Intra-individual factors influencing efficacy of interventions for stereotyped behaviours: a meta-analysis.

The efficacy of treatments targeting stereotyped behaviours has been the focal point of several reviews. This study examined efficacy as a function of intra-individual characteristics, including age, gender, level of disability and topography of the behaviour. A meta-analysis of studies reporting treatments of stereotyped behaviours appearing in 23 journals over 20 years was conducted. Efficacy was determined using two metrics, Percentage Non-overlapping Data and Percentage Zero Data, which indicate treatment success as a function of the degree to which the behaviour fell below baseline levels, and once reaching zero, remained there. Non-parametric analyses indicated differences in treatment efficacy according to age and the form of the stereotypy. Implications for the design of treatments to address stereotypies are discussed.