Sudden hearing loss

Sudden Idiopathic Hearing Loss Molly Simpson and Beth Burlage

Definition - Distinction needed 

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Idiopathic Hearing Loss(ISSHL)- Perceptive hearing loss, etiology remains unknown after clinical, laboratory and imaging studies, hearing loss occurred within 24 hours, hearing loss is nonfluctuating, severity of the hearing loss averages at least 30 dB HL for three subsequent one octave steps in frequency, blank otological history in an otherwise healthy individual Sudden Hearing Loss (SSHL) - a sensorineural hearing loss of 30 dB over less than three days affecting three contiguous frequencies, symptom of a greater condition

Symptoms 

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Unilateral (only 2% of cases experience bilateral deafness) Roaring tinnitus Short- lived dysequilibrium/vertigo

Audiometry Examples 

Possible Slopes of HL 

Low Frequency

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Low through Mid-High Frequency

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High Frequency - downward sloping loss has a worse prognosis than low and midfrequency loss

Causes  

The term “idiopathic” indicates an unknown origin Research suggests SSHL etiology as:        

Compromised Vascular Supply Intracochlear Membrane Breaks, Perilymph Fistula Neurologic lesions Viral Infections Traumatic insults Autoimmune Inner Ear Disease Enlarged Vestibular Acqueduct Syndrome Syphillis

Diagnosis 

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ISSHL can often be mistakenly diagnosed as a middle ear disorder Testing will reveal       

Normal Tympanometry; Abnormal Reflexes Tuning fork tests will indicate a sensorineural loss OAE/ABR abnormal Audiometry will usually show a unilateral loss CT Scan/MRI needed to rule out neuroma Negative fistula test Urinalysis, blood work

Treatment 

Depends on identification of lesion 

Vascular  Hyperbaric oxygen therapy (HBOT) involves breathing pure oxygen in a specially designed chamber and it is sometimes used as a treatment to increase the supply of oxygen to the ear and brain in an attempt to reduce the severity of hearing loss  Carbogen treatment: 95% oxygen and 5% carbon dioxide. Carbogen inhalation therapy is given for about 10 minutes each 6–8 hours over a three-day period by a respiratory therapist. This treatment is thought to increase the oxygen in the perilymph by dilating the cochlear artery 

These treatment routes may not be covered by insurances

Treatment, cont. 

Structural defects may require surgical treatment  

Fistulas Acoustic neuromas

Treatment, cont.  

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If no site of lesion is found, aggressive steroid treatment is usually prescribed Prednisone: 1mg/kg per day for 2–4 weeks, rapidly tapering the drug if there is a complete recovery of hearing. If hearing does not recover, reduction of medication is slowed. The best outcome: when steroids are administered as quickly as possible Some may benefit from antivirals, diuretics, a lowsodium diet, a restriction in the use of stimulants, (alcohol and tobacco) and avoidance of excessive physical activity and noise exposure.

Treatment, cont. 

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35-50% of people have hearing return to normal levels If the hearing does not return, hearing aids, cochlear implants or assistive listening devices may be prescribed ASHA recommends a multi-memory, digitally programmable hearing aid, or with a volume wheel for flexibility.

Prevention 

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Most studies find no seasonal, geographic, ethnic, racial or sexual predilection for SHL. The right and left ears appear equally vulnerable. It affects about 4,000, usually between 40-60 years old

Our Role 

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Test to rule out middle ear pathology and confirm sensorineural lesion Understand the emotional aspect to this type of hearing loss and need for counseling Three step approach: administrative, medical, rehabilitative

Clincial Example 

46-year-old female

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Sudden onset of unilateral tinnitus and decreased hearing while at work

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Awoke in the morning to limited hearing in left ear

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MRI indicated no structural anomalies

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Audiometry = Profound loss across all frequencies tested

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Diagnosed as an idiopathic viral infection, treated with steroids

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Currently, hearing has not improved

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Complains of inability to localize Habit of answering the phone with poor ear Discussed possibilities for ALD’s for phone use and CROS hearing aids

Any other suggestions?

