Hemodilution Therapy With Hydroxyethyl Starch Solution (130/0.4) in Unilateral Idiopathic Sudden Sensorineural Hearing Loss

Vertebrobasilar System Laterality and Idiopathic Sudden Sensorineural Hearing Loss

INTRODUCTION

The etiology of idiopathic sudden sensorineural hearing loss (ISSNHL) remains elusive, with vascular compromise as a proposed cause. This study aimed to explore the correlation between the vertebrobasilar vascular system laterality (VBVSL) and ISSNHL laterality.

METHODS

We conducted a retrospective analysis of consecutive patients diagnosed with ISSNHL from 2015 to 2020. The VBVSL pattern was established via magnetic resonance imaging scans by a neuroradiologist. ISSNHL occurring contralaterally to the basilar artery (BA) curvature or ipsilaterally to the dominant vertebral artery (VA) was designated as a "positive match," with all other scenarios classified as a "negative match."

RESULTS

Our study included 191 ISSNHL patients (median age 57 years, 89 males, 93 right ears). The majority of patients did not exhibit a positive match between ISSNHL laterality and the sides of BA curvature or dominant VA (28.8% and 36.6% for BA and VA, respectively). Notably, VA-positive match patients were significantly older than VA-negative match patients (59 vs. 53 years, p = 0.043), with a similar trend observed in BA-positive match compared to BA-negative match (59 vs. 54.5 years, p = 0.057). However, there was no significant difference in any other clinical, audiometric, or outcome factors between the positive and negative match groups.

CONCLUSION

The findings suggest no association between VBVSL and ISSNHL laterality. Furthermore, patients in the positive match group did not exhibit distinct clinical or audiometric features compared to those without a match.

Nomogram for predicting the prognostic role in idiopathic sudden sensorineural hearing loss

PURPOSE

A nomogram model was constructed to assist in early prediction of idiopathic sudden sensorineural hearing loss (ISSHL) prognosis. Additionally, this study contributed to evaluating and analyzing the usefulness of the nomogram model in ISSHL clinical intervention.

METHODS

A retrospective analysis was performed concerning 355 ISSHL patients who were hospitalized between June 2021 and August 2022. Single-factor analysis was used to filter variables, which were subsequently used for multivariate analysis to construct a nomogram. The discriminative capability and clinical usefulness of the predictive model were estimated by calculating the area under the curve (AUC), calibration curve, and decision curve analysis (DCA).

RESULTS

Hearing loss type, duration from onset to treatment, vertigo, periauricular paresthesia, and batroxobin use were included in the nomogram for ISSHL. The predictive model showed fair discrimination values (AUC =0.764; 95%CI: 0.715-0.813) and was well-calibrated, the C-index was 0.746 (95%CI: 0.715-0.793) in the internal validation. DCA indicated that the model was also clinically beneficial when the threshold range was between 0.246 and 0.840.

CONCLUSIONS

The nomogram prediction model may have potential clinical practicability in effectively assisting clinicians in predicting ISSHL prognosis and optimizing treatment protocols.

Spontaneous recovery rate of idiopathic sudden sensorineural hearing loss: A systematic review and meta-analysis

PURPOSE

Steroids comprise the mainstay of treatment for idiopathic sudden sensorineural hearing loss (ISSNHL). Since steroidal treatment was integrated to clinical practice guidelines, newly published no-treatment or placebo arms in clinical trials are scarce. To evaluate the effectiveness of steroidal treatment ± hyperbaric oxygen therapy, the data should be compared to spontaneous recovery. The aim of this paper is to find the most accurate spontaneous recovery rate, in the light of which, other treatment modalities should be judged.

MATERIALS AND METHODS

Eligible studies published until July 2021 were identified through systematic searches of 'PubMed', 'Web of Science' and 'Google Scholar'. Retrospective studies and randomised/non-randomised control trials involving only adult participants (≥18 years) with ISSNHL, and placebo/no treatment were included. Only articles that used the American Academy of Otolaryngology-Head and Neck Surgery's diagnostic criteria for ISSNHL were included.

