There are two causes of congenital deafness among children. One is the lack of hair cells, receptors in the inner ear that convert sounds into pulse signals that activate the auditory nerve. The second cause is a malfunction of the nerves. A child may be born with what appears to be a normal inner ear, but the hair cells do not "communicate" with the auditory nerves and the child cannot hear. To date, doctors have recommended the same treatment for all children born deaf.
Prof. Joseph Attias, a neurophysiologist and audiologist in the Department of Communication Disorders at the University of Haifa, who made the discovery stresses that a cochlear implant is an excellent treatment for children with congenital deafness whose hearing does not improve over time. However, it appears that some children are born with "temporary deafness" – a condition previously unidentified.
This discovery was made by chance. A child who was born with malfunctioning hair cells and was scheduled for a cochlear implant was referred to Prof. Attias for a pre-surgical evaluation. The evaluation found that the child's brain and auditory nerves exhibited beginning responses to sound stimuli. The surgery was postponed.
Follow-up visits showed increasing function of the hair cells and eventually the child reached a state of normal hearing. Prof. Attias looked in the department archives and found other, similar cases. “I called parents and found another seven cases of children who were diagnosed as deaf, did not have the procedure done, and began to hear," said Prof. Attias.
Prof. Attias then found another five children who had been referred to him for pre-operative testing who had begun to hear. At the end of his clinical research, he identified a "window of opportunity" of 17 months during which deaf children may begin to hear. "A child whose deafness is caused by a malfunctioning connection between hair cells and the auditory nerve should not have a cochlear implant in the first 17 months of life," explained Prof. Attias.
MEDICA.de; Source: University of Haifa