A diagnostic paradigm for childhood idiopathic sensorineural hearing loss

OBJECTIVE: Our objective was to determine the diagnostic yield of laboratory testing, radiological imaging, and GJB2 mutation screening in a large cohort of patients with differing severities of idiopathic sensorineural hearing loss (SNHL). DESIGN AND SETTING: We undertook a retrospective study of patients presenting with SNHL at our institution from 1993 to 2002. RESULTS: Laboratory testing had an extremely low yield. Patients with unilateral SNHL had a significantly higher imaging yield than those with bilateral. The diagnostic yield of GJB2 screening was significantly higher in patients with severe to profound SNHL than in those with less severe SNHL. However, a relatively large number of patients with mild to moderate SNHL had positive GJB2 screens. CONCLUSIONS: Based on diagnostic yields, we propose a cost-effective stepwise diagnostic paradigm to replace the more commonly used and costly simultaneous testing approach. EBM RATING: C.     

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.     

Genetic testing for hearing impairment

For some patients, genetic testing can reveal the etiology of their hearing impairment, and can provide evidence for a medical diagnosis. However, a gap between fundamental genetic research on hereditary deafness and clinical otology emerges because of the steadily increasing number of discovered genes for hereditary hearing impairment (HHI) and the comparably low clinical differentiation of the HHIs. In an attempt to keep up with the scientific progress, this article enumerates the indications of genetic testing for HHI from a clinical point of view and describes the most frequently encountered HHIs in Belgium. Domains of recent scientific interest, molecular biological aspects, and some pitfalls with HHIs are highlighted. The overview comprises bilateral congenital hearing loss, late-onset progressive high frequency hearing loss, progressive bilateral cochleo-vestibular deficit, and progressive low frequency hearing loss. Also, several syndromal forms of HHI are summarized, and the availability of genetic tests mentioned. Finally, the requirements for successful linkage analysis, an important genetic research tool for localizing the potential genes of a trait on a chromosome, are briefly described.     

Intratympanic dexamethasone for profound idiopathic sudden sensorineural hearing loss

OBJECTIVES: To determine hearing recovery by using intratympanic dexamethasone for profound, idiopathic sudden sensorineural hearing loss (ISSNHL). STUDY DESIGN AND SETTING: A prospective, clinical study was performed of 25 consecutive patients seen with profound ISSNHL. Patients received 4 intratympanic treatments of dexamethasone over the course of 2 weeks. Complete hearing recovery was defined as the final pure-tone average (PTA) within 10 dB of baseline. Partial recovery was defined as a final PTA with >/=50% hearing. The hearing in the contralateral ear was used as baseline. RESULTS: The average time to treatment was 28 days. Two patients had significant hearing recovery, and 1 additional patient had partial recovery. The 2 patients with significant hearing recovery were treated within 9 days of onset of hearing loss. CONCLUSIONS: By using the treatment protocol and definition of hearing recovery of this study, intratympanic dexamethasone does not result in significant hearing improvement for patients with profound ISSNHL. There is a possible trend for improved hearing results if intratympanic treatment is performed within 11 days of onset of hearing loss.     

Oral steroid regimens for idiopathic sudden sensorineural hearing loss.

OBJECTIVE: To determine hearing recovery in patients with idiopathic sudden hearing loss treated with varying amounts of oral steroids. STUDY DESIGN AND SETTING: A retrospective chart review (n = 75) in a tertiary care clinic examined sudden hearing loss patients treated with 1 60-mg prednisone taper, 1 course of steroid less than a 60-mg taper, or any 2 courses of oral steroid. RESULTS: Overall, 35% of the patients recovered a clinically significant amount of hearing. Recovery was associated with immediate treatment (within 2 weeks from onset), better hearing at the onset of treatment, and treatment with the higher dose of prednisone in patients with just 1 additional symptom (dizziness or tinnitus). Patients tended to continue to experience some recovery in hearing up to 4 months after treatment. CONCLUSION: Immediate treatment of patients with unilateral idiopathic sudden hearing loss and additional symptoms (dizziness or tinnitus) with a 14-day course of 60 mg prednisone (with taper) is recommended. EBM rating: B-3.     

Intratympanic steroid perfusion for refractory sudden sensorineural hearing loss.

