Effect of profound hearing loss on a central auditory nucleus

The present study was designed to investigate the type and extent of degeneration occurring in the human central auditory system subsequent to profound hearing loss. The authors have examined the size of one population of neurons in the ventral cochlear nucleus in seven subjects with profound hearing loss (audiometric responses poorer than 90-100 dB HL). Six normal subjects, ages 35-78, were used as controls. Cell size in the hearing-impaired subjects ranged from normal to reduced by more than 50 percent. Two factors appear to contribute to the variability in cell size reduction. The correlation coefficient (Spearman rs) of cell size with duration of profound deafness was -0.48, indicating a moderate tendency for neurons to become smaller with longer periods of deafness. The correlation coefficient of cell size with number of surviving cochlear ganglion cells was 0.73, indicating a stronger tendency for neurons to be larger with greater eighth nerve innervation of the cochlear nucleus. Two cases of Scheibe degeneration showed the most severe degenerative change in the central auditory system.     

The role of hypotension in the pathogenesis of sudden hearing loss

The generic term 'sudden hearing loss' indicates the lack of knowledge about the etiology and pathogenesis of this phenomenon. In most cases it would seem feasible to consider infections or organic circulatory defects, but there are cases, generally affecting young subjects in whom the damage is often reversible, in which a functional origin is possible. We therefore investigated the possible effect of systemic arterial pressure in a retrospective study in a group of 36 patients aged not more than 40 years, treated for sudden hearing loss, comparing the mean values of their arterial pressure with those of a control group of 25 subjects, of similar age, admitted for other disorders. The significantly lower mean values of arterial pressure in the group affected by sudden hearing loss and the easier reversibility of the damage in these patients suggests that, at least in some cases, the cochlear damage may be caused by a perfusion deficit due to the combined effect of hypotension and imperfect vasomotor regulation.     

Hemorheological disorders in patients with sudden deafness]

Fourteen hemorheological and related parameters of blood samples derived from 59 patients with sudden deafness were observed and were compared with those of blood samples got from 512 healthy persons. The ratio viscosity of whole blood (6.50 +/- 1.07), reduced viscosity of whole blood (12.37 +/- 1.80), and plasma viscosity (1.84 +/- 0.14) in male patients were significantly higher than those (6.05 +/- 0.63, 11.06 +/- 1.04, and 1.70 +/- 0.07, respectively) in male controls. The reduced viscosity of whole blood (16.62 +/- 3.87) and plasma viscosity (1.92 +/- 0.13) in female patients were also significantly higher than those (14.40 +/- 2.27 and 1.72 +/- 0.06, respectively) in female controls. The findings above suggest that there is an intimate relationship between the microcirculationary disorder resulting from hemorheological changes and the onset of sudden deafness. The parameters related to plasma viscosity revealed that there were higher concentrations of plasma fibrinogen and triglyceride in male patients than those in male controls, while the concentrations of plasma cholesterol and triglyceride were higher in female patients than in female controls. These results indicate that the factors which induce the change of plasma viscosity in male patients could not be the same as those in female patients. Thus, in the process of treating sudden deafness, besides the use of common devices such as reducing blood viscosity and improving microcirculation, some other special steps based on the hemorheological parameters derived from different sexes or individuals, should also be considered.     

Low prevalence of hearing aid use among older adults with hearing loss: the Epidemiology of Hearing Loss Study

