title: Age-related differences in autism: The case of white matter microstructure.
abstract: Autism spectrum disorder (ASD) is typified as a brain connectivity disorder in which white matter abnormalities are already present early on in life. However, it is unknown if and to which extent these abnormalities are hard-wired in (older) adults with ASD and how this interacts with age-related white matter changes as observed in typical aging. The aim of this first cross-sectional study in mid- and late-aged adults with ASD was to characterize white matter microstructure and its relationship with age. We utilized diffusion tensor imaging with head motion control in 48 adults with ASD and 48 age-matched controls (30-74 years), who also completed a Flanker task. Intra-individual variability of reaction times (IIVRT) measures based on performance on the Flanker interference task were used to assess IIVRT-white matter microstructure associations. We observed primarily higher mean and radial diffusivity in white matter microstructure in ASD, particularly in long-range fibers, which persisted after taking head motion into account. Importantly, group-by-age interactions revealed higher age-related mean and radial diffusivity in ASD, in projection and association fiber tracts. Subtle dissociations were observed in IIVRT-white matter microstructure relations between groups, with the IIVRT-white matter association pattern in ASD resembling observations in cognitive aging. The observed white matter microstructure differences are lending support to the structural underconnectivity hypothesis in ASD. These reductions seem to have behavioral percussions given the atypical relationship with IIVRT. Taken together, the current results may indicate different age-related patterns of white matter microstructure in adults with ASD. Hum Brain Mapp 38:82-96, 2017. © 2016 Wiley Periodicals, Inc.
authors: Dutch Autism & ADHD Research Center, Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands.|Amsterdam Brain and Cognition (ABC), University of Amsterdam, Amsterdam, The Netherlands.
authors: P Cédric M P
authors: PC
authors: Koolschijn
authors: Department of Radiology, Brain Imaging Center, Academic Medical Center, University of Amsterdam, The Netherlands.
authors: Matthan W A
authors: MW
authors: Caan
authors: Department of Radiology, Brain Imaging Center, Academic Medical Center, University of Amsterdam, The Netherlands.|Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: Jalmar
authors: J
authors: Teeuw
authors: Department of Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, University of Amsterdam, The Netherlands.
authors: Sílvia D
authors: SD
authors: Olabarriaga
authors: Dutch Autism & ADHD Research Center, Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands.|Amsterdam Brain and Cognition (ABC), University of Amsterdam, Amsterdam, The Netherlands.|Dr Leo Kannerhuis, The Netherlands.
authors: Hilde M
authors: HM
authors: Geurts
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001321:Autistic Disorder / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D016022:Case-Control Studies; D015331:Cohort Studies; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging; D011930:Reaction Time / Q000502:physiology; D018709:Statistics, Nonparametric; D066127:White Matter / Q000000981:diagnostic imaging / Q000473:pathology*
keywords: DTI; adults; autism; interference control; intra-individual variability; underconnectivity; white matter