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ABSTRACT: There is increasing evidence to show that indicators other than socio-cognitive abilities might predict communicative function in Autism Spectrum Disorders (ASD). A potential area of research is the development of speech motor function in toddlers. Utilizing a novel measure called "articulatory features," we assess the abilities of toddlers to produce sounds at different timescales as a metric of their speech motor skills. In the current study, we examined (1) whether speech motor function differed between toddlers with ASD, developmental delay (DD), and typical development (TD); and (2) whether differences in speech motor function are correlated with standard measures of language in toddlers with ASD. Our results revealed significant differences between a subgroup of the ASD population with poor verbal skills, and the other groups, for the articulatory features associated with the shortest-timescale, namely place of articulation (POA), (p < 0.05). We also found significant correlations between articulatory features and language and motor ability as assessed by the Mullen and the Vineland scales for the ASD group. Our findings suggest that articulatory features may be an additional measure of speech motor function that could potentially be useful as an early risk indicator of ASD.
Frontiers in Integrative Neuroscience 01/2013; 7:17.
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ABSTRACT: Despite an extremely rich and complex auditory environment, human beings categorize sounds effortlessly. While it is now well-known that this ability is a result of complex interaction of bottom-up processing of low-level acoustic features and top-down influences like evolutionary relevance, it is yet unclear how these processes drive categorization. The objective of the current study was to use functional neuroimaging to investigate the contribution of these two processes for category selectivity in the cortex. We used a set of ecologically valid sounds that belonged to three different categories: animal vocalizations, environmental sounds and human non-speech sounds, all matched on acoustic structure attributes like harmonic-to-noise ratio to minimize differences in bottom-up processing as well as matched for familiarity to rule out other top-down influences. Participants performed a loudness judgment task in the scanner and data were acquired using a sparse-temporal sampling paradigm. Our functional imaging results show that there is category selectivity in the cortex only for species-specific vocalizations and this is revealed in six clusters in the right and left STG/STS. Category selectivity was not observed for any other category of sounds. Our findings suggest a potential role of evolutionary relevance for cortical processing of sounds. While this seems to be an appealing proposition, further studies are required to explore the role of top-down mechanisms arising from such features to drive category selectivity in the brain.
Neuroscience 04/2012; 214:49-58. · 3.38 Impact Factor
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ABSTRACT: The objective of this study was to find a pattern in vocalizations of children with Autism Spectrum Disorder (ASD). We compared the intonational features of 15 children with ASD who showed speech, aged 4-10 years, with 10 age-matched typically developing controls. Exaggerated pitch, pitch range, pitch excursion and pitch contours were observed in speech of children with autism, but absent in age-matched controls. These exaggerated features, which are distinctive characteristics of motherese, were also seen in interactions of an independent group of 8 mothers of typical infants using child-directed speech. Our findings provide the first evidence of a distinct pattern in vocal output from children with autism. They also demonstrate that speech patterns might follow a delayed developmental trajectory in these children.
Neuroscience Letters 06/2010; 478(1):42-5. · 2.11 Impact Factor
