Cases reported "Deafness"

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1/68. Acoustic trauma from the bone cutting burr.

    The amplitudes of the stapes footplate movements were determined in human temporal bones when the ossicular chain was drilled with a cutting and a diamond burr. High movements result in comparison to physiological data. The frequency distribution resembles the dB (A) curve. The intensity compared to sound pressure levels on the ear drum is higher than I30 dB. The pressure is constant over the period of contact between the burr and the ossicle. Most likely these unphysiologic movements of the stapes footplate can cause inner ear damage as we had to admit in a case of facial nerve decompression.
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2/68. Intraoperative loss of auditory function relieved by microvascular decompression of the cochlear nerve.

    BACKGROUND: Brainstem auditory evoked potentials (BAEP) are useful indicators of auditory function during posterior fossa surgery. Several potential mechanisms of injury may affect the cochlear nerve, and complete loss of BAEP is often associated with postoperative hearing loss. We report two cases of intraoperative auditory loss related to vascular compression upon the cochlear nerve. methods: Intra-operative BAEP were monitored in a consecutive series of over 300 microvascular decompressions (MVD) performed in a recent twelve-month period. In two patients undergoing treatment for trigeminal neuralgia, BAEP waveforms suddenly disappeared completely during closure of the dura. RESULTS: The cerebello-pontine angle was immediately re-explored and there was no evidence of hemorrhage or cerebellar swelling. The cochlear nerve and brainstem were inspected, and prominent vascular compression was identified in both patients. A cochlear nerve MVD resulted in immediate restoration of BAEP, and both patients recovered without hearing loss. CONCLUSION: These cases illustrate that vascular compression upon the cochlear nerve may disrupt function, and is reversible with MVD. awareness of this event and recognition of BAEP changes alert the neurosurgeon to a potential reversible cause of hearing loss during posterior fossa surgery.
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keywords = wave
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3/68. Inherited susceptibility to aminoglycoside ototoxicity: genetic heterogeneity and clinical implications.

    PURPOSE: Aminoglycoside-induced ototoxicity appears to have a genetic susceptibility in some individuals, and the A1555G mutation in the mitochondrial 12S ribosomal rna gene has been shown to be responsible for this susceptibility in all familial cases. An Italian family with 5 family members who became deaf after aminoglycoside exposure presented to us, and molecular analysis excluded the A1555G mutation. The purpose of this study is to identify the molecular basis for the aminoglycoside susceptibility in this family. patients AND methods: Two sisters and three of their children developed severe to profound high-frequency hearing loss after aminoglycoside exposure. dna was extracted from the blood of these individuals and their unaffected relatives, and analyzed for mitochondrial dna mutations. The region around nucleotide 961 was also cloned and individual clones were sequenced. RESULTS: Sequencing of the 12S ribosomal rna gene revealed a thymidine deletion at position 961, with a complex pattern of sequence around this mutation. Sequencing of individual clones around the 961 mutation demonstrated a varying number of inserted cytosines in different mitochondrial molecules. CONCLUSION: This family establishes the nucleotide 961 thymidine deletion associated with a varying number of inserted cytosines in the mitochondrial 12S ribosomal rna gene as the second pathogenic mutation that can predispose to aminoglycoside ototoxicity. It demonstrates the clinical relevance of taking a family history before administering aminoglycosides to any patient. In addition, it would be desirable for sporadic patients with aminoglycoside-induced hearing loss to be screened with molecular tests for the presence of the 1555 and 961 mutations. Such screening could significantly decrease the prevalence of aminoglycoside-induced hearing loss.
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4/68. Mitochondrial maculopathy: geographic atrophy of the macula in the MELAS associated A to G 3243 mitochondrial dna point mutation.

    PURPOSE: To report ocular findings in the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (melas syndrome) in a family with the A to G 3243 mitochondrial (mt) dna point mutation. methods: case reports. Ocular findings are described from four family members with the MELAS associated A to G 3243 mt dna point mutation. RESULTS: Findings included ophthalmoplegia, neurosensory deafness, reduction of photopic and scotopic electroretinogram b-wave amplitudes, and myopathy, as well as macular retinal pigment epithelial atrophy. No family members had nyctalopia, attenuation of retinal blood vessels, or retinal bone spicule pigmentation. CONCLUSION: The finding of slowly progressive macular retinal pigment epithelial atrophy expands the reported phenotypic diversity of patients with A3243G mt dna mutations.
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5/68. Surgical considerations regarding cochlear implantation in the congenitally malformed cochlea.

    A 4-year-old girl with congenital profound deafness underwent cochlear implant surgery. Preoperative CT and MRI revealed that her inner ears had common-cavity or aplasia-type malformation. The bilateral internal auditory meatus were markedly narrowed. Audiometric examination demonstrated that only slight residual hearing remained in the low-frequency range and that a hearing aid would be of no benefit. cochlear implantation was performed in her left ear. Because of the abnormal position of the facial nerve, the routine facial recess approach could not be performed. A canal-wall-down mastoidectomy was performed, and multichannel cochlear implant electrodes were inserted by careful drilling of the bony wall of the semicircular canal area. All 22 electrodes were completely inserted into the cavity. The patient can perceive sounds and her hearing ability is progressively improving.
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6/68. Globodontia in the otodental syndrome.

