Download How should we treat Idiopathic Sudden Sensorineural Hearing Loss?

HOW SHOULD WE TREAT IDIOPATHIC
SUDDEN SENSORINEURAL HEARING
LOSS?
Aims of our project:
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To explore and identify the main pathophysiologies of Sudden Sensorineural Hearing
Loss (SSNHL).
To investigate hypotheses for the proposed cause of Idiopathic Sudden Sensorineural
Hearing Loss.
To assess the evidence for the benefit of using steroids, both oral and intratympanic, to
treat Idiopathic SSNHL.
To determine if the method of administration of steroids has an effect upon their efficacy.
To identify the risks of steroid administration in treating Idiopathic SSNHL.
To determine the efficacy of alternative treatments to steroid therapy for Idiopathic
SSNHL.
To assess the evidence for therapies using steroids in combination with a non-steroidal
therapy for the treatment of Idiopathic SSNHL.
To explore the existing research surrounding stem cell therapy in order to restore the
function of Hair cells and neurones.
To highlight areas for future research in stem cell therapy to treat Idiopathic SSNHL.
To explore the use of hearing aids in those with SSNHL.
To identify the factors which may cause a reduced Quality of Life in those with SSNHL.
The importance of the aims are discussed in the introduction and evaluated throughout.
This site was made by a group (see Contributions page) of University of Edinburgh medical
students who studied this subject over 10 weeks as part of the SSC (SSC Web Pages).
This website has not been peer reviewed.
We certify that this website is our own work and that we have authorisation to use all the
content (e.g. figures / images) used in this website.
We would like to thank Mr. Alex Bennett for his guidance throughout this project.
Total word count: 8707
Word count minus Contributions page, References page, Information Search Report and
Word Version
appendix: 5983
Header Photo
Picture of outer ear anatomy and cochlea
Taken from: http://commons.wikimedia.org/wiki/File:Cochleaimplantat.jpg
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INTRODUCTION
Sudden sensorineural hearing loss (SSNHL) is described as hearing loss of 30dB or greater
over at least three contiguous audiometric frequencies occurring within a 3 day period.1
Surveys have placed the incidence of SSNHL at around 5 to 20 per 100,000 per year,2
although a study completed in Germany found it to be as high as 160 per 100,000 per year.3
In the USA, 4,000 new people are diagnosed with SSNHL annually2 and there are over
15,000 new cases worldwide. The aetiology of SSNHL is poorly understood, and extensive
testing may be required to determine the cause, which can range from virulent agents to
vascular complications.2 This causes difficulties with treatment and management, as without
an obvious cause a specific treatment is unavailable,2 with 55-93% of cases being idiopathic
in nature.4 There are a myriad of currently used treatments, such as corticosteroids,2 but the
efficacy of these treatments for idiopathic SSNHL is still vague. Research is currently being
undertaken to evaluate the viability of stem cells in the treatment of SSNHL, to replace
damaged hair cells and their nervous connections.5 The lack of understanding about the
varying success of treatments and causative agent in idiopathic SSNHL can be extremely
frustrating for the patient. After many tests a distinct diagnosis may still be unavailable.6 The
condition itself can significantly decrease the patient’s quality of life.7 Conversation often
becomes difficult and symptoms such as disorientation can even be dangerous. Dizziness and
tinnitus often accompany SSNHL, adding to the distressing list of symptoms.7 This can have
a tremendous physical and psychological effect. Our SSC2B project aims to review the
current literature around the treatment of idiopathic SSNHL.
Whilst completing our literature review, we were aware of the usefulness of each study
depending on the level of evidence. In order to complete our literature review we tried to
limit our sources to mainly RCTs, using other study types in order to gain a more
comprehensive analysis of idiopathic SSNHL and the scope of results of existing research.
These levels of evidence are8:
1a: Systematic review of randomised, controlled trials
1b: Individual Randomised Control trials
2a: Systematic review of cohort studies
2b: Individual cohort study
3a: Systematic review of case-control studies
3b: Individual case-control study
4: Poor quality cohort and case-control studies
5: Expert opinion without critical appraisal
We used CONSORT guidelines when assessing studies using a randomised control trial.9
These guidelines allowed us to assess how transparent the reporting of studies was and
therefore determine whether there was bias within the paper, which may have affected the
validity of results. Some more recent randomised control trials had indicated that they had
used the CONSORT guidelines.
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PATHOPHYSIOLOGY OF IDIOPATHIC
SSNHL
There are several different causes of SSNHL with different pathophysiologies. In our
research we have been focusing on the idiopathic causes of SSNHL, which make up the
majority.1 That is to say that the cause of the patient’s SSNHL is unknown. However, there
are several hypotheses to suggest what the causes are – the most widely accepted of which is
that they are similar to that of the known causes. Identifiable causes for SSNHL are only
found in 7-45% of cases.2
Chau et al1 performed a meta-analysis of 23 studies on SSNHL. This is a paper of the highest
evidence level (level 1) and so is a reliable source of information. They found that the most
frequent causes were: infectious (13%), otologic (5%), traumatic (4%), vascular (3%),
neoplastic (2%), and other (2%). Many hypotheses for the idiopathic diagnoses have been
proposed such as vascular compromise,3 cochlear membrane rupture5 and viral infection2 but
these have yet to be confirmed.
Taken from:
http://commons.wikimedia.org/wiki/Category:Anatomy_of_the_human_ears?uselang=engb#/media/File:Blausen_0328_EarAnatomy.png
The vascular pathologies that can cause SSNHL include emboli, transient ischaemic attacks,
anaemia, macroglobulinemia and subdural hematoma.5 The mechanism by which they cause
SSNHL is related to hypoxia of the cells of the cochlea. The cochlea is known to be sensitive
to even brief hypoxic episodes as it is supplied by only two small terminal arteries – the main
cochlear artery and the cochlear ramus. Thus, these pathologies can cause transient or
permanent hearing loss by damaging the structures of the cochlea.
Trauma to the inner ear can also cause SSNHL. The delicate membranes of the inner ear,
especially Reissner’s membrane, can tear or rupture during strenuous activity or raised
intracranial pressure leading to SSNHL.6
Infections are the most common known pathologies of SSNHL. Lyme disease and syphilis
are the most frequent bacterial infections.1 Other viruses that have been found to cause
SSNHL include herpes simplex, varicella zoster, enteroviruses and influenza.1 The most
common viral cause of SSNHL is the mumps virus.7 These infectious agents cause
inflammation and/or damage to the cells of the cochlea, particularly the organ of corti, and so
cause transient or permanent hearing damage.
Doctors will often perform investigations to determine the underlying cause of their patient’s
SSNHL. Blood tests are performed to ascertain the infectious agent that is believed to have
caused it.8 An appropriate treatment plan can then be enforced. MRI imaging can be used to
investigate if trauma, neoplasm or vascular problems are thought to be the cause of the
patient’s symptoms.8 A vestibular assessment can be used to predict the prognosis for hearing
recovery.9
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STEROIDAL TREATMENT FOR
IDIOPATHIC SSNHL
Sudden sensorineural hearing loss (SSNHL) is a serious otological emergency which can
have a major impact upon a patient’s quality of life. It is important that the best treatment is
given to patients with SSNHL as quickly as possible, to ensure the best outcome. The use of
steroids as a treatment for idiopathic SSNHL (ISSNHL) is widely debated. This section will
explore the evidence for the use of this medication, examining whether the method of
administration – oral or intratympanic (injection directly into the middle ear) – has an effect
upon on outcome. The side effects of steroid treatment will also be evaluated.
Steroid medication can reduce inflammation and oedema which may be the cause of
ISSNHL.1 As previously discussed, causes of ISSNHL include damage to cochlear
membranes and infectious agents. Many of these underlying causes result in inflammation
which can possibly be controlled by using steroid medication, restoring hearing.
There is a lot of evidence for the use of oral steroids as initial treatment for ISSNHL,
however, it is conflicting. A Cochrane Collaboration review2(2013) looked at a number of
papers on the use of steroids for ISSNHL, but only included 3 in the final report.3-5 Other
sources listed these 3 papers as the best evidence available as they are randomised controlled
trials.6 Of these three papers, two showed no significant effect of oral steroids and the other
trial did. However, the Cochrane report emphasised that all three of these papers were at high
risk of bias and all had different sample sizes – the Cinnamon 2001 paper had a total of 43
participants, whereas Wilson 1980 had 123 – meaning the studies may be of varying
reliability. The sample sizes are also fairly low, decreasing the reliability of the results,
meaning they may not be applicable to the general population.
Oral methylprednisolone tablets, one of the major oral steroids used
Taken from: http://commons.wikimedia.org/wiki/File:Sandoz.Methylprednisolone.4mg.jpg
Meta-analysis of two leading studies3,4 which examined the impact of oral steroids and a
placebo in the treatment of ISSNHL found that there was no statistical difference between the
treatment outcomes.7 Data was collected from 88 patients – whilst this is not considered to be
