Association for Behavior Analysis International

In language interventions for children who have severe language delays due to autism or other developmental disabilities, clinicians must often make decisions regarding an appropriate verbal response modality (e.g., vocal speech, manual signing, or picture-based communication). Establishing vocal speech has obvious advantages, but may be complicated by limited prerequisite repertoires, such as low frequency of speech sound vocalizations and lack of echoic control over vocalizations. Thus, the benefits of vocal communication may, at least initially, be outweighed by a need for quickly establishing efficient mand repertoires for minimally verbal children. The first two studies in this symposium describe assessments developed to identify an optimal response modality for early mands on an individual basis. The third and the fourth study addressed prerequisites for vocal communication by comparing procedures for increasing free-operant speech sound production and establishing echoic control over vocalizations, respectively.

Mands have been successfully taught to children with autism and intellectual disabilities using many response modalities. A few studies have compared the effectiveness of modalities such as the Picture Exchange Communication System and sign language. Some of these studies have found that the usefulness of either modality varied across students without a clear indication of the relevant child characteristics that might predict effectiveness. Thus, one modality is unlikely to prove optimal for all children. This study examined the utility of an assessment of prerequisite skills for three response modalities (i.e., vocal, sign language, exchange based communication) to determine if performance on the skills assessment predicts the rate of mand acquisition in each modality. The three pre-requisite assessments (motor imitation, vocal imitation, matching) each consisted of 20 trials. Subsequently, three equally preferred items were selected from a preference assessment and one item was assigned to each condition. The speed of acquisition during mand training was evaluated using a multi-element design. If one response modality was acquired more quickly than the others, the other two responses were trained in the successful modality. Four 2-year-old participants were included in the study and data illustrate typical response patterns and the assessments predictive value.

There is limited investigation of procedures for establishing echoic responses. This study evaluated three commonly used teaching procedures for establishing an echoic repertoire with three students with autism or related disabilities. Preference assessments were conducted to identify highly preferred items, including edibles, tangibles and social stimuli. At least two sets of three target sounds were then selected for each participant. Stimulus-stimulus pairing, echoic training and a mand-model procedure were compared. Data were collected on the percentage of correct vocalizations during training sessions and on the frequency of target vocalizations during play sessions completed prior to and after training sessions. These data, in addition to the participants performance during probes assessing the function of their vocalizations were compared to assess the efficacy of each teaching procedure. Interobserver agreement data were collected on over 33% of all sessions above and have averaged above 90% agreement. The results of this study suggested that the most effective teaching procedure may differ across participants thus supporting the need for additional research focusing on the development of assessment tools to identify learning profiles instead of generally effective teaching methods.