RESULTS

942 records initially identified, 166 duplicates and 753 articles were excluded based on article subject, title, and abstract. The full texts of 13 articles were reviewed. Seven studies were included for qualitative synthesis, five papers included in quantitative synthesis. 180 ears were included in pooled statistics. The pooled spontaneous recovery was 60.28% (95% confidence interval [CI] = 38.88%-79.94%) with a heterogeneity of 86.0% (95% CI = 69.4%-93.6%).

CONCLUSIONS

Spontaneous recovery of ISSNHL should not be over-looked, as it may be close to 60%. This may have both clinical and research implications.

Intratympanic corticosteroids for sudden sensorineural hearing loss

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSNHL) is common, and defined as a sudden decrease in sensorineural hearing sensitivity of unknown aetiology. Systemic corticosteroids are widely used, however their value remains unclear. Intratympanic injections of corticosteroids have become increasingly common in the treatment of ISSNHL.

OBJECTIVES

To assess the effects of intratympanic corticosteroids in people with ISSNHL.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Trials Register; CENTRAL (2021, Issue 9); PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials (search date 23 September 2021).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving people with ISSNHL and follow-up of over a week. Intratympanic corticosteroids were given as primary or secondary treatment (after failure of systemic therapy).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods, including GRADE to assess the certainty of the evidence. Our primary outcome was change in hearing threshold with pure tone audiometry. Secondary outcomes included the proportion of people whose hearing improved, final hearing threshold, speech audiometry, frequency-specific hearing changes and adverse effects.

MAIN RESULTS

We included 30 studies, comprising 2133 analysed participants. Some studies had more than two treatment arms and were therefore relevant to several comparisons. Studies investigated intratympanic corticosteroids as either primary (initial) therapy or secondary (rescue) therapy after failure of initial treatment. 1. Intratympanic corticosteroids versus systemic corticosteroids as primary therapy We identified 16 studies (1108 participants). Intratympanic therapy may result in little to no improvement in the change in hearing threshold (mean difference (MD) -5.93 dB better, 95% confidence interval (CI) -7.61 to -4.26; 10 studies; 701 participants; low-certainty). We found little to no difference in the proportion of participants whose hearing was improved (risk ratio (RR) 1.04, 95% CI 0.97 to 1.12; 14 studies; 972 participants; moderate-certainty). Intratympanic therapy may result in little to no difference in the final hearing threshold (MD -3.31 dB, 95% CI -6.16 to -0.47; 7 studies; 516 participants; low-certainty). Intratympanic therapy may increase the number of people who experience vertigo or dizziness (RR 2.53, 95% CI 1.41 to 4.54; 1 study; 250 participants; low-certainty) and probably increases the number of people with ear pain (RR 15.68, 95% CI 6.22 to 39.49; 2 studies; 289 participants; moderate-certainty). It also resulted in persistent tympanic membrane perforation (range 0% to 3.9%; 3 studies; 359 participants; very low-certainty), vertigo/dizziness at the time of injection (1% to 21%, 3 studies; 197 participants; very low-certainty) and ear pain at the time of injection (10.5% to 27.1%; 2 studies; 289 participants; low-certainty). 2. Intratympanic plus systemic corticosteroids (combined therapy) versus systemic corticosteroids alone as primary therapy We identified 10 studies (788 participants). Combined therapy may have a small effect on the change in hearing threshold (MD -8.55 dB better, 95% CI -12.48 to -4.61; 6 studies; 435 participants; low-certainty). The evidence is very uncertain as to whether combined therapy changes the proportion of participants whose hearing is improved (RR 1.27, 95% CI 1.15 to 1.41; 10 studies; 788 participants; very low-certainty). Combined therapy may result in slightly lower (more favourable) final hearing thresholds but the evidence is very uncertain, and it is not clear whether the change would be important to patients (MD -9.11 dB, 95% CI -16.56 to -1.67; 3 studies; 194 participants; very low-certainty). Some adverse effects only occurred in those who received combined therapy. These included persistent tympanic membrane perforation (range 0% to 5.5%; 5 studies; 474 participants; very low-certainty), vertigo or dizziness at the time of injection (range 0% to 8.1%; 4 studies; 341 participants; very low-certainty) and ear pain at the time of injection (13.5%; 1 study; 73 participants; very low-certainty).  3. Intratympanic corticosteroids versus no treatment or placebo as secondary therapy We identified seven studies (279 participants). Intratympanic therapy may have a small effect on the change in hearing threshold (MD -9.07 dB better, 95% CI -11.47 to -6.66; 7 studies; 280 participants; low-certainty). Intratympanic therapy may result in a much higher proportion of participants whose hearing is improved (RR 5.55, 95% CI 2.89 to 10.68; 6 studies; 232 participants; low-certainty). Intratympanic therapy may result in lower (more favourable) final hearing thresholds (MD -11.09 dB, 95% CI -17.46 to -4.72; 5 studies; 203 participants; low-certainty). Some adverse effects only occurred in those who received intratympanic injection. These included persistent tympanic membrane perforation (range 0% to 4.2%; 5 studies; 185 participants; very low-certainty), vertigo or dizziness at the time of injection (range 6.7% to 33%; 3 studies; 128 participants; very low-certainty) and ear pain at the time of injection (0%; 1 study; 44 participants; very low-certainty).  4. Intratympanic plus systemic corticosteroids (combined therapy) versus systemic corticosteroids alone as secondary therapy We identified one study with 76 participants. Change in hearing threshold was not reported. Combined therapy may result in a higher proportion with hearing improvement, but the evidence is very uncertain (RR 2.24, 95% CI 1.10 to 4.55; very low-certainty). Adverse effects were poorly reported with only data for persistent tympanic membrane perforation (rate 8.1%, very low-certainty).