a large sample size, it is reflective of the low incidence of this idiopathic condition. This may
have impacted the results of the analysis by introducing bias.7 The findings suggest that
steroids are of limited use, contrary to them being considered the gold standard treatment, and
raises the question of whether there is a requirement to reevaluate best treatment guidelines.
There have also been several retrospective trials conducted on this topic. These are less
useful, as they cannot prove a direct causal link between the use of steroids and recovery, but
still may be useful in assessing the effectiveness of treatment. Chen CY et al carried out such
a study in Taiwan,8 analysing hospital records of 318 patients with SSNHL. A strength of
this study was the allocation of patients into those with severe hearing loss and mild hearing
loss. For those with severe hearing loss, recovery was better when steroids were used, but in
mild cases there was no difference between steroidal treatment and non-steroidal
treatment. Another limitation of this trial is that there is a much smaller number of controls
than cases (52:266) and lack of randomisation.
Oral v Intratympanic Steroidal Treatment
Intratympanic steroidal treatment has been a contentious issue, particularly in comparison to
oral treatment and regarding the potential improved alleviation of ISSNHL symptoms .
Recently it has been suggested as a potential replacement for oral systemic steroids and is
therefore an important avenue to discuss.9 A systematic review found that intratympanic
steroids utilised as primary treatment of ISSNHL were equivalent in effectiveness to oral
prednisolone therapy.10 A level 1 evidence article evaluating intratympanic treatment found
that groups of patients who were treated had an improved outcome in comparison to the
control group only treated with oral steroids. Compared with the findings of studies in all
other levels, it is impossible to form a definitive evaluation, however, all the evidence is
suggestive that intratympanic steroids are at minimum equivalent to that of oral steroids.10
There are limitations attributed to the findings of this review, due to the lack of high quality
literature surrounding this topic.
Intratympanic Steroids
As oral steroids are the first line treatment for ISSNHL, the studies evaluating their use focus
mainly on them as the initial therapy used. However, intratympanic steroids can be used in 2
different ways: either as the initial treatment or as salvage therapy after the initial treatment
(usually a course of oral steroids) has failed.
Intratympanic steroids: initial treatment
Research by Battaglia et al conducted a double-blinded, randomised controlled trial that was
one of very few studies which found that there was indeed a benefit of treatment with both
intratympanic and systemic in comparison to systemic alone.11 The study included 51 patients
who were randomised into three separate groups: treated with intratympanic steroids only;
treated with oral steroids only and combination of the two.11 Whilst there was a distinct
improvement in the outcome in the combination group, it has been argued that the validity of
this trial must be questioned due to their questionable methods of statistical analysis.8
Other studies have also found benefit in using a combination of intratympanic and oral
steroids when compared to using oral steroids alone, but these are limited by both design and
features. Papers by Battista et al12 and Kakehata et al13 both found that using combination
therapy to be of benefit, but neither are randomised controlled trials and so are of minimal
benefit. They also had small sample sizes and the study by Kakehata et al was only on
patients with diabetes, meaning the results of these trials cannot be extrapolated to the general
population.
Excluding the Battaglia trial, and other papers which are of limited use, we are left with
studies which have found that there has been limited impact by intratympanic steroids in the
initial treatment of ISSNHL.8 It has been noted that there is difficulty in comparison of trials
regarding treatment options of ISSNHL due to the considerable variation between each study
that has been conducted.12 Of the steroids used, dexamethasone and methylprednisolone were
the most frequently utilised. This means that there is an assumption that there is no significant
statistical difference between the two of them.12 There remains considerable questions over
what the best treatment schedule would be, in terms of dosage and length.12
Dexamethosone ready for injection
Taken from: http://commons.wikimedia.org/wiki/Category:Dexamethasone?uselang=engb#/media/File:Dexamethasone_phosphate_for_injection.jpg
Intratympanic steroids: salvage treatment
A recent meta-analysis evaluated all randomised controlled trials looking at intratympanic
steroids as salvage treatment and found that those treated using this method showed a
significantly better outcome than the control groups. 5 randomised controlled trials were
included in this paper, resulting in a large sample size which improves the reliability of
results. This analysis also looked at the best method of administration and which steroid to
use. Injection was found to be superior to use of a catheter to administer. Dexamethasone was
found to be a better treatment than methylprednisolone when used intratympanically, with
patients treated with dexamethasone more likely to report positive results. The paper also
noted that intratympanic steroids were all administered within one month and emphasised
that all of the studies used a similar dosage regimen and also the same practicalities for
treatment – for example it was noticed that all patients were told not to swallow immediately
after the injection. This paper is useful in not only showing efficacy of intratympanic steroids
as a salvage treatment, but also forming the basis for future treatment guidelines based on
those used in the trials it analysed.14
Another study – a double blind randomised controlled trial – found that using intratympanic
steroids after failure of initial therapy was of minimal benefit in regaining hearing function.15
Patients were selected who had experienced no change in their condition after administration
of oral steroids and were split into a treatment group and a placebo group. The treatment
group showed greater hearing recovery when compared to the placebo group, but not by a
great margin. Other studies conducted have reported benefit in using intratympanic steroids
as a salvage treatment,12 but again these trials are limited by factors, such as a low sample
size, which mean they are of limited use when evaluating treatment.
Advocates of intratympanic treatment argue that the primary benefit of localised treatment
is the overall reduced systemic exposure in comparison to that of oral steroids. This means
that there is an anticipated reduction of adverse effects in comparison to that of oral
steroids. The value of this has to be taken into account as currently side effects resulting
from oral steroidal treatment are generally easily identified and well managed.4 Another
advantage of intratympanic treatment is the hypothesis that intratympanic steroidal treatment
may increase the concentration of medication within the cochlea, leading to an improvement
in the outcome of treatment. However, this has yet to be proven to have a beneficial impact
on outcome.8
Side Effects
Side effects associated with high dosage of oral steroids include glucose intolerance, immune
suppression, and osteoporosis as well as avascular necrosis of the femur head.16 Regarding
intratympanic steroids, side effects can include tinnitus, ear pain and dizziness, all of which
are minor effects14 but may also be symptoms of the underlying ISSNHL. The literature on
this is scarce, but a meta-analysis looked briefly at the one severe side effect of intratympanic
injection, which is tympanic membrane perforation. This was found to be uncommon, with 3
patients out of 203 developing it,14 and in all cases it was repaired successfully afterwards.
Side effects of oral steroid therapy can be severe
Taken from: http://commons.wikimedia.org/wiki/File:Osteoporosis_vertebrae.jpg
Should steroids be used to treat ISSNHL?
A number of factors have to be taken into consideration when determining what the best
treatment is in patients who have ISSNHL. This is limited by the lack of high quality
literature concerning the efficacy of steroidal treatment. The cost of intratympanic steroidal
injections are substantially more expensive than the oral alternative; this may have an impact
on treatment guidelines.12 There remains insufficient evidence to deter from the current first
line treatment of oral steroids unless this is contraindicated in conditions, such as
uncontrolled Type 1 diabetes.12 This may change when increased research is conducted,
which would be able to provide greater clarity concerning the overall benefit of steroidal
treatment. Currently, oral steroids should remain the first line treatment as some evidence
shows them to be effective,3 and intratympanic steroids can be used if oral steroids are
contraindicated. Combined oral and intratympanic treatment has not been shown to be
significantly more effective, and there is insufficient evidence to support the use of this
method. There is evidence to support the use of intratympanic steroids as a salvage treatment
when the first line treatment has failed, so this is a potential significant future use of
intratympanic steroids.
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ALTERNATIVE TREATMENTS FOR
IDIOPATHIC SSNHL
There are many alternative methods to sole steroidal use for the treatment of idiopathic
sudden sensorineural hearing loss (ISSNHL) to be considered. One such method is the use of
anti-viral drugs. A 2012 Cochrane Review1 into literature available for anti-viral drug use in
ISSNHL selected four randomised controlled trials that used a combination of steroids and
anti-viral therapy which met their specific criteria.2-5 Interestingly, none of these papers were
able to show a statistically significant positive impact of anti-viral therapy in the treatment of
