1. Belmonte MK, Bonneh YS, Adini Y, Iversen PE, Akshoomoff NA, Kenet T, Moore CI, Simon HJ, Houde JF, Merzenich MM. {{Autism Overflows with Syntheses}}. {Neuropsychol Rev};2009 (May 16)
2. Hudenko WJ, Stone W, Bachorowski JA. Laughter Differs in Children with Autism: An Acoustic Analysis of Laughs Produced by Children With and Without the Disorder. J Autism Dev Disord;2009 (May 16)
Few studies have examined vocal expressions of emotion in children with autism. We tested the hypothesis that during social interactions, children diagnosed with autism would exhibit less extreme laugh acoustics than their nonautistic peers. Laughter was recorded during a series of playful interactions with an examiner. Results showed that children with autism exhibited only one type of laughter, whereas comparison participants exhibited two types. No group differences were found for laugh duration, mean fundamental frequency (F(0)) values, change in F(0), or number of laughs per bout. Findings are interpreted to suggest that children with autism express laughter primarily in response to positive internal states, rather than using laughter to negotiate social interactions.
3. Pugliese L, Catani M, Ameis S, Dell’acqua F, de Schotten MT, Murphy C, Robertson D, Deeley Q, Daly E, Murphy DG. {{The anatomy of Extended Limbic Pathways in Asperger Syndrome: A preliminary Diffusion Tensor Imaging Tractography Study}}. {Neuroimage};2009 (May 13)
It has been suggested that people with Autistic Spectrum Disorder (ASD) have altered development (and connectivity) of limbic circuits. However, direct evidence of anatomical differences specific to white matter pathways underlying social behaviour and emotions in ASD is lacking. We used Diffusion Tensor Imaging Tractography to compare, in vivo, the micro-structural integrity and age-related differences in the extended limbic pathways between subjects with Asperger syndrome and healthy controls. Twenty-four males with Asperger Syndrome (mean age 23+/-12 years, age range: 9-54 years) and 42 age-matched male controls (mean age 25+/-10 years, age range: 9-54 years) were studied. We quantified tract-specific diffusivity measurements as indirect indexes of microstructural integrity (e.g. fractional anisotropy, FA; mean diffusivity, MD) and tract volume (e.g. number of streamlines) of the main limbic tracts. The dissected limbic pathways included the inferior longitudinal fasciculus, inferior frontal occipital fasciculus, uncinate, cingulum and fornix. There were no significant between-group differences in FA and MD. However, compared to healthy controls, individuals with Asperger syndrome had a significantly higher number of streamlines in the right (p=0.003) and left (p=0.03) cingulum, and in the right (p=0.03) and left (p=0.04) inferior longitudinal fasciculus. In contrast, people with Asperger syndrome had a significantly lower number of streamlines in the right uncinate (p=0.02). Within each group there were significant age-related differences in MD and number of streamlines, but not FA. However, the only significant age-related between group difference was in mean diffusivity of the left uncinate fasciculus (Z(obs)=2.05) (p=0.02). Our preliminary findings suggest that people with Asperger syndrome have significant differences in the anatomy, and maturation, of some (but not all) limbic tracts.
4. Yoder P, Stone WL, Walden T, Malesa E. {{Predicting Social Impairment and ASD Diagnosis in Younger Siblings of Children with Autism Spectrum Disorder}}.{ J Autism Dev Disord};2009 (May 16)
Later-born siblings of children with autism spectrum disorder (Sibs-ASD) are at elevated risk for social impairments. Two putative predictors of later social impairment-measures of responding to joint attention and weighted triadic communication-were examined in a sample of 43 Sibs-ASD who were followed from 15 to 34 months of age. Results revealed that initial level of responding to joint attention and growth rate of weighted triadic communication predicted the degree of social impairment at the final measurement period. Additionally, both predictors were associated with later ASD diagnosis. In contrast, unweighted triadic communication, age of entry into the study, and initial language level did not predict later social impairment. The importance of considering social outcome as a continuous variable in prospective studies of Sibs-ASD is discussed.
