Hearing loss after spinal anesthesia. An audiological controlled trial

Audiological tests were conducted on 34 patients before and after undergoing an operation in spinal anaesthesia. One of these patients developed a considerable unilateral hearing loss in the low-frequency range, which persisted until an epidural blood-patch was given. Unexpectedly, we also found a general small but significant threshold shift at 500 Hz, which has never before been described in the literature. The biological mechanism is discussed, and the results suggest that the explanation of the hearing loss could be a condition similar to endolymphatic hydrops, resulting from perilymphatic hypotension due to loss of liquor during and after the spinal anaesthesia.     

Further characterization of the DFNA1 audiovestibular phenotype

BACKGROUND: Autosomal dominant, nonsyndromic, hereditary hearing impairment in a large Costa Rican kindred is caused by a mutation in the human homolog of the Drosophila diaphanous gene. OBJECTIVE: To further characterize the phenotype of DFNA1 with comprehensive audiovestibular evaluation and computed tomography of the temporal bone. PATIENTS: One affected child and 2 affected adults of the Costa Rican kindred who harbor a mutation in the diaphanous gene. SETTING: Medical Center at the University of California, San Francisco. INTERVENTION: Otologic and neuro-otologic examination; pure tone audiometry, speech audiometry, and immitance testing; auditory evoked potentials, electrocochleography, and otoacoustic emissions; electronystagmography and vestibular autorotation tests; and computed tomography of the temporal bone. RESULTS: The youngest subject, an 8-year-old boy, had a mild hearing loss, intact stapedial reflexes, otoacoustic emissions at high frequencies, normal auditory evoked potentials, and electrocochleographic findings consistent with endolymphatic hydrops. The two adults had severe to profound bilateral sensorineural hearing impairment. Electronystagmography disclosed normal vestibular function. Computed tomography demonstrated normal external, middle, and inner ear structures. CONCLUSIONS: These results suggest that the early low-frequency hearing loss in this family is associated with endolymphatic hydrops. Elucidation of the role of the diaphanous gene in hearing will therefore lead to a better understanding of the mechanism of endolymphatic hydrops.     

The efficacy of tympanic electrocochleography in the diagnosis of endolymphatic hydrops

Electrocochleography (ECoG), an objective electrophysiologic test, is useful in the clinical diagnosis of endolymphatic hydrops. The purpose of this study was further to define the role of ECoG in the diagnosis of this disease. A retrospective chart review of 100 patients undergoing tympanic ECoG was undertaken comparing symptoms, degree of hearing loss, duration of disease, and diagnosis with ECoG results. The apparent sensitivity and specificity of ECoG in the diagnosis of endolymphatic hydrops were determined to be 57% and 94%, respectively. Three of 30 positive ECoG results were falsely positive. Fluctuating hearing loss and the degree of hearing loss (< 40 dB) and duration of disease (< 48 months) were statistically significant in predicting positive ECoG results. We conclude that a positive ECoG result is helpful in objectively confirming the disease. However, a negative result does not rule out hydrops.     

Tumor necrosis factor and AIDS

A guinea pig model with surgically induced endolymphatic hydrops of the inner ear has been developed and studied over the past thirty years. The aim of such studies is to obtain insight into physiological processes associated with endolymphatic hydrops in man and in particular in Menière's disease where endolymphatic hydrops is systematically encountered at post-mortem examination of the temporal bones. The present review attempts to draw together the data pertaining to functional modifications of inner ear function in the animal model. For simplicity the data are categorised under five main titles: electrochemical modifications, electrophysiological modifications, pressure and hydrops, sensitivity to other insults and vestibular dysfunction. One of the most striking observations that can be made is that the data originating from different authors are very variable. There is, however, some evidence suggesting that the evolution of the auditory dysfunction could be considered as consisting of a series of different phases. This kind of information could serve as a basic framework for future research on the animal model.     