ISSNHL. However, all authors alluded to the possible viral cause of ISSNHL, and they
reached some conclusions which could have implications with regards to clinical practice.
Stokroos et al proposed a two-phase treatment regimen for ISSNHL, whereby only the
patients who present in the very earliest of stages of ISSHNL are treated with the combined
therapy of steroids and anti-virals.2 Similarly, Uri et al noted that earlier treatment may result
in better prognosis,4 because the viral damage to the ear occurs within a short time span and
cannot be effectively treated thereafter, as also concluded by Tucci et al.3 The problem with
these hypotheses is that most patients do not present with symptoms of SSNHL early enough
for the combined therapy to produce its proposed effects. To properly ascertain the benefits
of anti-viral drug use in ISSNHL, further randomised controlled trials with larger patient
populations that have a standardised inclusion criteria, use of antivirals and outcome
measures are needed.
Another method of treatment recommended for use in ISSNHL is hyperbaric oxygen. The
pathology of ISSNHL explains the proposal of hyperbaric oxygen as a treatment method with
potential. It is understood that the high metabolism and poor vascularity of the cochlea
makes it particularly susceptible to hypoxia.6 Thus, hyperbaric oxygen is seen as a method of
improving this oxygen deficit, as well as reducing the effect of inflammation. A Cochrane
review7 looked into treatment with hyperbaric oxygen, analysing all available literature. 7
papers were deemed to have met criteria for inclusion in this review, incorporating data from
392 participants. Pooling of the relevant data found that for every 5 patients treated early with
hyperbaric oxygen, one patient would receive an improvement in hearing by 25%.7 However,
given the poor methodology of the respective trials, the variability of the entry criteria and
variable timing of patient outcomes, this result must be taken with a pinch of salt. One of the
papers included in the study8 concluded that additional hyperbaric oxygen therapy
significantly improves the outcome of ISSNHL over a range of frequencies. However, as
with many of the studies analysed, the sample size of 51 is rather small, and there was a
distinct lack of blinding or random allocation practices used.
A patient climbs out of a hyperbaric oxygen chamber
Taken from: http://commons.wikimedia.org/wiki/File:USMC-070509-M-9539H040.jpg?uselang=en-gb
Vasodilators, vasoactive substances and haemodilution techniques have also been indicated
in the treatment of idiopathic SSNHL. A meta-analysis of the randomised controlled trials
available for vasoactive substances and haemodilution techniques by Conlin and
Parnes9 found a total of five studies were. These looked into the use of substances such as
pentoxifylline, dextran, Ginkgo biloba and nifedipine. Not only did these studies fail to
produce statistically significant differences between treatment and control groups, the
treatment methods described varied widely, meaning that meta-analysis of the data wasn’t
possible.9 A Cochrane review10 looked into the effects of vasodilators and other vaso-active
substances in the treatment of ISSNHL. After assessing the validity of many randomised
controlled trials that used vasodilators for treatment and grading them for bias, the review
focussed on 3 trials that best satisfied selection criteria. 11-13 Ni and Zhao11 found that 76.92%
of patients on carbogen treatment combined with drug therapeutics (including
dexamethasone, vitamin B and dextran) had improved hearing, compared to 50% of patients
in the control group who received all but the carbogen treatment. This difference was
statistically significant; however, the small sample size of 52 significantly lowers the validity
of the results. This was also a problem in the other trials reviewed; Ogawa et al12 only found a
significant difference in improved hearing at the higher frequencies with use of
prostaglandins, whilst Poser and Hirche13 noticed a significant difference in treatment success
at only the lower frequencies when using natidrofuryl with dextran, as opposed to dextran
monotherapy. Due to the inconsistencies of each study, such as differing treatment types,
methods, control comparisons and definitions of hearing improvement, the results could not
be combined to provide sufficient evidence for the use of vasodilators in ISSNHL treatment.10
A further proposed treatment method for ISSNHL is rheopheresis; a technique which reduces
blood viscosity. A large randomised controlled trial of 240 patients14 compared the efficacy of
two rheopheresis treatments to the standard treatment of ISSNHL according to German
guidelines (either steroidal therapy or IV haemodilution techniques over a 10 day period).
Whilst none of the therapeutic methods met the primary outcome parameter of absolute
hearing recovery after 10 days, rheopheresis did result in an improved quality of life
score.14 These results are worth considering; however, the improved quality of life score for
rheopheresis most likely reflects its limited therapeutic course of two treatments, compared to
the 10 day regimen of steroids or haemodilution. As it does not significantly improve actual
hearing recovery compared to other treatment methods, and due to the limited
literature available, one cannot currently conclude that rheopheresis should be used as the
first line treatment of ISSNHL.
There are many different treatment methods that have been recommended for the treatment of
ISSNHL. None of these methods have shown statistically significant improvement in the
prognosis of ISSNHL, and so don’t warrant usage in a clinical setting. However, some
studies (such as the one looking at rheopheresis) have produced results which call for further
research to evaluate their efficacy. This research must be carried out in the correct way: large
sample sizes, clear treatment methods and clear outcome measures which allow for direct
comparison.
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THE POTENTIAL USE OF STEM CELL
THERAPY FOR IDIOPATHIC SSNHL
Inner ear stem cell research could radically change treatment of sensorineural hearing loss
(SNHL). The inner ear is a complex and delicate environment and there are many challenges
to overcome. This chapter aims to discuss existing studies of stem cell transplantation and
highlight areas that need future research.
The ideal treatment would be the activation of endogenous stem cells within the inner ear.
The majority of SSNHL is caused by damage to the hair cells in the organ of corti. Oshima
found that isolated chicken stromal cells can be directed to become hair cells using a
procedure that mimics early embryonic development.1 Importantly, some cells became
functional; however, only 0.36% developed as hoped.2 This shows that endogenous stem cells
could have the potential to improve hearing capabilities. However, birds have a permanent
population of stem cells that allows for recovery from repeated ototoxic insults, but recent
studies suggest that inner ear stem cells may be low or even absent in mature mammalian
cochlea.3 Despite this, there remains careful optimism that endogenous cells could be reverted
to stem cells, to allow regenerative capacity similar to avian cochlea. However, there are
many obstacles before that goal is realistic.
Despite the advantages that endogenous stem cells may offer, research has largely been
aimed at the more viable transplantation of exogenous stem cells, usually through injection
into the inner ear. This method has several advantages; one being that stem cells can be
biased toward hair cell fate prior to transplantation and injected into the targeted area.
Numerous labs have transplanted different forms of stem cells into the inner ear and the
results have been widely varied.4-6 Some studies have had positive results; injected olfactoryderived stem cells have significantly improved hearing thresholds in mice with sensorineural
hearing loss.
Scanning electron microscopy images
showing auditory sensory epithelia. Taken from:
http://commons.wikimedia.org/wiki/File:The_kinocilia_is_mislocalized_in_Tailchaser_hair_cells.png
?uselang=en-gb = kinocilia
Regardless of the varied results, our understanding of the genetic pathways has greatly
improved. It has been shown that the Atoh1 transcription factor is essential to formation of
hair cells from early sensory progenitor cells. A 2014 study has shown that the Atoh1 gene is
activated by the combination of Pax2 and Sox2.7 This demonstrates that our control over hair
cell fate is improving. Despite no changes in hearing threshold, guinea pigs treated with
ATOH1 gene therapy had significantly more cells with hair cell markers. Indeed,
understanding in this field is constantly improving, but this is yet to translate into reliable
results.
There are many challenges to ensuring that injected stem cells become functional and
improve hearing thresholds. In many studies, despite some transplanted cells differentiating
as hoped, the majority of the stem cells couldn’t be found after a couple of weeks.2 It is
unknown whether these cells die or leave the ear; recruitment to distant locations is a
suggested hypothesis. The fate and consequences of these missing stem cells needs to be
researched further.
Another challenge is that hair cells throughout the cochlea have different properties. Ensuring
that stem cells develop to have the correct cellular characteristics is a daunting challenge. The
consequences of having hair cells that have inappropriate traits is not known. Interestingly, in
birds regenerating hair cells develop with location specific cilia and make appropriate
connections with afferent neurons.8 Understanding these pathways and the role they could
play in mammals will hopefully make hair cell generation much more effective. In particular,
ensuring hair cells make functional connections with neurons will be a big progression.
Alternatively, stem cells may be used to regenerate spiral ganglion neurons. Indeed, neurons
have been successfully derived and have extended neurites towards hair cells.9 Despite
