Declarative Memory and Structural Language Impairment in Autistic Children and Adolescents

Area of Science:

• Neuroscience
• Developmental Psychology
• Linguistics

Background:

• Language impairment and learning disability affect a significant portion of the autistic population.
• The underlying factors contributing to these disabilities in Autism Spectrum Disorder (ASD) are under-researched.
• Existing research lacks explanations for lexical-semantic abnormalities observed in ASD.

Purpose of the Study:

• To test the hypothesis that impaired declarative memory contributes to structural language impairment in ASD.
• To investigate the roles of familiarity (semantic memory) and recollection (episodic memory) in autistic individuals with and without language impairments.
• To explore the relationship between declarative memory processes and lexical-semantic knowledge in ASD and learning disability (LD).

Main Methods:

• Two experiments were conducted comparing groups of teenagers with ASD and language impairment/learning disability (ASD ^LI/LD ), children with ASD and typical language (ASD ^TL ), teenagers with learning disability (LD) without autism, and typically developing (TD) children.
• Participants' declarative memory processes (familiarity and recollection) and lexical-semantic knowledge were assessed.
• Statistical analyses were used to examine the links between memory functions and language abilities across groups.

Main Results:

• Both experiments supported the hypothesis linking declarative memory processes to lexical-semantic abilities in the ASD ^LI/LD and ASD ^TL groups.
• These links were not observed in the typically developing (TD) group.
• Declarative memory and lexical-semantic knowledge were also linked in the LD group.
• ASD groups, and to a lesser extent the LD group, showed evidence of compensating for declarative memory impairments using visual-perceptual abilities.

Conclusions:

• Difficulties with declarative memory, specifically familiarity and recollection, may contribute to structural language impairment in ASD.
• These memory deficits could also explain broader learning disabilities observed in ASD and LD populations.
• Compensatory use of visual-perceptual abilities in ASD and LD has potential educational implications for supporting learning.