Individual who is either born deaf or who lost his or her hearing early in childhood, before acquiring language. Infants usually start saying their first words around one year, therefore for a child to be considered prelingually deaf, they would have to have lost their hearing before age one (which is the age at which the majority of hearing losses in children occur). Congenital hearing losses are those that are present at birth, but a child with a congenital hearing loss is also considered prelingually deaf since a newborn infant has not acquired speech and language capabilities yet.
Each year in the United States, approximately 12,000 babies are born with a hearing loss. Profound hearing loss occurs somewhere between 4-11 children per every 10,000 children.Prelingual hearing loss can be either acquired, meaning it occurred after birth due to illness or injury, or it can be congenital, meaning it was present at birth. Congenital hearing loss can be caused by genetic or nongenetic factors. The nongenetic factors account for about one fourth of the congenital hearing losses in infants. These factors could include: Maternal infections, such as rubella, cytomegalovirus, or herpes simplex virus, lack of oxygen, maternal diabetes, toxemia during pregnancy, low birth weight, prematurity, birth injuries, toxins including drugs and alcohol consumed by the mother during pregnancy, and complications associated with the Rh factor in the blood/jaundice. Genetic factors account for over half of the infants with congenital hearing loss. Most of these are caused by an autosomal recessive hearing loss or an autosomal dominant hearing loss. Autosomal recessive hearing loss is when both parents carry the recessive gene, and pass it on to their child. The autosomal dominant hearing loss is when an abnormal gene from one parent is able to cause hearing loss even though the matching gene from the other parent is normal.