innervating the hair cells, no working neuronal circuits were formed. These neurones have to
establish connections between hair cells and specific target fields in the auditory brain stem to
function – this is difficult to achieve.
Understanding of the developmental pathways in the inner ear has increased significantly in
recent years; in particular, our understanding of hair cell formation has vastly improved.
However, knowledge gaps do exist, such as the understanding of downstream pathways that
regulate hair cell type and the mechanism that controls the hair cell variation throughout the
cochlea. Future research could focus on hair cell regeneration in birds – a trait which
mammals may have lost due to inhibitory signals, as is the case in other adult tissues.10 What
are these inhibitory signals and can they be manipulated safely? Will this allow more specific
control of stem cell differentiation? The recent progress in stem cell research has been
remarkable and suggests that the future is bright for the usage of stem cell therapy as a
treatment for those affected by SSNHL.
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SSNHL AND QUALITY OF LIFE
Aside from the physical effects of SSNHL, there can be significant mental and psychological
effects. There is a clear correlation between an elevated level of depression and a loss of
hearing, which is unsurprising1. Conversation can become considerably more difficult and
those affected by SSNHL may find it difficult to adjust to these changes.1,2 This can lead to
social isolation and a cycle of increased depression.
Woman with a Bone-anchored Hearing Aid. Taken from:
http://commons.wikimedia.org/wiki/File:Baha_user_sound_processor_behind_ear.PNG?uselang=en
-gb – baha
A lack of understanding of the treatment of idiopathic SSNHL can compile this, as without a
clear, effective treatment it can decrease the patient’s hope for a resolution to the hearing
loss. As hearing handicaps can develop, hearing aids are often used. The air-conduction
contralateral routing of sound (CROS) hearing aid improves speech perception and in the past
was the traditional response to a diminished hearing ability.3 However, these devices can
cause discomfort and there is a level of stigmatisation due to their unsightly appearance.
Alternatively, bone-anchored hearing aids (BAHA) are available. Patients have been found to
prefer BAHA over CROS hearing aids.4 A meta-analysis comparing the two different types
found that BAHA provided an advantage with speech discrimination in noise and subjective
auditory abilities.5 Therefore, it may be more appropriate to use BAHA instead of CROS
hearing aids.
Other symptoms of SSNHL, such as tinnitus, can also reduce quality of life.2 Two separate
studies examined the effect on the Quality of Life that SSNHL had in adults.1,2 Both found
that tinnitus was a very important marker for quality of life in those with SSNHL. This was
directly correlated with the length of time it persisted; the longer it went on for, the worse the
mood of the person was.2 Unfortunately, chronic tinnitus can often become lifelong.6 It is
therefore important to make sure that although the condition may be established, that it in
itself does not lead to a lifelong disability. Tinnitus is difficult to quantify and therefore,
similar to other sensations such as pain, has been found at times to have a mental component.
By providing appropriate psychiatric help it may be possible to alter the patient’s perception
of the tinnitus and subsequently reduce the overall disability.6
With SSNHL there is an accompanying risk of disability. Therefore measures, such as
hearing aids, should be taken in order to minimise the effect on the patient’s quality of life.
These dramatic changes which occur could create problems in a variety of situations, so a
multi-disciplinary team approach should be taken in order to produce a cohesive
rehabilitation. Although the loss of hearing and symptoms, such as tinnitus, may appear to
give rise to a strictly medical disability, it may have a mental component which can be treated
and improve the patient’s quality of life.
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CONCLUSION
The variety of treatments for idiopathic sudden sensorineural hearing loss (ISSNHL) stems
from a poor understanding of the pathophysiology. Antiviral treatment has been deemed to be
ineffective in idiopathic cases,1 whereas there have been some relatively promising results
concerning the use of hyperbaric oxygen and vasodilators in this same group of patients.2
Both treatments aim to increase the supply of oxygen to the cochlea and have statistically
improved hearing in some parameters, supporting the theory that there is a vascular nature to
some of the idiopathic SSNHL cases. The current first line treatment is administration of oral
steroids. When compared with the use of a placebo it was found to be no more effective.3
Without solid evidence that steroids do in fact make a difference, it does question whether
should be the gold-standard treatment. In combination with intratympanic administration of
steroids, there is no evidence to suggest that this is a more beneficial treatment than either
one alone.4 In all of these studies, there are similar problems which call into question the
validity of the results. Almost all of them have a very low sample size resulting in a poor
reflection of the population affected by ISSNHL, reducing the power of these studies. There
is also an inconsistent application of therapies and outcome measures.
The use of intratympanic injection of steroids after oral steroids have failed, as a salvage
method, has been shown to be effective.5 The larger sample used in this study means that the
subsequent results are more applicable to the population. This alone is not enough to justify
the usage of intratympanic administration of steroids over oral, but signifies that this is an
approach which should be further investigated.
Currently, the cost of intratympanic injection of steroids greatly exceeds that of oral steroids.6
Although cost should not be a barrier to receiving appropriate healthcare, there is insufficient
evidence to suggest that the more expensive option would be beneficial. A placebo-controlled
study would be an appropriate step to take in testing the efficacy of intratympanic steroids
alone.
As an alternative to treatments currently in use, exciting work is being done in the field of
stem cell research as a solution to SSNHL. Although early in development, there has been
evidence to show that hair cells can be regenerated to some extent, restoring hearing to a
degree.7 Further work in this area could revolutionise the treatment of SSNHL, although it is
important to be cautious about possible long term effects and viability of such a treatment.
Our chosen topic of ISSNHL has highlighted one difficulty which we may face within our
professional careers; that for some things we may not have the answer. It has emphasised to
our group how conflicting research in one area can be, and the importance of continuous
critical appraisal to allow for informed decision making. As this decision making is
evidence-based, it made discovering the conflicting evidence around oral steroid use in
ISSNHL – despite it being regularly a first line treatment – surprising.
With the dramatic and potentially life changing effect of ISSNHL it is important to remember
the condition has both physical and psychological effects. Despite the variety of medications,
a holistic approach should always be maintained; in those with ISSNHL restoring their
hearing is obviously the aim, but this should not compromise their quality of life which is of
paramount importance.
Oral steroids should remain the first line treatment as there is no evidence which suggests a
more effective treatment. Throughout this project we have found that a large proportion of
the studies into the treatment of ISSNHL lack the power to base definitive recommendations
on. The poorly understood pathology of the condition makes linking a cause to treatment
extraordinarily difficult. 65% of ISSNHL cases recover naturally8 which makes it difficult to
know if the treatment itself has actually had an effect; this figure could realistically be a lot
higher, as a natural recovery could occur whilst undergoing treatment. After a period of time,
if the oral steroids have no effect, it would be appropriate to try alternative methods, namely
intratympanic steroids, due to the evidence suggesting they would be an effective salvage
treatment.5
<–Previous
REFERENCES
Introduction
1. Schreiber BE, Agrup C, Haskard DO, Luxon LM. Sudden sensorineural hearing loss. The
Lancet. April 2010. Volume 375, Issue 9721. 1203-1211. (Review)
2. Stachler RJ et al. Clinical Practice Guideline Sudden Hearing Loss. Otolaryngology–Head
and Neck Surgery. 2012. 146(3 suppl), S1-S35. (Primary research article)
3. Klemm E, Deutscher A, Mösges R. A present investigation of the epidemiology in
idiopathic sudden sensorineural hearing loss. Laryngorhinootologie 2009. 88, pp. 524–
527. (Primary research article)
4. Byl FM, Jr. Sudden hearing loss: Eight years’ experience and suggested prognostic table.
Laryngoscope. 1984. 94(5 Pt 1), 647-661. (Primary research article)
5. Matsumoto M, Nakagawa T, Kojima K, Sakamoto T, Fujiyama F, Ito J. Potential of
embryonic stem cell-derived neurons for synapse formation with auditory hair cells.
Journal of Neuroscience Research. 2008. 86(14), 3075-3085. (Primary research article)
6. Hart CK, Sami RN. Sudden Sensorineural Hearing Loss. In: Editors: Pensak, Myles L.
Otolaryngology Cases. New York: Thieme, 2010. (Book)
7. Carlsson P et al. Quality Of Life, Psychosocial Consequences, and Audiological
Rehabilitation After Sudden Sensorineural Hearing Loss. International Journal of
Audiology. 2011. 50.2:39-144. (Primary research article)
8. Phillips R, Ball C, Sackett D, Badenoch D, Straus S, Haynes B, Dawes M. ‘Oxford Centre
For Evidence-Based Medicine – Levels Of Evidence’. Centre for Evidence Based
Medicine. March 2009. [cited 12/03/2015] Available from :
URL: http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidencemarch-2009/

