Gene Therapy Breakthrough: Restoring Hearing in Children Born Deaf

Gene Therapy Breakthrough: Restoring Hearing in Children Born Deaf

In a remarkable medical advancement, five children who were born completely deaf due to a genetic mutation have regained their ability to hear after undergoing innovative gene therapy treatment. This groundbreaking development offers new hope for individuals with inherited deafness and showcases the potential of gene therapy in treating genetic disorders.

The Treatment

The gene therapy approach targeted a specific form of inherited deafness caused by mutations in the OTOF gene, which is responsible for producing the otoferlin protein. This protein plays a crucial role in transmitting signals from the ear to the brain [1] [2].

The treatment involved:

  • Delivering a functional copy of the OTOF gene to the hair cells in the inner ear
  • Using a modified virus (AAV) as a vector to carry the gene
  • Injecting the gene therapy mixture into both ears of the children

The Participants and Results

The trial, conducted in China, included five children aged between 3 and 7 years old [1].

Key outcomes include:

  • Hearing restoration: All five children gained the ability to hear in both ears
  • Hearing levels: Approximately 50-60% of normal hearing levels were achieved six months after treatment
  • Speech recognition: The children can now hear voices at conversational volumes
  • Sound localization: Participants gained the ability to locate the source of sounds

Significance of the Study

This trial marks several important milestones in the field of gene therapy and audiology:

  1. Bilateral treatment: This is the first clinical trial to administer gene therapy to both ears, providing enhanced benefits compared to single-ear treatments [4].
  2. Overcoming gene size limitations: The researchers successfully addressed the challenge of the large OTOF gene by splitting it into two parts and using separate viral vectors [2].
  3. Potential for wider application: The success of this approach opens doors for treating other forms of genetic deafness and possibly other genetic disorders [1].

Looking Ahead

While these results are extremely promising, researchers emphasize the need for further studies and longer follow-up periods. The team plans to treat the other ear of children who previously received treatment in just one ear.

This breakthrough not only offers hope for individuals with DFNB9, the specific form of deafness targeted in this study, but also paves the way for developing treatments for other genetic causes of hearing loss. As research progresses, gene therapy may become a viable option for many of the millions of people worldwide affected by genetic hearing impairments.The success of this trial represents a significant step forward in medical science, demonstrating the power of gene therapy to address previously untreatable genetic conditions and potentially transform lives.

If you are concerned about your children’s hearing, please visit our Children’s Hearing Test for more information.

 

 

References:

[1]. Le Page, M. (2024, June 5). Gene therapy enables five children who were born deaf to hear. New Scientist. https://www.newscientist.com/article/2434183-gene-therapy-enables-five-children-who-were-born-deaf-to-hear/

[2]. Powell, A. (2024, January 25). Experimental Gene Therapy Enables Hearing in Five Children Born Deaf | Harvard Medical School. Hms.harvard.edu. https://hms.harvard.edu/news/experimental-gene-therapy-enables-hearing-five-children-born-deaf

[3]. Ungar, L. (2024, January 25). Gene therapy enables five children who were born deaf to hear. New Scientist. https://www.newscientist.com/article/2434183-gene-therapy-enables-five-children-who-were-born-deaf-to-hear/

[4]. Eye, M., & Ear. (2024, June 5). Gene therapy trial restores hearing in both ears of children who were born deaf. Medicalxpress.com. Retrieved July 16, 2024, from https://medicalxpress.com/news/2024-06-gene-therapy-trial-ears-children.html

[5]. Irving, M. (2024, January 28). Groundbreaking gene therapy trial allows 5 children born deaf to hear. New Atlas. https://newatlas.com/medical/born-deaf-hearing-restored-gene-therapy/

Hearing Loss in Children

Hearing Loss in Children

Hearing Loss in Children

Hearing loss can have a lifelong impact on children. It can affect their speech, language and learning, their social, physical and emotional development, and their long-term education and employment opportunities.

Colds, infections, allergies and flu can temporarily affect your child’s hearing, however some children have or develop permanent hearing loss. In Australia, between 9-12 children in every 10,000 will be born with a moderate or greater hearing loss in both ears. Around another 23 children per 10,000 will acquire a hearing impairment that requires hearing aids by the age of 17 through accident, illness or other causes.

Most Australian newborns are tested before they leave hospital to identify if they require further hearing and middle ear function testing. If a hearing loss is diagnosed, other tests may include blood tests, an electroencephalogram and a CT scan of the middle and inner ear. The earlier you find out your child has a hearing impairment, the earlier they can begin therapy and develop language to communicate with. It also means you and your family can receive advice and support as soon as possible, all to help give your child the best start in life.

hearing loss in children

Hearing loss can have a lifelong impact on children.

