Attention Engagement in ASD

Background:

Deficits in attention related to disengaging from a stimulus and shifting to another is said to be impaired in autism spectrum disorders (ASD). This has been referred to as “sticky attention”, and tends to occur more in specific experimental paradigms versus being a central deficit in ASD (e.g., see McMorris & Bebko, this conference). Sticky attention has typically been measured by the latencies in participants’ responses to a new peripheral stimulus once presented. However, disengaging and shifting times may also be impacted by the degree to which participants are engaged in the previous stimulus prior to presentation of the new stimulus. That is, previously identified delays in disengaging or shifting may be secondary to events that preceded the onset of the new stimulus versus what occurs once the new stimulus is presented. In this study we look at variability of engagement that children and youth with ASD demonstrate with what has been termed the “central” stimulus in previous studies. Attention difficulties are often present in children with ASD (Keehn et al., 2010) and these differences are hypothesized to manifest in different degrees of engagement with stimuli, measured by time spent looking at a single stimulus prior to onset of a new stimulus.

Objectives:

Using an eye-tracking attention task, we examined the degree of attention engagement of children with ASD compared to typically developing (TD) peers as measured by duration of fixations to stimuli.

Methods:

Twenty TD children and 20 children with ASD matched on chronological age (range: 75-184 months) and cognitive abilities, watched a series of videos where stimuli would appear for 3 seconds sequentially in 4 quadrants of a TV screen. To examine potential differences in engagement by stimulus type, 2 types of stimuli were presented, social (a person telling a story) and non-social (e.g, hand playing a piano). Eye fixations were recorded using a Tobii eye-tracker.

Eye fixations were analyzed in two ways: 1) the sum total of all durations on each stimulus (SUMTOT); and 2) the duration of the last fixation before a new stimulus appeared (DLF). If sticky attention is related to the degree of engagement of attention before a new stimulus is shown, then longer durations should be seen in both methods for ASD.

Results:

Analysis of the DLF data yielded a main effect of group with TD being significantly more engaged than ASD, F(1, 38) = 16.00, p < .001. Similarly, SUMTOT was greater for TD, F(1,36) = 9.78, p < .01. Further analyses looking at the effect of stimulus type within groups are ongoing.

Conclusions:

These results suggest that differences in disengagement and shifting times in ASD found in previous research need to be re-evaluated in light of significant differences in degree of engagement with the central stimulus prior to the presentation of a second stimulus. Differences in engagement with one stimulus may facilitate/interfere with recognition of a changing display when a new peripheral stimulus is presented, altering the latency of response.