Useful website that provided comprehensive information on the importance of ranking
studies and helped us critically appraise papers
9. Schulz KF, Altman DG, Moher D, for the CONSORT Group. CONSORT 2010
Statement: updated guidelines for reporting parallel group randomised trials. BMJ
2010;340:c332.
Pathophysiology of Idiopathic SSNHL
1. Chau JK, Lin JR, Atashband S, Irvine RA, Westerberg BD. Systematic review of the
evidence for the etiology of adult sudden sensorineural hearing loss. The Laryngoscope.
2010; 120(5): 1011-1021. (Systematic Review)

A very useful and well written article highlighting the major causes of SSNHL.
2. Byl FM, Jr. Sudden hearing loss: Eight years’ experience and suggested prognostic table.
The Laryngoscope. 1984; 94(5 Pt 1): 647-661. (Primary Research Article)

A distinct summary of the causes and their pathophysiologies. Other aspects of SSNHL
are also discussed in detail.
3. Fisch U, Nagahara K, Pollak A. Sudden hearing loss: Circulatory. Otology &
Neurotology. 1984; 5(6): 488-491. (Primary Research Article)
4. Harris I. Sudden hearing loss: Membrane rupture. Otology & Neurotology. 1984; 5(6):
484-487. (Primary Research Article)
5. Lee H, Lopez I, Ishiyama A, Baloh RW. Can migraine damage the inner ear?. Archives of
Neurology. 2000; 57(11): 1631-1634. (Primary Research Article)
6. Simmons FB. Sudden idiopathic sensori-neural hearing loss: Some observations. The
Laryngoscope. 1973; 83(8): 1221-1227. (Primary Research Article)
7. Westmore GA, Pickard BH, Stern H. Isolation of mumps virus from the inner ear after
sudden deafness. British Medical Journal. 1979; 1(6155): 14-15. (Primary Research
Article)
8. Stachler RJ, Chandrasekhar SS, Archer SM et al. Clinical Practice Guideline – Sudden
Hearing Loss. Otolaryngol Head Neck Surg. 2012; 146(S3): S1-S35. (Primary Research
Article)
9. Korres S, Stamatiou GA, Gkoritsa E et al. Prognosis of patients with idiopathic sudden
hearing loss: role of vestibular assessment. The Journal of Laryngology & Otology. 2011;
125(03): 251–7. (Primary Research Article)
Steroidal treatment of Idiopathic SSNHL
1. Thevasagayam R, Lawrence R. Controversies in the management of sudden sensorineural
hearing loss (SSNHL): an evidence based review. Clin Otolaryngol. 2014. DOI:
10.1111/coa.12363 (Review Article)

