1. Kasuga K, Ikeuchi T, Arakawa K, Yajima R, Tokutake T, Nishizawa M. {{A patient with fragile x-associated tremor/ataxia syndrome presenting with executive cognitive deficits and cerebral white matter lesions}}. {Case Rep Neurol};2011 (May);3(2):118-123.
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that primarily affects males who are carriers of a premutation of a CGG expansion in the FMR1 gene. In Asian populations, FXTAS has rarely been reported. Here, we report the case of a Japanese FXTAS patient who showed predominant executive cognitive deficits as the main feature of his disease. In contrast, the patient exhibited only very mild symptoms of intention tremor and ataxia, which did not interfere with daily activities. A gene analysis revealed that the patient carried a premutation of a CGG expansion (111 CGG repeats) in the FMR1 gene. The mRNA expression level of FMR1 in the patient was 1.5-fold higher than in controls. On brain MRI scans, fluid-attenuated inversion recovery images showed high-intensity lesions in the middle cerebellar peduncles and the cerebral white matter, with a frontal predominance. The present case extends previous notions regarding the cognitive impairment in FXTAS patients. Recognizing FXTAS patients with predominant cognitive impairment from various ethnic backgrounds would contribute to our understanding of the phenotypic variation of this disease.
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2. Langen M, Leemans A, Johnston P, Ecker C, Daly E, Murphy CM, Dell’acqua F, Durston S, Murphy DG. {{Fronto-striatal circuitry and inhibitory control in autism: Findings from diffusion tensor imaging tractography}}. {Cortex};2011 (May 30)
INTRODUCTION: Repetitive behaviour and inhibitory control deficits are core features of autism; and it has been suggested that they result from differences in the anatomy of striatum; and/or the ‘connectivity’ of subcortical regions to frontal cortex. There are few studies, however, that have measured the micro-structural organisation of white matter tracts connecting striatum and frontal cortex. AIMS: To investigate differences in bulk volume of striatum and micro-structural organisation of fronto-striatal white matter in people with autism; and their association with repetitive behaviour and inhibitory control. METHODS: We compared the bulk volume of striatum (caudate nucleus, putamen and nucleus accumbens) and white matter organisation of fronto-striatal tracts using (respectively) structural magnetic resonance imaging (sMRI) and tract specific diffusion tensor imaging (DTI) measures in 21 adults with autism and 22 controls. We also assessed performance on a cognitive inhibition (go/nogo) task. RESULTS: Bulk volume of striatal structures did not differ between groups. However, adults with autism had a significantly smaller total brain white matter volume, lower fractional anisotropy of white matter tracts connecting putamen to frontal cortical areas, higher mean diffusivity of white matter tracts connecting accumbens to frontal cortex and worse performance on the go/nogo task. Also, performance on the go/nogo task was significantly related to anatomical variation when both groups were combined; but not within the autism group alone. CONCLUSIONS: These data suggest that autism may be associated with differences in the anatomy of fronto-striatal white matter tracts.
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3. Limeres JR, Feijoo JF, Diz P. {{Children with autism}}. {J Am Dent Assoc};2011 (Jul);142(7):793-794.
4. Moskal JR, Burgdorf J, Kroes RA, Brudzynski SM, Panksepp J. {{A novel NMDA receptor glycine-site partial agonist, GLYX-13, has therapeutic potential for the treatment of autism}}. {Neurosci Biobehav Rev};2011 (Jun 27)
Deficits in social approach behavior, rough-and-tumble play, and speech abnormalities are core features of autism that can be modeled in laboratory rats. Human twin studies show that autism has a strong genetic component, and a recent review has identified 99 genes that are dysregulated in human autism. Bioinformatic analysis of these 99 genes identified the NMDA receptor complex as a significant interaction hub based on protein-protein interactions. The NMDA receptor glycine site partial agonist d-clycoserine has been shown to treat the core symptom of social withdrawal in autistic children. Here, we show that rats selectively bred for low rates of play-induced pro-social ultrasonic vocalizations (USVs) can be used to model certain core symptoms of autism. Low-line animals engage in less social contact time with conspecifics, show lower rates of play induced pro-social USVs, and show an increased proportion of non frequency modulated (i.e. monotonous) ultrasonic vocalizations, compared to non-selectively bred random-line animals. Gene expression patterns in the low-line animals show significant enrichment in autism-associated genes and the NMDA receptor family was identified as a significant hub. Treatment of low-line animals with the NMDAR glycine site partial agonist GLYX-13 rescued the deficits in play-induced pro-social 50-kHz and reduced monotonous USVs. Thus, the NMDA receptor has been shown to play a functional role in autism, and GLYX-13 shows promise for the treatment of autism. We dedicate this paper to Ole Ivar Lovaas (May 8, 1927-August 2, 2010), a pioneer in the field of autism.
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5. Reed P, McCarthy J. {{Cross-Modal Attention-Switching is Impaired in Autism Spectrum Disorders}}. {J Autism Dev Disord};2011 (Jul 1)
This investigation aimed to determine if children with ASD are impaired in their ability to switch attention between different tasks, and whether performance is further impaired when required to switch across two separate modalities (visual and auditory). Eighteen children with ASD (9-13 years old) were compared with 18 typically-developing children matched with the ASD group for mental age, and also with 18 subjects with learning difficulties matched with the ASD group for mental and chronological age. Individuals alternated between two different visual tasks, and between a different visual task and an auditory task. Children with ASD performed worse than both comparison groups at both switching tasks. Moreover, children with ASD had greater difficulty when different modalities were required than where only one modality was required in the switching task in comparison with participants matched in terms of mental and chronological age.
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6. Roberts JE, Hatton DD, Long AC, Anello V, Colombo J. {{Visual Attention and Autistic Behavior in Infants with Fragile X Syndrome}}. {J Autism Dev Disord};2011 (Jul 1)
Aberrant attention is a core feature of fragile X syndrome (FXS), however, little is known regarding the developmental trajectory and underlying physiological processes of attention deficits in FXS. Atypical visual attention is an early emerging and robust indictor of autism in idiopathic (non-FXS) autism. Using a biobehavioral approach with gaze direction and heart activity, we examined visual attention in infants with FXS at 9, 12, and 18 months of age with a cross-sectional comparison to 12-month-old typically developing infants. Analyses revealed lower HR variability, shallower HR decelerations, and prolonged look durations in 12-month old infants with FXS compared to typical controls. Look duration and increased latency to disengage attention were correlated with severity of autistic behavior but not mental age.
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7. Thiemann-Bourque KS, Brady NC, Fleming KK. {{Symbolic Play of Preschoolers with Severe Communication Impairments with Autism and Other Developmental Delays: More Similarities than Differences}}. {J Autism Dev Disord};2011 (Jul 1)
Children with autism are often described as having deficient play skills, particularly symbolic play. We compared the play of 35 children with autism to 38 children with other developmental delays. All children were preschool-age and produced less than 20 different words. Results indicated no significant differences across the two groups in their play. Children with autism engaged in more conventional play, that is, putting objects together according to how the toys were constructed (e.g., pieces in a puzzle, lid on a teapot). Results also indicated high correlations between play, language, and cognitive measures. Findings indicate that play relates to language and cognitive levels yet may not discriminate children with autism and children with other developmental delays early in their development.
