Cortical gray and white brain tissue volume in adolescents and adults with autism.
BACKGROUND
A number of studies have found brain enlargement in autism, but there is disagreement as to whether this enlargement is limited to early development or continues into adulthood. In this study, cortical gray and white tissue volumes were examined in a sample of adolescents and adults with autism who had demonstrated total brain enlargement in a previous magnetic resonance imaging (MRI) study.


METHODS
An automated tissue segmentation program was applied to structural MRI scans to obtain volumes of gray, white, and cerebrospinal fluid (CSF) tissue on a sample of adolescent and adult males ages 13-29 with autism (n = 23) and controls (n = 15). Regional differences for brain lobes and brain hemispheres were also examined.


RESULTS
Significant enlargement in gray matter volume was found for the individuals with autism, with a disproportionate increase in left-sided gray matter volume. Lobe volume enlargements were detected for frontal and temporal, but not parietal or occipital lobes, in the subjects with autism. Age and nonverbal IQ effects on tissue volume were also observed.


CONCLUSIONS
These findings give evidence for left-lateralized gray tissue enlargement in adolescents and adults with autism, and demonstrate a regional pattern of cortical lobe volumes underlying this effect.
Hazlett
Heather Cody
HC
Department of Psychiatry and the Neurodevelopmental Disorders Research Center, School of Medicine, Chapel Hill, NC 27599, USA. heather_cody@med.unc.edu
Poe
Michele D
MD
Gerig
Guido
G
Smith
Rachel Gimpel
RG
Piven
Joseph
J
D000293:Adolescent; D000328:Adult; D001321:Autistic Disorder / Q000473:pathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male