A very useful review of existing evidence on the treatment of SSNHL, which then
proposes treatment guidelines based on the available literature
2. Wei BPC, Stathopoulos D, O’Leary S. Steroids for idiopathic sudden sensorineural
hearing loss. The Cochrane Library of Systematic Reviews.2013;7. DOI:
10.1002/14651858.CD003998.pub3. (Systematic Review)


A 2013 update of a systematic review which looked initially at hundreds of articles and
selected only three for analysis, examining the effectiveness of using steroids in the
treatment of ISSNHL.
Used only randomised controlled trials for the final article, so a very reliable source.
3. Wilson WR, Byl FM, Laird N. The efficacy of steroids in the treatment of idiopathic
sudden hearing loss. Archives of Otolaryngology 1980;106(12):772–6. (Primary Research
Article)
4. Cinnamon U, Bendet E, Kronenberg J. Steroids, carbogen or placebo for sudden hearing
loss: a prospective double-blind study. European Archives of Oto-Rhino-Laryngology
2001; 258(9):477–80. (Primary Research Article).
5. Nosrati-Zarenoe R, Hultcrantz E. Corticosteroid treatment of idiopathic sudden
sensorineural hearing loss: randomized triple-blind placebo-controlled trial. Otology &
Neurotology 2012;33(4):523–31. (Primary Research Article)
6. Weber PC. Sudden sensorineural hearing loss. Up To Date. ©2015. [cited 2015 March 1].
Available from: URL: http://www.uptodate.com/contents/sudden-sensorineural-hearingloss(Website)
7. Conlin AE, Parnes LS. Treatment Of Sudden Sensorineural Hearing Loss. Arch
Otolaryngol Head Neck Surg6 (2007): 582. (Meta-analysis)
8. Chen C, Halpin C, Rauch S. Oral Steroid Treatment of Sudden Sensorineural Hearing
Loss: A Ten Year Retrospective Analysis. Otology & Neurotology. 2003;24(5):728-733.
(Review Article)
9. Rauch S. Oral vs Intratympanic Corticosteroid Therapy for Idiopathic Sudden
Sensorineural Hearing Loss. JAMA. 2011;305(20):2071. (Primary Research Article)
10. Spear S, Schwartz S. Intratympanic Steroids for Sudden Sensorineural Hearing Loss: A
Systematic Review. Otolaryngology — Head and Neck Surgery. 2011;145(4):534-543.
(Review Article)

A highly useful review which included 6 randomised trials and 2 randomised controlled
trials. Provides an insight into comparison of oral v intratympanic as well as identifying
the possible role of intratympanic steroids as a salvage treatment.
11. Battaglia A, Burchette R, Cueva R. Combination therapy (intratympanic dexamethasone 1
high-dose prednisone taper) for the treatment of idiopathic sudden sensorineural hearing
loss. Otol Neurotol2008;29:453–460. (Primary Research Article)
12. Battista RA. Intratympanic dexamethasone for profound idiopathic sudden sensorineural
hearing loss. Otolaryngol Head Neck Surg. 2005;132:902-905 (Primary Research Article)
13. Kakehata S, Sasaki A, Oji K, et al. Comparison of intratympanic and intravenous
dexamethasone treatment on sudden sensorineural hearing loss with diabetes. Otol
Neurotol. 2006;27: 604-608. (Primary Research Article)
14. Ng J, Ho R, Cheong C, Ng A, Yuen H, Ngo R. Intratympanic steroids as a salvage
treatment for sudden sensorineural hearing loss? A meta-analysis. European Archives of
Oto-Rhino-Laryngology. 2014. (Review Article)

A review article which only accepted randomised controlled trials. From an initial 184
papers there were only 5 papers selected to be utilised during the study. These measures
have meant that this article has maximised validity, allowing it to be a useful component
of research.
15. Plontke S, LÃ wenheim H, Koitschev A, Zenner H. Response to Randomized, Double
Blind, Placebo Controlled Trial on the Safety and Efficacy of Continuous Intratympanic
Dexamethasone Delivered Via a Round Window Catheter for Severe to Profound Sudden
Idiopathic Sensorineural Hearing Loss After Failure of Systemic Therapy. The
Laryngoscope. 2009;119(12):2481-2482. (Review Article)
16. Lim HJ, Kim YT, Choi SJ, et al. Efficacy of 3 different steroid treatment for sudden
sensorineural hearing loss: a prospective, randomized trial. Otolaryngol Head Neck
Surg2013;148:121–127. (Primary Research Article)
Alternative treatments of Idiopathic SSNHL
1. Awad Z, Huins C, Pothier DD. Antivirals for idiopathic sudden sensorineural hearing loss.
Cochrane Database of Systematic Reviews. 2012; Issue 8. DOI:
10.1002/14651858.CD006987.pub2 (Review Article)

