Sudden Sensorineural Hearing Loss (SSNHL): What You Need to Know
Reviewed by Yahav Oron, M.D. and Noga Lipschitz, M.D., on Nov. 11, 2023
In this article
What is Sudden Sensorineural Hearing Loss (SSNHL)?
Not all instances of sudden hearing loss meet the medical criteria for Sudden Sensorineural Hearing Loss (SSNHL). In this article, we'll focus on SSNHL and begin by defining when a sudden hearing loss is categorized as SSNHL.
SSNHL is a sudden and significant loss of sensorineural hearing, without a known cause, impacting one ear, occurring for the first time, and not associated with recent health changes. Bilateral SSNHL is rare and should prompt consideration of other causes.
How will my doctor determine Sudden Sensorineural Hearing Loss (SSNHL)?
SSNHL is determined by the following criteria:
Sudden loss of hearing: the hearing loss occurred within a 72-hour period
Significant loss of hearing: there is a hearing loss of 30 decibels or more, affecting at least three consecutive frequencies on the audiogram. An audiogram is a type of hearing test done by an audiologist. You can read more about it here.
The type of hearing loss is a sensorineural hearing loss, indicating it originates from the inner ear or the auditory nerve.
The cause is unknown
The loss of hearing affected only one ear
Occurring for the first time: the classical definition of SSNHL and the accompanying guidelines refer to the first occurrence of sudden hearing loss, and not to recurring events. Such events may be managed in a similar fashion or differently.
It is not associated with recent health changes unrelated to the ear. While SSNHL can be accompanied by symptoms like tinnitus or vertigo, any other recent health changes not connected to the ear should be evaluated.
What do we think causes Sudden Sensorineural Hearing Loss (SSNHL)?
The cause of sudden sensorineural hearing loss (SSNHL) is not well-defined, but possible reasons include viral infections, issues with blood circulation, and autoimmune diseases. If the underlying cause of the sudden hearing loss is identified, treatment should be adjusted accordingly. But in many cases, the exact cause remains unknown.
Is Sudden Sensorineural Hearing Loss (SSNHL) common?
The incidence of SSNHL ranges from 5 to 27 cases per 100,000 people annually, resulting in 66,000 new cases of SSNHL annually in the United States [1].
Can Sudden Sensorineural Hearing Loss (SSNHL) recover without any treatment?
About half of the individuals experiencing Sudden Sensorineural Hearing Loss (SSNHL) may recover spontaneously without treatment. However, it's challenging to predict who will recover on their own and who will not. Given the significant long-term impacts of hearing loss, most doctors recommend pursuing treatment to aid recovery, unless there are compelling reasons to avoid it.
How is Sudden Sensorineural Hearing Loss (SSNHL) managed?
Over the years, numerous management approaches have been proposed for Sudden Sensorineural Hearing Loss (SSNHL), encompassing both diagnostic and treatment aspects. Eventually, these approaches have converged into a few clear recommendations effectively summarized in the guidelines published by the American Academy of Otolaryngology-Head and Neck Surgery Society (AAO-HNS)[1]. This publication is authored by highly experienced clinicians and researchers who have thoroughly analyzed the most up-to-date research available and matched it with their clinical experience. Their goal was to strike a balance between several key factors including:
The seriousness and distressing consequences of living with hearing loss
The potential for spontaneous recovery
The possibility for further improvement with treatment
Risks associated with treatment side effects
The burden on patients undergoing these treatments in terms of physical inconvenience, time commitment, and associated healthcare and transportation costs.
Based on these considerations, the following recommendations have been made for the management of SSNHL.
If you suddenly experience hearing loss, what actions do the AAO-HNS guidelines suggest your doctor should take in the initial evaluation?
Review your medical history and conduct a physical examination to check for bilateral sudden hearing loss (SHL), recurrent episodes of Sudden Sensorineural Hearing Loss (SSNHL), or other unusual neurological findings. These might indicate a known cause for the sudden hearing loss that should be managed.
Refer you to an audiologist for a formal hearing test to confirm that you have SSNHL. The test should be conducted as soon as possible, and within 14 days from symptom onset. This test will clarify whether the hearing loss is sensorineural (SNHL) or conductive (CHL) and will also determine if the hearing loss is occurring in one or both ears.
Routine lab tests and a computed tomography (CT) scan of the head are usually not needed in the initial evaluation, as they won’t provide the necessary diagnostic information at this point.
Once SSNHL has been established what other steps should be taken in the management of SSNHL according to AAO-HNS guidelines?
Patients with SSNHL should get an MRI to check for rare problems in the hearing nerve or brain. One of these rare issues is a small, non-cancerous tumor called vestibular schwannoma (often referred to as acoustic neuroma), found in about 5% of cases. It's typically tiny and might only need a follow-up MRI, but it's essential to know if it's there.
According to the AAO-HNS guidelines, auditory brainstem response (ABR) testing may be considered as an alternative to MRI. However, its sensitivity may not match that of an MRI in all cases. Importantly, a brain CT is not a suitable replacement for an MRI in this context due to its insufficient sensitivity [4].
What do the AAO-HNS guidelines recommend for treating SSNHL?
Treatment recommendations for SSNHL are divided into three main periods - the first two weeks after onset of SSNHL, the subsequent four weeks, and the long-term management period.
