Screening Key to Detecting Early Childhood Hearing Loss

Prentiss Headlight, 6/17/2009

          Most of us associate hearing loss with getting older. We assume as we age that becoming “hard of hearing” comes with the territory.  However, many of us may not consider the effects of hearing loss in our younger generations, notably in newborns infants and young children.

            Hearing and speech are essential tools for normal child development.  Without these a child can grow up to have problems with speech and language development, experience isolation and social problems, and have academic difficulties.  The American Speech-Language-Hearing Association (ASHA) estimates that 1-6 out of every 1,000 newborns are born with some degree of congenital hearing loss.  This implies that hearing loss was present at birth.  At least half of these cases are attributed to heredity.  However other factors such as contracting an infection while in the womb, complications associated with the Rh factor in the blood, prematurity, maternal diabetes, toxemia, and lack of oxygen can also contribute to congenital hearing loss. 

          Early detection plays a significant role in combating problems that may arise later on.  In Mississippi, every newborn is required to undergo an ALGO hearing test before they are discharged from the hospital.  The ALGO test is a basic screening tool to detect congenital hearing loss.  If an infant passes the ALGO test, it is assumed that their hearing is normal.  However, if the test results come back abnormal, further testing may need to be done.

          “If an infant fails the test, it doesn’t necessarily mean that their hearing is abnormal.  It just means it needs to be verified with more in depth testing,” says John Sobiesk, MD, otolaryngologist with Hattiesburg Clinic’s Ear, Nose, and Throat Associates.  “We have two measures with which to verify our findings.  One test is called the ABR [auditory brainstem response] and the other is known as otoacoustic emissions [OAE].”

          ABR testing involves the use of electrodes to measure an infant’s brainwaves.  The electrodes are taped to the infant’s head and a series of clicking noises are made through a set of headphones in the baby’s ear.  A computer records the amount of time it takes for the brain to register the sound.  The clicks are presented at varying frequencies to determine the lowest volume the baby can hear.  The entire test takes about 15 minutes.  If the waveforms appear normal, the baby is considered to have normal hearing.  If they are abnormal, the physician may repeat the test or conduct an OAE to confirm their findings.

          During OAE testing, a small microphone is placed in the infant’s ear.  “There is an imperceptible sound generated by the nerve cells in the ear when we give the ear a clear sound,” explains Sobiesk.  “What we are looking for is a reflection of sound that will be given back from the ear.  In a person with a normal functioning ear, when I present sound in their ear, the ear will reflect an emission which I can register with a small microphone.”  The test takes about 6-8 minutes to complete.  It is very important that the infant is resting quietly while both tests are being conducted since noise or movement can skew the results.

          Even if an infant is determined to have normal hearing at birth, ear infections, damage to the auditory system, viruses, head injuries, and excessive noise exposure can lead to hearing loss as the child gets older.  Both the ABR and OAE test are useful in measuring hearing loss in older children and can be performed without a physician’s referral.

          If the infant fails both tests, a complete evaluation will be done to determine if the child has partial or total hearing loss, if they need to be fitted with hearing aids, and if the use of a speech language pathologist will be helpful in the development of the child’s speech, language, and cognitive communication.

          “Early intervention is essential for children.  An experienced speech language pathologist can evaluate the child’s speech and language development, and design a treatment plan based on the child’s individual needs,” said Martha Woodall, M.S., CCC/SLP, Speech Language Pathologist and Director of Education at Hattiesburg Clinic’s Connections.  “Children begin to learn language very early in life.  As they grow and develop, their language skills become increasingly more complex.  They learn to comprehend and use language to acquire knowledge and to communicate effectively with others.”

          For more information on infant hearing tests, please contact Hattiesburg Clinic Ear, Nose, and Throat Associates at 601-579-3310 or Ear, Nose, and Throat Associates – Lucedale at 601-947-9187.  For more information on speech pathology services, please contact Hattiesburg Clinic Connections at 601-261-5159.