1. Brieber S, Herpertz-Dahlmann B, Fink GR, Kamp-Becker I, Remschmidt H, Konrad K. {{Coherent motion processing in autism spectrum disorder (ASD): an fMRI study}}. {Neuropsychologia} (Feb 11)
A deficit in global motion processing caused by a specific dysfunction of the visual dorsal pathway has been suggested to underlie perceptual abnormalities in subjects with autism spectrum disorders (ASD). However, the neural mechanisms associated with abnormal motion processing in ASD remain poorly understood. We investigated brain responses related to the detection of coherent and random motion in 15 male subjects with ASD and 15 age- and IQ-matched healthy controls (aged 13 to 19 years) using event-related functional magnetic resonance imaging (fMRI). Behaviorally, no significant group differences were observed between subjects with ASD and controls. Neurally, subjects with ASD showed increased brain activation in the left primary visual cortex across all conditions compared with controls. A significant interaction effect between group and condition was observed in the right superior parietal cortex resulting from increased neural activity in the coherent compared with the random motion conditions only in the control group. In addition, neural activity in area V5 was not differentially modulated by specific motion conditions in subjects with ASD. Functional connectivity analyses revealed positive correlations between the primary visual cortex and area V5 within both hemispheres, but no significant between-group differences in functional connectivity patterns along the dorsal stream. The data suggest that motion processing in ASD results in deviant activations in both the lower and higher processing stages of the dorsal pathway. This might reflect differences in the perception of visual stimuli in ASD, which possibly result in impaired integration of motion signals.
2. Buoni S, Zannolli R, Felice CD, Nicola AD, Guerri V, Guerra B, Casali S, Pucci B, Corbini L, Mari F, Renieri A, Zappella M, Hayek J. {{EEG features and epilepsy in MECP2-mutated patients with the Zappella variant of Rett syndrome}}. {Clin Neurophysiol} (Feb 11)
OBJECTIVE: To assess the presence/absence of peculiar EEG features and epilepsy in MECP2-mutated Rett patients with the Zappella-Rett variant (Z-RTT) also known as preserved speech variant. METHODS: Retrospective analysis of 16 (age 19.4+/-8.4years; range 8-38years) MECP2 mutated Z-RTT cases, including 11 high or intermediate performance (HIP), and five low-performance (LP) patients was performed. Peculiar EEG features were analyzed as a function of the HIP or LP Z-RTT categories: (1) centro-temporal spikes, (2) multifocal EEG activity, (3) EEG encephalopathy (i.e. multifocal EEG activity associated with the presence of background slowing and diffuse slow activity), (4) spindles and K-complex. Furthermore, we assessed the occurrence of epilepsy. Correlations between electroclinical features and category of Z-RTT genotype (missense or truncation mutation) were also tested. RESULTS: The Z-RTT HIP group showed a very abnormal EEG (presence of centro-temporal spikes: p=0.004808), although the cases studied were not epileptogenic and did not develop encephalopathy. The LP group showed multifocal EEG activity (p=0.000229), EEG encephalopathy (p=0.000229) and epilepsy (p=0.299451). No significant differences between the prevalence of centro-temporal spikes, multifocal EEG activity, EEG encephalopathy, and epilepsy between the patients with the truncation or missense mutation were observed. CONCLUSIONS: EEG electrophysiological patterns and epileptogenic susceptibility differ in Z-RTT according to the level of performance (i.e. HIP or LP). SIGNIFICANCE: These results indicate that HIP and LP Z-RTT should be considered as distinct entities, not only on a clinical basis, but also as it concerns EEG features and epileptogenic susceptibility. These results could offer support in the practical management of patients and family counseling.
3. Combi R, Redaelli S, Beghi M, Clerici M, Cornaggia CM, Dalpra L. {{Clinical and genetic evaluation of a family showing both autism and epilepsy}}. {Brain Res Bull} (Feb 9)
Autism is a strongly genetic disorder, with an estimated heritability greater than 90%. Nonetheless, its specific genetic aetiology remains largely unknown. Autism is associated with epilepsy in early childhood and epilepsy occurs in 10-30% of individuals with autism. Here we report the case of a woman affected by a severe epileptic disorder with an onset at 14 years old. She is affected by a cryptogenetic focal epilepsy with complex partial (psychomotor) and secondarily generalized tonic-clonic seizures, which are drug resistant. The woman is married to a healthy man and has six children: two girls are healthy, a girl and two boys are affected by autism while one boy shows partial seizures. The three children with autism show moderate mental retardation and an EEG with no epileptiform alterations. The child with epileptic seizures shows an asymmetric EEG that is not necessarily pathological. In this family, no chromosomal rearrangements were detected by means of classical cytogenetic analyses. The presence of FRAXA alterations and of microdeletions of the 15q11-q13 chromosome region were also excluded. A genome-wide linkage analysis using microsatellite markers revealed several chromosome regions as possible susceptibility loci.
4. Fatemi SH. {{Co-occurrence of neurodevelopmental genes in etiopathogenesis of autism and schizophrenia}}. {Schizophr Res} (Feb 12)
5. Fujikawa-Brooks S, Isenberg AL, Osann K, Spence MA, Gage NM. {{The effect of rate stress on the auditory brainstem response in autism: A preliminary report}}. {Int J Audiol} (Feb);49(2):129-140.
