A rational approach to psychological testing of adults with mental retardation

Intelligence (IQ) tests and scales of adaptive behavior are typically used to evaluate adults with mental retardation. Personality tests and instruments designed to measure behavior problems and psychopathology are also used. Repeated IQ testing is common but not useful for adults. Adaptive behavior scales and measures of psychopathology do appear useful, although the latter are relatively new and not widely used in clinical practice. Tests requiring skilled language responses are not useful for people with severe and profound disabilities. The problem of administering the tests is addressed by interviewing people who are knowledgeable about the person being evaluated; this method is limited by the actual knowledge of the person interviewed. Neuroimaging, still in the research stage, may be especially relevant in the future.