Hearing loss is one of the most prevalent health conditions, affecting people of all ages. According to the World Health Organization, over 5% of the world’s population experiences disabling hearing loss. As people grow older, age-related hearing loss becomes more common. About one third of people over 65 years old are affected by hearing loss. Thankfully, a wide range of treatment options exist today to help those with hearing impairment.
What Causes Hearing Loss?
Hearing loss can stem from problems in any part of the auditory system, which includes the outer ear, middle ear, inner ear and auditory nerve pathways leading to the brain.
Age-Related Hearing Loss
As we grow older, our ears gradually lose some of their sensitivity to sounds. This age-related hearing loss is medically known as presbycusis. It arises due to cumulative effects of aging on the ear structures. The tiny hair cells in the cochlea which detect sound waves become damaged and degrade over time. The auditory nerves connecting the ear to the brain also diminish with age. Genetic factors play a role in presbycusis as well.
Prolonged exposure to loud sounds is another major cause of hearing loss. Noises above 85 decibels can permanently injure the hair cells in the cochlea. Music concerts, motorcycles, power tools and even loud music through earphones can contribute to noise-induced hearing loss over time. This type of sensory-neural hearing loss is preventable by limiting noise exposure and properly using hearing protection gear.
Bacterial and viral infections of the ear can lead to fluid buildup and inflammation of the middle ear. If left untreated, these inner ear infections may cause conductive hearing loss. The eardrum and tiny middle ear bones are not able to transmit sound properly due to fluid pressure. Chronic ear infections can even erode the cochlea and auditory nerve cells.
Heredity plays a role in some types of hearing loss. Genetic conditions present at birth, such as Waardenburg syndrome and Alport syndrome, disrupt normal development of the ear. Later in life, conditions like Usher syndrome also lead to progressive hearing loss. Your genes can also make you more susceptible to age-related and noise-induced hearing impairment.
Medications and Chemicals
Certain prescription drugs are toxic to the ear, especially in high doses. These ototoxic medications include powerful antibiotics like gentamicin and cancer drugs like cisplatin. Exposure to solvents like toluene and styrene in an occupational setting can also damage hearing over time. The chemicals cause sensory hair cells in the cochlea to die off.
Abnormal development of the ear structures during gestation can lead to profound hearing loss at birth. Malformation of the external ear, ear canal atresia, and cochlear nerve hypoplasia are some congenital defects which impair hearing. Genetic mutations, maternal infections during pregnancy, and improper prenatal nutrition contribute to these conditions.
Types of Hearing Loss
Not all hearing loss is the same. Doctors classify hearing disorders based on which part of the auditory pathway is affected.
Conductive Hearing Loss
This arises from obstructions or damage to the outer and middle ear which prevent sound waves from being transferred. Buildup of earwax, ear infections, perforated eardrum, or malformation of the outer ear can all lead to conductive hearing problems. Since sound is not reaching the inner ear properly, hearing becomes muffled. Medical or surgical treatment can often restore conductive hearing.
Sensorineural Hearing Loss
This occurs when there is damage to the delicate hair cells in the cochlea or to the auditory nerve pathways. As sound signals cannot be transmitted to the brain properly, hearing sensitivity suffers. Age-related hearing loss and noise-induced hearing loss are common causes. Unlike conductive loss, sensorineural loss cannot be medically corrected and is usually permanent.
Mixed Hearing Loss
Some people suffer from both conductive damage and sensorineural damage. This results in a mixed hearing loss. Chronic untreated ear infections, for example, can cause both outer ear canal problems as well as inner ear nerve damage. Treating the conductive portion can improve hearing to some degree. Hearing aids help make up for the non-reversible sensorineural loss.
