Examining the relationship between sensory processing and attention in individuals with autism spectrum disorders
Date
2017
Authors
Crasta, Jewel E., author
Davies, Patricia L., advisor
Gavin, William J., advisor
Bundy, Anita, committee member
Rojas, Donald, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Attention is a crucial element of our goal-directed, purposeful response to sensory information in our social and physical environments. Individuals with autism spectrum disorders (ASD) have significant deficits in sensory processing and attention. However, there is limited research examining the relationship between attention and sensory processing in individuals with autism spectrum disorders (ASD). The purpose of this dissertation was to examine the relationship between attention and sensory processing in individuals with autism spectrum disorders (ASD) and neurotypical individuals. Specifically, the objective was to examine if consciously directing attention to incoming information would result in more typical neural processing in individuals with ASD. To answer this question, study 1 was designed to understand how attention and distraction impacted sensory processing in neurotypical individuals. Studies 2 and 3 examined neural measures of sensory processing in individuals with ASD as compared to age-matched neurotypical controls during passive and active attentional states. In Study 1, electroencephalography (EEG) data were recorded while 60 adults (18-35 years) heard random presentations of 4 auditory stimuli at 2 frequencies (1 and 3 kHz) each at 2 intensities (50 and 70 dB). Participants were randomly divided into 2 viewing conditions; one group watched a silent movie and the other viewed a fixation point during the recording. All participants completed 2 attention conditions, the passive condition involved only listening to the stimuli, followed by the active condition, wherein participants were instructed to press a button to the 1 kHz 50 dB tone. Amplitude and latency measures were obtained for the N1, P2, N2, and P3 components for each of the auditory stimuli. The ANOVAs revealed a significant main effect of attention condition for the N1, P2, N2, and P3 amplitudes. There were also significant attention-by-viewing condition interaction effects at the P3 component. Results indicated that actively directing attention to the tones impacts auditory processing at all components. Additionally, manipulation of attention by changing the viewing environment significantly interacted with sensory processing, such that movie viewing resulted in larger P3 amplitudes compared with fixation viewing. Thus, viewing environment or distraction impacts sensory processing. In study 2, we examined the effect of attention on auditory filtering using the sensory gating paradigm in individuals with ASD. EEG data were recorded during 2 attention conditions from 24 adults with ASD and 24 neurotypical individuals during the sensory gating paradigm. During the passive condition, participants were presented with single and paired clicks. For the active condition, participants made a motor response following the single click but not the paired click. Attending to the clicks resulted in larger P50 and N1 amplitudes, and reduced gating for all participants. Although, the ASD group had P50 and N1 gating during both attention conditions, they had significantly longer N1 latencies to the Click 1 during both the attention conditions, suggesting a delayed orienting response. However, click 2 latencies were delayed only in the passive condition and not the active condition for the ASD group compared to the neurotypical group. This finding suggests of attention-based amelioration of processing speed in individuals with ASD. Individuals with ASD also had significantly more deficits on behavioral measures of social responsivity, attention, sensory and perceptual processing. Additionally, neural measures of gating were associated with several behavioral measures of sensory processing as measured by self-report questionnaires and a performance-based measure of attention, such that efficient neural processing was associated with more typical sensory processing and attention. In study 3, we examined the effect of attention on auditory discrimination in individuals with ASD. EEG data were recorded from 24 individuals with ASD and 24 neurotypical individuals, while they heard random presentations of 4 auditory stimuli at 2 different frequencies (1 and 3 kHz) each at 2 different intensities (50 and 70 dB). All participants completed two attention conditions; the passive condition involved only listening to the stimuli, followed by the active condition, wherein participants were instructed to press a button to the 1 kHz 50 dB tone. Attention impacted N2, and P3 amplitudes, and P2 and N2 latencies. The ASD group had significantly longer N1, N2, and P3 latencies, suggesting delayed processing. N2 and P3 latency delays in the ASD group were present during the passive but not active condition, implying an attention-based amelioration of processing delay. Behavioral measures of sensory processing and attention correlated with neural measures of auditory processing. Thus, through the series of studies, we found that actively directing attention to the tones impacts auditory processing, and may result in more typical processing in ASD. The study findings also suggest that sensory processing deficits observed in ASD may be associated with underlying deficits of attention. Study findings have significant implications related to understanding auditory discrimination in individuals with ASD and examining the impact of attention on sensory processing. Additionally, these results can help practitioners understand the neural basis of behavioral manifestations of ASD, especially those atypical behaviors that occur in response to sensory experiences in everyday activities.
Description
Rights Access
Subject
autism spectrum disorder
EEG
ERPs
sensory processing
auditory processing
occupational therapy