References 

Menner, A. (2003) A pocket guide to the ear. New York: Thieme.

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Vause, N. (2002) Idiopathic Sudden Sensorineural Hearing Loss—On the Other Side of the Audiometer. Military Audiology Short Course. http://www.militaryaudiology.org/masc2002/07_ISSHL.html. Retrieved April 15, 2008.

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Wynne, M., Diefendorf, A., Fritsch, M. (2001) Sudden Hearing Loss. The ASHA Leader Online, http://www.asha.org/about/publications/leader-online/archives/2001/. Retrieved April 20, 2008.

Autoimmune Disorders Molly Simpson and Beth Burlage

Autoimmune disorder 

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“An autoimmune disorder is a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue” Medline Plus Women are more commonly affected than men Autoimmune disorders can cause   

Destruction of different body tissues Changes in organ function Abnormal growth of an organ

Autoimmune Inner Ear Disease (AIED) 

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Syndrome with progressive, fluctuating bilateral sensorineural hearing loss, dizziness and sometimes tinnitus which progresses over weeks to months First proposed in 1979 Can be confused with Meniere’s Disease Responsible for a very small number of hearing impairment cases (< 1%) Most common in middle-aged women

Causes of AIED 

Caused by antibodies or immune cells that damage the inner ear 

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Bystander damage= inner ear damage causes cytokines to be released which create further immune reactions after a delay (fluctuating symptoms) Cross- reactions*= antibodies or T-cells accidentally damage the inner ear if the ear shares common antigens with a harmful substance the body is already trying to fight off (COCH5B2) Intolerance= the body may not know all of the antigens in the inner ear. When they are released (after surgery, trauma or infection), the body attacks them (partially immune privileged locus) Genetics= some people are genetically pre-disposed to immune disorders

* This is the currently favored theory

Diagnosis of AIED       

Audiological Evaluation Vestibular Testing ABR (to rule out AN) ECochG (to rule out Meniere’s) Responsiveness to steroids Blood tests for general autoimmune disorders Blood tests for inner ear disorders  

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Anti-cochlear antibodies (HSP70) Lymphocyte transformation assay

Blood tests for diseases/problems that mimic AIED   

FTA (syphilis infection) Lyme disease Diabetes

Treatment of AIED Corticosteroids (managed by a Rheumatologist) 

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Prolonged usage is shown to have serious negative side effects Broughton, Meyerhoff and Cohen, 2004 Dosage is often tapered to the lowest one that prevents fluctuations in hearing Broughton et.al

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Benefit is not found in all patients and high dosages may be needed occasionally as a “booster”

Treatment continued… 

Cytotoxic Agents (chemotherapy-type medications) 

Methotrexate 

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Highly toxic and studies show limited benefit

Cochlear Implants 

For individuals who do not respond to medical treatment and profound hearing loss is permanent

Take home message… 

“AIED is one of the few reversible causes of sensorineural hearing loss” Gopen, Keithley and Harris, 2006

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Early diagnosis and treatment are crucial to reversal or progression!

References 

Mathews, J., Kumar, B.N. (2003), Autoimmune sensorineural hearing loss, Clinical Otolaryngology, 28:479-488.

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Broughton, S.S., Meyerhoff, W.E., Cohen, S.B. (2004), Immunemediated inner ear disease: 10-year experience, Seminars in Arthritis and Rheumatism, 34:544-548

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Gopen, Q., Keithley, E.M., Harris, J.P. (2006), Mechanisms underlying autoimmune inner ear disease, Drug Discovery Today: Disease Mechanisms, 3(1):137-142.

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Vestibular Disorders Association  http://www.vestibular.org/vestibular-disorders/specificdisorders/autoimmunity.php

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American Hearing Research Foundation  http://www.americanhearing.org/disorders/autoimmune/autoimmune.html