A Single-Arm Pilot Trial for Mitigating Relapse of Severe Problem Behavior

Functional Communication Training (FCT) focuses on teaching an appropriate functional communicative response (FCR) to access the reinforcer maintaining severe problem behavior (SPB). This procedure involves selecting an appropriate topography for the FCR (e.g., touching a card, exchanging a picture) and using a backward chaining approach. The training will progress from full physical prompts to partial prompts and eventually to independent, unprompted responses, all within a trial-based format.

A distinct extinction-correlated stimulus (e.g., a laminated picture card) will be used in all treatment sessions where severe problem behavior (SPB) is subject to extinction contingencies. This stimulus will also be present during relapse challenges (described below). The selection of the stimulus will be individualized for each participant to ensure it has no prior association with treatment-related contexts, minimizing the influence of pre-existing learning histories.

"Behavioral Skills Training (BST) will be used to teach caregivers to (1) implement the behavioral intervention package (i.e., differential reinforcement of alternative behavior with extinction) in a controlled setting with confederates and (2) transition into behavioral sessions with the participant while gradually phasing out the clinical therapist.~Caregivers will begin by implementing mastered intervention components alongside the therapist during sessions with the participant, where the therapist will provide in-situ feedback. Once the caregiver demonstrates at least 80% treatment integrity across two consecutive sessions, the therapist will systematically increase their distance by 3 meters each session (maintaining at least 80% integrity) until they are fully removed from the treatment area."

"Once a clinically significant decrease in severe problem behavior (SPB) is achieved (defined as an 80% reduction from the baseline mean rate), schedule thinning will be implemented. This process involves reducing the density of reinforcement by introducing a multiple schedule with alternating periods where reinforcement for the functional communication response (FCR) is available and unavailable.~Schedule thinning will begin immediately at the terminal schedule, with an 80% reduction in reinforcer density from treatment. Specifically, the FCR will be placed on extinction for 540 seconds and reinforced for 60 seconds during each session. This schedule was selected based on prior analyses of effective reductions in reinforcer density. If the treatment effect remains strong (defined as maintaining at least an 80% reduction in SPB relative to baseline), schedule thinning will proceed at this step until three consecutive sessions show consistent results."

In multiple-context training, treatment will be implemented at the terminal schedule (i.e., after completing schedule thinning) in new contexts, including unique locations and with different individuals, distinct from the setting used during the initial treatment phase.