A Preliminary Study on the Assessment of Restrictedness in High Functioning Autism

Restricted and repetitive behavior is one of the two cardinal symptoms of autism, and it might find its root in the neuropsychological trait of “insistence on sameness”. Conceived from the perspective of embodied psychology, our study aimed to investigate whether “restrictedness” might be embodied in the patient’s motor activity. Four patients with high functioning autism (ASD) and five participants of typical development (TD) aged between 6 and 13 years were recruited to perform a horizontal left–right movement with their dominant hand. Instructions were to perform as complex movement as possible by demonstrating variant amplitude and frequency. Entropy of movement amplitude, frequency, and velocity was calculated as indices of movement “restrictedness”. Results demonstrated that the velocity entropy was significantly lower in ASD than in TD (both p < 0.01), indicating a higher level of restrictedness in ASD’s movement. Given the fact that current evaluation of RRB is questionnaire-based, which might be biased by subjective factors of the evaluator, our finding sheds light on potential objective assessment of restrictedness in autism. A discussion on the comparison between our approach and recent method on automatic RRB pattern recognition was formulated.