The properties of spontaneous and evoked acoustic emissions in neonates and children: a preliminary report

Summary Evoked acoustic emissions (EAEs) and spontaneous acoustic emissions (SAEs) recordings hold some promise as a fast, objective and non-invasive audiological procedure, especially in children. However, accurate interpretation in the emission response must be based on the basic properties of the emissions present in a younger age group. In so doing, the properties of emissions were investigated in 49 ears from 26 children, whose ages varied between 2 days and 10 years. EAEs could be recorded in all normal ears, but the incidence of long-duration EAEs decreased with age. There were no statistically significant variations in recording the EAEs detection threshold with age. The incidence of SAEs also decreased with age.Presented at the First European Congress of Oto-Rhino-Laryngology and Cervico-Facial Surgery, Paris, 26–29 September 1988     

The properties of spontaneous and evoked acoustic emissions in neonates and children: a preliminary report

Evoked acoustic emissions (EAEs) and spontaneous acoustic emissions (SAEs) recordings hold some promise as a fast, objective and non-invasive audiological procedure, especially in children. However, accurate interpretation in the emission response must be based on the basic properties of the emissions present in a younger age group. In so doing, the properties of emissions were investigated in 49 ears from 26 children, whose ages varied between 2 days and 10 years. EAEs could be recorded in all normal ears, but the incidence of long-duration EAEs decreased with age. There were no statistically significant variations in recording the EAEs detection threshold with age. The incidence of SAEs also decreased with age.     

Suppression of rabbit ear skin homograft rejections with sheep anti-thymus globulins. A preliminary report

Two electrophorectically distinct “7s” γ₁, and γ₂ globulins were isolated from sheep anti-rabbit thymus serum. The γ₁ fraction was effective in prolonging skin homograft retention in rabbits but did not suppress humoral antibody formation. The γ₂ fraction appears to contain other antibodies which react with rabbit tissue to cause anaphylactic-like reactions.     

Immunologic detection of acoustic neuroma: preliminary report

In an attempto to provide preoperative histologic identification of internal auditory canal and cerebellopontine angle tumors, and to attempt to detect small tumors and recurrent tumors, immunologic aspects of acoustic neuroma patients and control subjects were studied. Reactions based upon the interaction of patients' fresh lymphocytes in contact with acoustic neuroma antigens were studied by a leukocyte migration inhibition (LMI) assay and a locally developed refinement, the plasma effect assay. These were performed either preoperatively, postoperative, or both, in 17 patients with surgically confirmed acoustic neuromas and in 24 controls subjects. Preoperative tumor patients had a higher likelihood of having elevated LMI and plasma effect assay values than normals. False positive results were rare and the combination of the LMI and plasma effect assay decreased false negative responses to 20%. Meaningful conclusions must await more extensive testing but it has been demonstrated that tumor associated antigens do exist on the membranes of schwannoma cells and that most patients with an acoustic neuroma mount a cell-mediated immune response against these antigens.     

植入式人工中耳听器离体状态下的声学特性

人工中耳听器是为鼓膜与听骨链受损但又不能以手术修复者,尤其是那些伴有中度或中度以内感觉神经聋者所设计的一种可植入式声-电-振动换能装置。它将代替损伤了的鼓膜或听骨链,完成近乎生理状态下的声传导过程。本研究是用声-电-振动信号分析技术来研究在生物离体状态下声学特征与振动模式,以分析本装置在语言传输过程中的保真度,提供植入人耳后听觉恢复的总体效果,作为对人工中耳听器的临床应用提供理论及技术性能评估的基础。     

Cytokeratin expression in cholesteatoma matrix, meatal epidermis and middle ear epithelium. A preliminary report

The cytokeratin expression of cholesteatoma matrix, meatal epidermis and middle ear epithelium was investigated with six anticytokeratin monoclonal antibodies. One of these was broad specific and the other antibodies were directed against cytokeratins 4, 8, 10, 18 and 19 respectively. Immunoperoxidase staining of cryosections revealed the presence of cytokeratin 10 in cholesteatoma matrix and meatal epidermis. In contrast, middle ear epithelium was characterized by cytokeratins 4, 8, 18 and 19 and not by cytokeratin 10. An infrequent focal presence of cytokeratins 4, 18 and 19 was found in cholesteatoma. In general, the divergence between the cytokeratin expression of middle ear epithelium versus that of cholesteatoma and meatal epidermis suggests an epidermal origin of cholesteatoma. However, a metaplastic origin of cholesteatoma cannot be excluded because of the infrequent focal presence of cytokeratins 4, 18 and 19 in cholesteatoma.     