AUTHORS' CONCLUSIONS

Most of the evidence in this review is low- or very low-certainty, therefore it is likely that further studies may change our conclusions.   For primary therapy, intratympanic corticosteroids may have little or no effect compared with systemic corticosteroids. There may be a slight benefit from combined treatment when compared with systemic treatment alone, but the evidence is uncertain. For secondary therapy, there is low-certainty evidence that intratympanic corticosteroids, when compared to no treatment or placebo, may result in a much higher proportion of participants whose hearing is improved, but may only have a small effect on the change in hearing threshold. It is very uncertain whether there is additional benefit from combined treatment over systemic steroids alone. Although adverse effects were poorly reported, the different risk profiles of intratympanic treatment (including tympanic membrane perforation, pain and dizziness/vertigo) and systemic treatment (for example, blood glucose problems) should be considered when selecting appropriate treatment.

Efficacy and safety of systemic, high-dose glucocorticoid therapy for idiopathic sudden sensorineural hearing loss : Study protocol for a three-armed, randomized, triple-blind, multicenter trial (HODOKORT)

BACKGROUND

Systemic glucocorticosteroids ("steroids") are widely used worldwide as a standard of care for primary therapy of idiopathic sudden sensorineural hearing loss (ISSHL). The German ISSHL guideline recommends high-dose steroids without evidence from randomized controlled trials (RCTs) and refers solely to retrospective cohort studies. This RCT aims to assess the efficacy (improvement in hearing) and safety (especially systemic side effects) of high-dose steroids versus standard of care (standard dose systemic steroids) for the treatment of unilateral ISSHL, when given as a primary therapy.

METHODS

The study is designed as a multicenter (approximately 40 centers), randomized, triple-blind, three-armed, parallel group, clinical trial with 312 adult patients. The interventions consist of 5 days of 250 mg/day intravenous prednisolone (intervention 1) + oral placebo, or 5 days of 40 mg/day oral dexamethasone (intervention 2) + intravenous placebo. The control intervention consists of 60 mg oral prednisolone for 5 days followed by five tapering doses + intravenous placebo. The primary efficacy endpoint is the change in hearing threshold in the three most affected contiguous frequencies between 0.25 and 8 kHz 1 month after ISSHL. Secondary endpoints include further measures of hearing improvement including speech audiometry, tinnitus, quality of life, blood pressure, and altered glucose tolerance.

