Comparative analysis of self-injurious behaviour topographies in young children with and without developmental delay

Background: The present study presents post hoc analyses of specific topographies of self-injurious behaviour (SIB) exhibited by young children with developmental delay (DD) and children with typical development (TD). We conducted these analyses to better understand similarities and differences between the groups from a developmental perspective. No previous study has compared the prevalence, severity and co-occurrence of specific topographies of SIB in young children. Method: The participants were parents of two groups of children one with DD (n = 49, mean age = 37.5 months) and one with TD (n = 49, mean age = 36.6 months). Individual items of the SIB subscale from the Repetitive Behaviour Scale-Revised were used in the analyses. Results: Seven of the eight Repetitive Behaviour Scale-Revised SIB categories were reported for both groups. Children in the DD group were significantly more likely to engage in Hits Self against Surface or Object, Hits Self with Body Part, Inserts Finger or Object, Skin Picking and Bites Self. Parental ratings of severity were also significantly greater for the DD group for these five topographies. The DD group engaged in a significantly greater number of SIB topographies than the children in the TD group. Children in the TD group were more likely to exhibit a single SIB topography while the DD group were more likely to engage in two or more topographies. Topographies involving self-hitting were not only more frequent among the children in the DD group but also more likely to be rated as moderate or severe in nature. Conclusions: Compared with the TD group, the topographies of SIB exhibited by the DD group were more prevalent, more severe and co-occurred with greater frequency. Inclusion of a group of children with TD provided an important comparative context for the occurrence of SIB in children with DD.