Lexical Processing in Toddlers with ASD: Does Weak Central Coherence Play a Role?
Susan Ellis Weismer, Eileen Haebig, Jan Edwards and 2 others
PMID 27696177WHAT IT FOUND
Toddlers with ASD did not show the predicted detail-focused processing pattern on a word recognition task.
They looked less reliably at named pictures than matched peers, but that difference disappeared once receptive vocabulary was considered.
Key findings
01The ASD group did not show the predicted greater disruption by perceptually similar distractors; the TD group showed a larger gap between neutral and perceptually similar conditions.
02Toddlers with ASD looked less reliably and more slowly at the target than TD children matched on nonverbal cognition, but this group difference disappeared when receptive vocabulary was included.
03Within the ASD group, smaller receptive vocabulary was linked to greater disruption by perceptually similar distractors, and low-vocabulary children looked about equally at target and distractor.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The ASD toddlers were older and had lower parent-reported receptive vocabulary than the TD toddlers, even though the groups were matched on nonverbal cognitive raw scores. The ASD group contributed fewer valid trials than the TD group in the semantically similar condition (average 18.1 versus 20.8 trials; t(58)=2.115, p=.039), so the amount of usable data differed between groups. Vocabulary was measured by parent report of words understood and produced, not by a direct measure of vocabulary depth or word meaning. The study did not follow children over time or measure everyday communication, so it cannot show whether these patterns predict later language outcomes. The main analysis covered 200 to 1300 ms after the word began, so later looking back to distractors was not part of the reported model.
The easy way to misread this
Do not conclude that weak central coherence explains word recognition problems in toddlers with ASD. The study found no general support for that account, and the group difference in target looking disappeared when receptive vocabulary was included.