Children with autism spectrum disorder and attention deficit hyperactivity disorder have evidence of sensory nerve degeneration.

Researchers looked at nerve fibers in the eyes of children with autism and ADHD using a special microscope. They found that children with autism (with or without ADHD) had fewer and shorter nerve fibers compared to children without these conditions. This might help explain why many autistic children have difficulties with sensory experiences like touch, sound, or light sensitivity.

This exploratory study used corneal confocal microscopy to examine sensory nerve characteristics in children with autism spectrum disorder (ASD), ADHD, and combined ASD+ADHD compared to healthy controls. The research found evidence of sensory nerve degeneration in both ASD+ADHD (n=21) and ASD-only (n=6) groups compared to controls (n=15). Specifically, corneal nerve branch density was significantly lower in both clinical groups, and nerve fiber length was reduced in the ASD-only group. However, no differences were found between ASD+ADHD and ASD groups, and nerve measures did not correlate with ASD symptom severity.

The findings suggest potential sensory nerve abnormalities in autism that may relate to documented sensory processing differences.

Findings suggest potential biological markers for sensory processing differences in autism. May inform future screening approaches and sensory intervention strategies. However, clinical utility requires validation through larger studies integrating nerve measurements with detailed sensory and cognitive assessments.

Small sample size, particularly for ASD-only group (n=6). Exploratory study design limits generalizability. Lacks integration with clinical sensory assessments or cognitive measures. Future research needs larger samples and comprehensive sensory evaluation protocols.

An increasing body of evidence supports the role of altered sensory processing in autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). This exploratory study undertook corneal confocal microscopy (CCM) to assess for differences in corneal nerve fiber density (CNFD), branch density (CNBD) and fiber length (CNFL) in relation to ASD severity in children with ASD+ADHD (n = 21), ASD (n = 6) and healthy controls (HC) (n = 15). CNBD was significantly lower in children with ASD+ADHD (P = 0.002) and ASD (P < 0.001) and CNFL was significantly lower in children with ASD (P = 0.02) compared to HC. However, CNFD (mean difference = 2.28, 95% CI [-5.84, 10.40], P > 0.99) CNBD (mean difference = 14.1, 95% CI [-8.22, 36.4], p = 0.37) and CNFL (mean difference = 2.46, 95% CI [-2.28, 7.20], p = 0.61) did not differ between ASD+ADHD and ASD.

CNFD (P = 0.876), CNBD (P = 0.405) and CNFL (P = 0.606) did not correlate with the severity of ASD. Corneal confocal microscopy reveals sensory nerve degeneration in children with ASD+ADHD and ASD alone compared to controls. Larger studies integrating CCM with sensory and cognitive assessment are required to determine the utility of CCM as a clinical screening strategy for neurodegneration in ASD, ADHD and ASD-ADHD combined.