Rightward hemispheric asymmetries in auditory language cortex in children with autistic disorder: an MRI investigation.
OBJECTIVE
determine if language disorder in children with autistic disorder (AD) corresponds to abnormalities in hemispheric asymmetries in auditory language cortex.


METHODS
MRI morphometric study in children with AD (n = 50) to assess hemispheric asymmetries in auditory language cortex. A key region of interest was the planum temporale (PT), which is larger in the left hemisphere in most healthy individuals.


RESULTS
(i) Heschl's gyrus and planum polare showed typical hemisphere asymmetry patterns; (ii) posterior Superior Temporal Gyrus (pSTG) showed significant rightward asymmetry; and (iii) PT showed a trend for rightward asymmetry that was significant when constrained to right-handed boys (n = 30). For right-handed boys, symmetry indices for pSTG were significantly positively correlated with those for PT. PT asymmetry was age dependent, with greater rightward asymmetry with age.


CONCLUSIONS
results provide evidence for rightward asymmetry in auditory association areas (pSTG and PT) known to subserve language processing. Cumulatively, our data provide evidence for a differing maturational path for PT for lower functioning children with AD, with both pre- and post-natal experience likely playing a role in PT asymmetry.


BACKGROUND
The online version of this article (doi:10.1007/s11689-009-9010-2) contains supplementary material, which is available to authorized users.
Gage
Nicole M
NM
Juranek
Jenifer
J
Filipek
Pauline A
PA
Osann
Kathryn
K
Flodman
Pamela
P
Isenberg
A Lisette
AL
Spence
M Anne
MA