Neural Responses to Novel and Existing Words in Children with Autism Spectrum and Developmental Language Disorder

Area of Science:

• Neuroscience
• Developmental Psychology
• Linguistics

Background:

• Establishing new phonological representations is vital for mental lexicon development.
• Repetition, time, and sleep stabilize phonological forms.
• Children with developmental language disorder (DLD) and autism spectrum disorder (ASD) exhibit atypical word form establishment.

Purpose of the Study:

• To compare neural changes in response to novel word forms over time in typically developing (TD) children, and children with DLD or ASD.
• To investigate habituation of event-related potentials (ERPs) to novel and known words across two sessions 24 hours apart.

Main Methods:

• ERP recordings using dry electrodes in 21 TD children, 19 children with ASD, and 16 children with DLD.
• Passive listening to known and novel words over two consecutive days.
• Analysis of auditory N400 amplitude modulation to assess lexical processing and habituation.

Main Results:

• No habituation effect was observed within sessions for any group.
• Habituation occurred between sessions, but this effect was reduced in the DLD group.
• Reduced between-session habituation in DLD indicates less pre-activation of lexical representations for previously encountered words.
• No significant differences in change over time were found between TD and ASD groups.

Conclusions:

• Sleep-related consolidation plays a significant role in word learning.
• Children with DLD demonstrate difficulties in overnight consolidation of new word forms.
• The findings support theories emphasizing the importance of sleep in stabilizing new lexical items.