Saturday, May 22, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
10:00 AM
Background: Pupillary light reflex (PLR) refers to the involuntary pupillary responses induced by a transient light stimulus. No comprehensive study has previously been conducted to assess PLR in children with autism spectrum disorders (ASDs).
Objectives: To compare PLR responses in children with an ASD with those in typically developing children.
Methods: A computerized binocular pupillography was used to measure transient PLR in 29 children with autism spectrum disorders (age 12.2 ± 4.4 years, 2 females and 27 males), including 12 with autistic disorder, 12 with Asperger’s syndrome and 5 with PDD-NOS. The same tests were also conducted in a control group of 44 typically developing children (age 10.4 ± 2.7 years, 23 females and 21 males). The PLR was induced using a 100 ms light stimulation under both light- and dark-adapted conditions. Five basic PLR parameters, the resting pupil diameter, the latency (delay from stimulus onset to the beginning of constriction), relative constriction amplitude (ratio of pupil constriction to resting pupil size), constriction velocity and redilation velocity were calculated from the PLR profiles for quantitative analysis.
Results: We found that participants with an ASD showed significantly longer PLR latency (p < 0.0001), smaller relative constriction amplitude (p < 0.05), lower constriction velocity (p < 0.05) and lower redilation velocity (p < 0.05) than children with typical development. In addition, the variance in resting pupil diameters of children with an ASD was significantly larger (p < 0.0001). A discriminant analysis with cross-validation indicated that 90.3% of the participants were correctly classified by using PLR latencies alone. The cross-validated classification rate was further improved to 94.4% by using both resting pupil diameter and PLR latency. Further detailed analysis suggested that the observed group differences were not affected by gender, age and IQ.
Conclusions: We found that children with an ASD showed significantly different PLR responses from those with typical development. Further investigations are necessary to understand the implications of these findings and to explore the originations of the observed differences.
Objectives: To compare PLR responses in children with an ASD with those in typically developing children.
Methods: A computerized binocular pupillography was used to measure transient PLR in 29 children with autism spectrum disorders (age 12.2 ± 4.4 years, 2 females and 27 males), including 12 with autistic disorder, 12 with Asperger’s syndrome and 5 with PDD-NOS. The same tests were also conducted in a control group of 44 typically developing children (age 10.4 ± 2.7 years, 23 females and 21 males). The PLR was induced using a 100 ms light stimulation under both light- and dark-adapted conditions. Five basic PLR parameters, the resting pupil diameter, the latency (delay from stimulus onset to the beginning of constriction), relative constriction amplitude (ratio of pupil constriction to resting pupil size), constriction velocity and redilation velocity were calculated from the PLR profiles for quantitative analysis.
Results: We found that participants with an ASD showed significantly longer PLR latency (p < 0.0001), smaller relative constriction amplitude (p < 0.05), lower constriction velocity (p < 0.05) and lower redilation velocity (p < 0.05) than children with typical development. In addition, the variance in resting pupil diameters of children with an ASD was significantly larger (p < 0.0001). A discriminant analysis with cross-validation indicated that 90.3% of the participants were correctly classified by using PLR latencies alone. The cross-validated classification rate was further improved to 94.4% by using both resting pupil diameter and PLR latency. Further detailed analysis suggested that the observed group differences were not affected by gender, age and IQ.
Conclusions: We found that children with an ASD showed significantly different PLR responses from those with typical development. Further investigations are necessary to understand the implications of these findings and to explore the originations of the observed differences.