DISCUSSION

There is an unmet medical need for an effective medical therapy of ISSHL. Although sensorineural hearing impairment can be partially compensated by hearing aids or cochlear implants (CI), generic hearing is better than using hearing aids or CIs. Since adverse effects of a short course of high-dose systemic corticosteroids have not been documented with good evidence, the trial will improve knowledge on possible side effects in the different treatment arms with a focus on hyperglycemia and hypertension.

TRIAL REGISTRATION

EudraCT (European Union Drug Regulating Authorities Clinical Trials Database) Nr. 2015-002602-36; Sponsor code: KKSH-127.

Effects of hearing aids in patients with unilateral tinnitus with acquired ipsilateral sensorineural hearing loss

OBJECTIVES

To evaluate the effectiveness of sound therapy using hearing aids in patients experiencing tinnitus with acquired unilateral sensorineural hearing loss.

METHODS

A total of 97 patients with unilateral tinnitus with acquired ipsilateral sensorineural hearing loss were included. Evaluation involved self-report questionnaires administered at entry, 3 months after treatment, and 1 year after treatment.

RESULTS

The mean Tinnitus Handicap Inventory score before treatment decreased significantly (p < 0.01) at 3 months (50.0 ± 24.5-12.7 ± 16.2), and 1 year (53.3 ± 25.5-8.79 ± 13.9), after treatment. Moreover, the visual analog scale score decreased significantly at 3 months (loudness, 69.6 ± 21.9-29.1 ± 27.2; annoyance, 71.1 ± 24.7-22.7 ± 25.5) and 1 year (loudness, 69.8 ± 22.0-21.1 ± 26.1; annoyance, 72.7 ± 25.6-19.4 ± 27.6). Approximately 80-90% of patients noticed improvements in tinnitus annoyance and loudness, as determined by their responses to the questionnaires of subjective symptom improvement.

CONCLUSIONS

Hearing aids are remarkably effective for patients with unilateral tinnitus with acquired ipsilateral sensorineural hearing loss.

The role of explorative tympanotomy in patients with sudden sensorineural hearing loss with and without perilymphatic fistula

PURPOSE

The purpose of this study was to describe the role of explorative tympanotomy in patients with Profound Sudden Sensorineural Hearing Loss (SSNHL) without clinical evidence of perilymphatic or labyrinthine fistula and to compare intraoperative findings with the postoperative hearing outcome.

STUDY DESIGN

Retrospective study of all patients diagnosed with SSNHL who underwent explorative tympanotomy between 2002 and 2005.

SETTINGS

Tertiary care university-affiliated hospital.

SUBJECTS AND METHODS

Eighty-two patients were diagnosed with unilateral profound SSNHL and underwent tympanotomy with sealing of the round and oval windows. Values of pure tone audiograms and percentage hearing loss of patients with and without intraoperative diagnosed perilymphatic fistula (PLF) were compared and analyzed.

RESULTS

PLF was diagnosed in 28% cases intraoperatively. In most cases, hearing improved significantly after surgery. Interestingly, patients with PLF had a 2.4 times greater decrease of percentage hearing loss compared to patients without PLF.

CONCLUSIONS

Explorative tympanotomy seems to be useful in patients with profound SSNHL. Patients with PLF benefit more from the surgical procedure and have better outcome than patients without PLF.

Characteristics and Spontaneous Recovery of Tinnitus Related to Idiopathic Sudden Sensorineural Hearing Loss

Objective:

To evaluate the characteristics and spontaneous recovery of tinnitus related to idiopathic sudden sensorineural hearing loss (ISSNHL).

Study Design:

Retrospective analysis from two randomized placebo-controlled clinical trials for treatment of ISSNHL within 48 hours from onset (Study A), or of tinnitus related to ISSNHL within 3 months from onset (Study B).

Setting:

Forty-eight European sites (academic tertiary referral centers, private ENT practices).