Degrees of Hearing Loss in Children

There are various degrees of hearing loss, classified as mild, moderate, moderate to severe, severe or profound.

Mild hearing loss
Children with mild hearing loss usually have normal speech and can hear normal conversation but may not hear whispers or soft sounds, and will have trouble in the school setting because it will be difficult to hear speech from more than 4 metres away or when there is background noise. Some children with a mild loss are not suspected of poor hearing until they reach grade one. They are often thought to be ‘slow’ learners because they cannot understand when the teacher speaks from a distance and, therefore, respond erratically. When these children receive hearing aids, they usually find that school is easier and their school performance improves.

Moderate hearing loss
Children with moderate hearing loss can clearly hear speech only when the speaker is very close – less than one metre away. They need hearing aids to hear the softest sounds and to acquire understandable speech. If they receive hearing aids before four years of age, they usually progress rapidly in learning speech. They can attend regular schools, but may need some special help.

Moderate to severe hearing loss
Children with moderate to severe hearing loss need conversations to be very loud to be able to hear them. Even when speech is loud, not all words and sounds will be heard clearly. Speech and language development will be affected and specialised professional help will be beneficial.

Severe hearing loss
Children with severe hearing loss will not hear normal conversation and will only be able to pick out a few loud sounds and words. Speech and language development will be affected and hearing aids and specialised professional help will be needed.

Profound hearing loss
Children with a profound hearing loss receive even less auditory information. No sounds can be heard without the help of a hearing aid. The younger a child is when fitted with hearing aids or a cochlear implant, the greater the likelihood he/she will develop improved speech. Children with a profound loss often depend greatly on their vision to perceive speech.

Phonak hearing aids for children

Leo the Lion from Phonak has hearing aids just like your child! Ask your audiologist for more information.

Types of Hearing Loss in Children

There are two main types of hearing impairment, based on which part of the ear is affected: conductive or sensorineural.

Conductive hearing loss
Conductive hearing impairment indicates there is a problem with the mechanism that conducts sound from the environment to the inner ear. It can be caused by a wax blockage, middle ear infections (otitis media), a punctured eardrum, a build-up of fluid or abnormal bone growth. This kind of hearing loss can usually be corrected by medication or surgery. If it cannot be corrected, the child with conductive hearing loss can usually do very well with hearing aids.

Sensorineural hearing loss
In the case of sensorineural hearing impairment, there is damage to the innermost part of the ear (cochlea) or to the nerve which carries hearing (the auditory nerve). It can be caused by abnormal inner ear development, a physical injury to the inner ear, or damage to the ear from diseases such as meningitis and rubella, or a tumour. This type of hearing loss is usually permanent. However, children with sensorineural hearing loss can benefit from hearing aids, FM systems, cochlear implants, communication therapies, and a careful analysis and implementation of educational and communication approaches.

Some children can have both types, which is called a mixed hearing loss, or another type called retrocochlear.

hearing loss in children

Image via www.resound.com

Causes of Hearing Loss in Children

Hearing loss can either be congenital or acquired. Congenital means that the hearing loss was present at the time of birth, or occurred very soon after birth. An acquired hearing loss occurs after birth, often as a result of an illness or an injury.

Congenital hearing loss
There are various causes of congenital hearing loss, though they are not always easily identified. There are both non-genetic and genetic factors that might cause hearing loss.

Non-genetic factors include:

  • Birth complications
  • Premature birth
  • A nervous system or brain disorder
  • The use of ototoxic medication by the mother during pregnancy
  • Infections that occur during pregnancy such as measles and toxoplasmosis
  • Maternal diabetes
  • Drug or alcohol abuse by the mother, or smoking during pregnancy

The above causes of congenital hearing loss are all non-genetic factors. However, non-genetic factors account for only around 25 percent of congenital hearing loss. Experts agree that genetic or hereditary factors cause more than 50 percent of all hearing loss in children, whether the loss is present at birth or manifests later in life.

Genetic factors that might cause congenital hearing loss include:

  • Autosomal recessive hearing loss, which is the most common type of genetic congenital hearing loss. It means that neither parent has a hearing loss, but each parent carries a recessive gene that gets passed to the child. Parents are usually surprised when their child is born with this type of hearing loss because people typically aren’t even aware they have the recessive gene.
  • Autosomal dominant hearing loss, which means that one parent carrying a dominant gene for hearing loss passes it to their child. This parent may or may not have hearing loss, but he or she might have other symptoms or signs of a genetic syndrome.
  • Genetic syndromes like Usher syndrome, Treacher Collins syndrome, Waardenburg syndrome, Down syndrome, Crouzon syndrome and Alport syndrome.

