Sudden Sensorineural Hearing
What is sudden sensorineural Scientists are focusing on two main
hearing loss? theories as to why sudden hearing loss
occurs in these unknown cases. The first
Sensorineural hearing loss may be either is that it may be of viral origin, as some
sensory (affecting the sense organ of viruses are known to damage the
hearing in the cochlea) or, less hearing, and a viral infection seems to
commonly, neural (affecting the nervous precede the hearing loss in some people.
pathways which connect the cochlea to The second theory is that it may be due
the hearing centres in the brain). to some vascular defect (relating to blood
Generally, sensorineural hearing loss is vessels), but there is no conclusive proof
described as sudden if you notice a drop at present to support either view.
in your hearing instantaneously or over a In the 15 per cent of cases where it is
short period not exceeding three days. possible to establish a firm cause of
You may notice a popping sound when it SSHL the cause may be due to the
happens, or you may detect it when you following:
first wake up or use the ear in a testing
situation, like making a phone call. Infections
Sudden sensorineural hearing loss Meningitis is one of the commonest
(SSHL) is considered a medical causes of severe or profound acquired
emergency and you will need to contact deafness in babies and children, though
your doctor immediately. It currently cases are falling due to the availability of
affects about 20 in every 100,000 people. vaccines. Hearing loss due to meningitis
As middle ear infection or accumulation of usually affects both ears (bilateral).
fluid behind the tympanic membrane Anybody who has suffered from
(eardrum) can also occur rapidly, causing meningitis, especially a child, should have
a temporary conductive hearing loss, and their hearing tested as soon as possible
these conditions are more common than after recovery.
SSHL, it is important to obtain a specialist Measles and mumps are also associated
examination with hearing tests, to with SSHL. In measles, the loss is usually
distinguish them from SSHL. moderate to profound and affects both
What causes sudden ears, whereas in mumps it usually affects
only one ear. The herpes zoster virus
sensorineural hearing loss? may, on rather rare occasions, cause
In 85 per cent of cases of sudden sudden hearing loss accompanied by
sensorineural hearing loss the cause is weakness of the facial muscles and
unknown. These cases are referred to as vertigo. This so-called Ramsay Hunt
idiopathic. In the majority, the hearing is syndrome may affect adults who have
affected in only one ear (unilateral) and been close to children with chicken pox,
may return to normal or near normal in 70 which is caused by the same virus.
per cent of cases. Some infections are confined to the ear
itself. Labyrinthitis is an inflammation of
the inner ear, caused by bacterial or viral against the risks to hearing, and these
infection, which can cause dizziness, issues should be discussed with a
tinnitus (noise heard in the ear or head specialist.
with no external source), and can lead to Barotrauma
sensorineural hearing loss, but usually
only in one ear. Bacterial labyrinthitis Barotrauma may occur when the ear is
often results in permanent hearing loss. exposed to sudden pressure changes,
possible when flying or diving.
One common cause of bacterial
labyrinthitis is an existing chronic middle Most commonly, the middle ear is
ear infection, often with cholesteatoma affected, causing a conductive hearing
(invasion of skin into the middle ear) loss. It is rarer for the inner ear to be
invading the cochlea. involved, but sensorineural hearing loss
can occur if the membrane of the round
Head injuries window (one of the two windows which
Head injuries, especially those associated separate fluid in the inner ear from air in
with a fractured skull, may produce the middle ear) ruptures, causing a
profound and often permanent hearing leakage of perilymph (one of the inner ear
loss. Even where there is no fracture, fluids).
sensorineural hearing loss may occur, Ototoxicity
caused by damage to the central nervous
system or the inner ear itself. Sudden sensorineural hearing loss is
sometimes attributed to ototoxic drugs
Noise (drugs that may damage the inner ear)
Hearing loss caused by exposure to loud however, the deafness related to
noise is usually gradual in onset and can ototoxicity is more often gradual than
be prevented by avoiding noisy situations sudden, and is often preceded by tinnitus.
or wearing appropriate ear protection. Drugs that are known to cause
However, sudden hearing loss may occur permanent hearing loss are usually given
from exposure to excessively loud noises, only when no other alternative exists for
for example from blast injuries (from a treating a life-threatening disease.
nearby explosion) or from firearms or
fireworks, especially in enclosed spaces. If the prescription of such a drug is
necessary, the potential effect on hearing
The degree of hearing loss can range should be explained by the patient’s
from total, permanent deafness in one or doctor and the hearing monitored
both ears to a relatively minor high regularly during treatment.
Where minor, hearing may recover
spontaneously in time. For more Ménière’s affects about one in every two
information about the effects of noise, see thousand adults in the UK. It is a disease
the Deafness Research UK factsheets on associated with later life, usually starting
this topic. between the ages of 30-50 years.
Ear surgery It is characterised by severe attacks of
vertigo combined with fluctuating
Sensorineural hearing loss may occur deafness, tinnitus and a feeling of
after any surgical procedure on the ear, pressure in the affected ear. Attacks often
and the degree of risk depends on many start without warning and can lead to loss
factors. These include the nature of the of confidence, anxiety and sometimes
procedure, the underlying disease and depression.
the skill of the surgeon.
