Neurobiological Abnormalities in the First Few Years of Life in Individuals Later Diagnosed with Autism Spectrum Disorder: A Review of Recent Data

Institute of Health and Wellbeing, University of Glasgow, RHSC Yorkhill, Glasgow, Scotland.
Behavioural neurology (Impact Factor: 1.45). 08/2013; 2014(3). DOI: 10.3233/BEN-130350
Source: PubMed


Despite the widely-held understanding that the biological changes that lead to autism usually occur during prenatal life, there has been relatively little research into the functional development of the brain during early infancy in individuals later diagnosed with autism spectrum disorder (ASD).
This review explores the studies over the last three years which have investigated differences in various brain regions in individuals with ASD or who later go on to receive a diagnosis of ASD.
We used PRISMA guidelines and selected published articles reporting any neurological abnormalities in very early childhood in individuals with or later diagnosed with ASD.
Various brain regions are discussed including; the amygdala; cerebellum; frontal cortex and lateralised abnormalities of the temporal cortex during language processing. This review discusses studies investigating head circumference, electrophysiological markers and inter-hemispheric synchronisation. All the recent findings from the beginning of 2009 across these different aspects of defining neurological abnormalities are discussed in light of earlier findings.
The studies across these different areas reveal the existence of atypicalities in the first year of life, well before ASD is reliably diagnosed. Cross-disciplinary approaches are essential to elucidate the pathophysiological sequence of events that lead to ASD.

Download full-text


Available from: Philip michael john Wilson, May 22, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Although accumulated evidence has demonstrated that autism is found with many varied brain dysfunctions, researchers have tried to find a single brain dysfunction that would provide neurobiological validity for autism. However, unitary models of autism brain dysfunction have not adequately addressed conflicting evidence, and efforts to find a single unifying brain dysfunction have led the field away from research to explore individual variation and micro-subgroups. Autism must be taken apart in order to find neurobiological treatment targets. Three research changes are needed. The belief that there is a single defining autism spectrum disorder brain dysfunction must be relinquished. The noise caused by the thorny brain-symptom inference problem must be reduced. Researchers must explore individual variation in brain measures within autism.
    Full-text · Article · Jan 2014 · Journal of Autism and Developmental Disorders
  • [Show abstract] [Hide abstract]
    ABSTRACT: Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with impairment of social communication and restricted and repetitive behaviors. Reduced fractional anisotropy (FA), a measure of white matter integrity, in the posterior superior temporal sulcus (pSTS) is related to ASD. However, there are several major fibers in pSTS, and it is unknown which of them is associated with ASD. We investigated FA in correlation with autistic traits assessed by autism spectrum quotient (AQ) in 91 healthy adults using tract-based spatial statistics (TBSS). Then, of the fibers in pSTS, we identified the one in which FA was linked to the AQ score using tractography. TBSS revealed that AQ was correlated with FA of white matter in several regions such as the frontal lobe, parietal lobe, occipital lobe and temporal lobe including pSTS. With further analysis using tractography, we confirmed that FA alteration in pSTS was located on the inferior fronto-occipital fasciculus (IFOF). IFOF has a critical role in processing socio-emotional information. Our findings suggest that of the fibers in pSTS, IFOF is a key fiber that links to autistic traits in healthy adults.
    No preview · Article · Sep 2014 · Journal of Psychiatric Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gender dysphoria (GD) and autism spectrum disorder (ASD) are associated. In 49 GD children (40 natal males), we examined ASD risk factors (i.e., birth weight, parental age, sibling sex ratio) in relation to autistic traits. Data were gathered on autistic traits, birth weight, parents’ ages at birth, sibling sex ratio, gender nonconformity, age, maternal depression, general behavioral and emotional problems, and IQ. High birth weight was associated with both high gender nonconformity and autistic traits among GD children. Developmental processes associated with high birth weight are, therefore, likely to underlie the GD–ASD link either directly or indirectly. The present study is the first to provide quantitative data bearing on possible mechanisms that lead GD and ASD to co-occur.
    No preview · Article · Dec 2014 · Journal of Autism and Developmental Disorders
Show more