Mental retardation

Mental retardation, low intellectual capacity, arising not from mental illness but from impairment of the normal development of the brain and nervous system. Causes include genetic defect (as in Down's syndrome); infection of the embryo or fetus (hydrocephalus or inherited metabolic defects), injury at birth, including cerebral hemorrhage and fetal anoxia (lack of oxygen), and disease in infancy (for example, encephalitis). Retardation is initially recognized by slowness to develop normal patterns of social and learning behavior; it is confirmed through intelligence measurements. Although mental retardation cannot be cured, it is most important that affected children receive adequate social contact and education, for their development is generally retarded, not arrested. Special schooling may help them achieve a degree of learning and social competence. Proper prenatal, perinatal, and postnatal care may help prevent some cases of mental retardation.