By Linda Weiford, WSU News
SPOKANE, Wash. – What if a simple penlight pupil test – like the one performed daily in doctors’ offices – could help diagnose autism?
Data from a unique pilot study done by scientists at Washington State University is so promising that they plan to conduct further testing among a larger pool of children in clinical settings, not just confined to a laboratory, said lead investigator Georgina Lynch, assistant clinical professor of speech-language pathology.
“Our results suggest that an inexpensive, noninvasive pupil penlight reflex test could be a physiological measurement of autism,” she said.
The study’s findings bolster a growing body of evidence showing that the pupils of children with autism constrict more slowly to flashes of light than pupils of their typically developing peers. But Lynch’s research goes beyond that premise. Her study is the first to examine whether social deficits seen in the disorder are linked to a sort of neural misfiring that occurs in the optic and oculomotor nerves located in the brainstem.
Potential for earlier diagnosis
An abnormality there could help explain why people with autism have difficulty making eye contact and are often sensitive to bright light, she said.
“Deficient functioning of these two cranial nerves makes it challenging for a child to maintain eye gaze, which is necessary for developing joint attention and for paying attention to dynamic features of a person’s face,” she explained. “These fundamental physical behaviors are needed to develop language and socialization.”
The penlight pupil reflex test appears to provide a “window” into the neural functioning of the brainstem and its effect on the child’s behavior, according to her study’s findings.
Once validated by larger studies, this straightforward, low-cost test may one day be used as a way to use more objective diagnoses of autism “instead of relying solely on behavioral assessments, which can be subjective and can’t definitively diagnose the disorder before a child is 2 or 3 years old,” said Lynch, adding that many kids don’t display all the features until then, or the features get missed so the diagnosis is made much later.
High accuracy rate
Lynch’s pilot study was funded by WSU and conducted at the university’s Sleep and Research Performance Center in Spokane with assistance from researchers Stephen James and Nancy Potter. Lynch presented her findings at the International Society for Autism Research in Salt Lake City in May. (See https://imfar.confex.com/imfar/2015/webprogram/Paper19589.html)
In the study, she and her colleagues tested 24 youths ages 10-17, half of whom had high-functioning autism and half without the disorder. Pupil reflexes were measured in response to light in each eye for four seconds for four trials.
The pupils of kids in the autism group took markedly longer to constrict in 70 percent of the trials, said Lynch.
The next step is to see if the result is confirmed in a larger group of children, including those younger than 10. Clinical trials in designated doctors’ offices and clinics are expected to begin next year, she said.
“If a simple technology can be used by pediatricians to spot a likely sign of autism during routine exams, then we can get these kids a quicker diagnosis and quicker treatment,” she said. “The sooner we can intervene with proven therapies, the better their chances in the world.”