Types of Hearing Loss

Types of Hearing Loss.

Not all hearing loss is the same. Treatment will depend on the type of hearing loss you have. With the help of doctor and audiologist, your hearing can be improve. Based on the classification of hearing loss, decisions will be made about the possibility of treatment and hearing recovery

There are many different types of hearing loss, but they are typically classified into three main categories:

• Conductive hearing loss occurs when there is a problem with the outer or middle ear, which blocks sound from reaching the inner ear. This type of hearing loss can be caused by:

  • Earwax buildup
  • Ear infections
  • Damage to the eardrum or bones of the middle ear
  • Barotrauma (pressure changes in the ear)
  • Congenital defects
  • Tumors

• Sensorineural hearing loss occurs when there is damage to the inner ear or the auditory nerve, which sends sound signals to the brain. This type of hearing loss is often caused by:

  • Aging
  • Noise exposure
  • Certain diseases, such as Meniere's disease, otosclerosis, and diabetes
  • Some medications
  • Head injuries

• Mixed hearing loss is a combination of conductive and sensorineural hearing loss. This type of hearing loss can be caused by a combination of factors, such as earwax buildup and age-related hearing loss.

In addition to these three main categories, there are also other types of hearing loss, such as:

• Central hearing loss occurs when there is a problem with the way the brain interprets sound signals. This type of hearing loss is rare and can be caused by certain diseases, such as stroke or multiple sclerosis.
• Functional hearing loss is a type of hearing loss that is not caused by any physical damage to the ears or the auditory system. This type of hearing loss is often caused by stress, anxiety, or depression.

The severity of hearing loss can be classified based on how loud sounds need to be for you to hear them.
Read more about The degree of hearing loss

Different types of hearing loss

Depending on the cause of hearing loss, Hearing loss also can be classified as:

Acute Sensorineural Hearing Loss

Acute sensorineural hearing loss is defined as a hearing loss greater than 30 dB in at least three consecutive audiometric frequencies over 72 hours.
This is usually classified as an otolaryngologic emergency condition, which requires prompt management.
There are several possible causes of acute SNHL, including trauma, infection, malignancy, and Meniere's disease; however, there is no identifiable cause of their hearing loss in most patients and will be classed as idiopathic.
Often routine blood tests and an autoimmune screen are sent off, although practice varies between departments.

Presbycusis or age-related hearing loss

Presbycusis or age-related hearing loss can be defined as a progressive bilateral SNHL of mid to late adult-onset.
The diagnosis of presbycusis is one of exclusion, and primary causes such as otosclerosis, Meniere's disease, and cytotoxicity, amongst many others, must be excluded first.
It is commonly associated with degeneration of cochlear hair cells, mainly OHCs in the cochlea's basal portion, and the changes begin in the basal end of the cochlea and spread towards the apex as the condition worsens.
Patients typically present with a slowly deteriorating hearing loss, especially in the presence of background noise.
It is often a lack of clarity rather than a loss of volume that the patient describes.
Tinnitus is frequently an accompanying symptom and can be the most challenging aspect for the patient.
A typical PTA will show a gradual downsloping hearing loss towards higher frequencies.
It has been shown that once a certain amount of hearing loss has occurred (roughly 70-80 dB), further progression is slow, especially in the higher frequencies. In terms of management options, hearing aids often benefit patients and prevent social isolation and depression.

Noise-induced Hearing Loss

This condition occurs when a patient experiences hearing loss due to excessive noise exposure, either recreational or occupational. Occupational noise exposure is one of the most prevalent, potentially preventable health conditions. It has a slight male predominance and usually affects the middle-aged population.
The symptoms present similar to most SNHL conditions, with the insidious progression of worsening hearing loss over many years, often accompanied by tinnitus.
Hyperacusis is found in 40% of tinnitus sufferers, and its severity can be determined using a hyperacusis questionnaire.
Bedside otological examination is usually normal, and the diagnosis is generally based on the history combined with the classical finding of a notched appearance at 4kHz, which appears to start recovering at 8kHz on a pure tone audiogram. This is known as the Carhart's notch; however, it is not always present.
Without a previous noise exposure history, it is not indicative of NIHL. Once a diagnosis is reached, it is essential to reduce further noise exposure as much as possible using ear protection. The Control of Noise at Work Regulations of 2005 sets out a framework for employers to ensure their employees' safety based on their average occupational sound exposure. 

Meniere's disease

Meniere's disease characterized by a triad of spontaneous episodic vertigo, hearing loss, and tinnitus.
Patients may also experience aural fullness.
Their PTA usually shows an up sloping curve indicating a low-frequency moderate SNHL. PTA remains the most useful investigation, but a brain MRI is done to rule out lesions such as a vestibular schwannoma.
Treatment ranges from conservative such as alcohol, coffee, and salt restriction, to treatments targeted at the symptoms most affecting the patients. Vestibular suppressants such as prochlorperazine can be helpful. Hearing aids and tinnitus retraining therapy can also be used. Psychological support can be key in those patients who suffer from the psychological complications of the condition.

Autoimmune Sensorineural hearing loss SNHL or Autoimmune inner ear disease (AIED)

Also called Autoimmune inner ear disease (AIED) was described in 1979 by McCabe as a rapidly progressive bilateral SNHL that responded to steroid therapy. Several antigens have been implicated in the etiology.
Many systemic autoimmune disorders have been reported, such as Wegener's granulomatosis, rheumatoid arthritis, and systemic lupus erythematosus.
Patients usually present in their early twenties.
Symptoms often start in one ear before becoming bilateral in the majority of patients.
A head injury that results in a temporal bone fracture can lead to conductive hearing loss or mixed SNHL.
Otic capsule fractures cause a severe SNHL through various mechanisms, including disruption of the membranous labyrinth, hemorrhage into the cochlea, perilymph fistula, and avulsion or trauma of the cochlear nerve. In those cases that result in bilateral deafness, a cochlear implant is a treatment option.

Ototoxic agents cause Sensorineural hearing loss SNHL

can cause SNHL in many ways. Aminoglycosides such as gentamicin cause hair cell death resulting in permanent hearing loss and balance dysfunction. This can occur after repeated administration of systemic therapy. The hearing loss initially affects the higher frequencies but continues progressively to the lower frequencies as more hair cells are damaged. Loop diuretics are thought to affect the stria vascularis and cause acute but completely reversible effects.

Conclusion

If you think you may have hearing loss, it is important to see a doctor or hearing specialist for diagnosis and treatment. There are many different treatments available for hearing loss, including hearing aids, cochlear implants, and assistive listening devices.

The sooner hearing loss is treated, the better the chances of improving hearing and preventing further damage. If you have any concerns about your hearing, please see a doctor or hearing specialist right away.

keywords: 
Hearing loss, Degrees of Hearing Loss, Normal hearing, Sensorineural Hearing Loss (SNHL), Difficulty hearing soft sounds, dizziness, presbycusis, age-related hearing loss, noise-induced hearing loss (NIHL), meniere's disease, autoimmune inner ear disease (AIED)