Therapy of idiopathic sudden sensorineural hearing loss: antiviral treatment of experimental herpes simplex virus infection of the inner ear

A novel cell-free therapy using exosomes in the inner ear regeneration

Cellular and molecular alterations associated with hearing loss are now better understood with advances in molecular biology. These changes indicate the participation of distinct damage and stress pathways that are unlikely to be fully addressed by conventional pharmaceutical treatment. Sensorineural hearing loss is a common and debilitating condition for which comprehensive pharmacologic intervention is not available. The complex and diverse molecular pathology that underlies hearing loss currently limits our ability to intervene with small molecules. The present review focuses on the potential for the use of extracellular vesicles in otology. It examines a variety of inner ear diseases and hearing loss that may be treatable using exosomes (EXOs). The role of EXOs as carriers for the treatment of diseases related to the inner ear as well as EXOs as biomarkers for the recognition of diseases related to the ear is discussed.

The Pathogenesis of Cytomegalovirus and Other Viruses Associated with Hearing Loss: Recent Updates

Virus infection is one of the most common etiologies of hearing loss. Hearing loss associated with viral infection can be unilateral or bilateral, mild or severe, sudden or progressive, and permanent or recoverable. Many viruses cause hearing loss in adults and children; however, the pathogenesis of hearing loss caused by viral infection is not fully understood. This review describes cytomegalovirus, the most common virus causing hearing loss, and other reported hearing loss-related viruses. We hope to provide a detailed description of pathogenic characteristics and research progress on pathology, hearing phenotypes, possible associated mechanisms, treatment, and prevention measures. This review aims to provide diagnostic and treatment assistance to clinical workers.

Effect of Herpes Zoster Treatment and Sudden Sensorineural Hearing Loss Using National Health Insurance Claims Data of South Korea

Background and objectives: Herpes zoster (HZ) is caused by the reactivation of a pre-existing latent varicella zoster virus, which is one of the viruses that causes hearing loss, and hearing loss may occur due to a systemic immune response even if it does not invade the auditory nerve. This study aimed to determine the correlation between sudden sensorineural hearing loss (SSNHL) in older adult patients who received HZ treatment. Materials and Methods: We used the cohort data of patients aged 60 years and above (n = 624,646) between 2002 and 2015 provided by the National Health Insurance Service. The patients were divided into two groups: those who were diagnosed with HZ between 2003 and 2008 (group H, n = 36,121) and those who had not been diagnosed with HZ between 2002 and 2015 (group C, n = 584,329). Results: In the main model (adjusted HR = 0.890, 95% CI = 0.839-0.944, p < 0.001) adjusted for sex, age, and income, and the full model (adjusted HR = 0.894, 95% CI = 0.843-0.949, p < 0.001) adjusted for all comorbidities, group H had a lower risk of SSNHL than group C. Conclusions: This study showed that patients who received HZ treatment had a lower incidence of SSNHL within five years after diagnosis.

Congenital Deafness and Recent Advances Towards Restoring Hearing Loss

Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.

Investigation of Stress Levels before the Onset of Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVES

We hypothesized that patients with idiopathic sudden sensorineural hearing loss (ISSHL) would have experienced more stress prior to the onset than they typically did. This study investigated stress levels in patients before the onset of ISSHL.

MATERIALS AND METHODS

Forty-two patients with ISSHL were investigated. We used an original questionnaire to evaluate subjective stress levels in 1 week before onset. Serum hemoglobin A1c (HbA1c) and total cholesterol were examined to evaluate biochemical stress markers reflecting the preceding 1 to 2 months. The results on admission were compared with those at the follow-up visit.

RESULTS

Significantly more patients reported greater physical exhaustion, greater mental exhaustion, or a worse physical condition on admission than at follow-up (p<0.01, for each variable). On admission, 81% of patients reported greater than normal stress with regard to at least 1 of 3 items. The mean serum HbA1c was slightly but nonsignificantly lower at the follow-up visit (p=0.10), while the mean serum total cholesterol was significantly lower at follow-up than on admission (p<0.01).

CONCLUSION

The results indicate that patients were under a greater degree of stress before the onset of ISSHL, suggesting that stress plays a role in inducing ISSHL.

