- The difficulty with sports in individuals with autism spectrum disorder may be caused by impairment in tool–body assimilation
The difficulty with sports in individuals with autism spectrum disorder may be caused by impairment in tool–body assimilation
Autism Spectrum Disorder (ASD) has been known to cause difficulty in sports, such as ball games, and difficulty in using tools. Problems with the body-space relationship and impaired prediction have been thought to be behind this, but it is still unclear.
Dr Makoto Wada, section chief of developmental disorders section of Research Institute of the National Rehabilitation Center for Persons with Disabilities, in collaboration with Professor Makoto Miyazaki at Shizuoka University, has discovered a phenomenon that may cause difficulty in sports by investigating the body perception with cutaneous rabbit illusion tasks in individuals with ASD.
The cutaneous rabbit illusion indicates the sensation as if a small rabbit hopping across the skin between two points when a quick succession of tactile stimuli is first applied to one point on the skin and then to another point. Tapping both index fingers while holding the stick with both fingers has been shown to produce this illusion on the stick (Fig. 1).
The research group found that although the cutaneous rabbit illusion occurs in autistic individuals to the same extent as in individuals with typically developing (TD), this illusion is less likely to occur on the stick in more than one-third of autistic individuals (Fig. 2). And all those with this tendency reported difficulty with sports, such as ball games. In other words, it was suggested that the inability to feel like tools are part of the body could be the cause of their difficulty in sports.
It is hoped that the development of this study will lead to the development of methods of support for various characteristics of disabilities, especially those related to tool use and the body.
Fig.1 Cutaneous and stick rabbit illusions (Illustration: Prof. Miyazaki’s works)
First, successive two taps are applied to one point on the skin, and then another tap is applied to another point, causing the illusion as if a small rabbit hopping between the two points on the skin (cutaneous rabbit illusion, left panel). In other words, an illusion of tactile sensation is produced at a point on the skin that is not actually being stimulated. Previously, Miyazaki et al (2010) reported that similar illusion is occurred on the stick while the stick was held by both index fingers (stick rabbit illusion, right panel). In the present study, we used these experimental tasks to investigate the background of difficulties with tool uses in individuals with ASD.
Fig.2 Touch perception of second stimulus
The cutaneous rabbit illusion itself was found to be prominent in both ASD and TD individuals. In contrast, we investigated where participants reported position of the second stimulus (stimulus 2) in the stick rabbit illusion. One ASD participant reported that it was between the sticks, similar to the results for TD participants (top left), while another participant reported that he did not feel the stimulus on the stick (bottom right). The latter was the case for over a third of the ASD participants who participated in the experiment. No such trend was observed in TD participants.
Wada M, Ide M, Ikeda H, Sano M, Tanaka A, Suzuki M, Agarie H, Kim S, Tajima S, Nishimaki K, Fukatsu R, Nakajima Y, Miyazaki M. Cutaneous and stick rabbit illusions in individuals with autism spectrum disorder. Scientific Reports. 10, 1665, 2020.