Acquired hearing loss

There are various causes of acquired hearing loss, including:

  • A perforated eardrum
  • Otosclerosis or Meniere’s diseases, which are progressive
  • Infections like meningitis, measles, mumps or whooping cough
  • Taking ototoxic medications
  • A serious head injury
  • Exposure to very loud noise over long periods
  • Untreated or frequent ear infections (otitis media)
  • Exposure to second-hand smoke

However, in some cases it may not be possible to identify the cause of deafness or hearing loss. Children of all ages should undertake a full hearing evaluation if they have experienced diseases that can cause hearing loss, if they have been taking medications that list hearing loss as a side effect, or if you have a family history of hearing problems.

hearing evaluations for children

Hearing loss can either be congenital (present at or soon after birth) or acquired (as a result of an illness or an injury).

Symptoms/Signs of Hearing Loss in Children

Awareness of communication milestones can help identify early signs of hearing loss.
Hearing impairment in infants may be difficult to detect, but the sooner hearing loss is detected, the better the chances for your child to socialise, communicate, learn, accept their hearing loss, and learn how to live with it.

Some signs that your infant may have hearing impairment include that they:

  1. 1. Do not startle at the sound of loud noises by four months of age, or do not turn towards the source of a sound
  1. 2. Notice you only when they see you
  1. 3. Do not make sounds other than gargles and other vibrating noises that they can feel
  1. 4. Need to search right and left to find the voice or sound
  1. 5. Have delayed speech or are hard to understand by 15 months of age
  1. 6. Do not always respond when called
  1. 7. Hear some sounds but not others
  1. 8. Have trouble holding their head steady, or are slow to sit up by themselves or walk

Older children could also acquire hearing loss that is either permanent or temporary. Here are some things to look for if you think your toddler or preschool-age child might have hearing loss:

  1. 1. Has difficulty understanding what people are saying
  1. 2. Speaks differently than other children of similar age
  1. 3. Doesn’t reply when you call their name, or doesn’t seem to notice that you have spoken to them
  1. 4. Responds inappropriately to questions (misunderstands)
  1. 5. Turns up the TV volume incredibly high or sits very close to the TV to hear
  1. 6. Has problems academically, especially if they weren’t present before. This can develop into apparent ‘behavioural problems’ at school (which are in fact masking a hearing problem)
  1. 7. Has speech or language delays or problems articulating things
  1. 8. Watches others in order to imitate their actions, at home or in school
  1. 9. Complains of ear pain, earaches or noises
  1. 10. Cannot understand over the phone or switches ears frequently while talking on the phone
  1. 11. Says “what?” or “huh?” several times a day
  1. 12. Watches a speaker’s face very intently. Many children’s hearing loss escapes detection because they are very successful lip readers
  1. 13. Appears inattentive and prone to daydreaming
  1. 14. Starts to develop low self-esteem. Teachers and peers may conclude that a child is cognitively delayed if they are missing information due to a hearing loss, and the child may start to believe they are not capable of doing the things their peers can
  1. 15. Acts shy particularly around people they don’t know (because they can’t understand everything they say)
  1. 16. Becomes quiet and withdrawn at school if they can’t hear the teacher well or follow instructions
  1. 17. Appears exhausted by the end of the day because hearing takes a lot of energy

Treatment Options

If your child suffers from hearing loss, hearing aids are one of the remedies that can help them to improve their hearing ability and minimise the adverse effects of their hearing problem. The choice you make about which type of hearing aids will depend on a number of factors including the type and degree of your child’s hearing loss; your child’s general abilities and level of activity (the hearing aids must be robust and able to withstand the impact from normal playing, and be resistant to dust and moisture. Many hearing aids for children also include special coverings and other accessories to ensure that young children don’t remove or misplace their hearing aids); your child’s age and school level (hearing aids for older children must have audio ports for hooking-up to radio transmission in classrooms and elsewhere); your child’s personal taste (children often like colourfully finished hearing aids and there are many options and styles to choose from).

There are several models of hearing aid devices to choose from, including behind-the-ear (BTE), in the ear (ITE) or in the canal (ITC) hearing aids.

BTE hearing aids:Young children will normally be fitted with hearing aids worn behind-the-ear (BTE). These come in compact sizes and a variety of bright, cheerful colours.

ITE hearing aids:Older children may be candidates for in-the-ear (ITE) hearing aids, which are custom made and fit inside the ear. These can help for children with mild to moderate hearing losses.

ITC hearing aids:One option for older children is in-the-canal (ITC) hearing aids. The microphone remains in the ITC casing but the receiver is externally placed in the ear canal. This allows the hearing aid to be smaller and more cosmetically appealing.

