The patient was a 6-year-old, typically-developing bilingual Hispanic female who underwent total surgical resection of a suprasellar cystic and solid, third ventricular craniopharyngioma at a children's hospital when aged 5 years. Eleven months after surgery, she was referred to the authors for assessment and treatment of physical aggression (hitting, pinching, scratching, hair pulling, and throwing objects at others). Additional problem behaviors included property destruction, fecal smearing, verbal threats, and cursing. Parental interview indicated that these behavioral problems emerged approximately 4 months post-surgery; the severity and intensity of the behaviors continued to increase over time to the point where her parents felt that they could no longer manage her behavior in the home setting. Therefore, 7 months following surgery, she was readmitted to the children's hospital as an in-patient for assessment and treatment. There was no evidence that her display of problem behavior was cyclical in nature. Because of the severity of these behaviors, the patient was assigned constant one-to-one supervision in an isolated hospital room. Although previously toilet trained, she was required to wear a diaper, and often was restricted to her hospital bed (i.e. to deter her display of behavior problems on the unit). She had also developed hyperphagia. Approximately 2 months following surgery, her body mass index (BMI) was 19.3 (normal range); within 7 months, it had increased to 27.3 (overweight range). At the time of her assessment and treatment, her BMI was 32.3 (obese range). Medications included perphenazine (an antipsychotic) and valproic acid (an antiepileptic). In an effort to reduce the severity of her behavioral outbursts, diphenhydramine (an antihistamine) also was prescribed as needed.
Assessment and treatment sessions were conducted in a therapy room at the children's hospital. The room was approximately 8 feet by 15 feet in dimension and contained two small side tables, a couch, two cushioned chairs, a television on a stand, and a one-way mirror. A wheelchair, which was used to transport the patient to the session room, also was present. Sessions were 5 minutes in duration, and 6 to 12 sessions were conducted 2 to 3 times per week over the course of 3 weeks with the primary therapist (JH). All sessions were videotaped for data collection purposes by the second therapist (SH) who was also present in the room. Before the initiation of assessment and treatment, parental consent was obtained. The therapists met with both parents and a Spanish interpreter (who was employed by the hospital) during which time functional analysis procedures were thoroughly reviewed, general treatment strategies were discussed, and permission to videotape the sessions was obtained. Prior to submitting this report for publication, parental consent also was obtained.
In order to isolate the conditions under which the patient's aggression occurred, a functional analysis was conducted. As stated above, the purpose of this assessment was to systematically identify the cause-and-effect relations between the patient's aggression and environmental variables. The results were used to inform the development of an effective, function-based treatment using principles of reinforcement.
The functional analysis was conducted using procedures similar to those described by Iwata et al. Five conditions, each lasting 5 minutes, were presented 3 to 4 times in a multi-element design. The conditions were: 'demand (escape)' (the patient received a brief break from task demands when aggression occurred), 'ignore' (the therapist did not respond to any of the patient's behaviors, including aggression), 'attention' (contingent on aggression, the therapist delivered a reprimand and brief physical contact), 'tangible' (a small piece of food was provided to the patient following aggression), and 'play' (the patient received non-contingent attention and food while she played with toysa).
Three behaviors were targeted: aggression (hitting, pinching, scratching, hair pulling, and throwing objects at others), compliance (completion of a task following the first verbal or second model prompt), and mands (vocal requests for a food item while saying 'please'). The primary observer (see Acknowledgements) recorded the frequency of each dependent variable using ObsWin for Windows software (Antam, London, UK). Interobserver agreement was assessed by having a second observer (JH) simultaneously but independently collect data (via observing and scoring the videotapes) for at least 25% of the sessions within each condition. Agreement was calculated for each behavior by comparing the two observers' records on a second-by-second basis with a 2 seconds tolerance window. Percentage occurrence agreement was 95% for aggression, 83% for compliance, and 97% for mands.
Treatment was evaluated using a reversal (ABAB) design and consisted of differential reinforcement of alternative behavior (DRA) plus extinction (EXT). Treatment was matched to the maintaining variables identified in the functional analysis (i.e. escape and tangible reinforcement). In sessions designed to treat the escape function (DRA + escape EXT), aggressive behavior no longer resulted in a brief break; rather, the patient was instructed to complete a task on her own (e.g. to pick up items she had thrown). If she refused following a second model prompt, she then was physically assisted to complete the task. During initial treatment sessions, the assistance of the second therapist often was necessary to implement escape EXT (i.e. if the patient was sitting on the floor, she needed to be lifted onto her feet in order to complete the task). As treatment progressed, however, two therapists were not required to ensure task completion because the patient would immediately comply with the directive. If she completed the task on her own, she received a small piece of food (DRA), which was paired with social reinforcers, such as praise, high-fives, and brief applause. Although it may seem counter-therapeutic to deliver food contingent on appropriate behavior, we chose this strategy for two reasons. First, the patient was heavily food-motivated; thus, during initial treatment sessions, it was important to deliver a highly-potent reinforcer that could effectively compete with her problem behavior. Second, although we could have reinforced compliance with the functional reinforcer - escape - this would have amounted to periods of non-instructional time. Therefore, we chose to reinforce compliance differentially with a small edible item so that reinforcer access (i.e. a break) would not compete with on-task behavior. Previous research has shown that providing an edible item contingent on compliance may be more effective than providing escape for problem behavior maintained by negative reinforcement. As the patient showed sustained improvements in compliance and low rates of aggression during the demand (escape) condition, task requirements were systematically extended, requiring that she complete a greater number of tasks before earning the small food item (Fig. 2). Specifically, in the second treatment phase, the schedule of reinforcement was increased by one response requirement (e.g. from a fixed-ratio [FR] 1 schedule, to an FR 2, then an FR 3, etc.) contingent on aggression being at or below 0.9 responses per minute (rpm; i.e. less than 2 responses per 5min session). Task variety was also increased, such that instructions included appropriate academic tasks (e.g. spelling and counting).
In sessions designed to treat the tangible function (DRA + tangible EXT), aggressive behavior no longer produced access to food. Rather, if the patient manded appropriately, she received a small edible item (e.g. piece of rice cake). As before, tangible reinforcement was systematically thinned over time as she showed sustained improvements in mands and concomitant reductions in problem behavior (however, verbal praise continued to be delivered on an FR 1 schedule). Specifically, in the second treatment phase, the schedule was systematically thinned by adding 5 to 15 seconds to the amount of time (the fixed interval [FI]) that she had to wait contingent on aggression being at or below 0.5rpm (e.g. 1 response or less per 5min session). In an effort to attenuate excessively high mand rates, a signaling procedure was also implemented to facilitate discrimination of times when requests for food would and would not be granted. A green card was displayed during times in which mands would be reinforced, whereas a red card was displayed during EXT periods (see Fig. 2 for the reinforcement thinning/ signal schedule.) If aggression occurred, the interval was reset according to the FI schedule in effect for that session.