Is microvascular compression of the vestibulocochlear nerve a cause of unilateral hearing loss?

OBJECTIVES: We sought to confirm earlier findings in the literature that microvascular compression of the vestibulocochlear nerve might cause unilateral sensorineural hearing loss. We measured the length and width of the internal auditory canal (IAC) to investigate a possible association between a narrow porus, the presence of an anterior inferior cerebellar artery (AICA) loop, and the development of a microvascular compression syndrome. METHODS: We performed a prospective blinded analysis of 167 magnetic resonance imaging scans of the cerebellopontine angle. The presence of an AICA loop was scored. We analyzed these 167 patients for unilateral sensorineural hearing loss, which was defined as an interaural difference of 20 dB at 1 frequency or 10 dB at 2 or more frequencies. Furthermore, the width and length of the IAC on magnetic resonance imaging were measured. RESULTS: An AICA loop was identified in 94% of the 167 patients. There were 196 type I loops, 106 type II loops, and 14 type III loops. Sixty-six patients had unexplained unilateral hearing loss. There was no association between type II and III vascular loops, the width of the IAC, and unilateral hearing loss (p > .05). CONCLUSIONS: In this study we found no association between the depth of extension of the AICA loop into the IAC and the presence of unilateral hearing loss.     

When is a conductive hearing loss not a conductive hearing loss? Causes of a mismatch in air-bone threshold measurements or a "pseudoconductive" hearing loss

The otolaryngologist is sometimes faced with a patient with an apparent conductive hearing loss on audiometric testing who appears to have normal and mobile middle ear structures on ear exploration. Some causes of these "pseudoconductive" hearing losses can be diagnosed without resorting to surgery. This article reviews several possible mechanisms for this condition with diagnostic procedures to distinguish etiologic diseases. Conditions discussed include poor audiometry, functional hearing losses, "third window" causes, obliterated round window, abnormal inner ear connection with the cerebrospinal fluid space, inner ear mechanical conductive hearing loss, and apparent inner ear loss owing to missed middle ear pathology.     

Is Susac syndrome (microangiopathy of the inner ear, retina, and central nervous system) an underdiagnosed cause of sensorineural hearing loss?

Susac syndrome is a rare disorder caused by the development of microangiopathic lesions in the inner ear, retina, and central nervous system. Although relatively few cases have been reported in the literature, this diagnosis is becoming more frequent as physician awareness increases. A high index of suspicion is needed to make the diagnosis because the signs and symptoms of Susac syndrome are those of a wide range of differential diagnoses. Otolaryngologists should be familiar with this syndrome because hearing loss may be the initial presenting symptom. We describe a new case of Susac syndrome to further promote physician awareness, and we discuss the options for diagnosis and treatment.     

Is familial adenomatous polyposis associated with sensorineural hearing loss?

Abstract

The mutation causing familial adenomatous polyposis (FAP) affects the adenomatous polyposis coli (Apc) gene, which has a role in the cytoskeleton and has been shown to be important in the structure of supporting cells in the cochlea. One previous study suggested that FAP sufferers may have sensorineural hearing loss. In order to demonstrate whether this is the case we invited patients known to suffer from familial adenomatous polyposis to take part in our study. Audiograms were performed and compared to normal values for that patient's age and gender calculated using ISO standard data. Thirteen patients were included in the study analysis. No conductive hearing losses were identified. A statistically significant greater hearing loss was identified at 500 Hz (2.8 dBHL, P = 0.03) and 1000 Hz (2.5 dBHL, P = 0.05). No audiometric difference could be identified between the patients with FAP and attenuated FAP. A power calculation demonstrated that the study was of adequate size. This study did not demonstrate a clinically significant difference in hearing loss between the FAP group and the calculated normal values.

Sumario

La mutación que causa la poliposis adenomatosa familiar (FAP) afecta el gene polipomatosis adenomatosa coli (Apc), que tiene un papel cuya importancia en el citoesqueleto y en la estructura de las células de sostén de la cóclea se ha demostrado. Un estudio previo sugirió que quienes sufren la FAP pueden tener una pérdida auditiva sensorineural. Con objeto de demostrar si esto es así, invitamos a pacientes que (sabíamos) sufrían la enfermedad para tomar parte en este estudio. Los audiogramas que se practicaron fueron comparados con los valores normales de acuerdo con la edad y el género de los pacientes, usando los datos ISO estándar. Se incluyeron trece pacientes para el análisis del estudio. No se identificaron pérdidas auditivas conductivas. Si hubo una pérdida auditiva mayor, estadísticamente significativa en 500 Hz (2.8 dBHL, P = 0.03) y en 1000 Hz (2.5 dBHL, P = 0.05). No se pudo identificar una diferencia audiométrica entre los pacientes con FAP o con FAP atenuada. Un cálculo especial demostró que el estudio fue de un tamaño adecuado. Este estudio no mostró una diferencia clínicamente significativa de la pérdida auditiva entre el grupo con FAP y los valores calculados como normales.     

