Watching your baby react for the first time to your voice is a memorable and heartwarming event. Unfortunately, thousands of families don’t experience this age-specific milestone because their babies are born with hearing loss.
Babies can hear sounds before they’re born and after birth, their hearing continues to develop every day. By 3 months old, most babies have visible reactions when their parents talk to them. Between the age of 6-12 months, babies start babbling and imitating some sounds.
If a newborn isn’t screened at the hospital, testing should be done before they’re 1 month old. When a baby doesn’t pass a hearing screening, a full hearing test should be scheduled before they’re 3 months old. Common hearing screenings used for newborns include:
According to the World Health Organization, of the estimated 466 million people worldwide with hearing loss, 34 million are children. About 25–50% of childhood hearing loss happens after infancy, and in nearly 50% of impacted children, hearing loss gets worse throughout childhood. The prevalence of hearing loss in children ages 6 to 19 is 14.9%.
A cochlear implant is a small implanted electronic device. It consists of an external portion that sits behind the child’s ear and a second element surgically placed under their skin. Cochlear implants are approved for children with severe to profound hearing loss in both ears who meet the following criteria:
Research studies indicate hearing and language performance of children with cochlear implants is influenced by the following factors:
Otosclerosis is a rare, abnormal growth of one of the tiny bones of the middle ear (stapes bone) that prevents proper functioning of the structures in the ear. Although this condition is more common in adults, research suggests it impacts 0.6% of children younger than age 5 and 4% of children ages 5 to 18. Management options for childhood otosclerosis include observation, hearing aids, bone anchored hearing aids, or stapedectomy surgery. While stapes surgery is a standard procedure in adults with otosclerosis-related conductive hearing loss, it’s less accepted in children due to the risk of postoperative SNHL.
Auditory brainstem implantation (ABI) is a new technique for restoring hearing in children with severe to profound hearing loss who won’t benefit from cochlear implantation. Children with malformed inner ears or an absence of auditory nerves can’t achieve desired outcomes from cochlear implants. During this procedure, an electrode array is inserted directly onto the cochlear nucleus of the brainstem, bypassing the child’s inner ear and auditory nerves.
If you’re worried about your child's or grandchild’s hearing, contact an audiologist as soon as possible. Children of all ages, including infants can be tested and treated for hearing loss. Early diagnosis and appropriate intervention can help ensure that your child has the necessary support to thrive in childhood and beyond.
Hearing loss in children can be sensorineural, conductive, congenital, acquired (after birth), fluctuating, or permanent and caused by genetic or environmental factors.
Sensorineural hearing loss (SNHL) is by far the most common type of hearing loss present at birth (congenital). It can occur as a result of a lack of development or damage to either the auditory nerve or the delicate hair cells in the inner ear (cochlea). About 25% of congenital SNHL cases are caused by acquired risk factors. Although SNHL is generally irreversible, an evaluation is important to:
Track progression of hearing loss in the affected ear and the unaffected ear in unilateral hearing loss
Conductive hearing loss is caused by blockage or damage to a child’s outer ear, ear canal, or middle ear, making it difficult for sounds to pass from their outer ear to their middle ear. In newborns, fluid in the middle ear space makes it difficult for sound to pass to the inner ear. In infants and children, fluid in the middle ear is usually secondary to an ear infection. Impacted earwax or a foreign body can also completely block a child’s ear canal. Once the fluid, earwax, or foreign body is resolved, the child's hearing typically returns to normal.
A small number of children are born with abnormal middle ear bones, so they don’t vibrate normally in response to sound. Other children are born with a condition called aural atresia, which results in partial development of their ear canal, eardrum, and tiny bones in one or both ears. These conditions can usually be repaired surgically.
Congenital Hearing Loss
Although prematurity and low birth weight are associated with congenital hearing loss, the precise mechanism involved is unclear. About 30% of congenital hearing loss is syndromic, which means it’s related to an existing syndrome, while 70% is non-syndromic, with hearing loss the only disability.
Despite thorough evaluations, the cause of an estimated 25–45% of SNHL cases is unknown. Either genetic or environmental (acquired) causes are responsible for all other cases. Hearing loss risk factors are often classified by periods of child development.
Prenatal (During Pregnancy)
Perinatal (One to Four Weeks Post-Birth)
Middle Childhood and Adolescence
A large number of late-onset SNHL cases are caused by congenital cytomegalovirus infection not detected during neonatal screenings. Research indicates about 30–60% of children with SNHL have co-occurring visual impairments or cognitive, motor, emotional, behavioral, or other problems. About 40–60% of children with hearing loss also have visual impairments.
Cytomegalovirus (CMV) is a common virus related to herpes that typically doesn’t cause symptoms in people with healthy immune systems. Congenital CMV is the most common infection impacting unborn infants. Although it’s more prevalent in low- and middle-income countries, CMV affects people from all backgrounds and geographic locations. During pregnancy, an unborn infant can be infected after the mother has a primary infection or recurrence of an existing infection or reinfection.
CMV is the leading cause of non-genetic congenital SNHL in children. Experts don’t know why the virus causes hearing impairment in some children and not others. Symptoms vary from mild to severe, with hearing loss often delayed in onset and progressive. Less than 50% of infants born with congenital CMV show symptoms at birth, which complicates hearing loss diagnosis. In children with congenital symptomatic CMV, hearing loss has been reported in up to 75% of cases. Children with asymptomatic CMV have a 10–15% chance of developing hearing loss. Other long-term symptoms include mental and developmental disabilities and impaired vision.
Oral valganciclovir (antiviral medication) for six months is the gold standard therapy for newborns diagnosed with congenital symptomatic CMV. Studies show this therapy preserves normal hearing or prevents the progression of hearing loss in infants, and also results in improved long-term neurodevelopmental outcomes.
Genes are responsible for 50–60% of cases of children born with hearing loss, yet about 90% of newborns with inherited forms of hearing loss are born to parents with normal hearing. Experts have identified more than 120 independent genes for deafness and at least 400 known genetic syndromes that include hearing loss as a symptom. Mutations in a single gene called GJB2, which is tied to inner ear cells, are thought to account for almost 50% of hereditary non-syndromic SNHL cases.
Select Syndromes Linked to Genetic Hearing Loss
Hearing is an essential component of a child’s social, emotional, and cognitive development. Even mild hearing loss can impact a child's ability to develop proper speech, language, and social skills. The early years of childhood, from birth to age 3, are thought to deeply affect lifelong health, and this also applies to hearing. Some studies have shown that profoundly deaf children have language and academic levels equivalent to fourth grade students with normal hearing when they graduate high school.
Being aware of key speech and hearing milestones can help you determine if your child has a potential hearing problem. Hearing milestones in infants and babies include:
Signs of Hearing Loss in Toddlers
The American Speech-Language-Hearing Association (ASHA) offers more in-depth milestones, classified by age.
Children with permanent childhood hearing loss should receive treatment as soon as possible after diagnosis. Hearing treatment/rehabilitation includes selection, fitting, and evaluation of technology; and a family-centered, interdisciplinary, and comprehensive early intervention program. When selecting a treatment approach, it’s important that your family's goals, preferences, values, beliefs, culture, and language background are taken into consideration.
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