The Sky V and Sky Q from Phonak, Sensei from Oticon, Motion M, Motion P and Aquaris from Seimens, Supremia Super Power from Bernafon, and the ReSound Up Smart from ReSound are a few examples of hearing aid options available for children.

When your child has begun using hearing aids, you must remember that it takes time to get used to them. Getting used to hearing aids requires strong motivation, support and participation from you as a parent. Advanced, well-fitted hearing aids are not very useful if the child does not wear them or if they are not maintained.

hearing aids for children

The Sky V hearing aid from Phonak has been specially designed for children with hearing loss.

At Ear & Hearing Australia, we are here to help you find the right hearing aid for your child, fit and adjust it, and inform you about all relevant aspects of hearing impairment and hearing aids. Do not hesitate to contact us on 1300 761 667 or find a clinic near you to discuss your child’s individual hearing needs.

Are your child’s toys causing them hearing loss or damage?

Are your child’s toys causing them hearing loss or damage?

Are your child’s toys causing them hearing loss or damage?

In today’s world of constant over-stimulation, children’s toys have evolved from rocking horses and pull toys, to advanced technological gadgets equipped with all kinds of bells and whistles designed to spark your child’s imagination, educate and delight them, and keep them entranced for hours. The problem is that many of these fancy new toys could be causing your child hearing damage, and in extreme cases, even hearing loss.

Hearing loss is cumulative, developing gradually as we age, and noise-induced hearing loss is permanent and not currently curable.

So it’s critical that we start protecting children’s hearing from an early age.

noisy toys and hearing loss

Are your child’s toys causing them hearing loss or damage? Image via livescience.com

How loud is too loud?

Unprotected exposure to sounds above 85 decibels (dB) for a prolonged period can lead to hearing impairment. And the louder a sound is, the less time it takes to cause damage.

So how loud does a toy have to be before it is considered dangerous for your child? To put it in perspective, the average conversation is about 65 dB loud, but some toys emit sounds that are more than 100 dB. For example, when used in ordinary play some types of battery-driven toy guns and action figurines can create noise levels between 100 and 140 dB, equivalent to the noise generated by a motorbike, a rock concert, or a jet at take-off.

noisy toys and hearing loss

Protect your child’s hearing: Some toys are emitting noises as loud as chainsaws.

And that’s assuming that your child is using the toy the way the designers intended for it to be played with. Toys are generally noise-tested at a distance of a child’s arm length; approximately 25cm. But if you watch a child playing with a hand held noise-emitting toy you will see them hold it close to their face, right next to their ears, which increases exposure to more than 120 dB of sound. As children are very sensitive to loud and high-pitched sounds, toys this loud can cause physical pain to some kids.

Which toys are too loud?

Each year the American Sight & Hearing Association (SHA) prepares a Noisy Toys List in time for Christmas, to help parents and caregivers make informed decisions about gift choices. Their most recent list, published on 24th November 2016, found 3 toys that were so loud they could cause hearing damage within 15 minutes of play time. The worst offender was the WWE 3-Count Crushers, Roman Reigns™ action figure by Mattel®, which was found to produce groans and growls that reach 104.4 dB. Other recent list-toppers include Road Rippers Lightning Rods, Let’s Rock Elmo and the I Am T-Pain musical microphone.

Check out the SHA Noisy Toys List top 20 here.

How can I protect my child’s hearing from noisy toys?

There are several free smartphone apps available that allow you to take a rough measurement of decibel levels. The apps are limited by the phone’s ability to pick up the sound, and they usually cap out at 100 dB. So if the app can’t pick up the audio from the toy, that toy is too loud for your child! Decibel 10th is a highly-rated decibel meter available on iTunes and Google Play.

Decibel 10th smartphone app noise meter

Decibel 10th is a handy smartphone app for measuring noise levels.

If you don’t own a smartphone, your ears will do the job just as well. Rule of thumb: if a toy sounds too loud to you, it is too loud for your child.

Other tips when choosing toys

  • Test toys for noise levels before you buy them. Push buttons, rattle components, and bring the toy up to your ear as your child would.
  • Avoid buying toys that display warnings about holding them too close to the ears (children will forget about this during play time).
  • Choose less noisy toys wherever possible, or find ways to reduce their noisiness (i.e., putting tape or glue over the speaker to muffle the sound).
  • Look for toys that have volume controls.
  • Pay attention to where the toy’s speaker is located (underneath it better than on top).
  • Designate noisy toys like musical instruments and toy guns as ‘outdoor use only’ and restrict their use.
  • Use play mats or rugs to reduce noise from toys that don’t emit sound but can still be noisy to play with (blocks for example).