Individuals with Agenesis of the Corpus Callosum Show Atypical Sensory Processing

Background: Individuals with agenesis of the corpus callosum (AgCC) have social and communication deficits similar to those reported in autism spectrum disorders (ASD). Furthermore, there are a growing number of studies reporting atypical corpus callosum structure in cohorts with ASD. Consequently, AgCC cohorts serve as an excellent model for studying the role of the corpus callosum in cognition and behavior. Objectives: Based on anecdotal reports of diminished pain threshold in this population, we hypothesize that a greater percentage of individuals with AgCC will have “altered sensory registration” as measured by the Sensory Profile relative to healthy controls. Methods: AgCC subjects (n=14: partial AgCC n=5, complete AgCC n=9) were recruited from the UCSF Brain Development Research Program and healthy controls (HC) (n=14) matched for age and gender were selected from the SP normative dataset. There were 6 adolescents (mean age 14 years, range 11-17) and 8 adults (mean age 33years, range 20-59) in each group. We selected individuals who were over the age of 11 and for whom we knew had IQ>70. We sent 20 adolescent and adult Sensory Profile (SP) questionnaires and received 14 (70% response rate.) The SP has 60 questions that are clustered to create 4 distinct quadrants: Low registration, sensory sensitivity, sensation seeking, and sensation avoiding. In order to combine the adolescent and adult score, all quadrants are broken into a 5-point classification system based on the normative dataset. A score of “5” or “1” indicates that the individual's behavior is greater than 2 standard deviations from the mean. Results: The AgCC group FSIQ fell in the normal range with a mean of 93.4 +/-13.5. Using a Fisher's exact test, the AgCC group showed significantly different scores on the low registration quadrant relative to HC (p=0.03). The AgCC group tended to have lower sensory registration than the HC group (which translates to higher scores on the low registration quadrant). On analysis of discrete sensory domains (auditory, tactile and visual), we found that the AgCC group scored significantly different only on the auditory domain (p=0.02). Conclusions: Individuals with AgCC, like those with ASD, show atypical sensory processing. This difference is mainly found in the auditory domain and in the low registration quadrant. These findings will help understand the pathophysiology of sensory processing and guide interventions for all those with abnormalities of the corpus callosum.