30568
Predictive Abilities during Visual Narrative Comprehension in Individuals with Autism
Individuals with autism spectrum disorder (ASD) often demonstrate impaired narrative comprehension. While the majority of work in this area has used linguistic (i.e. spoken or written) narratives, there is also evidence of comprehension impairments for non-linguistic narratives (e.g. picture sequences or comics), suggesting domain-general impairments in narrative comprehension.
Identifying contributors to comprehension impairments is important for developing effective treatment interventions. One such contributor is that of predictive abilities. Successful narrative and discourse processing entails a high degree of prediction to facilitate comprehension. However, recent work has proposed that autism is a disorder of prediction, such that individuals with ASD are less able to use previous experiences to interpret incoming information. Such deficits in predictive abilities could underlie domain-general comprehension impairments in individuals with ASD.
In language studies, prediction during sentence comprehension is examined by manipulating cloze probability, the expectancy of a specific word given the contextual constraints of a preceding sentence. In “high cloze” sentences, the final word is highly predictable given the context of the sentence; in “low cloze” sentences, the final word is less predictable. In studies using event-related potentials (ERPs), which are derived from the EEG, words in high cloze sentences generate a reduced negative amplitude (the “N400”) compared to words in low cloze sentences. That is, the more predictable a word is given the constraints of the preceding context, the smaller the N400 amplitude. Prediction in visual narrative comprehension can be tested using a similar paradigm, in which a given panel is more or less expected based on the prior narrative context.
Objectives:
In this exploratory study we use a cloze probability manipulation with EEG to determine whether individuals with ASD experience impaired predictive abilities during comprehension of visual narratives.
Methods:
Preliminary data is reported from 4 adults with ASD and 4 typically-developing (TD) adults. Participants viewed visual narrative sequences (Peanuts comic strips) one panel at a time during concurrent EEG recording. ERPs were time-locked to a “target” panel which was either highly predictable (“high cloze”) or not predictable (“low cloze”; Figure 1) given the context of the narrative, as quantified with a pretest. An additional “anomalous” condition was included, in which the target panel was highly incongruent with the context of the preceding narrative. This served as a control condition and was expected to elicit the highest N400 amplitudes of the three conditions.
Results:
Preliminary results show a significant group-by-condition interaction from 400-500 ms. Here, the TD group shows a significant modulation of the N400 effect by condition (anomalous > low cloze > high cloze). However, no such modulation of the N400 effect by condition occurs in the ASD group.
Conclusions:
These preliminary data indicate that TD adults show the expected manipulation of the N400 effect by cloze probability, but individuals with ASD do not. Although data collection is ongoing, these results suggest that individuals with ASD have impaired predictive abilities, which may underlie domain-general narrative comprehension deficits in this population.