Robot-mediated therapies for autism spectrum disorder (ASD) have shown promising results in the past. We have proposed a novel mathematical model based on an adaptive multi-robot therapy of ASD children focusing on two main impairments in autism: 1) joint attention and 2) imitation. Joint attention intervention is based on three different least-to-most (LTM) cues, whereas the adaptive imitation module uses joint attention for activation of the robot. The proposed model uses a multi-robot system as a therapist without any external stimuli (from the environment) to improve the skills of the ASD child. Another novel aspect of this paper is the deployment of a multi-robot system for introducing the ASD child to the concept of multi-person communication. This is particularly useful as, unlike humans, robots can be more consistent and relatively immune to fatigue. Two different therapies of human-robot interaction (i.e., with and without interrobot communication) have been conducted. The model has been tested on 12 ASD children, eight sessions for each intervention over a period of six months. The effectiveness of the model is validated by analyzing the cognitive state of the brain before and after the intervention with electroencephalogram (EEG) neuroheadsets. Moreover, results obtained using the childhood autism rating scale (CARS) to measure the effectiveness of therapy also support the conclusions firmly. The statistical results with the p-value = 3.79E-07 < 0.05 and the F value = 23.93>3.28 show reliability and significance of the data. The results strongly indicate significant improvements in both modules, along with a notable improvement in multi-communication skills of the participating children.

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Recent research has shown reliability in robotic therapies for improvement in core impairments of autism. To improve the efficiency of communication using robots, this study evaluates the effectiveness of three different stimuli in a robotic intervention for children with autism spectrum disorder. Three different reinforcement stimuli presented in least-to-most (LTM) order introduced in this therapy using NAO robot are: visual (color variation), auditory and motion cues. The therapy was tested on 12 ASD children, 4 out of 12 children fall under mild category whereas 8 fall under the minimal category of autism. The experimentation was conducted for 2 months. Total 8 experiments were conducted with 1 trial per week. Total 12 cues were given per trial, 4 cues corresponding to each category. In total 96 cues were given per subject, 32 cues from each category. The results indicate a general trend for linking a particular autism category with the most effective stimulus for that category. It can be concluded that visual cue (color variation) is the most effective reinforcement stimulus for children with minimal autism as 8 out of 8 i.e., 100% were more responsive to visual cues whereas for children with mild autism category, 3 out of 4 i.e., 75% are more receptive towards the motion stimulus. The parameters used for assessment were joint attention and the time eye contact is maintained. Single factor ANOVA was used for the statistical analysis of results with alpha is 0.05 and p-value 0.0342, F value is 3.7456 and F critical value is 3.2834. The test was performed on 96 (8x12) trails in total, therefore ensuring the significance and reliability of our results. INDEX TERMS Autism spectrum disorder (ASD), reinforcement stimulus, robotic therapy, joint attention.

The focus of this research is to study: 1) the distribution of joint attention of autistic (ASD) children in their left and right visual space, 2) the corresponding dominance of either left or right hemisphere of brain using electroencephalography (EEG), and 3) the relationship between the dominance of visual space and hemisphere of brain. The proposed multi-robot system includes sequential and simultaneous actuations of robots dealing with single and multi-robot communication. Results indicate that most of the autistic children initiate joint attention from right to left vision space. Similarly, for imitation, robot at right visual space is imitated and focused more. These findings are also supported by the results obtained from the dominance of brain and number of eye contacts. Eight participants, five males and three females, participated in this research. Six participants belong to minimal while two belong to mild case on autism spectrum. Minimal cases of autism indicated proper dominance of either left or right visual space and hence the respective dominance of hemispheres of brain too. While mild cases of autism showed balanced performance in visual space but distinguishable dominance of hemispheres of brain. The overall average followed imitation accuracy for robot at right visual space is 83.49 % while for robot at left visual space is 61.53 %. Similarly, overall average eye contacts with robot at right visual space are 16.47 and for robot at left visual space are 14.95 per minute. Power spectral density (PSD) values of EEG data also indicate the dominance of right hemisphere of brain. F value is 2.93, F-critical value 4.60, and p-value is 0.108.

This research article presents a preliminary longitudinal study to check the improvement in multi-human communication of children with Autism Spectrum Disorder (ASD) using a standardized multirobot therapy. The research is based on a 3 step framework: 1) Human-Human Interaction, Stage-1 (HHI-S1), 2) Human-Robot Interaction, Stage-2 (HRI-S2), and 3) Human-Human Interaction, Stage-3 (HHI-S3). All three stages of the therapy consist of two command sets: 1) Controls commands and 2) Evaluation commands (auditory commands, visual commands, and combination of both). The concept of multiple robots is introduced to help multi-human communication and discourage isolation in ASD children. The joint attention of an ASD child is improved by the robotic therapy in stage 2 considering it as a key parameter for a multi-human communication scenario. The improvement in joint attention results in better command following in a triad multi-human communication scenario in stage 3 as compared to stage 1. The proposed intervention has been tested on 8 ASD subjects with 10 sessions over a period of two and a half months (10 weeks). Each session of human-human interaction (stage 1 and 3) consisted of 14 cues whereas 18 cues were presented by each robot for human-robot interaction (stage 2). The results indicate an overall 86% improvement in the social communication skills of ASD children in case of a multi-human scenario. Validation of results and effectiveness of the therapy has been further accomplished through the use of the Childhood Autism Rating Scale (CARS) score. INDEX TERMS Autism Spectrum Disorder (ASD), Multi-robots, Human-robot interaction, Robotic therapy.