OBJECTIVES: To measure the prevalence of hearing aid use among older adults with hearing loss and to identify factors associated with those currently using hearing aids. DESIGN: Population-based cohort study. SETTING: The south-central Wisconsin community of Beaver Dam. PARTICIPANTS: A total of 1629 adults, aged 48 to 92 years, who have hearing loss and are participating in the Epidemiology of Hearing Loss Study and the Beaver Dam Eye Study. MEASUREMENTS: A hearing-related risk factor and medical history questionnaire, the Hearing Handicap Inventory for the Elderly (screening version), screening tympanometry, pure-tone air- and bone-conduction audiometry, and word recognition tests were administered by trained examiners using standard protocols. RESULTS: The prevalence of current hearing aid use among those with a hearing loss (pure-tone average > 25 decibels hearing level over 500, 1000, 2000, and 4000 Hertz, worse ear) was 14.6%. The prevalence was 55% in a subset of the most severely affected participants. In univariate analyses, current hearing aid use was associated with age, severity of loss, word recognition scores, self-reported hearing loss, self-perceived hearing handicap, and history of noise exposure. Factors associated with current hearing aid use in multivariate logistic regression models were age, severity of loss, education, word recognition scores, Hearing Handicap Inventory for the Elderly (screening version) score, and self-report of a hearing loss. CONCLUSIONS: Few older adults with hearing loss are currently utilizing hearing aids. Improved screening and intervention programs to identify older adults who would benefit from amplification are needed to improve hearing-related quality of life for this large segment of the population.     

Meningeal carcinomatosis producing bilateral sudden hearing loss: a case report

Meningeal carcinomatosis is characterized by diffuse infiltration of the leptomeninges by metastatic cancer in patients usually with a previous history of malignancy. Primary tumors are usually adenocarcinomas of the breast or lung, or malignant melanoma. Meningeal carcinomatosis can present with headache and/or a variety of cranial neuropathies. We report a case of meningeal carcinomatosis presenting as a complete, bilateral, sudden hearing loss without other cranial nerve findings--a previously unreported presentation. Our patient also exhibited an unusual primary tumor site (esophagus) and histopathology for meningeal carcinomatosis. The case was impressive for the subsequent abrupt onset of a series of cranial neuropathies and the rapid deterioration in the patient's condition.     

Hypercholesteremia and hyperfibrinogenemia in sudden deafness

BACKGROUND: The pathogenesis of sudden hearing loss has not been elucidated as yet. Insufficient perfusion of the cochlea due to an increased blood viscosity, microthrombosis, or altered vasomotion are assumed. Hypercholesterolemia and hyperfibrinogenemia are frequently observed in patients with sudden sensorineural hearing loss. The aim of this study was to investigate the incidence of hypercholesterolemia and hyperfibrinogenemia in patients suffering from sudden hearing loss compared to normal controls. In an intervention study the impact of drastic lowering of plasma cholesterol and fibrinogen by a selective extracorporal apheresis was studied. METHODS: In a case-control study of 23 patients suffering from sudden hearing loss, plasma cholesterol and fibrinogen levels as well as erythrocyte aggregation and plasma viscosity were determined. Seven sudden hearing loss patients from this group were treated with H.E.L.P. apheresis, an extracorporal procedure removing fibrinogen and idl-cholesterol from plasma. RESULTS: Plasma fibrinogen and cholesterol levels were higher in sudden hearing loss patients, leading to significantly elevated values of erythrocyte aggregation and plasmaviscosity. Six out of the seven patients treated with a single H.E.L.P. apheresis immediately showed an improvement of auditory thresholds. CONCLUSIONS: We conclude that hyperfibrinogenemia and hypercholesterolemia may contribute to the clinical event of sudden hearing loss. Our study shows for the first time that acute and drastic removal of plasma fibrinogen and low density lipoproteins can be an effective clinical tool in the treatment of patients with sudden hearing loss.     

Prevalence and relevant background characteristics of deafness and severe hearing loss in the Netherlands