Four systems involved with congenital abnormalities: a new type of syndromic hearing loss - ADOC Wang's syndrome?

Syndromic hearing impairment encompasses hundreds of phenotypes. We identified a young female patient affected by the unique combination of dysplasia of the auricular system, patent ductus arteriosus (PDA), choroideremia, and enamel hypoplasia. The patient was treated with PDA ligature and left exploratory tympanotomy. Impairment in all four systems suggests a correlation with the neural crest. It is presumed that all of the features result from the same origin, probably through autosomal recessive inheritance or a novel mutation during the embryonic period. When audio-dento-oculo-cardio systems are involved, we suggest that this new syndrome can be named 'ADOC Wang's syndrome', summarizing the disorders of the four systems and indicative of the founding person (Dr Wang, the first and corresponding author of the paper).     

Can self assessment of communication predict hearing loss?

A total of 120 subjects with hearing loss (75 men, 45 women), within the age range 18-70 years (mean, 38 years), and 15 normal subjects were administered a modified Hindi adaptation of the 'self assessment of communication' hearing loss inventory. The study aimed to determine whether there was any correlation between subjects' average pure tone thresholds and their inventory scores. Data was analysed using the Pearson coefficient of correlation and regression analysis. A negative correlation was obtained stating that the greater the hearing loss, the lower the inventory score. An equation could also be derived for the bilateral symmetrical sensorineural hearing loss group and the bilateral symmetrical conductive hearing loss group to enable calculation of patients' average hearing loss from their inventory scores, in the absence of an audiogram. This could aid rehabilitation in cases with either type of hearing loss (in which no medical intervention was required) when pure tone audiometry is not possible.     

Is auditory brainstem response a prognostic factor in patients with sudden sensorineural hearing loss?

Abstract

Background: Serum thyroid hormone levels are closely related to the normal functioning of the cochlea. However, the relationship between initial auditory brainstem response (ABR) results and levels of thyroid hormone remained unclear until we adopted ABR as a prognostic factor in Idiopathic sudden sensorineural hearing loss (ISSNHL) patients.

Objective: This investigation aimed to elucidate the association between ABR and outcomes in patients with ISSNHL.

Material and methods: Thirty-three patients presenting with unilateral ISSNHL underwent blood sampling and ABR tests on the day of admission. The mean latencies of the ABR results were compared among the groups which were classified by ISSNHL outcome, based on Siegel’s criteria. The association between the ABR results and the thyroid hormone serum levels (TSH, T3, and free T4) were assessed.

Results: The overall successful recovery rate was 60.6% (n?=?20). The mean latencies of all the ABR parameters were not significantly different between the different treatment outcome groups (Mann–Whitney U test). Wave V latency, III–V interval and I–V interval were negatively associated with T3 serum levels.

Conclusion: The results indicate that clinical caution should be exercised when conducting ABR tests without assessing thyroid hormone levels.     

Does tinnitus,hearing asymmetry,or hearing loss predispose to occupational injury risk?

Abstract

Objective: To determine the relative contributions of tinnitus, asymmetrical hearing loss, low frequency hearing loss (pure tone average of 0.5, 1, 2, 3 kHz; PTA.₅₁₂₃), or high frequency hearing loss (pure tone average of 4, 6 kHz; PTA₄₆), to acute injury risk among a cohort of production and maintenance workers at six aluminum manufacturing plants, adjusting for ambient noise exposure and other recognized predictors of injury risk. Design: Retrospective analysis. Study sample: The study considered 9920 workers employed during 2003 to 2008. The cohort consisted of 8818 workers (89%) whose complete records were available. Results: Adjusting for noise exposure and other recognized injury predictors, a 25% increased acute injury risk was observed among workers with a history of tinnitus in conjunction with high-frequency hearing loss (PTA₄₆). Low frequency hearing loss may be associated with minor, yet less serious, injury risk. We did not find evidence that asymmetry contributes to injury risk. Conclusion: These results provide evidence that tinnitus, combined with high-frequency hearing loss, may pose an important safety threat to workers, especially those who work in high-noise exposed environments. These at risk workers may require careful examination of their communication and hearing protection needs.     

Auditory neuropathy or endocochlear hearing loss?

