Hearing impairment and prematurity
Most research that connects prematurity and hearing loss has focussed on very low birth weight (VLBW) rather than the degree of prematurity. There is a growing understanding that VLBW probably does not cause hearing impairment by itself but that it introduces other risk factors that may do.
An increased understanding and consequent changes in practice in intensive care units and improvements in technology mean that these risks are diminishing. It is worth noting that the benefits associated with these risk factors outweigh the actual risks.
These risk factors include but are not restricted to:
- Some antibiotics – A group of antibiotics called aminoglycosides are sometimes the best or only choice of antibiotic to fight infection in newly born babies in intensive care. Unfortunately, in some instances they can also damage the cochlea and inner ear leading to hearing loss.
- Noise-induced hearing loss – Prolonged exposure to the background noise of life support equipment in intensive care units can occasionally cause hearing loss.
- Oxygen supply – A severe lack of oxygen, common in premature babies, can cause permanent damage to the cochlear causing hearing loss. Additionally, babies with respiratory difficulties are often treated with mechanical ventilation. This may also cause hearing loss on occasion.
Progressive and delayed-onset hearing loss
The relationship between very low birth weight and progressive hearing loss (hearing loss that worsens over time) and delayed-onset hearing loss (hearing loss that only begins some time after birth) remains poorly understood. However, some studies have suggested a relationship – the Canadian study mentioned previously found that a small number of those children had a progressive or delayed-onset hearing loss by three years of age.
The typical type of hearing impairment associated with preterm babies is sensori-neural. This occurs when the sensitive hair cells either inside the cochlea or the auditory nerve are damaged.
Babies are screened for hearing loss in the first few weeks of life. The possibility of sensori-neural hearing loss can be identified at this time and should lead to a referral to an audiologist for more detailed tests.
Further checks may be arranged for a premature baby even when the screening test shows clear responses. Given the possibility of progressive or delayed-onset hearing loss in premature babies it is recommended that they should have at least one further assessment by 24 to 30 months of age.
Following the first screening in the first few weeks of life parents are given checklists showing the sort of sounds their baby should react to and make as the baby grows. If parents have any concerns about their child’s hearing they should discuss them with their health visitor or family doctor.
Children with a sensori-neural hearing loss may benefit from the use of hearing aids in one or both ears. They may benefit the child by magnifying sound vibrations entering the ear. Surviving hair cells inside the cochlea or auditory nerve detect the larger vibrations and convert them into neural signals that are passed along to the brain.
Cochlear implants may be recommended for children with severe to profound hearing loss if they do not get enough benefit from hearing aids after trying them for three months. A cochlear implant team should carry out an assessment to find out if an implant would help before they consider proceeding.
Better developmental outcomes for children with hearing loss result when interventions of support and resources are put in place as early as possible. View more information about early intervention for children with hearing loss, other guidance and sign posting for parents.
Sense Children’s Specialist Services
Sense's Children's Specialist Services are a team of specialist advisory teachers, children’s therapists, and Children and Family Support Workers.
The team provides advice and information to multi-sensory-impaired children and young people, to their families or carers, and to the professionals who work with them. They also provide support in the home, at school or at their centres of excellence.
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Reviewed: May 2015
Review due: May 2017
First published: Wednesday 21 August 2013
Updated: Tuesday 22 December 2015