Differences in platelet-related parameters among patients with audiographically distinct sudden sensorineural hearing loss: A retrospective study

We explored possible relationships between sudden sensorineural hearing loss (SSNHL) in patients differing in terms of audiographic data and the levels of vascular markers in routine blood data.We included 37 patients with low-frequency SSNHL (LF-SSNHL), 28 with high-frequency SSNHL (HF-SSNHL), 32 with all-frequency SSNHL (AF-SSNHL), 32 with total-deafness SSNHL (TD-SSNHL), and 31 age- and sex-matched healthy controls. Peripheral venous blood samples were collected, and routine blood parameters including platelet and lymphocyte count, mean platelet volume (MPV), and platelet-to-lymphocyte ratio (PLR) were measured. Each group was divided into recovery subgroup and unrecovery subgroup in accordance with hearing level after 1 month therapy, then compared the difference of platelet and lymphocyte count, MPV, and PLR between the 2 subgroups.No significant difference was observed between platelet count of all SSNHL patients and control group (all P > .05). MPV of AF-SSNHL and TD-SSNHL, PLR of all SSNHL patients were significantly higher than those of control group (all P < .05), while lymphocyte count of all audiographically distinct SSNHL patients was significantly lower than that of control group (all P < .05). However, the difference of platelet count, lymphocyte count, MPV, and PLR among audiographically distinct SSNHL patients was not significant (all P > .05). In HF-SSNHL patients, lymphocyte count of unrecovery subgroup was significantly lower, while MPV and PLR of the unrecovery subgroup were significantly higher than those of recovery subgroup (all P < .05). In AF-SSNHL patients, MPV of the unrecovery group was significantly higher than that of recovery subgroup (P < .05).Lymphocyte count, MPV, and PLR may be relative to SSSNHL, but they could not be used to distinct SSNHL audiographically. Lower lymphocyte, higher MPV, and PLR may be indicative for the prognosis of HF-SSNHL patients; higher MPV may be related to bad treatment outcome of AF-SSNHL patients.

Intratympanic Steroid Treatment in Idiopathic Sudden Sensorineural Hearing Loss: A Control Study

BACKGROUND AND OBJECTIVE: Although systemic steroids in sudden sensorineural hearing loss (SSHL) appears to be the most effective and the most widely accepted treatment today, a significant number of patients do not respond to steroid treatment or they cannot receive steroids for medical reasons. Intratympanic (IT) administration of steroids appears to be an alternative or additional method of management without the side effects of intravenous steroids. The aim of this study is to investigate the effectiveness and safeness of IT administration of steroids in patients who had not responded to IV treatment and to compare treatment efficacy with controls.

STUDY DESIGN AND SETTING: Our study consisted of 37 patients with SSHL who, at the end of 10 days of therapy with intravenous steroids as a 1st line treatment, had pure-tone 4-frequency (0.5, 1, 2, and 4 kHz) average (PTA) of worse than 30 dB or worse than 10 dB from the contralateral ear (defined as failed intravenous treatment). They were randomized into 2 groups, treatment and control. The 19 patients of the treatment group received approximately 0.5 mL sterile aqueous suspension of methylprednisolone acetate in a concentration of 80 mg/2 mL by direct injection. The procedure was carried out 4 times within a 15-day period. An audiogram was performed before each injection and approximately 1.5 months after the last session.

RESULTS: All patients tolerated the procedure well. No perforation or infection was noticed in any of the patients at their last visit. With regard to the 19 patients who received intratympanic treatment, in 9 patients, the PTA threshold improved more than 10 db, in 10 patients there was no change greater than 10 db, and no patients deteriorated more than 10 db. In the control group, none of the patients showed any change greater than 10 db. The difference was statistically significant ( P = 0.002). The treatment group showed an improvement in mean PTA of 14.9 dB, whereas the control group showed a deterioration of 0.8 dB, and this difference also was statistically significant ( P = 0.0005). IT treatment ( P = 0.0001), better post-IV PTA ( P = 0.0008), and absence of vertigo ( P = 0.02) were good predictors of the outcome. In contrast, sex, age, affected ear, days to admission, and pattern of the initial audiogram showed no significant influence on the outcome.

