SEARCH · PubMed Health

Results for “Retrocochlear Diseases”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources

PubMed2001

[Tinnitus in noise-induced hearing impairment].

The analysis of the epidemiological data indicates that exposure to noise is widespread and it is one of the most common causes of tinnitus, estimated at about 20.7% according to Hazell; 28% according to Axelsson; and 42% according to Palmer. Bearing in mind the scantiness of reliable data on the incidence and nature of tinnitus in persons exposed to industrial noise, and especially the need for the objectivity of this subjective symptom, the authors have decided to undertake the study aimed at assessing the interrelation between tinnitus, the magnitude and kind of hearing impairment, and otoacoustic emission. The study group included 191 persons aged 42.5 +/- 7.6 years (range, 25 to 65), occupationally exposed to noise at the levels of 88-92 dB(A) for 26.9 +/- 4.6 years (range, 9 to 30) who had reported hearing disorders and tinnitus. The control group, matched by similar age and duration of employment, consisted of 80 persons with perceptive hearing impairment induced by industrial noise who had not complained of tinnitus. The results of the study revealed that in 59.7% of the study subjects, noise proved to be one of the most probable factors responsible for the development of tinnitus. The presence of tinnitus was found in 22.5% and in 46% of the study subjects after 10 years and 11-20 years of noise exposure, respectively. In 95.8% of workers, tinnitus was associated with hearing loss, and only in 4.2% of cases it occurred in ears with normal hearing. In persons exposed to noise, tinnitus was most frequently (59.2%) bilateral and permanent. Following the audiologic examinations, verified by objective audiometry (tympanometry, ABR), cochlear hearing impairment was found in 68.6%; retrochochlear in 8.37%; mixed and other forms of impairment, e.g. presbyacousis, in 19.4% of subjects. The audiologic assessment of tinnitus demonstrated that in 62.3% of persons, tinnitus occurred at high frequencies and correlated with the magnitude of hearing impairment in the tonal audiogram. The tinnitus intensity ranged between 10-15 dB and 45 dB. In 40.3% of those under study, noise was not the only tinnitus-risk factor. In this group of persons, the presence of predisposing diseases was also observed, e.g. hypertension, diabetes, atherosclerosis, disturbed lipid metabolism and other etiologic factors that might have impact on the tinnitus incidence, ototoxic drugs, for example. The measurements of evoked otoacoustic emission (EOAE and DPOAE) revealed in 58.63% of persons significant differences (p < 0.01) in the amplitude and spectrum of EOAE in the ears with tinnitus as compared to the ears without tinnitus with a similar hearing threshold. Whereas in 27.74% of subjects, no differences in the EOAE measurements in the ears with or without tinnitus were observed. The results of DPOAE measurements showed in 62% of subjects significant differences in DP-grams in the ears with tinnitus as compared to the ears without tinnitus (p < 0.01). Interestingly, the differences in measurements of both types of evoked emissions (EOAE and DPOAE), expressed by the lowered amplitude, narrowed spectrum, reduction of emission or its complete fading in a limited area of high frequencies, were demonstrated in the ears with tinnitus only in retrocochlear hearing impairment, as compared to those free from tinnitus. The evaluation of the EOAE and DPOAE measurements seems to prove that this method may be useful in assessing the contribution of the cochlear mechanisms to the incidence of tinnitus and in distinguishing between tinnitus generated in cochlea and tinnitus with the source at other levels of the hearing organ or beyond it. Our study failed to determine the interrelation between tinnitus and spontaneous emissions as the emission was registered only in about 12% of persons exposed to noise, including 2% of those with normal hearing.

Adult↗

PubMed1992

Speech in noise: a practical test procedure.

A simple and effective speech in noise test is described with clinical findings for patients with normal hearing, cochlear and retrocochlear pathologies and auditory dysacusis. The test utilizes material readily available in Audiology and ENT Departments. It was possible to obtain useful diagnostic information in patients who complain of hearing loss, but who demonstrate normal audiometric thresholds and normal speech in quiet discrimination.

Adolescent↗

PubMed1996

Sensorineural hearing deficit: a systematic approach based on imaging findings.