The hearing loss may occur immediately,
in the few days following the operation, or Less common causes of sudden
even many years later. It is important to sensorineural hearing loss include an
balance the potential benefits of surgery acoustic neuroma, which is a benign
(non-malignant) tumour. The hearing loss may be prescribed and some weeks may
associated with acoustic neuroma is pass before a correct diagnosis is made.
usually gradual and often unnoticed, but If you can’t see your GP, and you have a
may be sudden in as many as 10% of severe sudden hearing loss, you should
cases. go to your nearest hospital accident and
Even rarer is the neurological condition of emergency department.
multiple sclerosis, in which ‘plaques’ of
the disease may affect parts of the How can sudden sensorineural
brainstem associated with hearing. The hearing loss be treated?
diagnosis of this condition is made by As with any medical condition, treatment
electrical tests of brainstem function and depends upon the cause, when the cause
a magnetic resonance imaging (MRI) is known. As the cause is not known in so
scan, and fortunately the hearing often many cases of Sudden Sensorineural
recovers spontaneously. Hearing Loss, the treatment strategies
Immunological disorders may vary, being dependent on the
doctor’s observation and experience.
Disorders affecting the immune system
may have a role in causing sudden Treatment strategies used can include
sensorineural hearing loss but the link is, steroids, vasodilation (treatment to relax
at best, uncertain. blood vessels), antiviral agents, diuretics
and low-salt diets. The most often used of
There is a certain amount of debate over these is high-dosage steroid therapy
the diagnosis of the condition known as either given orally or intravenously (into
Autoimmune Inner Ear Disease (AIED), the bloodstream). However, after a
its relationship with sudden deafness, and course of treatment between 30 and 50%
potential treatments, but it probably of patients show no response.
accounts for less than one per cent of all
cases of hearing loss. New research suggests that better results
are obtained if a course of intravenous
What should you do if you lose steroids is followed up by a course of
your hearing suddenly? intratympanic steroids (steroids
administered directly into the middle ear),
As a sudden hearing loss can return to
but further trials are required to establish
normal or near normal in some cases, it
a firm evidence base.
may be tempting to adopt a ‘wait-and-see’
policy. However, if you think you have a Some viral infections respond to anti-viral
sudden hearing loss in one or both ears, agents like acyclovir, and for the Ramsay
you should be seen by a specialist as Hunt syndrome, short-term treatment with
soon as possible because even where a steroids and acyclovir is justified if started
cause is unknown any treatment may be early enough, as it may lead to a reversal
more successful the earlier it is given. of the hearing loss to near-normal
You should go to your GP (family doctor)
and ask for an urgent referral to an ear, There is no evidence of cardiovascular
nose and throat (ENT) specialist. It is disease in the majority of patients
especially important to make your GP suffering from SSHL, but there are certain
aware that the hearing loss was sudden ‘vascular’ conditions which may
to ensure you receive prompt medical occasionally cause sudden deafness.
attention. These include reduced blood flow in the
Family doctors may not have the facilities cochlea and disorders of coagulation
to distinguish SSHL from the commoner (clotting) of the blood.
conductive, middle ear hearing loss, and Research is being carried out on the
if an incorrect assumption is made that potential value of carbogen inhalation in
the deafness is caused by a fluid build up such cases, carbogen being a mixture of
or a middle ear infection; decongestants 95% oxygen and 5% carbon dioxide.
Sudden sensorineural hearing Coping with sudden
loss with a known cause sensorineural hearing loss
In many cases of Sudden Sensorineural When a hearing loss occurs suddenly, the
Hearing Loss, there is no effective shock and sense of loss can be
treatment for the hearing loss itself, but overwhelming.
further loss may be reduced and If you experience a sudden hearing loss,
occasionally hearing may even be you may go through a range of emotions
restored by preventive measures. For including denial, hope (for a cure or
example, the adverse effects of drugs improvement), anger, isolation,
that can cause hearing loss may be acceptance, embarrassment and resolve.
halted and to some extent reversed if the
patient stops taking that particular drug Other people may react to your hearing
(in consultation with a medical adviser) loss by feeling awkward, embarrassed or
and replaces it with a different agent. unsympathetic. You may feel
embarrassed about it yourself. It is
Similarly, the risk of noise-induced important to be open and honest with the
hearing loss can be greatly reduced by people around you, and explain what you
appropriate ear defenders, and the use of want them to do.
helmets in certain sports and by motor
cyclists undoubtedly reduces the risk of With time, and with the right sort of
deafness in skull fractures due to head professional support, as well as the
injuries. support of your friends and family, you
should find that you become more skilled
Finally, timely surgery for the ‘dangerous’ at being aware of your environment and
type of middle ear infection will prevent communicating. As your skills grow you
what is called suppurative labyrinthitis, will feel more in control and you might
which occurs if the infection spreads to find that you are able to adapt your
the inner ear. leisure interests, social life and hobbies to
When a perilymph leak (a leak of one of your hearing loss.
the inner ear fluids) is suspected, bed rest There are many sources of information
is advised for up to five days. If there is and advice available to help adjust if it
no improvement in the hearing after that seems that the hearing loss is permanent.
period, surgical exploration of the ear is This includes guidance on equipment and
needed, with repair of the leak when devices available, and implications for
possible. employment and benefits.