CONCLUSION AND SIGNIFICANCE: IT steroid administration after failed intravenous steroids is a safe and effective treatment in sudden sensorineural hearing loss.

The efficacy of combination therapy for idiopathic sudden sensorineural hearing loss

OBJECTIVES/HYPOTHESIS

The aim of this study was to compare the hearing results of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) who initially were treated with either a combination therapy of systemic steroids (SS) and intratympanic steroid injection (IT-S) or SS only.

METHODS

The study followed a retrospective case-control design. One-hundred five patients who were diagnosed with ISSNHL and required treatment via admission were enrolled in this study. The control group (n = 53) was treated with SS, and the study group (n = 52) received SS as well as IT-S. We divided the patients according to pretreatment hearing levels. The outcome measured was improvement after the treatment audiology data at pretreatment were compared with those at day 10 and > 90 days after the treatment. Outcome data were analyzed using the t test, Pearson's χ(2) test, Fisher's exact test, and multivariate analyses of covariance with adjustment for pretreatment hearing levels.

RESULTS

After more than 90 days, the average pure tone audiometry (PTA) in the control and study groups were 54.8 ± 31.4 dB and 43 ± 31.2 dB, respectively (P = 0.013). Hearing recovery rate was 57.7% in the control group and 69.8% in the study group. The hearing gain of the study group was higher than that of the control group at high frequencies within the 10 days of the treatment period. Analysis between subgroups, divided according to the severity of pretreatment hearing level, showed that the recovery rate was higher at all frequencies in the study group than in the control group in patients with mild to moderate hearing loss (pretreatment PTA < 70 dB). However, in patients with severe to profound hearing loss (pretreatment PTA ≥ 70 dB), the hearing outcomes of the study and control groups were not significantly different, except at a low frequency.

CONCLUSION

The results of this study suggest that the treatment of ISSNHL with combination therapy results in higher hearing recovery rates when compared to treatment with SS alone, even in patients with severe hearing loss.

LEVEL OF EVIDENCE

3b. Laryngoscope, 126:1871-1876, 2016.

Viral causes of hearing loss: a review for hearing health professionals

A number of viral infections can cause hearing loss. Hearing loss induced by these viruses can be congenital or acquired, unilateral or bilateral. Certain viral infections can directly damage inner ear structures, others can induce inflammatory responses which then cause this damage, and still others can increase susceptibility or bacterial or fungal infection, leading to hearing loss. Typically, virus-induced hearing loss is sensorineural, although conductive and mixed hearing losses can be seen following infection with certain viruses. Occasionally, recovery of hearing after these infections can occur spontaneously. Most importantly, some of these viral infections can be prevented or treated. For many of these viruses, guidelines for their treatment or prevention have recently been revised. In this review, we outline many of the viruses that cause hearing loss, their epidemiology, course, prevention, and treatment.

Antivirals for idiopathic sudden sensorineural hearing loss

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) is characterised by sudden loss of hearing of cochlear or retro-cochlear origin without an identifiable cause. Antivirals are commonly prescribed, but there is no consensus on the treatment regimen or their effectiveness.

OBJECTIVES

To determine the effectiveness and side effect profile of antivirals in the treatment of ISSHL.

SEARCH METHODS

We systematically searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 5), PubMed, EMBASE, CINAHL and other databases to 12 June 2012. We also scanned the reference lists of identified studies for further trials.

SELECTION CRITERIA

Randomised controlled trials comparing different antivirals versus placebo (both with or without other treatment).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data, met to resolve disagreements and contacted study authors for further information. We assessed study risk of bias independently. We considered meta-analysis inappropriate and ultimately not possible due to differing treatment protocols of varying dose and duration, together with differing inclusion criteria and outcome measures between studies. The results of each study are reported individually.