Patients:

One hundred thirteen adult patients of which 65 with hearing loss ≥30 dB (Study A) and 48 with persistent acute tinnitus (Study B) at baseline.

Interventions:

Intratympanic (i.t.) injection of placebo gel in single dose or in triple dose during 3 consecutive days.

Main Outcome Measures:

Frequency of tinnitus, subjective tinnitus loudness, rates of complete tinnitus remission, and complete hearing recovery during 3 months follow-up.

Results:

In acute ISSNHL, tinnitus loudness decreased rapidly in cases of mild-moderate hearing loss, and tinnitus had completely resolved in two-thirds of patients after 3 months. Hearing recovery preceded tinnitus resolution. When associated with severe-profound hearing loss, tinnitus improved significantly less. Complete hearing recovery and full tinnitus remission were both about three times more frequent in mild-moderate hearing loss patients than in severe-profound cases. Improvement in tinnitus loudness over time can be approximated by a negative exponential function.

Conclusions:

Prognosis for ISSNHL-related tinnitus is relatively poor in case of severe-profound hearing loss and the longer it has persisted. Alleviation or management of tinnitus should be a key therapeutic objective especially in pronounced ISSNHL cases.

A software tool for pure‑tone audiometry. Classification of audiograms for inclusion of patients in clinical trials. English version

Objective

Selecting subjects for clinical trials on hearing loss therapies relies on the patient meeting the audiological inclusion criteria. In studies on the treatment of idiopathic sudden sensorineural hearing loss, the patient’s acute audiogram is usually compared with a previous audiogram, the audiogram of the non-affected ear, or a normal audiogram according to an ISO standard. Generally, many more patients are screened than actually fulfill the particular inclusion criteria. The inclusion criteria often require a calculation of pure-tone averages, selection of the most affected frequencies, and calculation of hearing loss differences.

Materials and methods

A software tool was developed to simplify and accelerate this inclusion procedure for investigators to estimate the possible recruitment rate during the planning phase of a clinical trial and during the actual study. This tool is Microsoft Excel-based and easy to modify to meet the particular inclusion criteria of a specific clinical trial. The tool was retrospectively evaluated on 100 patients with acute hearing loss comparing the times for classifying automatically and manually. The study sample comprised 100 patients with idiopathic sudden sensorineural hearing loss.

Results and conclusion

The age- and sex-related normative audiogram was calculated automatically by the tool and the hearing impairment was graded. The estimated recruitment rate of our sample was quickly calculated. Information about meeting the inclusion criteria was provided instantaneously. A significant reduction of 30 % in the time required for classifying (30 s per patient) was observed.

Supplementary file

Additional material to this article (Rahne_InclusionCriteria_v.en2.1.xlsx) will be available online at 10.1007/s00106-015-0089-3

Ischemia as a potential etiologic factor in idiopathic unilateral sudden sensorineural hearing loss: Analysis of posterior circulation arteries

The association between idiopathic sudden sensorineural hearing loss (ISSNHL) and the radiologic characteristics of the vertebrobasilar artery is unclear. We hypothesized that the degree and direction of vertebrobasilar artery curvature in the posterior circulation contribute to the occurrence of ISSNHL. We consecutively enrolled patients diagnosed with unilateral ISSNHL in two tertiary hospitals. Magnetic resonance images were performed in all patients to exclude specific causes of ISSNHL, such as vestibular schwannoma, chronic mastoiditis, and anterior inferior cerebellar artery infarct. We measured the following parameters of posterior circulation: vertebral and basilar artery diameter, the degree of basilar artery curvature (modified smoker criteria), and vertebral artery dominance. Pure tone audiometries were performed at admission and again 1 week and 3 months later. A total of 121 ISSNHL patients (mean age, 46.0 ± 17.3 years; 48.8% male) were included in these analyses. The proportion of patients with the left side hearing loss was larger than the proportion with the right side hearing loss (left, 57.9%; right, 42.1%). The majority of patients were characterized by a left dominant vertebral artery and right-sided basilar artery curvature. The direction of the basilar artery curvature was significantly associated with hearing loss lateralization (p = 0.036). Age and sex matched multivariable analyses revealed the absence of diabetes and right-sided basilar artery curvature as significant predictors for left sided hearing loss. There was no statistical difference between atherosclerotic cardiovascular risk score (high versus low) and hearing outcomes at 3 months. In ISSNHL, the laterality of hearing loss was inversely associated with the direction of basilar artery curvature. Our results, therefore, indicate the importance of vascular assessment when evaluating ISSNHL.

