Age-Related Changes in the Anatomy of Language Regions in Autism Spectrum Disorder

Abstract

Impairments in language and communication are core features of autism spectrum disorder (ASD). The anatomy of critical language areas has been studied in ASD with inconsistent findings. We used MRI to measure gray matter volume and asymmetry of Heschl's gyrus, planum temporale, pars triangularis, and pars opercularis in 40 children and adolescents with ASD and 40 typically developing individuals, each divided into younger (7-11 years) and older (12-19 years) cohorts. The older group had larger left planum temporale volume and stronger leftward asymmetry than the younger group, regardless of diagnosis. The pars triangularis and opercularis together were larger in ASD than controls. Correlations between frontal language areas with language and symptom severity scores were significant in younger ASD children. Results suggest similar developmental changes in planum temporale anatomy in both groups, but group differences in pars triangularis and opercularis that may be related to language abilities and autism symptom severity.

Defining language impairments in a subgroup of children with autism spectrum disorder

“…In a quantitative study of anatomic differences in the brains of carefully diagnosed children with SLI and age-matched controls, Gauger and colleagues [50] found that children with SLI had significantly narrower right hemispheres, significantly smaller pars triangularis in the left hemisphere, and greater rightward asymmetry of the total planum, compared to typical controls. However, several more recent studies of boys with SLI carefully matched on age, handedness, and gender to typical controls found greater leftward asymmetry in the planum temporale region [7,48,51].…”

“…Specifically, both SLI and ASD, particularly those with ALI, show reduced left hemisphere asymmetry in inferior frontal gyral regions (particularly pars opercularis), and exaggerated left asymmetry in posterior planum temporale [7,48,49,51,53]; though see Gage et al [54] for different findings. The volume of left inferior frontal gyral regions is generally reduced in ASD [55] and SLI [50], but the planum continues to show age-related increases in volume through adolescence in ASD based on cross-sectional data [51]. One study [56] investigated white matter in the arcuate fasciculus using diffusion tensor imaging.…”

Structural and functional magnetic resonance imaging of autism spectrum disorders

“…However, reduced left PT volume was reported in a study of children, as well as in a study of adults, with autism versus healthy controls (Rojas et al, 2002; Rojas et al, 2005). Recently, Knaus et al (2009) conducted a study of children and adolescents with ASD, dividing them up into a 7–11 year-old group and a 12–19 year-old group. The authors found increased left PT volume and a stronger leftward asymmetry in the older group in comparison to typically-developing controls.…”

Mirror Neuron Forum

“…However, as illustrated in Table 4, a study that MI doesn't cite (Knaus et al, 2009) reports that autistic participants have larger Broca's areas, and another study that MI doesn't cite (DeFosse et al 2004) reports no difference between autistic and non-autistic participants in volume of Broca's area or its right-hemisphere equivalent.…”