Leo Kanner was the first who discovered Autism as a distinct case in the 1940s and brought out a report narrating the disorder which he stated as "Autistic disturbances of affective contact'. (Keane, 2004) Presently Autism falls third among the list of childhood disorders, after mental handicap and language difficulties. (Zager, 2005) Autism is an intricate disorder of mental development which is defined in terms of behavior. Autism spectrum disorder - ASD is a broad expression which covers a diverse mix of children having such manifestations and numerous biological etiologies. (Hollander, 2003) Diagnosis of ASD can be unfailingly done when the child attains the age of 3, and in certain instances much previously by the age of 18 months. Researchers recommend that several children ultimately may be conclusively detected while attaining 1 year or much less than that. (Autism Spectrum Disorders (Pervasive Developmental Disorders)) Collectively, children detected as having ASD can be distinguished by dearth of proficiency in vocal and non-vocal communications at an early age, socio-communicative function, and monotonous behaviors. (Hollander, 2003).

             It is the parents who are the first witnesses of these queer behaviors in their children. In certain instances, differences could be discovered congenitally, as being indifferent to humans or concentrating on a particular thing attentively for extended periods of time. The initial signals of an ASD can also be seen in children who appear to have a normal development. If a charming, blathering child, at once turns mum, reserved, self-abusive, or aloof to social advances, matters are not right. The manifestation of any of the cautioning signals of ASD constitutes sufficient worry to get the child examined by a professional expert in dealing with the disorder. (Autism Spectrum Disorders (Pervasive Developmental Disorders)) The National Institute of Mental Health - NIML holds that the accurate incidence of Autism is not known.