A comprehensive review of all the literature available on the use of antivirals for
idiopathic SSNHL, with 4 articles selected for final analysis. It concluded that more largescale randomised control trials were needed to ascertain the benefits of anti-viral treatment
in ISSNHL.
2. Stokroos RJ, Albers FW, Tenvergert EM. Antiviral treatment of idiopathic sudden
sensorineural hearing loss: a prospective, randomized, double-blind CT. Acta
Otolaryngologica. 1998; 118(4): 488–95. (Primary Research Article)
3. Tucci DL, Farmer JC Jr, Kitch RD, Witsell DL. Treatment of sudden sensorineural
hearing loss with systemic steroids and valacyclovir. Otology & Neurotology. 2002;
23(3): 301–8. (Primary Research Article)
4. Uri N, Doweck I, Cohen-Kerem R, Greenberg E. Acyclovir in the treatment of idiopathic
sudden sensorineural hearing loss. Otolaryngology – Head and Neck Surgery. 2003;
128(4): 544–9. (Primary Research Article)
5. Westerlaken BO, Stokroos RJ, Dhooge IJM, Wit HP, Albers FWJ. Treatment of idiopathic
sudden sensorineural hearing loss with antiviral therapy: a prospective, randomized,
double-blind clinical trial. Annals of Otology, Rhinology and Laryngology. 2003;
112(11): 993–1000. (Primary Research Article)
6. Murphy-Lavoie H, Piper S, Moon RE, Legros T. Hyperbaric oxygen therapy for
idiopathic sudden sensorineural hearing loss. Undersea and Hyperbaric Medicine. 2012;
39(3), 777. (Review Article)

A useful review that provides analysis on all relevant literature available on Hyperbaric
oxygen therapy, including retrospective studies, randomised control trials and metaanalyses.
7. Bennett MH, Kertesz T, Perleth M, Yeung P, Lehm JP. Hyperbaric oxygen for idiopathic
sudden sensorineural hearing loss and tinnitus. Cochrane Database of Systematic Reviews.
2012; Issue 10. DOI: 10.1002/14651858.CD004739.pub4 (Review Article)
8. Topuz E, Yigit O, Cinar U, Seven H. Should hyperbaric oxygen be added to treatment in
idiopathic sudden sensorineural hearing loss?. European Archives of Oto-RhinoLaryngology and Head & Neck. 2004; 261(7), 393-6. (Primary Research Article)

A study into the effects of additional hyperbaric oxygen on 51 patients with ISSNHL,
which concluded that additional hyperbaric oxygen resulted in improved hearing over a
range of frequencies. However, the small sample size and poor methodology reduces its
validity.
9. Conlin AE, Parnes LS. Treatment of sudden sensorineural hearing loss: II. A Metaanalysis. Archives of otolaryngology–head & neck surgery. 2007; 133(6), 582-6. (MetaAnalysis)
10. Agarwal L, Pothier DD. Vasodilators and vasoactive substances for idiopathic sudden
sensorineural hearing loss. Cochrane Database of Systematic Reviews. 2009; Issue 4.
DOI: 10.1002/14651858.CD003422.pub4 (Review Article)
11. Ni Y, Zhao X. Carbogen combined with drugs in the treatment of sudden deafness. Lin
Chuang Er Bi Yan Hou Ke Za Zhi [Journal of Clinical Otorhinolaryngology]. 2004; 18(7):
414–5. (Primary Research Article)
12. Ogawa K, Takei S, Inoue Y, Kanzaki J. Effect of prostaglandin E1 on idiopathic sudden
sensorineural hearing loss: a double-blinded clinical study. Otology and Neurotology.
2002; 23(5): 665–8. (Primary Research Article)
13. Poser R, Hirche H. A randomized, double-blind study for the treatment of sudden
deafness: low-molecular weight dextran and naftidrofuryl versus low-molecular weight
dextran and placebo. HNO. 1992; 40(10): 396–9. (Primary Research Article)
14. Mösges R, Köberlein J, Heibges A, Erdtracht B, Klingel R, Lehmacher W, RHEO-ISHL
study group. Rheopheresis for idiopathic sudden hearing loss: results from a large
prospective, multicenter, randomized, controlled clinical trial. European Archives of OtoRhino-Laryngology. 2009; 266(7): 943-53. (Primary Research Article)

A large-scale randomised control trial carried out on 240 patients, which found that
rheopheresis resulted in an improved quality of life score than the standard German
ISSNHL treatment procedures.
The potential use of Stem Cell Therapy for Idiopathic SSNHL
1. Oshima K, Jeon SJ, Heller S, Edge AS. Bone marrow mesenchymal stem cells are
progenitors in vitro for inner ear hair cells. Molecular and Cellular Neuroscience. 2007.
34(1), 59-68. (Primary Research Article)
2. Okano T, Kelley M. Stem Cell therapy for the Inner Ear; Recent Advances and Future
Directions. 2012. Trends in Hearing. 16(1): 4-18. (systematic review)

A 2012 literature review that highlights important new findings and future areas of
research that are needed for inner ear stem cell therapy to be viable.
3. Ronaghi M, Nasr M, Heller S. Concise Review: Inner Ear Stem Cells—An Oxymoron, but
Why? STEM CELLS. 2007. 30: 69–74. doi: 10.1002/stem.785 (systematic review)
4. Han Z et al. Survival and fate of transplanted embryonic neural stem cells by Atoh1 gene
transfer in guinea pigs cochlea. Neuroreport: Regeneration and Transplantation. 2010
21(7): 490-496 (Primary Research Article)
5. Parker et al. Neural Stem Cells Injected into the Sound Damaged Cochlea Migrate
Throughout the Cochlea and Express Markers of Hair Cells, Supporting Cells and Spiral
Ganglion Cells. Hearing Research. 2007. Hear Res. 2007 Oct; 232(1-2): 29–43. (Primary
Research Article)
6. Hildebran M et al. Survival of Partially Differentiated Mouse Embryonic Stem Cells in the
Scala Media of the Guinea Pig Cochlea. Journal of the Association for Restoration in
Otolaryngology. 6(4): 341–354. (Primary Research Article)
7. Kempfle JS, Edge A. Pax2 and Sox2 Cooperate to Promote Hair Cell Fate in Inner Ear
Stem Cells. Otolaryngology – Head and Neck Surgery. 2014. 151. p221. (Primary
Research Article)

