Is there a natural cure for mental retardation like learning to crawl again, etc?

No: With extremely rare exceptions, true mr is not something physicians currently can treat. Several disorders, if picked up early, can be treated to prevent mr, and mild mr caused by social deprivation or isolation should respond to an improved environment. The rest, the majority of unknown causes, are not responsive to available treatments.

Beware the snake oil: In the 60's & 70's "patterning" was pushed by therapists Doman & Delacoto with the promise if you did it every 4 hrs/24hr/d it would rewire the brain and fix many issues.It was debunked in the late 70's. Therapy can help improve some physical limitations.Mental impairment caused by injury, disease, chromosome defect,etc. does not improve with such treatments.