- Sudden sensorineural hearing loss (SSNHL) affects 5-20 per 100,000 population, with about 4000 new cases per year in the United States.
- Sudden hearing loss (SHL) is defined as the rapid onset of a subjective sensation of hearing impairment in one or both ears occurring over a
- Sensorineural hearing loss (SNHL) indicates an abnormality of the
cochlea, auditory nerve, or higher aspects of central auditory perception
- SNHL should be distinguished from conductive hearing loss (CHL) by
physical examination and tuning fork test, at the least.
- The most common cause of SHL is CHL from cerumen impaction, perforation or middle ear effusion.
- The patient with sudden hearing loss (SHL) may be very frightened. The nearly universal accompanying tinnitus seen in SSNHL will frequently contribute intensely to his or her anxiety and depression.
- 32%-65% of cases of SSNHL may recover spontaneously. However, in cases of unrecovered SSNHL, there is accompanying significant detriment in Quality of Life.
- Long-term follow-up is recommended because some patients will have an underlying cause identified that may not be evident at initial presentation.
- The distinction between SSNHL and other causes of SHL is one that should be made by the initial treating health care provider. (KAS 1) — by history, physical examination, and use of tuning fork tests (see Table 2)
- Nonidiopathic causes of SSNHL must be identified and addressed during the course of management. (KAS 2)
- Notable among these are vestibular schwannoma (acoustic neuroma) and stroke.
- Up to 90% of SSNHL, however, is idiopathic at presentation and is presumptively attributed to vascular, viral, or multiple etiologies.
- The most frequently used audiometric criterion is a decrease in hearing of ≥30 dB, affecting at least 3 consecutive frequencies.
- It is common clinical practice to treat patients with SSNHL that is of less severity than this definition according to the principles of the clinical practice guideline.
- Because premorbid audiometry is generally unavailable, hearing loss is defined as related to the opposite ear’s thresholds.
Table 1. Recommended Technique for Weber and Rinne Testing
- Place vibrating tuning fork (256 or 512 Hz) at midline of forehead or on maxillary teeth (not false teeth)
- Ask where the sound is heard. It is normal to hear at the midline or “everywhere”
- If the sound lateralizes to one ear then:
a. There is a CHL in that ear, OR
b. There is SNHL in the opposite ear
- Place vibrating tuning fork (256 or 512 Hz) over the mastoid bone of one ear, then move the tuning fork to the entrance of the ear canal (not touching the ear)
- The sound should be heard better via air conduction (at the entrance to the ear canal)
- If the sound is heard better by bone conduction, then there is a CHL in that ear
- Repeat for the other ear
Table 2. Modifying Factors: Checklist of Features Often Associated with Specific Disorders Underlying Hearing Loss
Note: Presence of any of these findings alerts the clinician to perform other types of targeted diagnostic tests. (KAS 2)
- Sudden onset of bilateral hearing loss
- Antecedent fluctuating hearing loss on one or both sides
- Isolated low-frequency hearing trough suggesting Ménière disease
- Concurrent onset of severe bilateral vestibular loss with oscillopsia
- Accompanying focal weakness, dysarthria, hemiataxia, encephalopathy, severe headaches, diplopia
- Downbeating or gaze-evoked nystagmus
- Brain imaging indicating stroke or structural lesion likely to explain the hearing loss
- Severe head trauma coincident with the hearing loss on one or both sides
- Recent acoustic trauma
- A history of concurrent or recent eye pain, redness, lacrimation, and photophobia
Table 3. Common Issues Raised by Individuals with SSNHL
- What are the risks of treatment?
- Will I ever get over the loss of a major sense organ?
- Are there any device options that can help me?
- How will I be able to manage with hearing in just one ear?
- Do I have to wear a hearing aid?
- Is there any surgery I can have to get my hearing back?
- Discuss benefits and risks of treatment options
- Address the emotional components of hearing loss.
- Introduce amplification and rehabilitation options
Discuss various treatment options and possible outcomes. (See Figure 1)
- Discuss support groups.
- Discuss types of hearing aids and contralateral
routing of signal (CROS and BiCROS) option if appropriate.
- Discuss surgical options if a candidate.
Table 4. Patient Education Discussion Points for Idiopathic Sudden Sensorineural Hearing Loss (ISSNHL)
- Routine head CT is NOT indicated in the management of isolated ISSNHL (KAS 3)
- Routine laboratory testing is NOT indicated in the management of isolated ISSNHL (KAS 5)
- Although treatment may be instituted before formal audiometric assessment, a hearing test should be obtained as quickly as possible to confirm the diagnosis and the degree and type of hearing loss. (KAS 4)
- The cause of SSNHL is often not readily apparent and thus is called idiopathic. It rarely affects both ears and can often be associated with other symptoms such as tinnitus, vertigo, and fullness in the ear.
- Approximately 1/3-2/3 of patients with ISSNHL may recover some percentage of their hearing within 2 weeks. Those who recover half of their hearing in the first 2 weeks have a better prognosis. Patients with minimal change within the first 2 weeks are unlikely to show significant spontaneous recovery.
- Early recognition of ISSNHL is important. Although there is a lack of evidence-based research, it is generally accepted that early intervention may increase recovery.
- Many treatments have been proposed for ISSNHL, but research about their efficacy may be limited. The benefits of therapy may include better recovery of hearing, but side effects also must be considered when choosing among the available options.
- Watchful waiting is an alternative to active treatment since between 1/3 and 2/3 of patients may recover hearing on their own and can be monitored with repeat hearing tests.
- Sudden hearing loss can be frightening and may result in embarrassment, frustration, anxiety, insecurity, loneliness, depression, and social isolation. Individual or group counseling can be helpful in supporting patients with ISSNHL.
- Audiologic rehabilitation needs to be addressed as soon as the hearing loss is identified. This includes counseling and discussion of nonsurgical and surgical amplification and hearing restoration options.
- Financial concerns should be addressed to ensure appropriate follow-up and testing.