Sensorineural hearing loss (SNHL) can be classified audiometrically into two varieties: sensory (cochlear) and neural (retrocochlear). Individuals with sensory SNHL have damage to the "end organ" (the cochlea) at a macroscopic or microscopic level. When present, imaging manifestations may involve the bony labyrinth or membranous labyrinth. Abnormalities of the bony labyrinth are demonstrable primarily with computed tomography and include demineralization, congenital deformities, traumatic lesions, and erosive or destructive lesions. Abnormalities of the membranous labyrinth include enhancement and hemorrhage, which are demonstrable with magnetic resonance (MR) imaging, and obliteration, which may be diagnosed with either modality. Individuals with neural (retrocochlear) SNHL have involvement of the remainder of the auditory pathway exclusive of the cochlea. This type of SNHL requires study of the internal auditory canal, cerebellopontine angle, brain stem, thalamus, and temporal lobe. The entirety of this type of examination is best performed with high-resolution MR imaging in virtually all cases.

Cochlear Diseases↗

PubMed1994

Acoustic neuroma presented as repeated hearing loss.

Up to 15% of patients with acoustic neuroma may have a history of sudden hearing loss. Recovery from sudden hearing loss with acoustic neuroma is rare. In this paper, a case of bilateral acoustic neuromas presented as repeated sudden hearing loss with recovery on the left side after removal of right-sided tumor were reported. She experienced three episodes of sudden hearing loss, showing various types of audiograms and ABR on the left side. There was no relationship between the type of audiograms and ABR findings. Factor influencing ABR might be different from the cause of hearing impairment. Acoustic neuromas can be reliably identified by performing MRI properly. However, MRI showed negative scan and ABR finding was abnormal in the first episode of our case. ABR continues to be a sensitive diagnostic back-up test to MRI for the detection of acoustic neuromas. Even if the patient, who showed abnormal ABR findings suggesting retrocochlear pathology, showed normal MRI, acoustic neurinoma should not be ruled out and both ABR and MRI must be re-examined at regular intervals.

Adult↗

PubMed1984

Dichotic alignment, phonetic, and language variables as predictors of SSW performance.

Itemized error scores on the SSW test were acquired for 134 adults in six clinical groups. Using regression analysis, predictors of SSW performance by each group were sought from among variables descriptive of the SSW spondaic words on the EC tape. These included 13 alignment variables, 14 phonetic variables, and 10 speech-language variables. Results showed that for normal subjects, asynchronous dichotic onsets reduced errors significantly. Retrocochlear subjects were sensitive to dichotic phonetics . Cochlear subjects and those with Heschl 's gyrus lesions were both affected by word familiarity variables. Those with cortical lesions sparing Heschl 's gyrus were affected by dichotic alignment. None of the 37 predictor variables was related to SSW performance by adult mentally retarded subjects.

Adolescent↗

PubMed1981

[A factor analysis of cochleovestibular findings. (author's transl)].

Using the variables auditory threshold, speech audiometry, SISI, ABLB, stapedius reflex, Carhart-test, Békésy audiometry and calorization three factors could be extracted: 1. The quality of peripheral speech-coding in combination with central processing; 2. the degree of damage of the inner ear (threshold, distance between hearing-threshold and reflex-threshold, SISI and calorization); 3. a retrocochlear factor. SISI and ABLB are both tests concerning the inner ear, but must be regarded separately as it is to be supposed that these two findings are caused be two different pathologic processes.

Audiometry↗

PubMed2004

Hearing evaluation in two sisters with a T8993G point mutation of mitochondrial DNA.

We report on two sisters with a T8993G point mutation of mitochondrial DNA, and their hearing evaluation. Considering auditory function, hearing in the elder sister remains almost normal. However, in the younger sister, the auditory brainstem response (ABR) threshold has fluctuated remarkably during a 3-year follow-up. The threshold changes of ABR in the younger sister suggest that her hearing problems may well be caused by both cochlear nerves and retrocochlear lesions. Our experience is clinically important because there have been only a few reports on hearing evaluation in patients with a T8993G point mutation of mitochondrial DNA.

Audiometry, Pure-Tone↗

PubMed1982

Temporal resolution in hard-of-hearing patients.

Temporal resolution is, next to frequency resolution, the most important ability of the ear for perceiving speech. A simplified method for measuring temporal resolution clinically is described. It is based on masking period patterns, but measures only their maximum and minimum through the use of continuous and square-wave amplitude-modulated masking noises. Test tones and filtered masking noises are presented at 500, 1 500, and 4 000 Hz. Temporal resolution data of a normally hearing group and of seven pathological groups are given: Patients with conductive hearing loss show normal resolution; those with noise-induced, age-induced, and sudden hearing loss show normal resolution at low and middle frequencies, but reduced resolution at 4 000 Hz; patients with retrocochlear hearing loss and Menière's disorder show a tendency for reduced resolution at all frequencies, but reduction at 4 000 Hz, while ototoxic hearing loss shows the greatest reduction at 1 500 Hz. The method used also gives an indication for reduced frequency selectivity.

