Risk Factors Of Hearing Loss

Good hearing in children is essential to normal development. If undetected, hearing loss can lead to delayed speech and language development, social and emotional problems and learning difficulties which may not be outgrown.

Hearing loss in infants and children is more common than you might expect:

  • 1 child in 1000 will be born with a severe/profound hearing loss.
  • An additional 2 children in 1000 will develop a severe/profound hearing loss.
  • 1 child in 50 or 34% of those who need intensive medical care in the newborn period will have a hearing loss.
  • 65% of babies with significant hearing loss are from well-baby nurseries
  • 50% of babies with significant hearing loss have NO risk factors.

Routine medical care often fails to identify babies with significant sensorineural or nerve hearing losses because this type of problem is invisible and unable to be detected during a physical examination. As a result, routine hearing screening is mandatory at birth in order to identify hearing loss before it has adverse effects on the baby. However, sometimes babies with hearing loss may not be identified at birth or sometimes hearing losses develop after hearing screening has been passed, Therefore, it is important for parents to be aware of the warning signs of hearing loss.

Parents are usually the first to suspect a problem but they may reach wrong conclusions when they notice their baby not responding to sound. Therefore, identification of a hearing loss is often not made for 1 to 2 years after it is first suspected, causing the baby to experience delays in development which persist throughout the child's life.

To determine whether a baby or young child may have a hearing loss, the 1991 Joint Committee on Infant Hearing developed the following risk factors, so that hearing loss can be identified early, preferably by 6 months of age or no later than 12 months of age.

RISK CRITERIA FOR INFANTS FROM BIRTH TO 28 DAYS OF AGE

  • Family history of sensorineural hearing loss, occurring at birth or early in life.
  • Infection at birth known or suspected to be associated with sensorineural hearing impairment, such a toxoplasmosis, syphilis, rubella, cytomegalovirus and herpes.
  • Abnormal appearance of the head, face or ears, such as ear tags or pits, cleft lip/palate and misshapen ears.
  • Birth weight less than 1500 grams (around 3.3 lbs.)
  • Extremely high bilirubin levels which required a blood transfusion.
  • Birth weight less than 1500 grams (around 3.3 lbs.)
  • Medications which have a side effect of hearing loss which include the aminoglycosides such as Gentamicin, Tobramycin, Kanamycin, Streptomycin and loop diuretics when used for more than 5 days, particularly when used in combination with aminoglycosides.
  • Bacterial meningitis.
  • Severe medical problems at birth which may include infants with Apgar scores of 0 to 3 at 5 minutes, those who fail to initiate spontaneous respiration by 10 minutes and those with hypotonia (low muscle tone) persisting to 2 hours of age.
  • Prolonged mechanical ventilation for a duration equal to or greater than 10 days, such as persistent pulmonary hypertension.
  • Characteristics associated with a syndrome known to include sensorineural hearing loss.

RISK CRITERIA FOR INFANTS FROM 29 DAYS TO 2 YEARS OF AGE

  • Parent/Caregiver concern regarding hearing, speech, language and/or developmental delay.
  • Bacterial meningitis.
  • Risk factors at birth that may be associated with progressive sensorineural hearing loss such as cytomegalovirus, prolonged mechanical ventilation and inherited disorders.
  • Head trauma, especially when there has been a fracture of the temporal bone by the ear.
  • Characteristics associated with syndromes known to include sensorineural hearing loss.
  • Medications which have a side effect of hearing loss which include the aminoglycosides such as Gentamicin, Tobramycin, Kanamycin, Streptomycin and loop diuretics when used for more than 5 days, particularly when used in combination with aminoglycosides.
  • Children with neurodegenerative disorders such as neurofibromatosis, myoclonic epilepsy, Werdnig-Hoffman disease, Tay Sach's disease, infantile Gaucher's disease, Nieman-Pick disease, any metachromatic leukodystrophy or any infantile demyelinating neuropathy.
  • Childhood infectious diseases known to be associated with sensorineural hearing loss, such as mumps and measles.

HEARING EVALUATION

Any baby who manifests one or more of the risk criteria should have their hearing professionally evaluated by an audiologist. At Children and Family Hearing Associates, hearing evaluations are performed by an audiologist with over 35 years experience testing babies and young children. One of the procedures used is otoacoustic emission testing (OAE). This test involves inserting a tip in the baby's ear canal and obtaining responses from the hearing nerve for different tones for each ear. In addition, the audiologist may also observe the baby's responses to the loudness levels it takes for the baby to respond to a variety of sounds, including speech, music and different pitch wind-like noises. The sounds are presented through speakers placed on the right and left side of a special sound treated room. By observing the baby's responses, the audiologist determines whether there is a hearing loss.

Testing may also consist of tympanometry which measures eardrum movement. Abnormal tympanograms may be found where there is a conductive type of hearing loss which is often present when a baby has an ear infection. If testing indicates that a hearing loss is not present, then parents can be assured that there is no problem. If a problem is found, the amount of hearing loss, its type and the form of treatment will be specified. Hopefully by making parents aware of the risk signs of hearing loss and the importance of good hearing then babies with hearing loss will be identified so that appropriates remediation can be provided.

Remember that no baby or child is too young for a hearing evaluation. The sooner the hearing loss is identified, the sooner help can be obtained.