In cases of Ménière’s Disease, most A wide range of services and support,
forms of medical treatment are aimed at including rehabilitation courses can also
controlling the crippling attacks of vertigo, be accessed. Hearing Therapists and
while preserving the hearing if at all lipreading classes can be valuable
possible. In severe cases, if attacks sources of support. Details of relevant
persist despite medication, a consultant organisations to contact are given below.
may advise surgery.
A number of different operations have Coping with permanent hearing
been devised, some to reduce pressure loss
in the inner ear, others to diminish or Hearing Aids
abolish the abnormal impulses passing
from ear to brain. For more information When treatment is impossible or
about Ménière’s Disease, see the ineffective, most patients whose hearing
Deafness Research UK factsheet on this loss is diagnosed as permanent can be
topic. helped by a hearing aid or aids and/or by
other assistive devices. Hearing aids are
available free of charge through the NHS
and to receive one, patients are generally
referred within their local hospital to an Assistive Devices
audiologist. Even when a hearing loss is relatively
The type of hearing aid prescribed will mild, people with sudden sensorineural
depend on the severity of the hearing hearing loss often have difficulty hearing
loss, the frequencies affected and high frequency sounds such as
whether one or both ears are affected. On telephones, doorbells and alarm clocks,
the NHS, the main type of hearing aid is but may find it unnecessary to wear a
worn behind the ear. hearing aid all the time.
For people with one-sided deafness there To help, there is a wide range of special
is a particular type of hearing aid known equipment available, such as amplified
as a CROS (Contralateral Routing of doorbells, vibrating alert systems, loop
Signals) aid which can be of benefit in systems and headphones. Social
certain situations where the microphone services may help to pay for, or provide,
is located on the side of the worse ear equipment. For more information contact
and the signal from it is fed to the better your local social services department.
ear. The Government’s Access to Work
There is also a BICROS aid in which the scheme may help to pay for equipment
better ear receives an additional signal you need for work or for job interviews.
from a second microphone placed on the There are also a number of suppliers
better-hearing side. These systems can from whom you can purchase equipment.
mean that users are able to hear sounds
directed to the impaired ear more easily, See contact details below.
without turning the better ear towards the Lipreading
sound, and they also provide extra cues
for locating the direction of sound In combination with an efficient hearing
sources. aid, lipreading plays an important part in
helping people with acquired hearing loss
Another hearing aid suitable for single to communicate better and regain
sided sensorineural hearing loss is a confidence.
bone anchored hearing aid (BAHA),
which transfers sound through bone Learning to lipread is challenging, but it is
conduction. It works by stimulating the worth persevering, as the improvement in
cochlea of the normally hearing ear giving communication can be significant.
users the sensation of hearing sounds Lipreading classes can also be very good
from the deaf side. places to meet other people who have
An operation is required which takes had similar experiences. Lipreading
approximately thirty minutes to insert a classes are usually offered at local adult
small titanium implant into the mastoid education centres and/or colleges.
bone behind the ear. The site is then left If you have difficulty finding a class,
for three months allowing the implant to contact the Association of Teachers of
fuse with the skull bone in a process Lipreading to Adults (ATLA) whose
known as osseointegration before the address is given below.
hearing aid (a small rectangular box) can
be attached and easily removed for Hearing Therapy
sleeping and bathing. A qualified Hearing Therapist can play a
There are a number of hospitals in the UK vital role in helping someone with an
where the BAHA procedure is currently acquired hearing loss. They use a variety
performed and where a person would of methods to work out an individual
need to be referred for assessments. Part programme for each patient to assist
of the assessment involves a trial of the them in managing their hearing loss,
device on a headband which can give a improving their communication skills and
good idea of whether this type of aid will enabling them to participate fully in their
daily activities. Hearing Therapists can
• help with hearing aids;
• auditory training (working with the
• counselling both for the deafened
person and their family
• advice about environmental aids;
• lipreading instruction; and
• tinnitus management.
Some Hearing Therapists may also
specialise in cochlear implants, helping
with balance problems or working with
patients with learning disabilities or dual
Although not all NHS Trusts employ
Hearing Therapists, most are situated in
either the Audiology or Ear, Nose and
Throat departments of hospitals.
The cochlear implant is one of the major
scientific triumphs of the last few
decades. They are increasingly being
used to help adults with acquired total or
profound hearing loss in both ears, as
well as in children born profoundly deaf or
acquiring deafness before the
development of speech.
They work by electrically stimulating the
auditory nerve (nerve of hearing) to give
the user a sense of sound, and, in the
case of a child born profoundly deaf, the
potential to understand speech and to
learn to speak.
Although cochlear implants are available
through the NHS, rigorous assessment is
undertaken to ensure that each recipient
meets certain referral criteria. These
criteria change over time and may vary
between cochlear implant centres.