The role of the middle ear in acoustic trauma from impulses.

Exposure to high intensity impulse noise may produce a wide range of audiometric and histological effects in experimental animals. The objective of this study was to assess the changes in the middle ear mechanism after impulse noise exposure and to relate these changes to the audiometric and histological effects. Nine monaural chinchilla were exposed to either 161 or 166 db peak SPL impulses of 1 msec "A" duration, presented at a rate of 1 per minute for 50 minutes. The conductive mechanism of the chinchilla was assessed using standard clinical measures of static and dynamic impedance before and after the noise exposure. Auditory thresholds were measured before and after noise exposure using the average evoked response (AER) technique. At 30 days post-exposure, the animals were sacrificed for histology. Pre-exposure tympanometry showed that: 1. the total mean impedance of the chinchilla ear is considerably lower than that of man; 2. a method related hysterisis effect is present in both the susceptance and conductance tympanograms; and 3. sedation has a significant effect on the total impedance of the ear and on the shape of the tympanograms. After exposure to high level impulse noise: 1. tympanograms become irregular and double peaked, indicating tympanic membrane stress; 2. for the given exposure, 166 db is the impulse intensity needed to rupture consistently the tympanic membrane; and 3. audiometric and histological data correlate with the tympanometric findings and demonstrate a protective effect of a tympanic membrane rupture on the cochlea.     

Role of oral zinc in ear surgery a preliminary report

Peroral zinc sulphate in a dose of 220 mg t.d.s. was used in 19 cases of radical Mastoidectomy. Granulation tissue was resolved in 94%. Mastoid bowl was completely obliterated in 31% and incompletely obliterated in 63%. Histological findings are discussed.     

The human acoustic tensor tympani reflex. A case report

In a patient with unilateral lower motoneuron facial paralysis secondary to Bell's palsy, we evaluated the characteristics of what we believe to be an acoustically-evoked reflex contraction of the tensor tympani muscle. Ipsilateral stimulation of the involved ear yielded a pattern of impedance change different from the pattern characterizing normal stapedius muscle contraction. Threshold of the reflex was elevated, amplitude was large and variable, onset latency was greater, onset rise was more gradual, and offset decay was more rapid. Contralateral stimulation, with probe in the involved ear, failed to elicit the reflex contraction. Upon return of facial nerve function, the normal stapedius reflex contraction reappeared in response to both ipsilateral and contralateral stimulation.     

Cutaneous leishmaniasis of the ear muscle. A case report

Cutaneous leishmaniasis is a parasitic infection which is especially endemic in the southern parts of Europe, in several regions of Africa, and in South and Central America. Whether treatment is necessary or not depends on the virulence of the germ, the infection's localization, and the host's immunological reaction. Because of the high rate of recidivation and the large number of undesirable side-effects of systemic chemotherapy of localized cutaneous leishmaniasis, several methods of local therapy have been tested. This case report demonstrates one of several approaches to the local treatment of this disease. Despite progress in this field, cutaneous leishmaniasis will continue to be a considerable medical and sociopolitical problem, because successful treatments in under-developed countries must be highly efficient, cost little, be easy to administer, and have a low rate of undesirable side-effects.     

Low frequency air-bone gap in Menière's disease without middle ear pathology. A preliminary report

The audiograms of some patients suffering from Meniere's disease show an unexplained conductive component, or air-bone gap (ABG), predominantly in the low frequencies. Neither the history nor physical findings support poor eustachian tube function, ossicular chain abnormalities, chronic ear disease, physical trauma, or otosclerosis as a cause of this audiometric finding. In the present study, 40 patients diagnosed as suffering from classical Meniere's disease were evaluated audiometrically. Thirteen (32.5%) of these patients demonstrated a low frequency ABG. An otologic evaluation was performed on each patient who exhibited the abnormal finding, but no middle ear pathology was discovered. An otherwise unexplained low frequency ABG in patients with Meniere's disease suggests the possibility of an "inner ear" conductive hearing loss. This conductive component may result from endolymphatic hydrops or perilymphatic hypertension (i.e., an inner ear hyperpressure exerted against the medial surface of the stapedial footplate) rather than from middle ear pathology. "Inner ear" conductive hearing loss is thought to be caused by an increase in inner ear fluid volume (endolymphatic hydrops) and pressure (endolymphatic or perilymphatic hypertension), which dampens footplate mobility medially and which is directly related to a relative inner ear or labyrinthine hyperpressure. Since the footplate mobility is only dampened and not fixed, a stapedial reflex may still be elicited.