[1] Hiroshima Univ, Grad Sch Educ, Ctr Special Needs Educ Res & Practice, Hiroshima 7398524, Japan
[2] Univ Nebraska, Dept Special Educ & Commun Disorders, Barkley Mem Ctr 353, Lincoln, NE 68583 USA
[3] Nihonbashi Gakkan Univ, Dept Human Psychol, Kashiwa, Chiba 2770005, Japan
[4] Univ Cent Florida, Dept Commun Sci & Disorders, Orlando, FL 32816 USA
[5] Univ Ghent, B-9000 Ghent, Belgium