Accuracy of seven different tests for the diagnosis of Helicobacter pylori infection and the impact of H2-receptor antagonists on test results

The financial burden for the evaluation of patients for acoustic neuroma in an otolaryngology practice is substantial. Patients with sudden sensorineural hearing loss represent a portion of that population seen with unilateral, asymmetric auditory symptoms who require investigation for acoustic neuroma. For these patients, gadolinium-enhanced magnetic resonance imaging is the diagnostic gold standard. Auditory brain stem response testing has been used in the past as a screening test for acoustic neuroma, but its apparent sensitivity has fallen as the ability to image smaller acoustic neuromas has improved. Fast spin echo magnetic resonance imaging techniques without gadolinium have been shown to be as effective in the detection of acoustic neuroma as contrast-enhanced magnetic resonance imaging. Limited nonenhanced fast spin echo magnetic resonance imaging now provides an inexpensive alternative for high-resolution imaging of the internal auditory canal and cerebellopontine angle. Fast spin echo magnetic resonance imaging can now be done at a cost approximating auditory brain stem response testing while providing the anatomic information of contrast-enhanced magnetic resonance imaging. Cost analysis was done in the cases of 58 patients with sudden sensorineural hearing loss by comparing the costs for routine workup and screening of acoustic neuroma with the cost of fast spin echo magnetic resonance imaging with the use of screening protocols based on literature review. The potential cost savings of evaluating patients with sudden sensorineural hearing loss with fast spin echo magnetic resonance imaging for acoustic neuroma was substantial, with a 54% reduction in screening costs. In an era of medical economic scrutiny, fast spin echo magnetic resonance imaging has become the most cost-effective method to screen suspected cases of acoustic tumors at our institution by improving existing technology while reducing the cost of providing that technology and eliminating charges for impedance audiometry, auditory brain stem response testing, and contrast-enhanced magnetic resonance imaging.     

Dexamethasone perfusion of the labyrinth plus intravenous dexamethasone for Ménière's disease

Recent clinical and laboratory evidence indicates that Meniere's disease is an immune-mediated disease. Dexamethasone perfusion of the inner ear through the round window plus intravenous dexamethasone often will stop the dizzy spells, reduce the fullness and low-frequency tinnitus, and sometimes improve the hearing in patients with Meniere's disease. The dexamethasone must act mostly on the endolymphatic sac and, to a lesser extent, on the stria vascularis and spiral ligament, the known targets of immune response in the inner ear, to reduce the endolymphatic hydrops and restore the fluid dynamics of the endolymph. Despite the good results with streptomycin perfusion, the number of patients with further hearing loss is large, so dexamethasone perfusion with intravenous dexamethasone should be tried first. The initial response to dexamethasone perfusion plus intravenous dexamethasone has been very good, with very little risk of further hearing loss, and it holds great promise for the future.     

Delayed endolymphatic hydrops: an analysis of 12 cases

Delayed Endolymphatic Hydrops (DEH) is a clinical entity which is characterized by an early phase with a profound sensorineural hearing loss in one ear. After a prolonged period of time (from 1 to 68 years) a late phase of the disease appears with different otologic symptoms. The ipsilateral type of endolymphatic hydrops appears in the deaf ear with consequent episodic vertigo. The contralateral type develops symptoms of endolymphatic hydrop in the previously normal ear, with the onset of fluctuating hearing loss and/or episodic vertigo. This paper is a review of 12 cases of DEH (7 ipsilateral and 5 contralateral, age ranging from 19 to 79 years). Diagnosis was established on the basis of clinical history and the results of audio-vestibular investigations, specifically designed to detect signs of endolymphatic hydrops (including the glycerol-test and neuroradiological imaging of the cerebello-pontine angle). In 8 patients the levels and frequency of anti-collagen I-II-IV-V, anti-laminin autoantibodies, complement, Ig and immuno-complexes were measured. Viral infections (measles, mumps, influenza) were thought to have caused the early phase in 6 cases. In the entire group of 12 patients the delay between the onset of the ear loss and vertigo averaged 12 years. In the group of the ipsilateral DEH, caloric tests showed in 5 cases a reduced or absent response of the deaf ear. About contralateral DEH, caloric tests showed bilateral reduced response in 2 cases, and, in 3 cases, a decreased response only in the previously normal ear. Regarding immunological study, an abnormal level of Ig and Complement was detected in 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical presentation and diagnosis of small acoustic neurinomas

