## 1 Introduction  
### Background  
Smart environments have a positive impact on therapeutic practices aimed at children with autism [1; 2; 3; 4; 5; 6; 7; 8; 9]. In recent years, the authors have designed different tools, showing how interactive environments can have a positive impact when used in synergy with traditional therapeutic practices [10; 11; 12; 13]. Autism is characterized by deficits in social interaction, communication, and behavioral flexibility. Cognitive functioning in persons with autism, related to behavioral symptomatology, has been reported largely within the domains of theory of mind [14], executive functioning [15] and central [16]. So, there are several core underlying capabilities/deficits that coexist in ASD and that contribute to the pathogenesis of autism [17].  
Clinicians have recognized the potential of information technology in research and treatment. The use of new technologies is able to strengthen the motivation and interest of children, getting closer to their language and their cognitive functioning, is able to facilitate the processes of attention and concentration, providing constant and stable feedback, strengthening a positive self-awareness.  
Pervasive games are gaining importance in the last years: these games are usually played in an interactive space, in which several user interfaces following a multimodal approach work together. Pervasive games have proven to be useful in several fields, including the educational field and also in the field of treatment and rehabilitation for children with special needs, such as Attention Deficit Hyperactivity Disorder (ADHD) [18] or Autism. Children with special needs often experience a deficit in executive functioning (EF) and assistive technology can facilitate organization, time management and planning [19]. This work originates from a collaboration between the Signals and Images Laboratory of the Institute of Information Sciences and Technologies (ISTI) and the Institute of Clinical Physiology, both of the National Research Council of Italy, CNR.  
The present article describes, in particular, the design, implementation and evolution of an augmented interaction-based system that helps children with ASD to improve their communication and cognitive skills. Rather than superimposing digital information (images, audio, text) on the real world, as in \"classic\" AR (Augmented Reality) systems, in our system the technology is used to increase the sensorial relation with the environment. The systems are based on a computer connected to various sensors, so that it can reacts to movement with multimedia stimuli [8; 9; 10; 11; 12; 13].  
The learning content is conveyed by activities of production and perception of visual and auditory phenomena, aimed at increasing their communicative competence. The system is based on gestural interfaces and custom applications that extract features from the human gestures, mapping them to audio and visual stimuli under predefined schemes. The augmented interaction with the environment may improve the proprioception in the subjects. SEMI, the interactive multichannel expressive system [20], is a project that inherits the experience of previous implemented asset with SiREMI and SiDOREMI projects (auditory feedback-based system and its evolution in a home version prototype), enriching it with new interaction modes that also include the visual channel [10; 11; 12; 13].  
The setting of the present feasibility study is The Maria Assunta in Cielo Onlus Foundation (fMAiC Onlus), a not-for-profit organization set up in Pistoia in 1989, on the initiative of a group of volunteers already engaged in associations and activities for people with disabilities [20].  
These multimedia interactive devices have been experimented on a small group of children with autism [10].