Sudden Infant Death Syndrome (SIDS) is the sudden, unexplainable death of a baby less than a year old. The baby usually dies in its sleep. Rates of SIDS have decreased, perhaps due to public health campaigns that emphasize having infants sleep on their back only. But researchers still don't know exactly why SIDS occurs. This article discusses new research showing that the brains of babies who have died of SIDS have a similar histological pattern to those of children who died of accidental asphyxiation. The research showed that the histological pattern of the SIDS babies was different than that of babies who died from head trauma or infection.