OBJECTIVE: To determine the prevalence of deafness and severe hardness of hearing among the Dutch population and of some relevant background characteristics. DESIGN: Study of documents. SETTING: Dutch schools for deaf and hard-of-hearing children. METHOD: The number of deaf and severely hard-of-hearing children of 6-12 years who received education or ambulatory supervision at schools for deaf and hard-of-hearing children was counted in the period November 1996-April 1997, and a number of relevant background characteristics were collected. By means of consultation with experts, this number was corrected for children who could not be retrieved by means of the inventory at these schools. To estimate the total number of deaf and severely hard-of-hearing people in the Dutch population, this adjusted number was extrapolated to older and younger year cohorts. RESULTS: The number of deaf and hard-of-hearing children of 6-12 years, after correction for missing groups, was 0.74 (95% confidence interval (95% CI): 0.69-0.78) per 1000 persons. In 9% the age of onset of the handicap was postlingual; they more often received ambulatory supervision and more often received education at a school for hard-of-hearing children than those with a prelingual auditive handicap. Of the children 29% had a non-Western origin; they less often received ambulatory supervision, and more often received education from a school for deaf children than indigenous pupils. Among the total Dutch population, the number of deaf and hard-of-hearing persons in 1996 was estimated to be 11,400 persons (95% CI: 10,690-12,110). CONCLUSION: The prevalence of deafness and severe hardness of hearing in the Netherlands (15,490,000 inhabitants in 1996) was 11,400 persons (95% CI: 10,690-12,110).     

Changes in otoacoustic emissions in patients with idiopathic sudden deafness

Transiently click-evoked (TEOAE), distortion product (DPOAE) and spontaneous otoacoustic emissions (SOAE) were recorded and changes in these tests were studied during the recovery process in 15 cases of idiopathic sudden deafness (ISD). In all these cases the amplitudes of TEOAEs and DPOAEs increased concurrently with the recovery of the hearing threshold. Ears with ISD were not different in their OAE characteristics from ears with other forms of sensorineural hearing loss (SNHL). In 4 of the 15 cases, SOAEs could be detected when hearing had recovered. These results suggest that the function of outer hair cells (OHCs) had deteriorated when the hearing threshold was elevated and that OHC activity recovered as hearing improved to nearly normal levels in ISD cases with good outcome.     

Psychosomatic aspects of sudden deafness

PURPOSE: In patients with septic shock, the cardiac index is often increased. Maldistribution of blood flow and regional hypoperfusion has been implicated as a key factor in the pathogenesis of organ dysfunction in these patients. We have investigated the relationship between cerebral blood flow and cardiac index in patients with septic shock. MATERIALS AND METHODS: We used Doppler ultrasound techniques to investigate limb and carotid blood flow in 15 patients with septic shock and 9 nonseptic controls. RESULTS: In the nonseptic control patients, common femoral and brachial blood flow were proportional to cardiac index (r=0.73 and 0.76; P=.038 and .017, respectively) reflecting a protective redistribution of flow to more vital organs. However, this relationship was absent in patients with septic shock (r=0.23 and 0.21). Furthermore, in the septic patients but not the nonseptic controls, cerebral blood flow was correlated with the cardiac index (r=0.66, P < .05 vs r=-0.36, NS in nonseptic controls). Carotid flow was independent of mean arterial pressure, PaCO2 and PaO2 in patients with septic shock. CONCLUSIONS: These data are consistent with a loss of autoregulation of cerebral blood flow and a change in the control of limb blood flow in humans with septic shock.     

Stapedectomy in profound cochlear loss

Stapedectomy can be used in certain patients with profound sensorineural hearing loss and stapes fixation to improve hearing to a level at which a hearing aid may be effective. This study reviews the outcomes of 11 patients with profound cochlear loss secondary to otosclerosis who underwent stapes surgery performed by the senior author (M.E.G.) over a 25-year period. Postoperative hearing aid usage was effective in 9 of 11 patients. Preoperatively, these patients derived no benefits from hearing aids. Stapedectomy may be of immense value in patients with the proper history and profound cochlear loss.     

''Farmer''s ear'': sudden sensorineural hearing loss due to Chlamydia psittaci infection

Idiopathic dilation of the right atrium (IDRA) is a rare cardiac anomaly of unknown etiology. Whether it is an acquired or congenital lesion is controversial. A case of IDRA detected in utero and confirmed postnatally is reported. The postnatal course was complicated by the development of atrial flutter successfully treated with sotalol. A review of the literature concerning IDRA is presented.     

