The Neural Mechanism of Emotionally Metaphorical Comprehension in Schooling Children with and without High-Functioning Autism Spectrum Disorder

Background: Several studies have shown different processes for emotion-label and emotion-laden words in typical adults. While emotion-laden words directly describe affective state (e.g., happy), emotion-laden words refer to objects, events or personality traits that could evoke affective responses (e.g. prize). Individuals with autism spectrum disorder (ASD) have been documented deficits in understanding figurative languages (e.g., metaphor, ironic); however, little work investigated the process for the non-literal emotional expressions in terms of emotion-laden words in the clinical population.

Objectives: The current study aimed to explore the neural mechanism underlying comprehension in emotionally metaphoric expressions in related to adaptive behavior in children with high-functioning autism spectrum disorder (HFASD).

Methods: In the task the two-character Chinese emotion words were presented with factors of type (emotion-label, emotion-laden) and valence (positive, negative) in addition to neutral words. 11-14-year-old children with HFASD (N=25) and age-matched typically developing (TD) children (N=25) classified emotion valence of the words during electroencephalogram measurement. Their adaptive behavior were evaluated by parents’ questionnaire.

Results: No significant differences in reaction time and accuracy were found between both groups. The reaction time was faster for emotion-label words than for emotion-laden words in the two groups. The late positive component (LPC), an event-related potential (ERP) component usually indexing deeper processing for emotion contents, was larger for negative emotion-label words than for positive emotion-label words in both groups. However, the emotion effects distributed more broadly in the TD group compared to the HFASD group. Regarding emotion-laden words, the LPC differentiated between the two valence words at 600 m in the TD children. On the contrary, no such differences were statistically significant in the HFASD group. There was a trend showing correlations between the LPC amplitude and adaptive problems, particularly for communication domain.

Conclusions: Children with HFASD may have ability to distinguish emotion from straight emotional expressions, with using different strategies from typically developing peers. Comparatively, they fail to extract emotionally semantic efficiently when the expressions are non-literal.