MAIN RESULTS

We included four randomised trials (257 participants). The overall risk of bias in the included studies was low. Two trials compared the addition of intravenous acyclovir to a steroid (prednisolone). One included 43 participants, the other 70 patients. Neither demonstrated any hearing improvement with ISSHL. Another (84 patients) did not show any statistically significant difference between groups with the addition of valacyclovir to prednisolone (compared to steroid plus placebo) with respect to change in pure-tone audiogram. Comparing the addition of intravenous acyclovir to hydrocortisone with hydrocortisone alone, the final trial did not show any statistically significant difference between groups (60 patients). No trial documented any serious adverse effects related to the use of antiviral treatment. One study reported slight to moderate nausea equally in the acyclovir and placebo groups (one patient in each). Another reported insomnia, nervousness and weight gain with valacyclovir (number not specified). Even though no meta-analysis was possible, evidence from the four RCTs has demonstrated no statistically significant advantage in the use of antivirals in the treatment of ISSHL.

AUTHORS' CONCLUSIONS

There is currently no evidence to support the use of antiviral drugs in the treatment of ISSHL. The four trials included in this review were, however, small and with a low risk of bias. Further randomised controlled trials with larger patient populations, using standardised inclusion criteria, antiviral regimes and outcome measures, are needed in order for adequate meta-analysis to be performed to reach definitive conclusions. A uniform definition of ISSHL should also be established, together with what constitutes adequate recovery.

Combined intratympanic and systemic use of steroids for idiopathic sudden sensorineural hearing loss

OBJECTIVE

To compare hearing results in idiopathic sudden hearing loss patients treated with systemic steroids alone or combined intratympanic and steroids.

STUDY DESIGN

Prospective.

SETTING

Tertiary referral hospital.

PATIENTS

Idiopathic sudden sensorineural hearing loss patients.

INTERVENTIONS

The patients in the systemic therapy group received consecutive administration of 100 mg intravenous methylprednisolone in the first day, 80 mg/day oral prednisolone in 3 divided doses for the next 2 days, and continued with oral administration of steroids by tapering the dose 20 mg in every 2 days. The patients in the combined treatment group received intratympanic injection of methylprednisolone (an approximate dose of 0.5 ml of 125 mg/ml). A total of 5 injections on alternate days were performed.

MAIN OUTCOME MEASURES

The mean and median PTA gains of systemic corticosteroid therapy (SCT) group were 7.5 and 5 dB at 5th day, 12.1 and 7.5 dB at 10th day, and 13.0 and 8.8 dB at 15th day. The mean and median PTA gains for combined treatment (CT) group were 12.5 and 7.5, 17.8 and 13.8, 21.8 and 20.0 dB, respectively.

RESULTS

Both the mean and the median PTA gains were statistically significantly different between SCT and CT groups. According to improved hearing results (more than 10 dB gain), there was statistically significant difference between SCT and CT groups. None of the patients had an important complication.

CONCLUSION

The results of this study suggest that adding intratympanic methylprednisolone to systemic therapy increases the probability of hearing recovery in ISSHL patients.

Sudden sensorineural hearing loss: subclinical viral and toxoplasmosis infections as aetiology and how they alter the clinical course

AIM

To explore in a prospective study the evidence of certain viral and toxoplasmosis infections in sudden sensorineural hearing loss (SSHL).

METHODS

84 consecutive patients with SSHL meeting certain criteria. All patients were assessed for specific IgM antibodies against cytomegalovirus, herpes simplex virus, toxoplasma and Epstein-Barr virus. All were treated with intravenous steroids and assigned to two groups: 76 IgM negative (NV group) and 8 IgM positive (no history of acute infection - V group).

RESULTS

The mean hearing level at presentation was 86.5 dB HL (median, 100) in the V group and 60.7 dB HL (median, 61) in the NV group. The difference was statistically significant (p = 0.003). The mean hearing level following treatment was 81.8 dB HL (median, 88) in the V group and 48.7 dB HL (median, 39) in the NV group. The difference was statistically significant (p = 0.004). There was a considerable improvement in hearing after treatment only in the NV group (p < 0.000001).

CONCLUSIONS

Recent subclinical viral or toxoplasmosis infections may be involved in the pathogenesis of SSHL (in approx. 10% of cases), suggesting that SSHL is not a single disease. When certain viruses or toxoplasmoses are involved, the hearing is much worse in comparison to patients with no such indication of infection. An alteration in treatment dosage or method of steroid administration may be needed in such cases.

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.

Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos

Vários fatores têm sido postulados como causa da surdez súbita idiopática. Por meio de uma revisão bibliográfica foi feita uma análise crítica quanto aos aspectos etiológicos e fisiopatogênicos desta manifestação clínica. Estudos atuais sugerem que os distúrbios vasculares, a ruptura de membranas da orelha interna e as doenças auto-imunes são possíveis causas, mas a afecção viral tem recebido maior atenção nos últimos anos, embora ainda pouco se conheça sobre os mecanismos da surdez súbita idiopática. Os vírus podem causar a perda súbita da audição na infecção aguda, mas a forma latente, com uma possível reativação viral, também tem sido considerada no mecanismo de agressão à cóclea. Apesar de uma alteração da viscosidade sangüínea poder explicar a perda auditiva, estudos experimentais e clínicos não mostram sinais de ossificação e de fibrose na cóclea ou de ruptura de membranas do labirinto. Estes fatos contrapõem, respectivamente, a teoria vascular e a da fístula labiríntica. A eventual presença de anticorpos contra a orelha interna sugere que a surdez súbita idiopática possa ser de natureza auto-imune, fato este também não confirmado pela falta de relação entre os aspectos clínicos e morfológicos da doença auto-imune e da perda auditiva. A surdez súbita idiopática é, ainda, um tema controverso e obscuro em diversos aspectos.

Treatment of idiopathic sudden sensorineural hearing loss

CONCLUSION

The therapeutic role of corticosteroids and/or corticosteroids with antiviral agents for sudden sensorineural hearing loss (SSNHL) has yet to be fully elucidated; however, in cases where deafness is profound and of recent onset, a therapeutic trial is indicated.

OBJECTIVES

To investigate treatment regimens and their efficacies, as well as evaluating the potential prognostic correlates and allowing comparison between local and national standards of care for SSNHL.

PATIENTS AND METHODS

A retrospective evidence-based case series of 143 patients seen at the University of Rochester, Department of Otolaryngology between 1999 and 2002 was investigated. Treatment modalities included (1) observation, (2) steroids, and (3) steroids with antivirals.

RESULTS

The study demonstrates that steroid treatment, alone or in combination with antivirals, results in a significant improvement rate compared with observation. Results indicate that the more expediently a patient with SSNHL is seen by an otolaryngologist, the better their prognosis.

Idiopathic sudden sensorineural hearing loss: etiopathogenic aspects

Several factors have been postulated to elicit the etiology of idiopathic sudden sensorineural hearing loss. Through a bibliographic review, we made a critical analysis of the different etiopathogenic aspects of its clinical manifestation. The most recent studies concerning the possible causes of sudden hearing loss suggest vascular disorders, rupture of the inner ear membrane and autoimmune diseases; however, viral infections have received a great deal of attention in recent years. Little is known about the mechanism of sudden hearing loss. Viruses can cause sudden hearing loss in an acute infection, however the latent form, and its possible reactivation have also been considered as explanations of the cochlear injury mechanism. Even though hearing loss can be explained by a blood viscosity change, experimental and clinical studies do not show any evidence of labyrinthine fibrosis and new bone formation, or labyrinthine membrane breaks. These findings are not in agreement with vascular and rupture membrane factors, respectively. The eventual presence of antibodies against the inner ear suggests that sudden hearing loss pathogenesis may be of autoimmune nature, but the difficulty in establishing the correlation of its morphological and clinical aspects to the hearing loss also do not help to support this statement. Sudden hearing loss is still a controversial and obscure subject in several aspects.