With the invention of magnetic resonance imaging (MRI) and the auditory evoked brain stem responses (AEBR), it has become possible to diagnose acoustic tumours while they are still small. As a result, it has become obvious that the clinical presentation of smaller lesions can be some-what different from what is considered typical of an acoustic neuroma. Likewise, whereas the sensitivity of auditory brain stem responses for larger tumours is good, the sensitivity for smaller tumours has recently been in doubt, particularly if the patient presents early in the course of the disease with only mild otologic complaints. A retrospective study of patients treated for small acoustic neuromas, defined as less than 1 cm extension into the cerebellopontine angle, was conducted to assess ABR results as well as the clinical and audiological presentation in these patients. Of the 70 patients included in the study, auditory brain stem responses were abnormal in 65 (93%), based on wave V latency prolongation and intra-aural latency differences. These would indicate that auditory brain stem responses are a valid screening test for acoustic neuromas, even in the early stages of development. The clinical presentation of patients with small acoustic tumours was similar to the presentation reported for acoustic neuromas in general, but with vertigo occurring more often in patients with smaller tumours. Several atypical patterns of hearing loss were seen in this population.     

Meniere's disease of syphilitic etiology

Congenital or acquired syphilis is the cause of Meniere's disease in six percent of all cases. The pathogenesis is endolymphatic hydrops and osteitis of the otic capsule which produces the characteristic fluctuating hearing loss, tinnitus and ear pressure associated with episodic spells of vertigo. The ear symptoms are, at first, typical of Meniere's disease of other etiologies. Failure to establish the specific etiologic diagnosis can result in unnecessary surgical treatment or inappropriate medical therapy. In some cases, if a steroid, the specific treatment, is not given promptly, hearing can be quickly and permanently lost. The etiology is confirmed by obtaining a reactive fluorescent treponema antibody absorption (FTA-abs) test. The clinical features and natural history of Meniere's disease of syphilitic etiology are unique. Ear symptoms often begin in the fifth decade of life, first in one ear and, after a few years, involving the second ear. Reduced or absent caloric responses are characteristic. When hearing loss is severe and sudden, this condition represents a true medical emergency and should be treated with prompt administration of steroids. An endolymphatic subarachnoid shunt operation is occasionally necessary as adjunctive management. An analysis of 34 cases shows that long-term use of steroids can maintain effective hearing for more than 20 years.     

Endolymphatic sac obliteration for large vestibular aqueduct syndrome

The objective of this study was to investigate the effects of endolymphatic sac obliteration for stabilization of progressive hearing loss in patients with the large vestibular aqueduct syndrome. This was a retrospective case review conducted at a private neurootologic office in a metropolitan area. Seven ears in six patients were subjected to surgery for obliteration of the endolymphatic sac in an effort to stabilize progressive hearing loss associated with the large vestibular aqueduct syndrome. The study population was composed of four boys and two girls 4-17 years of age. The large vestibular aqueduct was unilateral in two patients and bilateral in four patients. All seven ears demonstrated progressive sensorineural hearing loss preoperatively. Surgical tissue obliteration was performed via a transmastoid approach in seven ears. The main outcome measure was comparison of pre- and postoperative hearing levels and stability. Magnetic resonance imaging also was performed in all cases at least 6 months postoperatively to determine patency of the endolymphatic sac and vestibular aqueduct. Six of seven ears maintained stable hearing during the follow-up period, which ranged from 6 months to 6 years (mean 3.2 years). One patient showed continued progression of hearing loss postoperatively. All seven ears demonstrated continued obliteration on postoperative imaging studies. Surgical obliteration of the endolymphatic sac may stabilize hearing in patients with the large vestibular aqueduct syndrome and progressive hearing loss. These results support the theory of pressure or fluid reflux into the labyrinth as a cause of progressive hearing loss in these patients.     

Laboratory experience with experimental endolymphatic hydrops

Experimental endolymphatic hydrops refers to the creation of hydrops in the experimental animal and represents a histologic correlate for Meniere's disease. Details of the surgical means to create this condition in guinea pigs are provided. Alterations in endolymph fluid composition and relative endolymph pressure occur with hydrops. Deterioration in auditory and vestibular function secondary to hydrops can develop.     