Signs and Symptoms
Hearing loss develops gradually in most cases. Early on, it may be difficult to notice the subtle signs. Symptoms tend to become more noticeable as hearing worsens over time. The main symptom is simply difficulty hearing conversations, television, phone calls, and other sounds. Here are some specific signs of hearing impairment:
- Asking people to constantly repeat themselves
- Turning up the volume very high on devices
- Having trouble understanding speech amid background noise
- Thinking that others are mumbling
- Favoring one ear over the other
- Avoiding social situations due to hearing issues
- Ringing in the ears, known as tinnitus
- Feeling pressure or fullness in the ears
Seeking medical treatment when these symptoms arise is important, as untreated hearing loss has major impacts on one’s quality of life. Early intervention can help stop additional damage before it becomes severe.
Diagnosing Hearing Loss
To determine the degree of hearing loss and the underlying cause, doctors perform certain tests. Initial examination includes otoscopy to visualize the ear canal and eardrum. Earwax blockage, infections, and perforations can be identified. The following are some common diagnostic hearing tests:
Tympanometry: This measures how the eardrum responds to air pressure changes. It assesses middle ear function.
Audiometry: This key hearing test determines the quietest tones you can hear at different pitches. Based on results, type and degree of hearing loss are determined.
Auditory brainstem response (ABR): Electrodes measure the ear and brain’s response to click sounds. It helps identify auditory nerve damage.
Otoacoustic emissions (OAEs): A tiny probe emits sounds into the ear canal to evaluate cochlea responses. It checks for inner ear hair cell damage.
Speech audiometry: You listen to and repeat words at different volumes to measure speech comprehension ability.
Imaging tests like CT and MRI scans may also be done to visualize ear structures and rule out tumors. Once hearing loss is diagnosed, appropriate treatments can begin.
Treating Hearing Loss
The goal of treatment is to restore hearing function, allow better speech understanding, and improve communication. Options include:
Hearing Aids: These portable electronic amplification devices fit in or behind the ear. They make sounds louder to overcome hearing loss. From basic models to smart hearing aids with Bluetooth, various types are available. Hearing aids require professional customization.
Cochlear Implants: This device is for people with severe inner ear damage. A surgically implanted part stimulates the auditory nerve directly. The external microphone and speech processor then amplify those signals. Months of auditory therapy follow surgery.
Surgery: Operations like stapedectomy and tympanoplasty can fix some conductive hearing loss causes like ossicle bone fractures. Cochlear implants also require surgery.
Medications: Drugs can treat underlying conditions leading to hearing loss, such as ear infections, Meniere’s disease, and autoimmune disorders. Some medications aid recovery after inner ear surgery.
Hearing Therapy: Also called aural rehabilitation, this involves speechreading training, hearing aid adjustment, and learning better communication tactics. It helps improve hearing function in daily life.
Preventing Further Damage
While age-related decline in hearing cannot be avoided, one can take steps to prevent avoidable hearing loss:
- Minimize exposure to loud noise from sporting events, machinery, construction, and loud music. Avoid noise levels above 85 decibels.
- Use proper hearing protection equipment like earmuffs and custom earplugs when around excessive noise.
- Turn down volume when listening with headphones and take breaks.
- Get regular hearing checkups and follow treatment for ear infections to prevent them from damaging hearing.
- Be aware of potentially ototoxic medicines and chemical solvent exposures in the workplace.
The Future of Hearing Loss Treatment
With growing understanding of the intricacies of the auditory system, new technologies aim to restore hearing in innovative ways. Research continues on:
- Stem cell regeneration to repair inner ear hair cells
- Gene and drug therapies to prevent progressive hearing loss
- Totally implantable hearing devices with improved auditory capabilities
- Customized in-ear chips that act like hearing aids and cochlear implants
Hearing loss can arise from many causes, but key types include age-related, noise-induced, genetic, and conductive loss. Symptoms like difficulty following conversations and tinnitus should prompt a hearing evaluation. By better understanding the problem through diagnostic audiology tests, appropriate treatment can begin. The extent of disability due to hearing impairment can be reduced through hearing aids, therapy, surgery in some cases, and prevention of additional damage. Ongoing research provides hope for improved treatments options to come. Managing hearing loss successfully greatly improves a person’s engagement with others and overall quality of life.