Abstract
In children with autism spectrum disorder (ASD), joint attention is regarded as a predictor of language function, social skills, communication, adaptive function, and intelligence. However, existing information about the association between joint attention and intelligence is limited. Most such studies have examined children with low intelligence. For this study, we investigated whether joint attention is related to intelligence in young children with autism spectrum disorder (ASD) without severe intellectual disability. We analyzed 113 children with ASD aged 40-98 months. Their Kaufman Assessment Battery (K-ABC) Mental Processing Index (MPI) scores are 60 and more (mean 93.4). We evaluated their intelligence using K-ABC and evaluated their joint attention using ADOS-2. After we performed simple regression analyses using K-ABC MPI and its nine subscales as dependent variables, using joint attention as the independent variable, we identified joint attention as a positive predictor of the MPI and its two subscales. From this result, we conclude that joint attention is related to intelligence in young children with ASD without severe intellectual disability. This result suggests a beneficial effect of early intervention targeting joint attention for children with ASD. LAY SUMMARY: Joint attention is the ability to coordinate visual attention with another person and then shift one's gaze toward an object or event. Impairment of joint attention is regarded as an early marker of autism spectrum disorder (ASD). This study revealed impairment of joint attention as associated with lower intelligence in ASD children. These results are expected to constitute a rationale for future studies, particularly addressing beneficial effects of early intervention targeting joint attention for children with ASD.