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An Overview of Sensorineural Hearing Loss (SNHL)

Sarah's background is in both creative and technical writing. She aspires to become a children's book author.

The inner ear is a delicate structure containing tiny hair cells, also known as nerve endings. These special cells hear sounds, transmitting them to the brain through nerves as electrical signals.[1] If the tiny hair cells within the inner ear are missing or are damaged, hearing impairment or loss is generally the result. It is known as sensorineural hearing loss (SNHL). Nerve deafness is not reversible and there is no cure. Depending on the extent of the damage, a hearing aid may assist individuals with mild to moderate loss.

To date, there are a variety of known causes and risk factors related to SNHL. They include the following:

  • Exposed to loud music or noise;
  • Family history/genetics;
  • Birth injury;
  • Barotrauma ("airplane ear");
  • Head trauma;
  • Ototoxic medications;
  • Diseases, including vascular and Meniere’s;
  • Acoustic neuroma;
  • Viral and bacterial infections, including herpes simplex and zoster, influenza, measles, meningitis, mononucleosis, mumps, syphilis, scarlet fever, and toxoplasmosis; and
  • Presbycusis (aging). [2,3]

Children may be born with SNHL (congenital hearing loss) due to more than 400 known genetic syndromes or from an infection passed along from the mother during pregnancy, such as herpes, rubella, or toxoplasmosis.

As much as patients want an answer or a reason for their hearing loss, unfortunately, there are times when the cause cannot be found.

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There Are Six Hearing Loss Ranges

Individuals may experience mild to profound hearing loss, either gradually or suddenly. What can or cannot be heard is attributed to one of six of hearing loss ranges the patient experiences:

  1. Slight loss: 16-25 (dB HL)
  2. Mild loss: 26-40 (dB HL)
  3. Moderate loss: 41-55 (dB HL)
  4. Moderately severe loss: 56-70 (dB HL)
  5. Severe loss: 71-90 (dB HL)
  6. Profound loss (deaf): 91-higher (dB HL) [4]

Hearing impaired persons may have trouble hearing faint sounds at a mild loss. Severe loss may prohibit individuals from hearing loud noises more than a foot away.

Sensorineural Hearing Loss

Symptoms Related to Hearing Loss

Patients may exhibit one or more symptoms related to their loss or impairment. These may include:

  • Tinnitus (ringing in the ears);
  • Vertigo;
  • Fever;
  • Drainage (such as blood or fluid);
  • Ear pain;
  • Hyperacusis (sounds appearing louder than normal);
  • Difficulty understanding female voices or conversations amongst background noise; and
  • Sounds are muffled or distorted.[5,6]
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Emergent Care

Sudden sensorineural hearing loss, presumed to be of viral origin, is an otologic emergency that is medically treated with corticosteroids.

— Hearing Loss Association of America

Treatment Is Based on Different Types of SNHL Cases

SNHL because of loud noise: It is possible that, if administered promptly, corticosteroid therapy can help heal hearing loss or recover some of what was lost. To prevent further loss, limit the volume of handheld devices, headphones, and ear buds that come into direct contact with the ears. Wear hearing protection when mowing the lawn or attending concerts.

SNHL because of head trauma or barotrauma: At times, emergency surgery can be a success to repair the inner ear, as any rupture or leakage can be toxic.

SNHL because of Meniere’s Disease: While there is no cure for Meniere’s, symptoms can be controlled by a low-sodium diet and medications, such as diuretics and corticosteroids.

SNHL because of tumors: There is a possibility that if the loss is mild and the tumor is small, as much as 50% of individuals who undergo this type of tumor removal surgery may regain their hearing.[7]

SNHL because of disease: If treatment is received for the underlying disease, it is possible that secondary hearing loss will be reversed.

Unfortunately, not all SNHL incidents are reversible. In that case, it may be time to consider hearing aids or, if an eligible candidate, cochlear implants.

What Do You Think?

Sources

[1,5] MedlinePlus website. Sensorineural Deafness. Accessed October 25, 2016. http://www.nlm.nih.gov/medlineplus/ency/article/003291.htm

[2,6] eMedicine Health website. Hearing Loss. Accessed October 25, 2016. http://www.emedicinehealth.com/hearing_loss/page2_em.htm

[3] MedlinePlus website. Hearing Loss. Accessed October 25, 2016. http://www.nlm.nih.gov/medlineplus/ency/article/003044.htm

[4] American Speech-Language-Hearing Association. Degree of Hearing Loss. Accessed October 25, 2016. http://www.asha.org/public/hearing/Degree-of-Hearing-Loss/

[7] Hearing Loss Association of American. Types, Causes, and Treatment. Accessed December 2, 2016. http://www.hearingloss.org/content/types-causes-and-treatment

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.