Hearing loss

Hearing loss may be caused by either a conductive problem, such that the sound waves do not reach the tympanic membrane, ossicles or inner ear, or a sensorineural problem, in which the cochlea and/or auditory nerve are somehow damaged. A combination of the above may also occur. The various causes of hearing loss and the options in treatment will be presented.     

Hearing in the elderly. Relation of hearing loss, loneliness, and self-esteem

1. The prevalence of hearing impairment increases with age. Hearing handicap resulting from hearing loss may lead to psychosocial problems in elders. 2. Previous studies have shown relations among hearing handicap, loneliness and low self-esteem, but those studies focused on populations other than elders. 3. Early detection of hearing handicap and appropriate interventions promote increased independence and preserve the ability of elders to interact with their environment.     

Cochlear neuronal loss are determined by use of a neurofilament protein antibody in cases of bilateral profound deafness

The temporal bones of two patients with profound bilateral deafness from infancy were studied immunohistochemically, using a neurofilament protein antibody to detect the cochlear neuronal elements. One patient exhibited Mondini dysplasia of the inner ear, with the organ of Corti almost completely deteriorated. The other patient is the first reported case involving complete aplasia of the organ of Corti in all turns. In both cases, the immunohistochemical staining clearly revealed a severe reduction in the number of afferent neurons, such as dendrites, spiral ganglion cells and cochlear axons. The number of efferent spiral bundles in the osseous spiral lamina and intraganglionic portion also decreased in parallel with the reduction in the number of cochlear afferent neurons. Our results are inconsistent with previously reported cases of presbycusis and acquired deafness induced by the measles virus, in which efferent neurons were preserved while afferent neurons degenerated. The loss of both the efferent and afferent neurons might be characteristics of congenital deafness.     

Disturbance of iron metabolism and sudden hearing loss: a prospective and retrospective survey

Two hundred and eighteen patients with disorders of disturbance of iron metabolism, 215 with hematonosis and 4850 in a normal control group were studied in a prospective with sudden hearing loss and were meanwhile investigated in a retrospective review in order to evaluate the relationship between the disorders of disturbance of iron metabolism and sudden hearing loss. The findings revealed a significantly higher incidence of sudden hearing loss in the cases of disturbance of iron metabolism, than in the patients with hematonosis as well as in the normal control group. Iron deficiency and iron deficiency anemia were found in 60.84% of 429 patients with sudden hearing loss. We concluded that the risk of disturbance of iron metabolism in the cochlea will significantly increase when systemic disturbance of iron metabolism is present although the one does not necessarily indicate the other. It seems that acute disturbance of iron metabolism in cochlea causes sudden hearing loss directly or provides a pathologic basis for the disorder.     

Improvements in speech perception by children with profound prelingual hearing loss: effects of device, communication mode, and chronological age

The present investigation expanded on an earlier study by Miyamoto, Osberger, Todd, Robbins, Karasek, et al. (1994) who compared the speech perception skills of two groups of children with profound prelingual hearing loss. The first group had received the Nucleus multichannel cochlear implant and was tested longitudinally. The second group, who were not implanted and used conventional hearing aids, was tested at a single point in time. In the present study, speech perception scores were examined over time for both groups of children as a function of communication mode of the child. Separate linear regressions of speech perception scores as a function of age were computed to estimate the rate of improvement in speech perception abilities that might be expected due to maturation for the hearing aid users (n=58) within each communication mode. The resulting regression lines were used to compare the estimated rate of speech perception growth for each hearing aid group to the observed gains in speech perception made by the children with multichannel cochlear implants. A large number of children using cochlear implants (n=74) were tested over a long period of implant use (m=3.5 years) that ranged from zero to 8.5 years. In general, speech perception scores for the children using cochlear implants were higher than those predicted for a group of children with 101-110 dB HL of hearing loss using hearing aids, and they approached the scores predicted for a group of children with 90-100 dB HL of hearing loss using hearing aids.     

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.