    A family of Polish extraction was studied in which massive, globe-shaped posterior teeth were found in a father and two of his sons, similar to those described in a previous family in which persons with this type of teeth also had a high-frequency sensorineural deafness. The audiograms in this family showed high-frequency air-conduction thresholds in the father and one son with globodontia and in other relatives without the tooth defect. The other son with abnormal teeth had a normal-appearing audiogram. Absence of premolar teeth and yellow-white spots of local hypomaturation of enamel on canine teeth were also findings in this kindred, as reported or observed in other kindreds. The disorder illustrates the problem of variable expressivity of a trait which makes it difficult to predict the risk of having an affected child when only one feature of a syndrome is present in a relative of a fully affected patient.
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7/68. Surviving cochlear function in the presence of auditory nerve agenesis.

    This case reports electrophysiological evidence for cochlear function in a child with radiological evidence of bilateral auditory nerve agenesis or severe hypoplasia. The diagnosis of auditory nerve agenesis was supported by a bilateral atresia of internal auditory canals on computed tomography (CT) scan and magnetic resonance imaging (MRI) absent auditory brainstem responses and absent behavioural responses to sound. Despite the apparent absence of an auditory nerve or spiral ganglion, electrocochleography revealed surviving cochlear function at 70-80 db HL and an abnormal electrocochleographic waveform. This case demonstrates that cochlear function may develop without afferent, or efferent innervation. It also emphasizes that cochlear function may occur in the presence of profound deafness.
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8/68. An acoustically evoked short latency negative response in profound hearing loss patients.

    In our auditory brainstem response (ABR) tests, a peculiar V-shaped negative wave at around 3 4 ms latency was observed. At present, this acoustically evoked short latency negative response (ASNR) is poorly understood. In order to study its appearance and origin, the ABR data of 3104 tests during 1980-98 were reviewed. The ASNR was found only in profound hearing loss ears under intense stimuli (80-120 dB nHL). Out of the total 653 profound hearing loss patients (981 ears), the click-evoked ASNRs were present in 80 patients (12.3%), 117 ears (11.9%). The age range was from 8 months to 70 years. Demographic outcome revealed significant higher appearance rates in young subjects especially in the 20-30 years group. The ASNR was excluded from an artifact by its reproducibility over time, equipment and institutes. Moreover, it became absent after external auditory canal occlusion, which simply blocked the air conduction without any influence upon scalp potentials or equipment. It had neural response characteristics that the latency and amplitude shortened and increased respectively in response to the increase of stimulus intensity. Because the peculiar V-shaped waveform obviously differs from ABR, the ASNR was not interpreted as a potential generated from the conventional auditory pathway. On the other hand, the ASNR individuals were of good vestibular function in sharp contrast with their poor hearing. This suggests the probable relation between the ASNR and the vestibular system. The saccule and vestibular nucleus are hypothesized to be the sense organ and the origin of the response respectively.
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9/68. Introducing music as a means of habilitation for children with cochlear implants.

    OBJECTIVE: To investigate the feasibility, methods and the primary results of utilizing music as a means of habilitation of children with cochlear implant. STUDY DESIGN: A habilitation program based on music training is developed. The results are presented as a case-series. methods: music Training Program is introduced as a new habilitation program. methods of training (based on Orff method) and measuring the outcomes are introduced in this paper. Effects of this program on other habilitation programs and overall hearing related skills of children were also investigated by open questioning of the parents and the habilitation staff. RESULTS: Twenty-three children, (age: 2.5-12.5 years) were selected. All children showed appreciable progress in playing a musical instrument. The effects on other habilitation processes were significant and all parents expressed their satisfaction with the program, as they perceived its benefits. DISCUSSION: The necessity of adding music Training Program to the routine habilitation may be summarized as follows: music is a feature of sound, which should be mastered. The psychological effects of being able to accomplish a hearing-related task can add to the self-esteem of children and help prevent and reduce anxiety. music is a habilitation method: Introducing new concepts of sound, like temporal and frequency-related characteristics, is a crucial part of the habilitation of a child with cochlear implant. Practising new concepts needs motivation, too. We emphasize on using all means of rehabilitation and encourage teaching music to cochlear implant children between 4 and 5 years of age having approximately 4 months of experience with cochlear implant.
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10/68. Search for mitochondrial dna mutation at position 3243 in German patients with a positive family history of maternal diabetes mellitus.

    Mitochondrial diabetes is one of the most common monogenetic forms of diabetes mellitus. However, variable prevalences have been reported by different investigators. Therefore, the aim of our study was to investigate the prevalence of the most prevalent mitochondrial dna mutation at position 3243 (A --> G) in german patients with a positive family history of maternally inherited diabetes mellitus and/or hearing loss. We screened 1460 patients with diabetes mellitus by a questionnaire and identified 122 patients with a positive family history of maternal diabetes mellitus. Seven of the 122 patients suffered from hearing loss in addition. An EDTA blood sample of each patient was examined by polymerase chain reaction followed by a digestion with Bsp120I. In addition all samples were further examined by denaturing gradient gel electrophoresis to increase the detection limit for heteroplasmy. Only one mt dna mutation at position 3243 could be detected in the 122 patients. The detection limit of denaturing gradient gel electrophoresis (DGGE) for heteroplasmy was 3%. We detected one new polymorphism at position 3333 (C --> T) of the mitochondrial genome (0.8% of the patients), and a known polymorphism at position 3197 (T --> C) in 10.6% of the patients. We therefore conclude that the frequency of the A3243G mutation is much lower in the investigated study population, mostly originating from Saxonia, than in asian populations.
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