In which of the following pervasive developmental disorder only one modality is impaired, others are normal -

Ans. is 'b' i.e., Asperger syndromeo Pervasive development disorders include several clinically similar conditions which are characterized by three symptom clustors:-i) Impairment of social interaction:- e.g., Lack of social smile or eye contact.ii) Impairment of communication (language and non-verbal):- Language problems, delayed or absent speech.iii) Restricted repititive and styerotyped behavior, interests and activities:- e.g., Sterotypy.iv) Another associated feature is mental retardation.o In Autism and Rett syndrome all three features are found. Where as:o In asperger syndrome -a) Only Social ineractiion is impaired, where asb) Intelligence is normal (The only pervasive development disorder in which intelligence is normal.)c) No language impairments.