Autism Res 2012 Feb 21;5(1):67-72. Epub 2011 Sep 21.
Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, The Netherlands.
The rooting reflex has long been studied by neurologists and developmentalists and is defined as an orientation toward tactile stimulation in the perioral region or visual stimulation near the face. Nearly, all previous reports of the visual rooting reflex (VRR) concern its presence in adults with neurological dysfunction. Previously, the VRR was reported to be present in a majority of individuals with autism and absent in control subjects. In the present larger study, we examined the presence of the VRR in 155 individuals with ASD and co-occurring Intellectual Disability (ASD + ID: autism, N = 60; Pervasive Developmental Disorder-Not Otherwise Specified (PDD_NOS), N = 95) and in a contrast group of 65 individuals with ID only. The VRR was present significantly more often in the ASD + ID (43.9%) group than in the ID-only group (24.6%; χ(1)(2)= 7.19; P = 0.007). Individuals with autism displayed a VRR more often (55.0%) than individuals with PDD-NOS (36.8%; χ(1)(2)= 4.92; P = 0.026) and individuals with ID only (24.6%; χ(1)(2)= 12.09; P = 0.001). A positive VRR was associated with lower IQ and adaptive functioning; in the ASD + ID group, ADI-R/ADOS domain scores were significantly higher in the VRR-positive subgroup. The results replicate and extend the finding of an increased occurrence of the VRR in autism. Although some association with IQ was observed, the VRR occurred substantially more often in the autism group compared with an intellectually disabled group, indicating some degree of specificity. Additional studies of infants and children with typical development, ASD and ID are needed to determine the utility of the VRR in ASD risk assessment and to elucidate possible specific behavioral associations.