A case-control analysis on the association between erectile dysfunction and sudden sensorineural hearing loss in Taiwan

INTRODUCTION

Although the cause of sudden sensorineural hearing loss (SSNHL) is yet to be elucidated, many theories have been proposed regarding potentially contributory etiologies. One increasingly well-supported theory purports an underlying vascular pathomechanism. If this is the case, SSNHL may also associate with conditions comorbid with vascular diseases, such as erectile dysfunction (ED). However, no studies to date have investigated the association between ED and SSNHL.

AIM

This study set out to estimate a putative association between ED and having been previously diagnosed with SSNHL using a population-based dataset with a case-control design.

METHODS

This study used administrative claim data from the Taiwan National Health Insurance program. We identified 4,504 patients with ED as the study group and randomly selected 22,520 patients as the comparison group. Conditional logistic regression was used to examine the association between ED and having previously received a diagnosis of SSNHL.

MAIN OUTCOME MEASURE

The prevalence and risk of SSNHL between cases and controls were calculated.

RESULTS

Of the sampled patients, 41 (0.15%) had been diagnosed with SSNHL before the index date; 22 (0.49% of the cases) were from the study group and 19 (0.08% of controls) were from the control group. Conditional logistic regression analysis revealed that after adjusting for the patient's monthly income, geographic location, hypertension, diabetes, hyperlipidemia, coronary heart disease, obesity, and alcohol abuse/alcohol dependence syndrome status, patients with ED were more likely than controls to have been diagnosed with SSNHL before the index date (odds ratio = 6.06, 95% confidence interval = 3.25-11.29).

CONCLUSIONS

There was an association between ED and prior SSNHL. The results of this study add to the evidence supporting an underlying vascular pathomechanism regarding the development of SSNHL and highlight a need for clinicians dealing with SSNHL patients to be alert to the development of ED.

[Pharmacotherapy of acute and chronic hearing loss]

The aetiology of acute hearing loss is mostly idiopathic like sudden sensorineural hearing loss and rarely infectious or vascular. Several studies and meta-analyses of pharmacotherapy are reviewed: In chronic tinnitus there is no indication for pharmacotherapy; sometimes a possible psychosomatic comorbidity has to be treated with psychopharmaceutical agents. Despite a low level of evidence treatment with steroids and initially plasma expanding infusions is recommended for acute tinnitus if there is no spontaneous remission. Intratympanic steroid therapy can be used as an alternative if there is severe hearing loss together with tinnitus.

Meta-analysis for the effect of medical therapy vs. placebo on recovery of idiopathic sudden hearing loss

OBJECTIVES

To estimate the effect of recovery of idiopathic sudden hearing loss under placebo (first aim) and under medical therapy (second aim).

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A total of 1,674 studies published between January 1974 and April 2009 were found following suggestions in the Cochrane Handbook for Systematic Reviews. After filtering by criteria of Cochrane Collaboration, four trials remained for continuous and two for dichotomous data.

RESULTS

Using Review Manager, weighted mean difference as well as standardized mean effect of hearing recovery were calculated and pooled. The values for weighted mean difference of hearing gain in dB were 0.79, 95% confidence interval (CI) (-2.04-3.61) and for standardized mean effect 0.06, 95% CI (-0.13-0.24), respectively, which computationally favors active treatment, but statistically is not significantly different from no effect (0 dB). This was in accordance to the comparison of descriptive means between recovery under placebo with 14.3 dB and active treatment with 15.8 dB hearing gain. Treatment effect of dichotomous data (hearing gain vs. no hearing gain) suggested a statistically significant better outcome for active treatment; the odds ratio (OR) [fixed] is 2.18 (1.06-4.46).

