Hsu, C.F. (2014). Cross-domain investigation of weak central coherence in people with Williams syndrome: Asymmetrical brain and behavioral performances in verbal and nonverbal domains. In Olivia H. Porter (Ed.), Semantic Memory: Neurobiology, Disorders and Therapeutic Strategies for Improvement, pp.71-82. Nova Science Publishers. ISBN: 978-1-63321-102-5. 

Background: Central coherence is a fundamental cognitive ability concerned with integrating information from parts into a whole. Deficiencies in contextual integration, termed weak central coherence (WCC), have been reported in people with autistic spectrum disorders (Frith, 1989). This study investigated whether WCC is a syndrome-specific or syndrome-general deficit. To examine this issue, people with Williams syndrome (WS), a population with a genetic disorder, were recruited. The reported cognitive profile of this clinical group is asymmetrical, with good language ability but poor visuospatial ability (Bellugi et al. 2000), so a secondary aim of this study was to examine whether different levels of WCC deficits are observed in the verbal and nonverbal domains of people with WS.

Studies and Results: Two studies were conducted to examine the verbal domain: a concept formation from a semantic network study and a causal inference on ambiguities study. The concept formation study used the false memory paradigm and revealed normal-like behavioral performance but abnormal brainwave patterns in people with WS. The causal inference on ambiguities study revealed that people with WS were not deviant but delayed in making causal inferences, both backward and forward, when comprehending ambiguous words in contexts. In the nonverbal domain, a face processing study and a series of contextual integration studies using unimodal or cross-modal methods were used. The face study involved showing faces to people with WS, and then showing them the same faces with changes to the features and configurations, and the differences in processing were recorded. The results showed that people with WS exhibited similar behavioral patterns to the healthy controls, but their brainwaves differed. The controls processed faces with changes in configurations differently from faces with changes in features, while the clinical group did not exhibit this distinction neurologically. The contextual integration studies, using different modality presentations, revealed a delay in semantic integration in people with WS. These findings challenge the traditional claim that people with WS are deficient in visuospatial construction ability. This clinical group demonstrated central coherence ability in terms of contextual integration, as long as the stimuli were socially meaningful rather than abstract block designs or pattern constructions.

Conclusion: WCC is a syndrome-general deficit manifested in the verbal and nonverbal domains of people with WS at both the behavioral and the neuro-physiological level. The finding of brain-behavioral asymmetry confirms the neuroconstructivist view that impairment in the early stages influences later development (Karmiloff-Smith, 1998) and has implications for educational intervention. People with WS may benefit from cross-modal learning, which is related to social knowledge. Further studies may lead to further insights regarding brain plasticity in people with developmental disabilities.

(Full paper is available upon request.)