Abstract Efforts to correlate peripheral neurophysiologic function with perceptional deficits seen in autistic disorder (AD) have resulted in mixed findings, reflecting the high degree of heterogeneity observed in these individuals. We used the auditory brainstem response to study the effect of stress (high click presentation rate) on the auditory system in 20 children with AD (7-13 years) and 20 age-matched typically developing (TD) children. We report latency prolongations in children with AD vs. TD at waves I, III, and V that differed by ear of presentation: overall, left ear showed significant prolongations by group while right ear did not. The ‘stressed’ condition produced prolongations for both groups at each wave. At wave V, children with AD showed significant prolongations vs. TD, particularly for the right ear. For children with AD, wave V latency prolongations corresponded to language outcome as measured by VIQ, with longer prolongations associating with lower VIQ. Preliminary results provide evidence for reduced synaptic efficiency in auditory pathways in children with AD, which may form the neural bases for sensory reactivity and language impairment. Sumario Los esfuerzos para correlacionar la funcion neurofisiologica periferica con los deficits de percepcion que se observan en el trastorno autistico (AD) han producido hallazgos mixtos que reflejan el alto grado de heterogeneidad que se aprecia en estos individuos. Usamos la respuesta auditiva de tallo cerebral para estudiar el efecto de tasas elevadas de presentacion de clicks al sistema auditivo de 20 ninos con AD (7-13 anos) y de otros 20, pareados en edad, con desarrollo tipico (TD). Reportamos latencias prolongadas en ninos con AD vs. TD en las ondas I, III y V que difirieron segun el oido estimulado. Globalmente, el oido izquierdo mostro prolongaciones significativas por grupo, mientras que no fue asi con el oido derecho. La condicion de « alta estimulacion » produjo prolongaciones en ambos grupos y con cada una de las ondas. En la onda V, los ninos con AD mostraron prolongaciones significativas vs. los ninos TD, particularmente con el oido derecho. En ninos con AD, las prolongaciones de latencia de la onda V, correspondieron a resultados linguisticos medidos con VIQ, con prolongaciones aun mayores que se asociaron con niveles VIQ mas bajos. Los resultados preliminares proporcionan evidencias de eficiencia sinaptica reducida en las vias auditivas de ninos con AD, que pueden ser el fundamento neural de la reactividad sensorial y de los impedimentos del lenguaje.
6. Gadow KD, Roohi J, Devincent CJ, Kirsch S, Hatchwell E. {{Brief Report: Glutamate Transporter Gene (SLC1A1) Single Nucleotide Polymorphism (rs301430) and Repetitive Behaviors and Anxiety in Children with Autism Spectrum Disorder}}. {J Autism Dev Disord} (Feb 13)
Investigated association of single nucleotide polymorphism (SNP) rs301430 in glutamate transporter gene (SLC1A1) with severity of repetitive behaviors (obsessive-compulsive behaviors, tics) and anxiety in children with autism spectrum disorder (ASD). Mothers and/or teachers completed a validated DSM-IV-referenced rating scale for 67 children with autism spectrum disorder. Although analyses were not significant for repetitive behaviors, youths homozygous for the high expressing C allele had more severe anxiety than carriers of the T allele. Allelic variation in SLC1A1 may be a biomarker for or modifier of anxiety symptom severity in children with ASD, but study findings are best conceptualized as tentative pending replication with larger independent samples.
7. Ingersoll B. {{Brief Report: Pilot Randomized Controlled Trial of Reciprocal Imitation Training for Teaching Elicited and Spontaneous Imitation to Children with Autism}}. {J Autism Dev Disord} (Feb 13)
Children with autism exhibit significant deficits in imitation skills. Reciprocal Imitation Training (RIT), a naturalistic imitation intervention, was developed to teach young children with autism to imitate during play. This study used a randomized controlled trial to evaluate the efficacy of RIT on elicited and spontaneous imitation skills in 21 young children with autism. Results found that children in the treatment group made significantly more gains in elicited and spontaneous imitation, replicating previous single-subject design studies. Number of spontaneous play acts at pre-treatment was related to improvements in imitation during the intervention, suggesting that children with a greater play repertoire make greater gains during RIT.
8. Minshew NJ, Keller TA. {{The nature of brain dysfunction in autism: functional brain imaging studies}}. {Curr Opin Neurol} (Feb 11)
PURPOSE OF REVIEW: Functional magnetic resonance imaging studies have had a profound impact on the delineation of the neurobiologic basis for autism. Advances in fMRI technology for investigating functional connectivity, resting state connectivity, and a default mode network have provided further detail about disturbances in brain organization and brain-behavior relationships in autism to be reviewed in this article. RECENT FINDINGS: Recent fMRI studies have provided evidence of enhanced activation and connectivity of posterior, or parietal-occipital, networks and enhanced reliance on visuospatial abilities for visual and verbal reasoning in high functioning individuals with autism. Evidence also indicates altered activation in frontostriatal networks for cognitive control, particularly involving anterior cingulate cortex, and altered connectivity in the resting state and the default mode network. The findings suggest that the specialization of many cortical networks of the human brain has failed to develop fully in high functioning individuals with autism. SUMMARY: This research provides a growing specification of to the neurobiologic basis for this complex syndrome and for the co-occurrence of the signs and symptoms as a syndrome. With this knowledge has come new neurobiologically based opportunities for intervention.
9. Zwaigenbaum L. {{Advances in the early detection of autism}}. {Curr Opin Neurol} (Feb 11)
PURPOSE OF REVIEW: Early detection and diagnosis of autism spectrum disorders (ASDs) allows opportunities for children and their families to benefit more fully from early supports and interventions. RECENT FINDINGS: Recent advances in early detection research have resulted from prospective studies of high-risk infants and large ASD screening studies conducted in community settings. With improvement in early detection of autism, exciting progress has been made in establishing the efficacy of ASD-specific interventions for toddlers as young as 18 months on the basis of controlled clinical trials. SUMMARY: There has been increasing emphasis on opportunities to link early behavioral expression to the underlying neurobiology of ASD, potentially bringing us closer to the fundamental mechanisms underlying this disorder.
