**8. Discussion**

The resultant t- value (5.92, p<.001) was highly significant. This indicated that PECS based intervention was effective than traditional intervention methods for children with autism.. Figure 10 shows the quantitative difference in performance of children in experimental and

Every child except one in the experimental group performed better than his/her counterpart in the control group. Some experimental children scored significantly higher than their control group peers. A similar trend was seen when mean scores on receptive and expressive language

control groups.

226 Autism Spectrum Disorder - Recent Advances

skills were compared (refer to Figure 11)

Among the various difficulties faced by individuals with autism, communication has been described as being at the core. It is believed that one third of all individuals with autism may never acquire oral expressive language sufficient to meet their daily needs [3]. It is imperative that they learn to use an alternative and augmentative mode for communication. As mentioned earlier, there are a variety of AAC systems available for children with disabilities. Selection of a suitable system must depend on its ability to respond to the unique features of a specific disability. One of the first communication difficulties with autism is with development of paralinguistics [25]. They do not understand the underlying meaning of a message that are embedded in the speaker's facial expression, body language, eye gaze and tone of voice. Learning to understand paralinguistics is important for development of receptive language. In a typically developing toddler paralinguitics emerge as a consequence of parent-child interactions. The parent smiles and waves a milk bottle before the infant, and asks in a high pitched tone if the infant wants milk. The infant looks at the smiling and nodding parent, and understands that something pleasant is going to happen. This is the premise that was used in PECS intervention. The communicating partner showed or pointed to a picture of the object that was desired. When the picture was exchanged the child was given the object with a smile and a nod from the communicating partner. Besides motivating the child to communicate, these paralinguitics provided social meaning to the exchange. Children with autism are visual learners. Research on graphic symbol learning indicates that symbols with iconicity are easier to learn [26]. The symbols used during the PECS intervention resembled their referents. The children could learn to identify and exchange them easily for desired items. The significant increase in children's receptive language skills post intervention could be attributed to this. Research also suggests that children with autism are more interested in inanimate objects than in human interaction [12]. They are able to process better when information is presented in static form. Pictures and symbols are inanimate and provide static information. The use of PECS as an AAC system in this study responded to the learning preferences of the selected children. PECS was designed specifically for children with autism who have limited verbal ability [27]. It addressed the difficulty children with autism have in social initiations. Teaching a child to approach an adult and request for a desired object using a picture not only improved communication but also developed social interaction. Successful outcome of each attempt reinforced a child's communicative behaviour. The performance of the experimental group children on FLAS was significantly higher than those in the control group. The control group children also attended school and received speech and language intervention. Notwithstand‐ ing that they belonged to the same age group, the intervention goals would essentially consist of teaching similar language concepts, the control group children did not demonstrate gains equal to their experimental group counterparts. The principles of applied behaviour analysis is central to the PECS program. The ABA methods such as rewards and prompts are system‐ atically used to shape a child's verbal behaviour though out the program, and much more rigorously in the initial phases. The ABA methods were used during the intervention period. This adherence to ABA principles might not be existing in the language interventions given to the control group children. Hence, as the children were not frequently rewarded or guided to produce correct response of identifying pictures, their gain on receptive language was below the children who received PECS training. Similarly, with respect to expressive language skills, in the traditional intervention setting the emphasis was on naming the picture orally. This might have been impacted their learning as the control group children like their peers in the experimental group were nonverbal or minimally verbal. The positive gains by the experi‐ mental group might be attributed to PECS training. That the change in ability to communicate was beyond the intervention settings was evidenced by parents, and borne by the positive correlation between observations made by the researchers and that by the parents.

### **9. Conclusion**

Difficulties in social relationships and interactions have been the defining features of autism. Therapists and teachers frequently use augmentative communication systems with children with autism to support development of interactive behaviour. AAC systems follow a topo‐ graphically based taxonomy. Some are selection-based systems in which each response is topographically identical and others are topography-based systems in which each response is topographically distinct [28]. PECS being a selection based system follows a topographically identical (e.g. card selection and exchange) pattern. It suits the literal thinking ability of a child with autism. The pictures and symbols are static, literal and clear, and enable children with autism to process information easily. The outcome of this study substantiate the findings of previous researches supporting use of PECS as a suitable augmentative communication system for children with autism.

#### **Acknowledgements**

The authors express their thanks to the children and parents who participated in this study. They are grateful to the school administrators for their support.