A study that shows for the first time that Pax2 and Sox2 activate Atoh1 expression. An
important step to understanding the underlying mechanisms that can regenerate hair cells
from stem cells.
8. Park D, Girod D, Durham D. Avian brainstem neurogenesis is stimulated during cochlear
hair cell regeneration. Brain Research. 2002. 949(1-2) – 1-10 (Review Article)
9. Matsumoto M et al. Potential of embryonic stem cell-derived neurons for synapse
formation with auditory hair cells. J. Neurosci. Res. 2008. 86: 3075–3085. (Systematic
Review)
10. Gurtner G, Callaghan M, Longaker M. Progress and Potential for Regenerative Medicine.
Annual Review of Medicine. 2007. Vol. 58: 299-312. (Review Article)
SSNHL and Quality of Life
1. Carlsson P, Hjaldahl J, Magnuson A, Ternevall E, Edén, M, Skagerstrand Å, Jönsson, R.
(2014). Severe to profound hearing impairment: quality of life, psychosocial consequences
and audiological rehabilitation. Disabil Rehabil, pp.1-8. (Primary research article)
2. Chen J, Liang J, Ou J, Cai, W. (2013). Mental health in adults with sudden sensorineural
hearing loss: An assessment of depressive symptoms and its correlates. Journal of
Psychosomatic Research, 75(1), pp.72-74. (Primary research article)
3. Chau JK, Cho JJW, Fritz DK. “Evidence-based practice: management of adult
sensorineural hearing loss.” Otolaryngologic Clinics of North America5 (2012): 941958. (Primary research article)
4. Bishop C, Eby T. (2010). The current status of audiologic rehabilitation for profound
unilateral sensorineural hearing loss. The Laryngoscope, 120(3), pp.552-556. (Primary
research article)
5. Baguley D, Bird J, Humphriss R, Prevost A. (2006). The evidence base for the application
of contralateral bone anchored hearing aids in acquired unilateral sensorineural hearing
loss in adults. Clin Otolaryngol, 31(1), pp.6-14. (Review)

Used a large sample of patients increasing the reliability of the results
6. Sullivan M. (1993). A randomized trial of nortriptyline for severe chronic tinnitus. Effects
on depression, disability, and tinnitus symptoms. Archives of Internal Medicine, 153(19),
pp.2251-2259. (Primary research article)
7. Baguley D. (2002). Mechanisms of tinnitus. British Medical Bulletin, 63(1), pp.195212. (Primary research article)
Conclusion
1. Awad Z, Huins C, Pothier DD. Antivirals for idiopathic sudden sensorineural hearing loss.
Cochrane Database of Systematic Reviews. 2012; Issue 8. DOI:
10.1002/14651858.CD006987.pub2 (Review Article)
2. Bennett MH, Kertesz T, Perleth M, Yeung P, Lehm JP. Hyperbaric oxygen for idiopathic
sudden sensorineural hearing loss and tinnitus. Cochrane Database of Systematic Reviews.
2012; Issue 10. DOI: 10.1002/14651858.CD004739.pub4 (Review Article)
3. Conlin AE, Parnes LS. Treatment Of Sudden Sensorineural Hearing Loss. Arch
Otolaryngol Head Neck Surg6 (2007): 582. (Meta-analysis)
4. Rauch S. Oral vs Intratympanic Corticosteroid Therapy for Idiopathic Sudden
Sensorineural Hearing Loss. JAMA. 2011;305(20):2071. (Primary Research Article)
5. Ng J, Ho R, Cheong C, Ng A, Yuen H, Ngo R. Intratympanic steroids as a salvage
treatment for sudden sensorineural hearing loss? A meta-analysis. European Archives of
Oto-Rhino-Laryngology. 2014. (Review Article)
6. Battista RA. Intratympanic dexamethasone for profound idiopathic sudden sensorineural
hearing loss. Otolaryngol Head Neck Surg. 2005;132:902-905 (Primary Research Article)
7. Okano T, Kelley M. Stem Cell therapy for the Inner Ear; Recent Advances and Future
Directions. 2012. Trends in Hearing. 16(1): 4-18.
8. Haynes DS. et al.. ‘Intratympanic Dexamethasone For Sudden Sensorineural Hearing Loss
After Failure Of Systemic Therapy’. The Laryngoscope. 117.1: 3-15. (Primary Research
Article)
Contributions–>
CONTRIBUTIONS
Michael Bennett wrote the introduction, and was the main author of the conclusion. He also
completed the section looking into the effects of SSNHL on mental health.
Toby Boote wrote the ‘Pathophysiology’ section.
Jake Dowell wrote the page on the potential use of stem cell therapy in ISSNHL.
Henry Millar wrote the ‘Alternative Treatments’ section. He organised meetings and
delegated tasks, and was the main point of contact between the group and our tutor.
William Rea co-wrote the ‘Steroidal Treatments’ section.
Greg Swan co-wrote the section looking into ‘Steroidal Treatments.’
All group members came together to complete the final editing of the website and standardise
the references. Each section was proof-read by all group members, and everyone had an input
in the website content and presentation.
<–References
Information Search Report–>
INFORMATION SEARCH REPORT
Initially the group, through discussions with our tutor and various internet searches, identified
areas to look at and explore in the project. Internet searches included: “sudden sensorineural
hearing loss treatment” and “steroidal treatment for SSNHL”. Websites such as the BMJ and
UpToDate, and several review articles, allowed us to gain a brief overview of the topic and
meant we could pinpoint areas to research and split up the project into sections.
Within individual groups, ways to find appropriate papers and literature was discussed.
PubMed, Medline and Google Scholar were the sources we felt would be the most useful for
our searches. We also decided to focus mainly on level one evidence – randomised controlled
trials, meta-analyses and systematic reviews – as these would give the most reliable results
and allow us to make the best informed decisions. Keywords and Boolean operators were
used to initially find lots of papers related to the subject, then individually going through the
results we selected papers that were appropriate for use in our report.
For example, searching for papers assessing the use of oral steroids against placebo on
Medline, the following strategy was used:
Search 1: ‘sudden sensorineural hearing loss’. Include subheadings: ‘Hearing Loss, Sudden’
and ‘Hearing Loss, Sensorineural’.
Search 2: ‘steroids’. Explode ‘steroids’.
Combine searches 1 and 2 using Boolean operator AND. Then limit the results to ‘Clinical
Trials, All.’
This returned a number of papers, which we then looked through and selected the most
relevant papers to use as sources.
Most of the articles we decided to use were accessible through the University of Edinburgh
computers using the network in the library. The university subscriptions to the major
literature providers meant we had no problem accessing the information we needed.
<–Contributions
Word Version–>
WORD VERSION
How should we treat Idiopathic Sudden Sensorineural Hearing Loss Word Document
<–Information Search Report
Homepage–>