An alphabet grid contains the symbols of an alphabet—in Higashida’s case, those of the Japanese alphabet. It is the means by which Higashida produced The Reason I Jump, by pointing at the appropriate symbols to form words and sentences.

Asperger syndrome, named after Hans Asperger, is a type of autism that has been incorporated into the autism spectrum disorder diagnosis as of 2013. Individuals prior to 2013 could be given a diagnosis of Asperger syndrome that was differentiated from autism spectrum disorder. Those with Asperger syndrome sometimes have a hard time acquiring interpersonal and relationship skills.

Autism is a developmental disability, referring to a range of conditions and symptoms. Autism is a diagnosis often characterized by repetitive behaviors and difficulties with social skills.