AIMS: The purpose of the study was to define boundaries between endocochlear hearing loss and auditory neuropathy in children with congenital profound hearing loss and positive otoacoustic emissions. PATIENT: A child presented with bilateral profound hearing loss, which was confirmed by the absence of evoked auditory potentials at 110 dB and with conserved otoacoustic emissions. The lack of any relevant medical history, a normal neurologic pediatric examination, and the improvement obtained with powerful hearing aids suggested an endocochlear cause. Genetic testing identified mutations in OTOF, responsible for the DFNB9 recessive form of hearing loss. RESULTS: In recent years, cases of children with hearing loss associated with positive otoacoustic emissions have been labeled as "auditory neuropathy." Classically, this form of hearing loss is refractory to the use of hearing aids and cochlear implants. Mutations in OTOF lead to inner hair cells dysfunction, whereas the outer hair cells are initially functionally preserved. As this form of endocochlear hearing loss can be detected at a molecular level, genetic testing can be proposed for cases of nonsyndromic auditory neuropathy, as those children could benefit from cochlear implantation. CONCLUSION: It is advisable to reserve the term "auditory neuropathy" for patients who present hearing loss and conserved otoacoustic emissions in the context of a neurologic syndrome or for children with suggestive perinatal history. In other cases, genetic testing for mutations in OTOF should be carried out.     

Is the C-reactive protein/albumin ratio a prognostic and predictive factor in sudden hearing loss?

IntroductionSudden hearing loss is a significant otologic emergency. Previous studies have revealed a coexistence of sudden hearing loss with chronic inflammation. The predictive importance of C-reactive protein/albumin values as a prognostic factor has been shown in various inflammatory and tumoral conditions.ObjectivesThe aim of this study was to determine whether the C-reactive protein/albumin ratio in sudden hearing loss can be used for prognostic purposes and whether there is a relationship between the neutrophil/lymphocyte ratio and the C-reactive protein/albumin ratio.MethodsA retrospective examination was made of 40 patients diagnosed with idiopathic sudden hearing loss and a control group of 45 healthy subjects. The pure tone averages of all the patients were determined on first presentation and repeated at 3 months after the treatment. The patients were separated into 2 groups according to the response to treatment. The neutrophil/lynphocyte ratio and the C-reactive protein/albumin ratios were calculated from the laboratory tests.ResultsThe patients included 16 females and 24 males with a mean age of 44.1 ± 14.2 years and the control group was composed of 23 females and 22 males with a mean age of 42.2 ± 13.8 years. The mean C-reactive protein/albumin ratio was 0.95 ± 0.47 in the patient group and 0.74 ± 0.13 in the control group. The difference was statistically significant (p = 0.009). The mean C-reactive protein/albumin ratio was 0.79 ± 0.12 in the response to treatment group and 1.27 ± 0.72 in the non-response group, with no significant difference determined between the groups (p = 0.418). The mean neutrophil/lymphocyte ratio was 3.52 ± 3.00 in the response to treatment group and 4.90 ± 4.60 in the non-response group, with no statistically significant difference determined between the groups (p = 0.261).ConclusionC-reactive/albumin ratio was significantly higher in patients with sudden hearing loss than in the control group. Although C-reactive protein/albumin ratio was found to be lower in sudden hearing loss patients who responded to treatment compared to those who did not, the difference between two groups was not statistically significant.     

Is otolithic vertigo accompanied by hearing loss caused by sacculocochlear endolymphatic hydrops?

Conclusion: Otolithic vertigo is sometimes accompanied by hearing loss. Otolithic vertigo accompanied by hearing loss seems to be caused by sacculocochlear endolymphatic hydrops. Objectives: To clarify the lesion site and pathophysiology of otolithic vertigo (OV) accompanied by hearing loss. Methods: The clinical records of four patients (two men and two women) that had been diagnosed with OV accompanied by hearing loss according to pre-determined diagnostic criteria were reviewed. Results: The patients’ main symptoms involved a sensation of movement in the pitch plane. All of the patients had low frequency-dominant hearing loss and either exhibited decreased cervical vestibular evoked myogenic potentials (cVEMP) or did not produce cVEMP. Two patients produced normal ocular VEMP (oVEMP). Caloric tests obtained normal results in all patients.     

Is corticosteroid therapy effective for sudden-onset sensorineural hearing loss at lower frequencies?

OBJECTIVE: To assess the efficacy of corticosteroid therapy for sudden-onset sensorineural hearing loss at lower frequencies. DESIGN: Retrospective, nonrandomized, controlled study. PATIENTS AND METHODS: The recovery rate, recovery/improvement rate, and period between the start of therapy and improvement of symptoms were studied in 2 groups: the control group, consisting of 36 patients treated with adenosine triphosphate disodium, kallidinogenase, and cyanocobalamin between March 1, 2000, and January 31, 2001; and the corticosteroid-treated group, consisting of 42 patients treated with corticosteroids in addition to the previously mentioned drugs between April 1, 1997, and February 29, 2000. RESULTS: No significant difference (P =.83) was noted in the recovery rate between the control group (81%) and the corticosteroid-treated group (79%), and the recovery/improvement rate was the same for the 2 groups (83%). In addition, there was no significant difference (P =.84) for the mean +/- SD period between the start of therapy and improvement of symptoms between the control group (3.9 +/- 2.7 days) and the corticosteroid-treated group (3.7 +/- 2.1 days). CONCLUSION: Corticosteroids were not effective for sudden-onset sensorineural hearing loss at lower frequencies.