An analysis of the association between brain gray matter volumes and working memory in children with autism spectrum disorder

• In Event: 2-008 - Open Developmental Science

Abstract

Background: In addition to impairments in communication and social interaction, individuals with autism spectrum disorder (ASD) have decreased working memory capacity, on average. In individuals without ASD, working memory capacity has been found to be associated with gray matter volumes in the orbitofrontal cortex, medial prefrontal cortex and the anterior cingulate cortex. However, the effects of ASD on the association between working memory capacity and brain gray matter morphology have not been studied.
Methods: Phenotypic and T1-weighted structural magnetic resonance imaging (MRI) data shared via the Autism Brain Imaging Data Exchange (ABIDE) II initiative was accessed. Records of individuals (i.e. both children and adults) with an age adjusted T-score for working memory capacity using the Behavior Rating Inventory of Executive Function scale (BRIEF-WM) were identified and their structural MRI data were downloaded. Structural data were analyzed with FSL-VBM, an optimized voxel-based morphometry (VBM) protocol carried out with tools available in the FMRIB Software Library (FSL). In a group-level analysis, the interaction between ASD and BRIEF-WM was modeled using the Threshold-free Cluster Enhancement option in the randomise function in FSL (i.e. a permutation-based approach) to examine the effects of ASD on the link between working memory capacity and brain regional gray matter volumes.
Results: BRIEF-WM was available for 484 individuals (age 10.30±2.29 [range 5.12, 18.00] years, 359 male, 214 with ASD, BRIEF-WM 54.4±12.4 [range 8, 98], 7 study sites). The ASD group had significantly higher BRIEF-WM compared to the non-ASD group after controlling for age and sex (Δ= 20.36, SE = 0.94, t = 21.74, P < 0.001). However, the interaction of the presence / absence of ASD and the BRIEF-WM was not significant in predicting brain gray matter volumes of the study sample (P ≥ 0.215).
Conclusions: Despite the significant differences in BRIEF-WM of the ASD and non-ASD groups, and the well-established association between working memory capacity and frontal gray matter volumes in individuals without ASD, the presence of ASD does not appear to moderate the potential association between BRIEF-WM and brain gray matter volumes. This may be due, in part, to the fact that BRIEF-WM is an indirect, teacher or parent reported scale as opposed to a neuropsychological test that directly measures working memory capacity of the individual. Future studies should aim to address this potential limitation.

Authors

• Rebecca Beights, Texas Tech University, Department of Human Development and Family Studies
  Presenting Author

• Chanaka Nadeeshan Kahathuduwa, Texas Tech University, Department of Human Development and Family Studies

• Wonjung Oh, Texas Tech University, Department of Human Development and Family Studies

• Ann Mastergeorge, Texas Tech University