The Bouba-Kiki Effect in Children With Childhood Apraxia of Speech

The bouba-kiki (BK) effect refers to associations between visual shapes and auditory pseudonames. Thus, when tested, people tend to associate the pseudowords bouba and kiki with round or spiky shapes, respectively. This association requires cross-modal sensory integration. The ability to integrate information from different sensory modalities is crucial for speech development. A clinical population that may be impaired in cross-modal sensory integration is children with childhood apraxia of speech (CAS). The purpose of this study was to examine the involvement of cross-modal sensory integration in children with (CAS).

The BK effect was assessed in participants with CAS (n = 18) and two control groups: One control group was composed of children with developmental language disorder (DLD), also termed specific language impairment (n = 15), and a second group included typically developing (TD) children (n = 22). The children were presented with 14 pairs of novel visual displays and nonwords. All the children were asked to state which shape and nonword correspond to one another. In addition, background cognitive (Leiter-3) and language measures (Hebrew PLS-4) were determined for all children.

Children in the CAS group were less successful in associating between visual shapes and corresponding auditory pseudonames (e.g., associating the spoken word "bouba" with a round shape; the spoken word "kiki" with a spiky shape). Thus, children with CAS demonstrated a statistically significant reduced BK effect compared with participants with TD and participants with DLD. No significant difference was found between the TD group and the DLD group.

The reduced BK effect in children with CAS supports the notion that cross-modal sensory integration may be altered in these children. Cross-modal sensory integration is the basis for speech production. Thus, difficulties in sensory integration may contribute to speech difficulties in CAS.