Computerized tomography in children and adolescents with suspected petrous bone abnormality

PURPOSE: To demonstrate HRCT findings and their therapeutic relevance in suspected congenital hearing disorders. MATERIAL AND METHODS: It was checked in 96 young patients if HRCT findings of the temporal bone could explain functional findings. Furthermore, the therapeutic consequences were noted. RESULTS: Normal CT and normal functional findings were obtained in 49 temporal bones (TB). In conductive hearing loss (41 TB), dysplasias of the conducting apparatus (37 TB) and inflammatory changes (3 TB) were found. Combined hearing loss (18 TB) was clarified completely or partially in half the cases. There were 22 dysplasias of the inner ear, 3 dysplasias of the middle ear, 1 abandoned examination (2 TB), and 55 normal CT findings in senorineural hearing disorders (82 TB). 1 retardate had a malformation of the inner ear and, contralaterally, inflammatory middle ear. In cases of vestibular disorders (24 TB), 14 malformations of the inner ear were detected. An indication for an operation was given in 23 TB. In 22 TB, it was contraindicated. The CT was one preliminary examination to a cochlea implant in 19 patients. The therapy was carried on with hearing devices in the other patients. CONCLUSION: HRCT is an important method in diagnosis and therapeutic planning of suspected malformations of the temporal bone.     

Endolymphatic subarachnoid shunt failure caused by Silastic allergy

During the period from 1964 through 1994, the endolymphatic subarachnoid shunt operation was initially successful in eliminating endolymphatic hydrops and the symptoms and findings it produces in 76% of 645 ears of patients with Meniere's disease. After initial success, lasting from five weeks to nine years, endolymphatic hydrops suddenly returned due to obstruction of the Silastic shunt tube in 11% of patients. In these cases, prompt revision can often restore an initial good result. Histologic and immunologic examination of the material surrounding and occluding the tubes showed an allergic response to the Silastic material in most instances. Efforts to eliminate this cause of failure using a tube of new design and different plastic material are described.     

Immune-mediated inner ear disease: report of clinical cases

Many clinical and experimental studies have obtained evidence of immune-mediated inner ear disease. Discrepancies between theories of the mechanisms of injury to the inner ear and the laboratory tests that identify it mean that the diagnosis is based on clinical symptoms and a positive response to treatment. We report four cases of immune-mediated inner ear disease characterized by endolymphatic hydrops, fluctuating hearing loss, sudden deafness (first symptom of primary Sj?gren's syndrome), and rapidly progressive sensorineural hearing loss.     

Mismatch negativity in the neurophysiologic/behavioral evaluation of auditory processing deficits: a case study

The subject of this case report is an 18-year-old woman with grossly abnormal auditory brain stem response (ABR), normal peripheral hearing, and specific behavioral auditory processing deficits. Auditory middle latency responses (MLRs) and cortical potentials N1, P2, and P300 were intact. The mismatch negativity (MMN) was normal in response to certain synthesized speech stimuli and impaired to others--consistent with her behavioral discrimination of these stimuli. Behavioral tests of auditory processing were consistent with auditory brain stem dysfunction. A neuropsychological evaluation revealed normal intellectual and academic performance. The subject was in her first year of college at the time of the evaluation. This case study is important because: (1) Although there have been several reports of absent/abnormal ABR with preserved peripheral hearing and deficits in auditory processing, little is known about the specific nature of the auditory deficits experienced by these individuals. Such information may be valuable to the clinical management of patients with this constellation of findings. (2) Of interest is the information that the mismatch negativity (MMN) cortical event-related potential can bring to the evaluation of patients with auditory processing deficits. The MMN reflects central auditory processing of small acoustic differences and may provide an objective measure of auditory discrimination. (3) From a theorectical standpoint, a patient with neural deficits affecting specific components of the auditory pathway provides insight into the relationship between evoked potentials and physiological mechanisms of auditory processing. How do various components of the auditory pathway contribute to speech discrimination? How might evoked potentials reflect the processes underlying the neural coding of specific features of speech stimuli such as timing and spectral cues?     

