Autism Spectrum Disorder is characterised by the defects in communication and social skills. This is the neuro developmental disorder, that is, the disorder in brain and its functioning that affects the emotion, communication, self-control and person's ability to learn by stopping the growth and development of the central nervous system. A number of studies have been made to find the accurate features to diagnose the ASD. This paper presents the review of the robust and accurate feature used for detection of this wide spectrum disease and also reviews the linguistic and acoustic feature for identifying Autism. It also presents the review of a similar disease called Parkinson's disease, which is mainly due to the loss of cells in the various part of the brain, is also reviewed. The purpose of this study is to expose to view the wide range of mechanisms used in the detection of speech related impairments from three similar researches.