Saturday, May 22, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)10:00 AM
Background: Children with and without autism experience sensory processing difficulties that may be at the core of their learning and behavioral deficits. We have previously found neural activity differences in primary somatosensory cortex as early as 50 ms after simple tactile stimulation. However, the neurophysiological underpinnings of sensory perception and integration in children with sensory behavioral deficits remain unclear. We used magnetoencephalography (MEG-I), a functional imaging tool with millisecond temporal resolution and millimeter spatial localization to measure resting state functional connectivity in children with sensory processing difficulties and matched controls. This study aims to understand how the functional connectivity of affected children differs during resting and whether these differences are regionally specific. Objectives: We hypothesized that children with sensory processing differences (SP) would have decreased connectivity in regions of the brain known to process and integrate sensory information relative to matched healthy controls (HC). Methods: Resting activity (eyes closed) was recorded for the SP group (N=9, mean age=10.6) and the HC group (N=9, mean age=10.1) using a 275-channel whole-head MEG. Oscillations in the alpha range (8-12Hz) across a 60 second window were isolated from 4 minutes of continuous MEG recording. Neural sources were estimated using an adaptive spatial filtering technique and functional connectivity was computed using global imaginary coherence. Connectivity volumes were compared between the SP and HC groups. Voxelwise correlations between global connectivity and measures of sensory processing behaviors and autism behaviors were also performed. These behaviors were measured using parent-report questionnaires: the Sensory Profile (SP) and the Social Communication Questionnaire (SCQ). Results: Robust resting alpha activity was identified in the HC and SP groups. The SP group showed significantly less connectivity in two discrete hubs: left temporal-parietal (TP) and right dorsolateral pre-frontal cortex (DLPFC), both with a p-value < 0.1 (FDR corrected). Decreased connectivity in the L-TP region correlated exclusively with sensory processing deficits as measured by the SP (p<0.1, FDR corrected), while decreased connectivity in the left dorsal premotor cortex (L-dPMC) region correlated exclusively with autism specific traits as measured by the SCQ (p<0.1, FDR corrected). Decreased connectivity in the R-DLPFC region correlated with both autism specific traits and sensory processing deficits (p<0.1, FDR corrected). Conclusions: Our results suggest that children with sensory processing deficits have measurable and reduced alpha range resting-state functional connectivity. Furthermore, the coherence of cortical regions known to participate in sensory integration may be independently predictive of success with sensory modulation, whereas connections of higher-order prefrontal cortical fields associated with top-down modulation and cognitive control appear to be more broadly predictive of both autism and sensory processing traits. This data will contribute to our knowledge of basic sensory processing in children with and without autism. Furthermore, this is an exciting new direction for early diagnosis using a non-invasive technique that does not require patient participation.