Semantics Is Importantly Significant: An Investigation into Lexical Errors in ASD

Thursday, May 11, 2017: 12:00 PM-1:40 PM
Golden Gate Ballroom (Marriott Marquis Hotel)
E. Zane, J. Mertens, W. J. Lancaster, A. Chugg and R. B. Grossman, FACE Lab, Emerson College, Boston, MA
Background:  There is evidence to suggest that language impairment and autism spectrum disorder (ASD) are separable conditions (Tager-Flusberg, 2006; Rapin et al., 2009). Accordingly, the Diagnostic Statistical Manual no longer includes language impairment as a necessary component of an ASD diagnosis (APA, 2013).

However, children with ASD who have good language skills still struggle with some aspects of semantics (Dunn et al., 1996; 1997). Semantic impairments have also been noted in “optimal-outcome” children, i.e., children previously diagnosed with ASD whose social communication skills had improved enough to move them out of the ASD range (Kelley et al., 2006). As yet, it is unclear what types of semantic errors children with ASD produce and whether issues with semantics in children with ASD persist through adolescence or are instead evidence of delayed acquisition in younger children.

Objectives:  To identify and categorize the semantic errors of children (ages 11-17) with ASD in order to determine an impact of ASD diagnosis on later stages of semantic language development.

Methods:  Preliminary results are based on ten adolescents with ASD (2 females, ages 11-17) and twenty typically-developing controls (8 females, ages 10-16). Groups were not significantly different on language ability as measured by the CELF-5 (ASD M = 114, TD M = 115; p = 0.9). Participants were audio-recorded as they interviewed a researcher. We transcribed recordings and coded them for semantic errors, defined as moments when an utterance’s meaning was unclear and/or redundant.

Results:  Error frequency: All participants with ASD produced at least one semantic error, and participants with ASD produced more semantic errors on average than their TD peers (ASD M = 7, TD M = 2; p < 0.05).

Error types: Participants with ASD misused words and produced neologisms (e.g., “mosquito nicked me”; “electroids”). They also made “lexical disinhibition errors,” by producing lexical neighbors, i.e. semantically related words, that were inappropriate to sentential semantics (e.g., “...was large and huge”; “[I see] family, friends, resemblance”). Word-choice errors were rare in the TD group; lexical disinhibition errors were not present.

Conclusions:  Even though both groups’ language scores fell within normal bounds on the CELF-5, adolescents with ASD produced more semantic errors than their TD peers during spontaneous speech, indicating that the ASD group has a subtle semantic impairment that is not captured by traditional language tests.

The types of errors produced by participants with ASD (incorrect word choices and strings of unnecessary lexical neighbors) suggest particular impairments in lexical semantics. Disinhibition errors have not previously been described as a feature of language in ASD; they indicate dysfunctional lexical access, which could be caused by executive dysfunction. Future research should explore whether and how lexical disinhibition contributes to semantic impairments in ASD and how these errors affect communicative effectiveness during conversation.