Introduction of a revised HEIM Scale for Evaluating the Psycho- educational Horseback Riding Program in Children with Pervasive Developmental Disorder

We examined the validity of our 10‐item Human‐Equids‐Interaction on Mental activity (HEIM) scale for evaluating the effect of psycho‐educational horseback riding (PEHR) programs in children with pervasive developmental disorders (PDDs). A total of 18 children participated in this program for up to 103 months and significant improvements in behavioral problems were detected (as determined by total HEIM scores) after exposure to the PEHR program, but the degree of improvement varied among specific items within the HEIM scale. In general, the length of program participation corresponded with score improvements. Arising from difficulties identified, in accurately measuring imitation and verbal communication, a revision of two HEIM scale items is proposed to improve measurement sensitivity.