OBJECTIVE: Patients with sudden sensorineural hearing loss (SSHL) can benefit from systemic steroid therapy. Unfortunately, some patients are not candidates for steroid therapy due to concern over possible complications. Furthermore, not all patients will benefit from steroid administration. This study evaluates the potential benefits and safety of treating patients with SSHL refractory to oral steroids with intratympanic steroid therapy. METHODS: A retrospective case review was performed on all patients who presented with sudden sensorineural hearing loss refractory to oral steroid therapy during the past year. Seventeen patients were identified. All patients underwent intratympanic steroid administration, via MicroWick placement and/or round window catheter placement. RESULTS: Nine patients with sudden sensorineural hearing loss showed an improvement with intratympanic steroid therapy, consisting of MicroWick placement with dexamethasone drop (Decadron) administration for 1-2 weeks and/or round window catheter placement with steroid perfusion. Only one of the patients presenting with hearing loss present for greater than 8 weeks benefited from intratympanic therapy. Complications were few and included tympanic membrane perforation, chronic otitis media, dysequilibrium, and dysguesia. CONCLUSIONS: Intratympanic steroid therapy can be beneficial in treating patients with sudden sensorineural hearing loss refractory to oral steroid use. EBM rating: C.     

Evaluation of super-high-dose steroid therapy for sudden sensorineural hearing loss.

OBJECTIVE: To determine the efficacy of a high-dose steroid regimen for patients with sudden sensorineural hearing loss (SSNHL) and to evaluate the relationship between outcome and initial steroid dose. STUDY DESIGN AND SETTING: We conducted a retrospective study of 112 patients presenting to Saitama Medical Center. Patients received tapering courses of hydrocortisone (HC) with an initial dose of either 1200 mg or 600 mg. RESULTS: More than 87% of patients had recovery of hearing. When hearing stabilized, there were no significant differences between the 1200 mg and 600 mg groups in terms of hearing outcome (P>0.05). However, at completion of treatment, the 1200 mg group exhibited significantly superior complete recovery rate and improvement rate (P<0.05). CONCLUSION: Application of our treatment protocol of a tapered course of 1200 mg HC significantly and rapidly improves recovery outcomes in patients of SSNHL. EBM rating: C-4.     

Etiologic diagnosis of sensorineural hearing loss in adults

OBJECTIVE: To determine the etiology of adult-onset sensorineural hearing loss. STUDY DESIGN AND SETTING: This is a prospective cohort study of 60 adult subjects with bilateral sensorineural hearing loss of no obvious etiology by medical history and physical examination. These patients were evaluated at an academic medical center and underwent evaluation by high-resolution computed tomography of the temporal bone, autoimmune panel, and DNA testing for mutations of both the GJB2 gene and the mitochondrial DNA (1555A>G and 7445A>G). RESULTS: An etiologic diagnosis was achieved in 6 patients: cochlear otosclerosis, 1 case; dilated vestibular aqueduct, 1 case; a mitochondrial DNA 7445A>G mutation, 3 cases; and a mitochondrial DNA 1555A>G mutation, 1 case. CONCLUSION: This result underscores the importance of a search for the etiology of a hearing deficit in adult patients. There are specific interventions now available for the management of hearing-impaired patients with cochlear otosclerosis and mitochondrial DNA mutations.     

Long-term sensorineural hearing deficit following radiotherapy in patients suffering from nasopharyngeal carcinoma: A prospective study.

BACKGROUND: This was a prospective study to evaluate the effect of radical external irradiation on inner ear function after treatment of nasopharyngeal carcinoma. METHODS: Pure tone audiograms were performed at regular intervals before, after, and up to 4.5 years following completion of radiotherapy. RESULTS: Two hundred ninety-four patients (526 ears) were included. Within 3 months after radiotherapy, deterioration of bone conduction threshold at 4 kHz and pure tone average (average of 0.5 kHz, 1 kHz, and 2 kHz) were noted in 164 ears (31%) and 75 ears (14%), respectively. Patients older than 50 years and ears with threshold below 60 dB at 4 kHz before radiotherapy were significant factors (p < 0.01 and p < 0. 001) associated with a 4 kHz loss. In 40% of these ears, recovery was evident at 2 years. With follow-up for 4.5 years, the probability of significant threshold deterioration increased with time. CONCLUSION: Sensorineural hearing loss started soon after radiotherapy. Early changes could be reversible while the probability of persistent hearing loss continued to increase.     

Diagnosis and treatment of sudden-onset sensorineural hearing loss: a study of 51 patients.

