A study of the effects of the Instrumental Enrichment cognitive intervention program with 41 severely hearing impaired secondary school students was conducted. Experimental and control groups were compared in regard to general cognitive functioning, problem-solving strategies, reading comprehension, and mathematics. Experimental subjects were provided systematic (at least twice a week) mediated learning experiences intended to help students understand their own thinking processes and promote generalization to both curricular and non-school situations. The specially trained teacher incorporated a series of sequenced visual, verbal, and geometric problems into the regular subject matter, helped students solve the problems, and then discussed how the students' mental strategies on these problems would be used in the subject matter. Experimental subjects demonstrated improvement in (1) systematic approaches to problems, (2) analysis of problem situations, (3) analysis of source-of-error in problem-solving situations, (4) completeness, organization, and planning in problem solving situations, (5) peer cooperation in problem solving, (6) abstract thinking, and (7) a variety of cognitive based classroom behavior. Results supported the value of systematic rather than incidental cognitive intervention. (Author/DB)