Students’ standardized test scores at the Lexington School for the Deaf in New York have risen since a pro gram called “Mediated Learning Experience,” begun at the school nine years ago. Lexington is the only school in the United States teaching the learning method developed by Reuven Feuerstein. Feuerstein, an Israeli psychologist, first used his learning theory to show that children held in concentration camps during World War II and later labeled mentally retarded were not retarded, but like many deaf children had been deprived of a normal learning environment. Oscar Cohen, the Executive Director of the School, is a CODA and will retire at the end of the current school year after a 35-year career at Lexington.