7 Billion people(1) live on our planet, with 6909 (2)languages spoken across the globe, Imagine life when it is hard to be able to hear these.
Hearing loss occurs when it becomes difficult for a person to hear speech and sound (3) resulting in a misunderstanding of the information they are told. The effect can either be temporary or permanent.
In the United Kingdom alone there are 10 million people that have a level of hearing loss, this is 1 in 6 people(4). Hearing impairment is divided into four main categories to understand the severity. Mild hearing impairment is between 25 and 40 db (include sound), it is known as hard of hearing where they still have the ability to understand the majority of a conversation. Moderate hearing impairment occurs between 40db and 70db (include sound), It becomes a lot harder to understand conversation. Severe hearing impairment is between 70 db and 95db (include sound) Finally, profound is above 95d (include sound) there is little speech heard even with help of a hearing aid. (5)(6)
How can we even hear sound?
Sound is heard by the auditory system which has three main components the inner, outer and middle ear. Sound waves hit the head and pass through the outer ear to the ear canal. From here It passes to the tympanic membrane known as the eardrum causing a vibration. In the middle ear there are three moveable bones known as ‘ the ossicles’ these tiny bones carry sound to the inner ear where the vibration stimulates the movement of the hair cells. Hair cells have stereocilia, a finger-like projection which responds to fluid motion. Hair cells transform the sound vibration to a neural signal which is transmitted to the brain by the auditory nerve. The brain interprets the impulse into to the sound that we hear.
Hearing loss can affect any part of the ear, making not all hearing loss the same.
An auditory processing disorder, is when there are difficulties understanding speech and where sounds originate from. It affects how the brain interprets sound rather than how the sound is carried through the ear to the brain. Someone that had APD, the sound enters the ear canal to the inner ear as usual to the brain through the auditory nerve but as the sound arrives at the brain there are problem interpreting it leading to a misunderstanding. It can be referred as a spectrum disorder whereby some people have a greater range of difficulties as conditions such dyslexia, poor short-term memory can worsen the effect. The main strategies to reduce the effect are to improve the ability to listen and reduce background noise eliminating any distractions. In many cases APD can improve with age.
Conductive hearing loss occurs when there is a problem with the outer or inner ear. As a result of an ear infection, punctured ear drum, excess fluid build-up or abnormal bone growth such as otosclerosis. The effect can be sudden occurring either single-sided or bilateral hearing impairment. Speech can appear unclear or delayed development. Treatment for conductive hearing impairment is individual to each patient, but cochlear implants, hearing aids, surgery and antibiotics can help to improve the ability to hear.
Sensorineural hearing loss occurs when there is damage to the hair cells often referred to as‘ sensory cells’ in the inner ear, the result is normally permanent as once the hair cells are damaged. They are unable to regenerate from when they are first generated at 10 weeks old during fetal gestation. We have a total of at least 17,500 hair cells, with each having the ability to pick up different sounds like the keys of piano. The hair cells can become easily damaged when moving back and forth in the ear large dB can cause them to break, damage or shatter off.
A type of sensorineural hearing loss is presbycusis, which is most common in the older generation as a result of natural aging and damage occurs to the hair cells
The occurrence of hearing impairment can be as a result of genetic and environmental conditions or a single-gene mutation. Genetic hearing loss doesn’t have to occur at birth, it can occur at any point in a person’s life leading to sudden hearing loss.
Syndromic hearing loss occurs in up to 30% of hearing loss, as a result of the chromosomal abnormalities that can cause over 400 syndromes which can be associated with the hearing impairment(7)
However, nonsyndromic hearing loss occurs when there are no other signs or symptoms, accounting for 70% of hearing loss. The effect can be from either an autosomal-dominant or autosomal recessive gene. A Dominant gene is when it is only required for one parent to have the gene, or a recessive gene where both the mother and father have the gene, therefore the parents are known as a carrier. Where they themselves don’t have symptoms.
Include interview with audiology team about this:
Questions:
What’s your role as an audiologist?
How important is it to diagnose hearing loss as early as possible?
How do you diagnosis hearing loss?
Is it important to raise awareness about hearing loss?
Hearing loss doesn’t mean that it has to limit someone’s ability to communicate.
Hearing aids can cost between £500 and staggering £3,500, and are only able to used if there is still some hearing ability, and therefore not suitable for someone with hearing impairment about severe. There are many type of hearing aids from tiny completely in the ear canal aids that are ‘invisible’ to receiver in the ear canal aids to a body worn hearing box. All having the ability to improve the hearing.
But unfortunately these cannot be used in all type of hearing impairment.
Middle ear implants are often used when the wear is allergic to the material used in a hearing aid or the device does not fit. If a hearing aid doesn’t fit properly it can cause a whistling sound to the wearer.
An auditory brainstem implant, is a device that is surgically implanted when an illness or damage to either the cochlear or auditory nerve to help provide a sense of sound, even if it is limited to someone that is profoundly deaf.
A bone anchored hearing aid is provided to allow for direct conduction through the bone to the inner ear.
A cochlear implant, is an electromagnetic device that is surgically implanted to replace the damaged in the inner section of the ear. They are designed to provide sound signal to the brain. Unfortunately it doesn’t cure hearing impairment but if the device is fitted at an early stage in children that are profoundly deaf, it can help the wearer to adjust quicker to the new surroundings and is more likely to increase their ability to understand speech. The implant can cause sounds that are unnatural for the ear due to the different way that the sound is interpreted, these sounds after often uncomfortable to hear at first and adults find it much harder to adjust to. But they device allows for the ability to hear danger and improve their quality of life.
Currently in recent years scientist are trying to explore ways that hearing aids can be improved further with method ranging from glasses that had 7 LED lights on that flash when and where a sound is present, to alert the person of danger. To an advancement on the cochlear implant, where infrared light stimulates the neurons in the inner to uses 3000 hair cells instead of only 20. They are also trying to work on an implant that can worn when sleeping, as people with hearing loss can often become anxious of being unable to hear any dangers. However the hearing aid that has been trailed at the moment is very fragile on the outer ear and allow for bodily noises such as swallowing and the heart to be heard.
Hearing aids, or a medical device are not the only method that can be used by deaf people to communicate.
Sign Language is one of the most common methods that people are aware of. However sign language is not universal and there many different forms depending on the country. For example we use british sign language. Sign language is a complicated language to learn and not all deaf people find it easy to pick up, especially if they become suddenly deaf later in life because the structure of the sentence and phrases are very different from the english we use use. For example to say my name is, you would sign name me what. Therefore some people use sign supported english which is different from sign language, it support both spoken english whilst borrowing signs from the british signing language.
I have created a short animation and little red riding hood to show how sign language is used.
However, some people choose to lip read. When lip reading a person can only make out 30% of the words in the british language, because many have similar mouth movements such as coffin, coffee, coughing.
I would like to welcome beverly who is hard of hearing and uses lip reading.
Hearing loss can sometime lead to isolation from the community, especially if it sudden during later life. Hearing dogs can provide people with the confidence they need and help improve the person’s quality of life. The dogs are trained to alert their owner of important sounds and allow the person to have their independence back.