Deficits in Autism Spectrum Disorder (ASD) include sensory dysfunctions which have a large impact on the communicative abilities of affected individuals, yet there has been little empirical investigation of these changes until recently. These findings, have led to the hypothesis that impairments in sensory integration may be a foundational deficit in ASD, inducing higher-order cognitive impairments including word-learning and communication impairments. We propose a line of translational research focused on the influence that the temporal relationship between different sensory inputs has on perceptual processing. We will apply these findings as a means of modulating the (multi)sensory integration processes in children with ASD, implementing and assessing the efficacy of a sensory integration training regimen founded on these data. To accomplish these goals, we will begin with behavioral and neural measures of the impacts of changes in the temporal relationship of auditory and visual sensory input. Throughout these experiments, three types of stimulus categories will be used, simple non-speech stimuli, complex non-speech stimuli, and speech stimuli. The use of these three categories of stimuli will allow us to measure differences in processing between simple and complex stimuli as well as speech and non-speech stimuli, both of which are relevant in ASD populations.
Our first aim will include the characterization of the temporal binding window (TBW) in typically developed (TD) and ASD children. This will be done through EEG and behavioral tasks with stimulus types mentioned above. Tasks will include direct (e.g. was the stimulus synchronous) and indirect (e.g. McGurk and flash beep illusions) measures of integration and temporal processing across varied stimulus onset asynchronies. We expect ASD children to exhibit wider TBWs, and group x stimulus interactions with ASD showing a bigger difference between TBWs with speech and non-speech stimuli. These measures will be correlated with word- learning abilities measured through a switch task.
Aim1 will serve 3 purposes: to measure the impact of complexity and speech on integration, to characterization the TBW in TD and ASD children with a number of tasks, and third and most importantly;to measure corollary impairments seen in word learning in ASD children.
Our second aim will be a training program in which ASD children receive feedback training that has been previously used with TD adults to narrow the TBW, with the goal of improving word-learning rates in ASD children. This training will be tested on two groups, one with speech stimuli, and one with simple non-speech stimuli. Pre- and post-training behavioral TBW, word-learning, and EEG sessions will be used to measure the effects of training, and follow-up visits will measure the stability of changes in the TBW and increases in word learning. Previous temporal training studies with TD adults suggest that the wider an individual's TBW, the greater the effect of training, giving reason to suspect that this training will be particularly useful with an ASD population, and may translate to increased effectiveness in enhancing word-learning abilities in ASD children.
Autism Spectrum Disorder (ASD) is a category of developmental disorders including autism, Asperger's, and pervasive developmental disorder (PDD) that has surged in reported prevalence, affecting one out of every 150 births in the United States. Two of the major dysfunctions seen in ASD that impact an autistic individual's ability to communicate are sensory (including multisensory) and temporal processing deficits. This series of studies will provide (1) an in-depth characterization of the impact that the temporal relationship of audiovisual sensory input has on multisensory integration and the effect that this has on communication deficits in autistic individuals, and (2) will translate this information into a training paradigm aimed at narrowing the temporal binding window in ASD and increasing an individual's word-learning ability with the goal of enhancing the integrative ability of ASD individuals and improving both sensory processing and communicative ability.
|Stevenson, Ryan A; Baum, Sarah H; Krueger, Juliane et al. (2018) Links between temporal acuity and multisensory integration across life span. J Exp Psychol Hum Percept Perform 44:106-116|
|Baum, Sarah H; Stevenson, Ryan (2017) Shifts in Audiovisual Processing in Healthy Aging. Curr Behav Neurosci Rep 4:198-208|
|Stevenson, Ryan A; Baum, Sarah H; Segers, Magali et al. (2017) Multisensory speech perception in autism spectrum disorder: From phoneme to whole-word perception. Autism Res 10:1280-1290|
|Stevenson, Ryan A; Sheffield, Sterling W; Butera, Iliza M et al. (2017) Multisensory Integration in Cochlear Implant Recipients. Ear Hear 38:521-538|
|Stevenson, Ryan A; Park, Sohee; Cochran, Channing et al. (2017) The associations between multisensory temporal processing and symptoms of schizophrenia. Schizophr Res 179:97-103|
|Nidiffer, Aaron R; Stevenson, Ryan A; Krueger Fister, Juliane et al. (2016) Interactions between space and effectiveness in human multisensory performance. Neuropsychologia 88:83-91|
|Stevenson, Ryan A; Segers, Magali; Ferber, Susanne et al. (2016) Keeping time in the brain: Autism spectrum disorder and audiovisual temporal processing. Autism Res 9:720-38|
|Krueger Fister, Juliane; Stevenson, Ryan A; Nidiffer, Aaron R et al. (2016) Stimulus intensity modulates multisensory temporal processing. Neuropsychologia 88:92-100|
|Stevenson, Ryan A; Nelms, Caitlin E; Baum, Sarah H et al. (2015) Deficits in audiovisual speech perception in normal aging emerge at the level of whole-word recognition. Neurobiol Aging 36:283-91|
|Stevenson, Ryan A; Ghose, Dipanwita; Fister, Juliane Krueger et al. (2014) Identifying and quantifying multisensory integration: a tutorial review. Brain Topogr 27:707-30|
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