Whenever mentally retarded persons are unable, because of the severity of their handicap, to exercise a11 their rights in a meaningful way or it should become necessary to restrict or deny sorne or a11 of these rights, the procedure used for that restriction or denial of rights must contain proper legal safeguards against every form of abuse. This procedure must be based on an evaluation of the social capability of the mentally r~tarded p~rs~n by qualified experts and must be subJect to penod1c review and to the right of appeal to higher authorities.