OBJECTIVE: The study purpose was to determine the efficacy of steroid and antiviral therapy in the management of idiopathic sudden sensorineural hearing loss (SSNHL). STUDY DESIGN AND SETTING: We conducted a retrospective study of patients presenting to an academic tertiary care center. Fifty-one patients were evaluated. All patients were placed on the same treatment protocol. RESULTS: Thirty-seven patients (73%) had recovery of hearing. Ninety-one percent of patients with vertigo and all patients with mid-frequency hearing loss and up-sloping hearing loss recovered with treatment (P < 0.05). Recovery was significantly related to age, onset of hearing loss, and audiogram type; however outcome was not significantly related to gender, vertigo, tinnitus, or laterality (P < 0.05). CONCLUSION: Our treatment protocol produced a recovery rate, which exceeds the spontaneous recovery rate. Unlike prior studies, all patients with up-sloping and mid-frequency SSNHL had recovery. In addition, vertigo did not indicate a poor prognosis. SIGNIFICANCE: Antiviral therapy and increased length of steroid treatment may play a role in the improved recovery rates.     

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.     

Investigations into the cause of vertigo in sudden sensorineural hearing loss

In this light microscopic study of the temporal bone, an attempt has been made to find a morphologic correlate of vertigo associated with idiopathic sudden sensori-neural hearing loss (ISSHL). Hair cell densities of the three cristae and both maculae, as well as vestibular ganglion cell (neuronal) count estimation, was done in nine ears that had documented histories of ISSHL. There were five ears with vertigo and four without. These quantitative data--i.e., hair cell densities and neuronal counts, of the vertiginous ears (group I) and nonvertiginous ears (group II)--was compared by histograms and statistically. Additionally, in each of the two groups, the data from three opposite normal hearing ears were taken as a control and used for comparison with the ISSHL ears. The differences between the vertiginous, nonvertiginous, and control ears were not significant at the 0.01 level, indicating that the vertigo was not caused by hair cell or neuronal degeneration. Gross morphologic alterations in the vestibular system, such as membrane ruptures, endolymphatic hydrops, etc., were also assessed, but no clear-cut pathology was identified in the vertiginous and nonvertiginous ears. The absence of a light microscopic morphologic correlate for vestibular disturbances associated with ISSHL suggests that the symptoms could result from ultrastructural changes in the hair cells and their synapses or from biochemical alterations in their environment.     

Iatrogenic impairment of hearing during surgery for acoustic neuroma

Isolated or combined labyrinthine, neural, and vascular damage account for failure to preserve hearing during removal of acoustic neuromas. However, the specific mechanisms of auditory impairment remain unclear unless surgical maneuvers can be related to peri- and postoperative hearing on the basis of intraoperative monitoring of auditory function.Among the different auditory monitoring techniques, recording of cochlear nerve action potentials (CNAPs) from the intracranial portion of the nerve has proven particularly useful for identifying the mechanisms of iatrogenic auditory injury.The present investigation analyzes intra- and postoperative auditory impairment in relation to surgical steps in a group of 38 subjects with acoustic neuroma (size ranging from 5 to 24 mm) undergoing removal via a retrosigmoid approach.Coagulation close to the cochlear nerve, drilling of the internal auditory canal, and removal of the intrameatal portion of the acoustic neuroma have prove to be the most critical surgical steps in hearing preservation.Changes were correlated with intra- and extrameatal tumor size, the relationship between the internal auditory canal and vestibule, and internal auditory canal enlargement, anatomic involvement of the cochlear nerve, preoperative auditory level, and ABR and ENG test findings.Changes in CNAP morphology and latency are detailed, and mechanisms of injury are analyzed and discussed as a function of these variables.     

The use of diagnostic testing in asymmetric sensorineural hearing loss

The etiology of an asymmetric sensorineural hearing loss can often be difficult to determine. Because a wide variety of pathologic processes may be responsible for the hearing loss, numerous diagnostic tests are usually used in the initial evaluation, including pure-tone audiometry, acoustic reflex testing, imaging, serologic testing, and auditory brainstem response testing. The diagnostic evaluations of 225 consecutive cases of asymmetric sensorineural hearing loss are reviewed. A cochlear site-of-lesion was demonstrated in the majority (194) of patients. Because all retrocochlear lesions (31) were associated with an abnormal auditory brainstem response, imaging should be performed in that group of patients. Magnetic resonance imaging offers greater specificity than computed tomography. Reflex decay, acoustic reflex testing, and rollover were all associated with a high false-negative rate. Whereas serologic testing for syphilis yielded several cases of otosyphilis, thyroid function testing was of little value. A diagnostic protocol for asymmetric sensorineural hearing loss is presented.