Fatores clínicos, etiológicos e evolutivos da audição na surdez súbita

Existem várias terapias preconizadas para o tratamento da surdez súbita, algumas apresentam riscos significativos necessitando inclusive de internação hospitalar. OBJETIVO: Este estudo prospectivo analisa aspectos clínicos, etiológicos e evolutivos nos casos de surdez súbita (SS) em pacientes tratados ambulatorialmente com medicação oral. FORMA DE ESTUDO: clínico com coorte transversal. MATERIAL E MÉTODO: 40 pacientes com perda súbita da audição submeteram inicialmente a avaliação clínica otorrinolaringológica, testes audiométricos, análise hematológica e ressonância magnética. Confirmado o diagnóstico de SS, todos os pacientes receberam inicialmente prednisona e pentoxifilina sendo acompanhados por pelo menos um ano. RESULTADO: 45% (n=18) apresentaram normalização dos limiares auditivos, 40% (n=16) apresentaram melhoras auditivas, 15% (n=6) mantiveram os mesmos limiares iniciais. Nove casos (22,5%) apresentaram manifestações clínicas que justificaram a perda auditiva (infecção viral, fatores imunomediados, alterações vasculares e outros), três (7,5%) apresentaram tumores na região do ângulo ponto-cerebelar. A evolução auditiva nestes 12 casos com etiologia presumida não apresentou diferença estatística significante em relação aos 28 casos sem etiologia definida. O tratamento clínico instituído nos primeiros sete dias de instalação da perda auditiva, nos pacientes que obtiveram melhora, foi o único parâmetro estatisticamente significante dos fatores prognóstico avaliado. CONCLUSÃO: A pesquisa exaustiva etiológica deve ser realizada em qualquer caso de perda auditiva neurossensorial aguda. A presença de 7,5% de tumores localizados na região do ângulo ponto-cerebelar nos casos de SS juntamente com outras causas tratáveis justifica a investigação clínica nestes pacientes. Nossos pacientes apresentaram uma boa melhora auditiva em 67,5% dos casos, independentemente da etiologia. O início da terapia nos primeiros sete dias de instalação da perda auditiva foi o único fator de melhora significante dos limiares auditivos.

Hyperbaric Oxygen Therapy for Sudden Sensorineural Hearing Loss: A Prospective Trial of Patients Failing Steroid and Antiviral Treatment

OBJECTIVE

To investigate the safety and efficacy of hyperbaric oxygen therapy (HBOT) in adult patients with sudden sensorineural hearing loss (SSNHL) who fail standard of care steroid and antiviral therapy.

STUDY DESIGN

Prospective cohort study.

SETTING

An urban tertiary referral center.

PATIENTS

Nine adult patients presenting with SSNHL from December 2002 through February 2004. Patients with acute onset SSNHL of greater than 30 dB in three contiguous frequencies who failed to show audiometric improvement after 2 weeks of systemic steroids and antivirals were enrolled.

INTERVENTIONS

Study patients received HBOT at 2.0 atmospheric pressure for 90 minutes while breathing 100% oxygen under a clear plastic hood in the chamber. Treatments were administered daily for 10 days over a 2-week period.

MAIN OUTCOME MEASURES

Pre-and postHBOT mean hearing gains measured in decibels for pure-tone audiometry at 0.5, 1, 2, 3, and 4 KHz for bone and additional 8 KHz for air; pure-tone averages for air and bone; speech reception thresholds; and speech discrimination levels. Patient-reported subjective recovery rates (completely, substantially, partially, not improved) were also recorded.

RESULTS

Overall, two patients had a dramatic improvement, and one patient had a dramatic improvement in his speech discrimination without improvement in other audiometric measures. Six patients had no demonstrable hearing gains. Two patients had complications of serous otitis media requiring myringotomy and pressure equalizing tube placement. No other complications were observed.

CONCLUSIONS

Secondary HBOT after failure of systemic steroid and antiviral therapy may be associated with hearing gains in some patients with SSNHL.

Clinical, etiological and progression factors of hearing in sudden deafness

Out of the many forms of therapy for sudden deafness, some require hospitalization and present significant risks.

AIM

This prospective study analyzes etiology and evolution in cases of sudden deafness (SD) where outpatient oral treatment was used.

STUDY DESIGN

Clinical with transversal cohort.

MATERIAL AND METHOD

Forty cases of sudden hearing loss were followed for at least one year. All were submitted to initial clinical evaluation, auditory tests, routine blood analysis, and magnetic resonance imaging. All received initial treatment with pentoxifylline and prednisone.

RESULTS

45% (n=18) presented normal auditory thresholds, 40% (n=16) showed some improvement in hearing, 15% (n=6) maintained initial hearing level. Nine cases (22.5%) presented clinical conditions possibly implicated in hearing loss (viral infection, immunomediated hearing loss, vascular disorders, and so on); three (7.5%) had cerebellopontine tumors. Evolution of hearing in these 12 cases with presumed etiology presented no differences from hearing in the 28 cases without any known etiological factor. Clinical treatment within the first seven days was the only statistically significantly different condition in patients who improved hearing.