Treatment during the first two weeks following onset of SSNHL
Primary treatment:
Within the first two weeks of symptoms, the primary treatment for SSNHL is corticosteroids. These can be administered systemically, in the form of oral pills or intravenous injections. Alternatively, steroids can be injected directly into the middle ear, a procedure known as intratympanic steroid administration or IT steroids, to manage SSNHL locally.
Combination treatment:
Hyperbaric oxygen therapy (HBOT) may be considered in combination with steroids, given some evidence supporting its efficacy [5].
Treatment approach and consideration:
Clinicians may offer systemic corticosteroids as initial therapy, but a 'wait and see' approach, refraining from immediate intervention, may also be deemed appropriate, based on individual patient circumstances and clinical judgment.
Treatment during weeks two to six following the onset of SSNHL
After the initial 2 weeks but before 6 weeks have passed since the onset of SSNHL, if recovery is unsatisfactory additional treatment options can be considered:
Intratympanic steroid therapy:
If recovery is not satisfactory after the initial 2 weeks but before 6 weeks from the onset of SSNHL, injecting steroids into the middle ear—a procedure known as 'intratympanic steroid therapy'—is recommended. This treatment is advised only for those who haven't previously undergone intratympanic steroid therapy.
Combined hyperbaric oxygen and steroid therapy:
After the initial 2 weeks, a combination of hyperbaric oxygen therapy (HBOT) and intratympanic steroid therapy can be considered. However, this is only an option if less than 4 weeks have elapsed since the SSNHL diagnosis and if the patient has not already received a course of systemic steroids.
Of note, intratympanic steroids can be given in 3 circumstances; as primary treatment (instead of oral steroids) for those presenting within 2 weeks of symptoms onset, as salvage treatment in patients who have not improved after systemic steroids; and as a treatment option in patients presenting late (2-6 weeks after symptoms onset).
Other treatments used in the past, such as antivirals, thrombolytics, vasodilators, or vasoactive medications, should not be routinely used to treat patients with SSNHL.
Follow-up and long-term management of SSNHL
Post-treatment audiometry:
Patients with SSNHL should undergo a follow-up formal hearing test (audiometry) at the end of their treatment and within 6 months afterward to assess the progress and the current state of their hearing.
Management of Residual Symptoms:
For those experiencing persistent hearing loss or tinnitus, a detailed explanation from a hearing health professional is crucial to understand the benefits available from hearing rehabilitation options and to manage ongoing symptoms effectively. Additionally, if vertigo accompanies the SSNHL, it is important that the vertigo be evaluated and treated according to the recommendations of your hearing health professional.
Treatment approach and consideration
Clinicians commonly treat all forms of sudden sensorineural hearing loss as they would SSNHL, even if it doesn't strictly match the classic definition. This approach stems from the severe impact of hearing loss and the potential benefits of available treatments.
Experiencing Sudden Sensorineural Hearing Loss (SSNHL) can be alarming and stressful, and it’s essential to address it promptly. This article summarizes the key steps for recognizing, managing, and treating SSNHL, following the trusted guidelines of the American Academy of Otolaryngology-Head and Neck Surgery Society (AAO-HNS) and peer-reviewed research. Getting a timely diagnosis and starting treatment early is key in the management of SSNHL. If you’re showing symptoms contact your healthcare provider.
References
[1] Chandrasekhar, Sujana S., Betty S. Tsai Do, Seth R. Schwartz, Laura J. Bontempo, Erynne A. Faucett, Sandra A. Finestone, Deena B. Hollingsworth et al. "Clinical practice guideline: sudden hearing loss (update)." Otolaryngology–Head and Neck Surgery 161, no. 1_suppl (2019): S1-S45.https://journals.sagepub.com/doi/full/10.1177/0194599819859885
[2] Alexander, Thomas H., and Jeffrey P. Harris. "Incidence of sudden sensorineural hearing loss." Otology & Neurotology 34, no. 9 (2013): 1586-1589. https://journals.lww.com/otology-neurotology/abstract/2013/12000/incidence_of_sudden_sensorineural_hearing_loss.8.aspx
[3] Attanasio, G., F. Y. Russo, E. Di Porto, L. Cagnoni, E. Masci, M. Ralli, A. Greco, and M. De Vincentiis. "Prediction of hearing recovery in sudden deafness treated with intratympanic steroids." Acta Otorhinolaryngologica Italica 38, no. 5 (2018): 453. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6265670/
[4] Wijn, Stan RW, Mayke A. Hentschel, Andy J. Beynon, Henricus PM Kunst, and Maroeska M. Rovers. "Auditory brainstem response prior to MRI compared to standalone MRI in the detection of vestibular schwannoma: A modelling study." Clinical Otolaryngology 47, no. 2 (2022): 295-303. https://onlinelibrary.wiley.com/doi/full/10.1111/coa.13894
[5] Joshua, Temitope G., Aysha Ayub, Printha Wijesinghe, and Desmond A. Nunez. "Hyperbaric oxygen therapy for patients with sudden sensorineural hearing loss: a systematic review and meta-analysis." JAMA Otolaryngology–Head & Neck Surgery 148, no. 1 (2022): 5-11. https://jamanetwork.com/journals/jamaotolaryngology/fullarticle/2785483
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