New brain stem and bone marrow abnormalities in victims of sudden infant death syndrome.

The study looked for new abnormalities in 31 victims of sudden infant death syndrome (SIDS). The focus was on respiratory control centers in the brain stem, because some SIDS victims have had abnormalities in respiratory control during sleep. A major respiratory control area (lateral reticular nucleus) of the medulla was hypomyelinated in 9 of the 31 SIDS victims. In a second study, the size of the 12th cranial nerve nucleus and its neuronal composition were analyzed because this nucleus regulates tongue movements, and the tongue has been postulated to help obstruct the airway in some SIDS victims. The 12th nucleus was found to have a neuronal deficit in more than two thirds of the SIDS victims. Finally, the SIDS victims were found to have a normoblastic hyperplasia in their bone marrows, a presumed response to chronic hypoxemia during sleep.