Auditory Perception↗

PubMed1988

Clinical application of brain-stem audiometry.

Based on the examination of 249 consecutive patients, the usefulness of brain-stem response audiometry in a major audiological clinic was evaluated. Auditory brain-stem responses were performed either for hearing threshold determination (67 patients) or for assessment of retrocochlear hearing loss (182 patients). The results demonstrate that ABR is a reliable method for the estimation of hearing thresholds in non-cooperative subjects. The rate of false positives was 5% and no false negatives were found. In combination with caloric testing, ABR is considered a valuable testing procedure in the audiological clinic and it may form the basis for submission to brain imaging examination when a suspicion of retrocochlear hearing disorder is raised. Concerning the diagnosis of retrocochlear hearing disorder, no false negatives have yet been found, while a rate of 13% of false positives has been indicated.

Adolescent↗

PubMed1992

[Critical ratio: effects of contralateral masking on normal and pathological ears].

In order to evaluate the central interferences on the auditory efficiency, the effect of contralateral masking noise on Critical Ratio (CR) has been studied in 14 normal ears (control group), in 12 ears with cochlear disorders and in 6 with retrocochlear lesion (acoustic neuromas); in all cases the impairment was unilateral, while the other ear was normal. CR values were calculated for 1 KHz pulsed tones (duration 500 ms, rise/fall 25 ms, duty cycle of 50%); the masking noise was a wide band (90-20,000 Hz) delivered at 40 dB SL. The results have demonstrated that in the presence of contralateral masking noise, CRs don't modify both in the normal ears and in those with retrocochlear disorder, whereas they increase, almost always, in ears with cochlear deafness. These results demonstrate that the involvement of central auditory pathways, because of contralateral noise, makes the auditory efficiency worse, only in ears with cochlear dysfunctions; this behaviour seems to confirm the peripheral origin of CR.

Adolescent↗

PubMedDate not supplied

Auditory brain stem response wave V latency-intensity function and three audiologic measures of cochlear function.

The purpose of this study was to compare the sensitivity of the ABR wave V latency-intensity (L-I) function to that of Alternate Binaural Loudness Balance, Loudness Discomfort Level, and Acoustic Reflex Threshold tests in identifying sensory hearing losses. Five audiometric groups were tested by each procedure. The groups included subjects with normal hearing, and with conductive, high-frequency sensory, flat sensory, and retrocochlear hearing losses. The ability of each test to separate sensory from retrocochlear impairments was investigated. A positive discriminator for cochlear impairments was of particular interest. A combination of wave V L-I slope at lower intensities and the dB HL value that separates steep and shallow slopes of the L-I function appears to meet this objective.

Adolescent↗

PubMed1997

Hearing loss from combined exposures among petroleum refinery workers.

Workers from a refinery (n = 438) were interviewed, had their hearing tested and had their exposures to noise and solvents assessed. Measurements suggested that most exposures to noise and solvents were within exposure limits recommended by international agencies; however, the prevalence for hearing loss within the exposed groups ranged from 42 to 50%, significantly exceeding the 15-30% prevalence observed for unexposed groups. The adjusted odds ratio estimates for hearing loss were 2.4 times greater for groups from aromatics and paraffins (95% CI 1.0-5.7), 3 times greater for the maintenance group (95% CI 1.3-6.9) and 1.8 times greater for the group from shipping (95% CI 0.6-4.9), when compared to unexposed workers from the warehouse and health clinic. The results of acoustic reflex decay tests suggest a retrocochlear or central auditory pathway involvement in the losses observed in certain job categories. These findings indicate that factors in addition to noise ought to be considered when investigating and preventing occupational hearing loss.

Adult↗

PubMed1988

The value of combining auditory brainstem responses and acoustic reflex threshold measurements in neuro-otological diagnosis.

