Mental retardation, a developmental disability, is defined as reduced intellectual function, as measured by intelligence tests. According to the "Encyclopedia of Mental Disorders," about 3 to 4 percent of mentally retarded individuals are diagnosed as severely retarded with IQs of 20 to 40. Profoundly retarded individuals make up 1 to 2 percent of the mentally retarded population, with IQ scores of less than 20. These two groups might master limited communication and the most basic of care and eventually live in a group home. Focus on teaching basic care skills as these students do not grasp abstract concepts. You can develop practical lessons plans by following a few simple steps. Things You'll Need Visual materials 1. Set a concrete, measurable goal for the students. The goal needs to be very simple, such as learning to perform a basic task. 2. Break the task down into small, actionable steps. Demonstrate each step visually as you explain it. For example, when teaching a child to wash his hands, talk about the process and show the child, by example, how to wash his hands. Do this by washing your hands first. Then, help him wash his hands. Next, let him wash his hands by himself. Discuss the procedure — getting soap, turning on the water, washing hands, rinsing hands and drying hands. 3. Integrate repetition into teaching. Children need to wash their hands several times a day. With practice, they will master this task. 4. Assess the child's progress and mastery of the task. Tips & Warnings Visual materials or demonstrations must accompany all lesson plans for severe and profoundly mentally retarded students. Provide the student with quick feedback. Consistent encouragement helps motivate the child in her efforts. Focus on her success. Foster a positive classroom atmosphere for optimal student progress. Know your students and their capabilities. Many severe and profoundly mentally retarded students will take medications that impact their responses, learning and behavior. Watch for any out-of-character behaviors.