CONCLUSIONS

An objective search for etiological bases should be conducted in any case of acute sensorineural hearing loss. The presence of cerebellopontine tumors in 7.5% of cases of SD, among other treated causes, justifies a thorough clinical investigation in these patients. Overall good evolution of hearing was observed in 67.5% of cases of SD, regardless of its etiology. Therapy within the first seven days of SD was significantly related to better outcomes in hearing.

Surdités brusques idiopathiques

Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) remains one of the major unsolved otologic emergencies. It is characterized by the onset of an unilateral sensorineural hearing loss developing within 24 hours, and averaging on pure tone audiogram at least 30 dB HL for three subsequent octave steps, with no marked vestibular symptoms and no identifiable cause. ISSHL is a syndrome covering several heterogeneous entities resulting from different pathogenetic mechanisms. At this time, the audiogram is the unique tool which may help clinicians to identify these entities and provide a classification based on 5 types of hearing loss. Numerous experimental and clinical studies have investigated the mechanisms by which infectious, ischemic, mechanic or immunologic insults may induce cochlear dysfunction. However, extrapolation to humans and rationale therapeutic approaches to ISSHL remain uncertain. SSHL being a diagnosis of exclusion, retrocochlear and neurologic etiologies should be eliminated. No argument allows to consider ISSHL a therapeutic emergency. More precisely, the experimental data presently available on cochlear physiology suggests that a treatment could have some chance to be effective if undertaken within minutes following the onset of ISSHL, a condition never encountered in daily practice. Conversely, it is not justifiable to impute the absence of hearing recovery to a delay in therapy. The various therapeutic strategies currently recommended are highly empirical and should be questionned in terms of cost-effectiveness, the most common being high-dose corticosteroids. New investigation tests are required for improving our approach to ISSHL.

Estudio estadístico y resultados clínicos de la comparación de dos protocolos diferentes en el tratamiento de la hipoacusia brusca

Sudden deafness goes on being a clinical entity of unknown cause for which several theories and treatments have been proposed. We are reporting a comparative study of two different protocols that we have performed on 60 patients (divided in two groups of 30) diagnosed and admitted with sudden hearing loss between 1989 and 2003. The main goal is to prove if there is a statistical and significant difference among both, in respect of the audiologic improvement obtained, after two weeks of therapy at east. We have applied the normal approximation of Mann-Whitney's test and we can argue, after its result, our current protocol (piracetam, pentoxifiline, metilprednisolone), which includes 4 days of endovenous treatment another 10 days at home. The presence of vestibular symptoms darkens the prognosis since about 95% of the patients with them have not improved significantly (p<0.05).

Idiopathic sudden hearing loss in patients with type 2 diabetes

The aim of the present study was to identify clinical and audiologic characteristics of idiopathic sudden hearing loss (ISHL) in patients with type 2 diabetes. We retrospectively investigated 148 cases of ISHL, whose age was more than 40 years, comparing clinical and audiologic valuables between diabetic and non-diabetic patients. Twenty-four patients (16.2%) had type 2 diabetes (16 male, 8 female). Prevalence of hypertension and hyperlipidemia were significantly greater in diabetic patients. Hearing in the affected ear was more impaired in diabetic than non-diabetic patients, although hearing in the unaffected ear and degree of recovery did not differ significantly. Mean BMI, duration of diabetes, HbA1c values, and ultrasonographically determined carotid intima-media thickness (IMT) and plaque scores in diabetic patients with ISHL were 24.0+/-3.7 kg/m(2), 9.8+/-7.8 years, 7.8+/-1.5%, 0.83+/-0.16 mm, and 3.8+/-2.8, respectively. Of 17 diabetic patients whose ISHL was treated with steroids, 12 required insulin for glycemic control during treatment. Compared with diabetic patients without ISHL, HbA1c value was significantly higher in diabetic patients with ISHL (7.2+/-1.2% versus 7.8+/-1.5%, P=0.0202). In conclusion, nearly 16% of our patients with ISHL had type 2 diabetes, and this subgroup was associated with more severe hearing loss. Further studies are needed to determine which subgroups of diabetic patients are most likely to develop ISHL, which patients are predisposed to more severe hearing loss, and how various factors and treatments influence outcome.