CONCLUSIONS

In five different statistical analysis methods used, treatment effect of medical therapy was slightly better than recovery under placebo in which spontaneous recovery could be assumed, but no significant effect was detected. Against the background of recovery under placebo of 14.3 dB vs. 15.8 dB hearing gain of active treatment as averages of all measured frequencies, recovery under placebo seems not to have worse outcome than recovery under medical therapy.

Hyperbaric oxygen therapy as salvage treatment for sudden sensorineural hearing loss: review of rationale and preliminary report

Background:

The management of sudden sensorineural hearing loss has not yet been standardised. Hyperbaric oxygen therapy influences recovery from sudden sensorineural hearing loss, but the underlying mechanism is unknown and the appropriate indications and protocols undetermined.

Materials and methods:

Nineteen patients affected by sudden sensorineural hearing loss were treated after unsuccessful medical therapy, either in an acute or chronic setting. Pure oxygen inhalation at 2.5 atmospheres absolute pressure was administered for 90 minutes, for 30 sessions. Frequency-specific and average pure tone hearing thresholds were determined before and after hyperbaric oxygen therapy. The number of hyperbaric oxygen therapy sessions, the patient's age and any therapeutic delay were considered as quantitative variables possibly influencing outcome. Stepwise multivariate analysis was performed.

Results:

Salvage hyperbaric oxygen therapy appeared to improve patients' pure tone hearing thresholds, particularly at low frequencies. Positive results were more likely with increased patient age and reduced delay in receiving hyperbaric oxygen therapy.

Conclusion:

Hyperbaric oxygen therapy has a strong scientific rationale, and improves pure tone hearing thresholds in cases of sudden sensorineural hearing loss unresponsive to medical therapy. Further research may be able to identify those patients with sudden sensorineural hearing loss for whom hyperbaric oxygen therapy would be most cost-effective.

Perspectives on the pathophysiology and treatment of sudden idiopathic sensorineural hearing loss

BACKGROUND

Sudden, idiopathic sensorineural hearing loss is an acute dysfunction of the inner ear whose cause cannot be determined with the currently available methods of clinical diagnosis.

METHODS

This continuous medical education article is based on a selective review of the literature and on the revised S2 guidelines for acute sensorineural hearing loss of the Association of the Scientific Medical Societies in Germany (AWMF), which were issued on 28 January 2009.

RESULTS

Recent surveys in Germany suggest that the incidence of sudden, idiopathic sensorineural hearing loss may be as high as 300 per 100,000 persons per year. To distinguish this entity from acute hearing loss of other causes, special tests are necessary, including ear microscopy, pure-tone audiometry, and acoustic evoked response audiometry. No clinical trial of the highest evidence level has yet been published to document the efficacy of any type of treatment for sudden, idiopathic sensorineural hearing loss. Nonetheless, there is evidence from trials with lower levels of evidence, post-hoc analyses, and assessments of secondary endpoints of clinical trials indicating that plasma-expander therapy, the systemic and local (intratympanic) administration of cortisone, and the reduction of acutely elevated plasma fibrinogen levels may be beneficial.

CONCLUSION

Further clinical trials are needed to validate these preliminary results. Until clear data are available, the predicted benefit and risk of any proposed treatment for sudden, idiopathic sensorineural hearing loss should be discussed in detail with the patient before the treatment is begun.

Sudden hearing loss

Sudden sensorineural hearing loss is a medical emergency in search of an appropriate treatment. Almost all aspects of this disease process are disputed in the literature. The natural course of the disease process has not been well defined, although spontaneous recovery in a percentage of patients appears well accepted. Little scientific data exist to develop an evidence-based treatment protocol. The more common elements of treatment in the United States include oral steroid therapy, transtympanic steroid therapy, and potentially oral antiviral therapy. Other therapies are used with great frequency, and their potential should not be discounted.