Effects of two levels of treatment intensity on a young child with severe disabilities

This single-case study evaluated the effects of two levels of center-based behavioral intervention for a young child with diagnoses of autism, severe attention deficit hyperactivity disorder, bipolar disorder, and severe developmental delay. The child entered an applied behavior analysis school and residential program at age 4 years. At that time he was receiving fluoxetine and valproic acid for control of challenging behavior. Six other medication trials had been attempted previously. Assessments completed just before the child entered the behavioral program estimated his overall functioning at the 8–16 month level. Throughout the study, the child participated in comprehensive behavioral programming for about 30 hours per week. For the first (A) phase of the study, the teacher:student ratio was 1:1. This phase lasted 12 months. At that point resource limitations necessitated changing the teacher:student ratio to 1:2 (the B Phase), which continued for 9 months. Then 1:1 intervention was reinstated. Dependent variables included out-of-seat behavior, aberrant behavior, motor imitation, stereotypic responses, matching to sample, and appropriate communication (recognizable signs and pictures used as mands). By the end of the first A phase (1:1 intervention), substantial improvements were documented in five of six dependent variables, and fluoxetine was discontinued. These improvements were maintained for all dependent variables three months into the B phase, but after an additional six months of 1:2 intervention gains were maintained on only one dependent variable. Nine months after a return to 1:1 intervention, improvements over B-phase levels were evident for five dependent variables, four of which returned to levels comparable to those at the end of the first 1:1 phase. © 1998 John Wiley & Sons, Ltd.