Herpes simplex virus and Meniere's disease

OBJECTIVE/HYPOTHESIS

This study was designed to investigate the hypothesis that Meniere's disease is associated with herpes simplex virus (HSV) reactivation in the vestibular ganglion.

STUDY DESIGN

Case control study.

METHODS

Vestibular ganglia were obtained from archival surgical pathology specimens from patients undergoing vestibular neurectomy for vertigo caused by Meniere's disease. All patients met criteria for classification as definite Meniere's disease according to American Academy of Otolaryngology/Head and Neck Surgery (AAO-HNS) criteria. Control specimens were obtained from willed body donors. Sections from each ganglion were studied for prevalence of viral DNA using a nested polymerase chain reaction designed to amplify the HSV DNA polymerase gene. Quantitative analysis determined the number of viral copies per standard unit of ganglionic DNA.

RESULTS

HSV DNA was more prevalent in paraffin embedded ganglia from patients with Meniere's disease (100%) than in fresh-frozen control ganglia (81%) (P =.02). Fixation and paraffin embedding substantially reduced recovery of HSV virus in selected control specimens. Quantitative analysis found no correlation between viral copy number in control ganglia processed frozen versus formalin fixed and paraffin embedded.

CONCLUSIONS

HSV is more commonly isolated from vestibular ganglia of patients with Meniere's disease than the general population. The routine histologic preparation of formalin fixation and paraffin embedding significantly altered the quantity of virus detected though not in a predictable manner. The study provides supportive evidence for a viral etiology in Meniere's disease.

Acyclovir in the Treatment of Idiopathic Sudden Sensorineural Hearing Loss

BACKGROUND: Idiopathic sudden sensorineural hearing loss (ISSNHL) is a vexing problem that continues to pose a diagnostic and therapeutic enigma for the otologist. The aim of the study, adopting the viral theory, was to discover whether patients with ISSNHL would benefit from early treatment with acyclovir and hydrocortisone compared with patients treated by hydrocortisone alone.

METHODS: Sixty patients with ISSNHL were treated in a prospective controlled randomized manner. Patients were seen within 7 days of onset and were divided randomly into 2 groups. The study group patients were treated with acyclovir and hydrocortisone, whereas those in the control group were treated with hydrocortisone alone.

RESULTS: We compared the 2 groups before and after treatment regarding SRT, mean hearing level at each frequency, speech reception threshold improvement, gender, age, tinnitus, and balance complaints. The overall improvement was 78%.

CONCLUSION: We conclude that there probably is no benefit from the addition of acyclovir in the treatment of ISSNHL.

Influenza A virus infection of human Schwann cells in vitro

OBJECTIVES

Sudden sensorineural hearing loss, vestibular neuronitis, vocal fold paralysis and Bell's palsy have been associated with a viral etiology, due to the infection of nerve cells. The goal of this research was to ascertain whether Schwann cells can support infection with human influenza A virus and thereby represent a plausible alternative site for virus-host interaction. Viral infection of Schwann cells may lead to secretion of inflammatory mediators, leukocyte recruitment, demyelination and nerve damage.

MATERIAL AND METHODS

Cultured human Schwann cells were exposed to human influenza A virus. Infection was assayed at various times post-inoculation (0, 24, 48 and 72 h) using light microscopy, immunocytochemistry and influenza A virus-specific reverse transcriptase polymerase chain reaction (RT-PCR). A group of unexposed cells served as controls.

RESULTS

Following exposure to the virus, vacuolization, cellular expansion and detachment from the dish were seen as early as 24 h post-inoculation. The exposed cells demonstrated positive immunocytochemical staining for influenza A virus antigen at 24, 48 and 72 h. Using RT-PCR, a sharp rise in influenza A virus-specific mRNA was detected.

CONCLUSIONS

Human Schwann cells can be infected with human influenza A virus. Further studies will assess the inflammatory response in this model.