categories. These categories, or subtypes, offer clues about the way the brain processes stimuli. The study’s findings could support the development of targeted therapies for certain forms of autism and sensory problems.

The researchers collected data on 228 children aged two to ten during diagnostic evaluations for autism. The children’s caregivers completed the Short Sensory Profile, a 38-item survey that asks about children’s sensory preferences regarding smell, taste, touch, and body movement. Based on the responses, the researchers separated the children into broad groups. The groups were created according to an algorithm that clustered symptom type and severity.

The results suggest four discrete groups of autism symptoms. The first and largest group (40% of the sample) exhibits acute sensitivity to taste and smell. The second group (10% of the sample) exhibits low levels of energy and difficulty maintaining an upright posture. Both the first and second groups have problems filtering sounds from noisy environments. They also seek sensation by touching objects or people and by making noise. The third group (12% of the sample) exhibits all of the traits from groups one and two. The fourth group (38% of the sample), surprisingly, did not demonstrate any clinically significant sensory problems.

Scientists do not yet know what produces these subtypes. Sensitivity to taste and smell may be caused by an overactive nervous system. Children with poor posture and energy levels may be affected by problems integrating the body’s feedback about movement and position to the brain.

These subtypes may help researchers understand the underlying brain structure behind the various manifestations of autism. Knowing which subtype an individual belongs to may help that person receive appropriate therapies. For their next study, the research team plans to use electroencephalography to determine how children in different subtypes respond to stimuli like sounds and vibrations.

This research is published in the journal Autism Research.

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