Alterations in the distributions of the basement membrane components after secondary inner ear immune reaction in guinea pigs

Alterations in the distributions of type IV collagen (C-IV), laminin (La), and fibronectin (Fib), which are important components of the basement membrane, in the inner ear following secondary endolymphatic sac immune response were studied immunohistologically using control animals for comparison. Endolymphatic hydrops developed following direct secondary keyhole limpet hemocyanin (KLH) challenge to the endolymphatic sac in systematically pre-sensitized animals. In the endolymphatic sacs of control animals, C-IV and La were localized continuously just under epithelial cells whereas Fib was present intermittently in subepithelial connective tissue. In the endolymphatic sac, following secondary KLH challenge, linear subepithelial localizations of C-IV and La were interrupted, thinner and more loosely aggregated with numerous inflammatory cellular infiltrates on days 2-4. Following these changes, endolymphatic hydrops in the cochlea developed and peaked on days 4-7. On days 1-7, Fib was strongly but sporadically localized in subepithelial cells. These results suggest that C-IV and La may play important roles in the regulation of endolymph whereas Fib may be related to the restoration of injured endolymphatic sac tissue in animals exposed to a secondary challenge.     

Confidentiality and privacy breaches in a university hospital emergency department

Six temporal bones and a brain tissue sample removed at autopsy from four patients with bilateral sudden hearing loss related to gastric adenocarcinoma were histologically studied. The pathological remains suggest that the sudden hearing loss of these patients may have occurred via one of two different mechanisms: (1) metastasis to the internal auditory meatus damaging the auditory nerve or (2) inner ear haemorrhage damaging Corti's organ. These two mechanisms may cause bilateral sudden deafness in patients with gastric adenocarcinoma.     

Electrocochleographic signal analysis: condensation and rarefaction click stimulation contributes to diagnosis in Menière's disorder

Thirty patients with Menière's disorder, 11 patients with cochlear hearing loss of other aetiologies and 10 normally-hearing subjects, were investigated using transtympanic electrocochleography (TT ECochG). Alternating polarity clicks, condensation and rarefaction clicks and long tone-bursts of 1 kHz were used for stimulation. The latencies of the AP responses to click stimulation were evaluated. It was found that the latency differences between the condensation and rarefaction click-evoked responses were significantly larger in patients with Menière's disorder as compared to normal subjects and to patients with other cochlear hearing losses. It was found that the sensitivity of TT ECochG, obtained by using measurements of SP-AP ratios and the SP amplitude at 1 kHz burst stimulation, increased from 83 per cent to 87 per cent by addition of the con-rar shift measurement. The specificity of TT ECochG obtained by this combination of variables was 100 per cent in our material. The results of the study indicate that the latency shift found in responses evoked by clicks of opposite polarities in TT ECochG, can be a useful parameter in the detection of suspected endolymphatic hydrops.     

Hearing, speech, language, and vestibular disorders in the fetal alcohol syndrome: a literature review

Fetal alcohol syndrome (FAS) is characterized in part by mental impairment, as well as craniofacial and ocular anomalies. These conditions are traditionally associated with childhood hearing disorders, because they all have a common embryonic origin in malformations of the first and second branchial arches, and have similar critical periods of vulnerability to toxic insult. A review of human and animal research indicates that there are four types of hearing disorders associated with FAS. These are: (1) a developmental delay in auditory maturation, (2) sensorineural hearing loss, (3) intermittent conductive hearing loss due to recurrent serous otitis media, and (4) central hearing loss. The auditory and vestibular systems share the same peripheral apparatuses (the inner ear and eighth cranial nerve) and are embryologically and structurally similar. Consequently, vestibular disorders in FAS children might be expected. The evidence for vestibular dysfunction in FAS is ambiguous, however. Like other syndromes associated with craniofacial anomalies, hearing disorders, and mental impairment, FAS is also characterized by a high prevalence of speech and language pathology. Hearing disorders are a form of sensory deprivation. If present during early childhood, they can result in permanent hearing, language, and mental impairment. Early identification and intervention to treat hearing, language, and speech disorders could therefore result in improved outcome for the FAS child. Specific recommendations are made for intervention and future research.     

Hearing loss from hemodialysis

A 47-year-old man with normal hearing had chronic progressive renal failure. He experienced hearing loss in additive increments with peritoneal dialysis and hemodialysis, until he was profoundly deaf in both ears. Postmortem studies showed collapse of the endolymphatic system and edema and atrophy of most of the specialized cell types of the auditory and vestibular sense organs. It is our interpretation that the alterations were caused by osmotic disequilibrium associated with hemodialysis.