Are there sample of case study about idiot savant?

You must be referring to an autistic savant. Basically, its an autistic person who has savant syndrome.

A case study is an intensive analysis of an individual unit (a person, group, or event) stressing developmental factors in relation to context.

Someone who is autistic but with a special talent or ability.

There is no universally accepted definition for a case study, and the case method means different things to different people. Consequently, all case studies are not structured similarly, and...

Case study is not a qualitative study - it is a research strategy which use qualitative and quantative data as well. You select a data sources if it provides good arguments. Knud r.