Making sense of senses
Many of the most noticeable symptoms of autism involve trouble with the five senses. Sometimes people with the disorder are extremely sensitive — cowering from sudden noises or bright lights, for example, or reacting aggressively to being touched. Others seek out extra sensation, such as through hand flapping.
Surprisingly, though, most experts don't consider these issues core features of the disorder. One reason is that no one has definitively calculated the extent to which these behaviors crop up in people with autism. Even if a high prevalence were confirmed, sensory impairments could simply be secondary consequences of a more fundamental deficit, such as a problem with attention or an aversion to social interactions.
But last week, a group of Australian researchers reported that these symptoms are probably universal among children on the autism spectrum. Their study also found that some children show both high and low sensitivities, and that specific combinations of sensory symptoms tend to arise more frequently than others.
For the study, the parents of 54 young children with autism filled out the Short Sensory Profile, a 38-item questionnaire designed to measure abnormal function of each sense.
Almost 90 percent of the kids in the study showed some kind of sensory difficulty. The most common were related to auditory filtering, such as responding to their name being called, and low tactile sensitivity, such as not noticing when their face or hands are messy.
Perhaps the study's most interesting finding is that the types of sensory issues tended to cluster in distinct ways. One group of kids, for instance, showed extreme sensitivity to taste and smell, but normal reaction to sudden movements; another had fairly normal sensing, except that they were distracted easily by noises or sights, excessively touched things, and couldn't stay focused on a task.
An obvious drawback of this study is that it's based on parental reports, which may be incomplete or inaccurate. Still, if confirmed using different methods, it should spur more basic research on the brain circuitry behind these striking sensory patterns.