Acoustic reflex thresholds (ART) and auditory brainstem responses (ABR) were measured in 69 patients referred to the Neuro-otological clinic on the suspicion of a retrocochlear lesion. The pure-tone selection criterion was an average hearing loss of less than 60 dB at 0.5, 1, 2, and 4 kHz, with no thresholds exceeding 70 dB and only one threshold exceeding 60 dB. Both tests proved independently to be most effective in the diagnosis of cerebello-pontine angle (CPA) tumours and to a lesser extent for brainstem lesions. The ABR was positive in 100% of CPA group and 90% in the brainstem group compared with 93% and 70% respectively for the ART. The combination of the two tests provides patterns of abnormality which are more disease specific. In the CPA cases the most common and consistent patterns of abnormality were the unilateral delay of Wave V or III and V of the ABR associated with a vertical ART pattern indicative of an abnormality of the ipsi and contralateral reflexes on stimulating the affected side. Intrinsic brainstem lesions most commonly resulted in bilateral ABR abnormalities combined with the full-house ART pattern indicative of bilateral abnormalities of both ipsi and contralateral reflexes.

Adolescent↗

PubMedDate not supplied

Vestibular findings in sensorineural hearing disorders. Results of caloric, oculomotor and hearing tests in 205 patients with unilateral hearing dysfunction.

In 205 patients with unilateral hearing loss, 117 of cochlear and 88 of retrocochlear origin, thorough audiovestibular examinations were performed to establish the occurrence and severity of vestibular dysfunction. The results were also analysed with the aim of determining the relationships between the severity of the hearing loss, the etiology and the topical location of the hearing disorder, on the one hand, and vestibular dysfunction, recorded as reduced caloric sensitivity and occurrence of oculomotor disturbances, on the other. No correlation was found between severity of hearing loss and recordable vestibular dysfunction, in either the cochlear or retrocochlear group of patients, or in the etiological subgroups of these main groups. With respect to the relations between the topic locations of the lesions and the results of vestibular tests, distinct characteristics were observed. In the affected ears, totally extinguished caloric reactions were more than six times as frequent in the retrocochlear group as in the cochlear group and appeared as a specific but rather insensitive sign of acoustic neurinoma. Oculomotor disturbances were only exceptionally observed in patients with cochlear lesions, but were noted in nearly half of the retrocochlear group; when only those patients with lesions of the brain stem or cerebellum were considered, all were found to exhibit such disturbances. The relations between audiometric hearing test pattern, caloric sensitivity and oculomotor disturbances seem to form interesting diagnostic paradigms of great value for the topical localization of audiovestibular disorders.

Auditory Pathways↗

PubMed1990

[Correlation function and power spectrum analysis of auditory brainstem responses (ABR)].

Correlation function and power spectrum analyses were made for ABR of 20 normal ears and 14 ears with retrocochlear lesions. Power spectrum of normal ABR had three peaks, F0, F1 and F2; their frequencies being 125, 552.5, 967.5Hz respectively; the spectrographic shapes were of good similitude. The curve of cross correlation function in normal ABR was V-shaped, with the valley at 6-8 ms delay. In ABR of the retrocochlear lesions, the peaks of power spectrogram appeared lower and smoother with F1, F2 shifting to left and varying obviously. Their curves of cross correlation function were even and had no regular pattern. We have found that, F1 and F2 shift may be a characteristic of hearing disorder and the analysis of cross correlation function could help for the detection of useful signal from distorted signals.

Auditory Diseases, Central↗

PubMed1986

Assessment of the effect of chemotherapy and radiotherapy on the auditory function of children with cancer.

Forty children with malignant disease underwent full audiological assessment with pure tone audiometry, tympanometry and measurement of brain stem auditory evoked potentials in an attempt to detect auditory dysfunction resulting from treatment. Significant auditory dysfunction was observed in 8 children. Three children with evidence of a conductive or sensorineural deafness on pure tone audiometry had normal brain stem evoked potentials. One child with a high tone hearing loss and 4 children with no detectable hearing loss on audiometry showed significant differences in the interaural interpeak latencies of selected brain stem auditory evoked potentials. In 2 children these abnormalities had resolved on subsequent testing, 2 had evidence of persistent retrocochlear dysfunction and the remaining child died prior to further evaluation. Routine measurement of brain stem auditory evoked potentials is probably not necessary for the majority of children undergoing treatment for cancer, although such measurements are of value when differentiation between cochlear and retrocochlear damage is required.

Acoustic Impedance Tests↗

PubMed1976

The effects of age on the diagnostic utility of the rollover phenomenon.

Articulation curves were constructed for 32 elderly listeners with hearing according to previously established decadal age norms. Each function was specifically examined for the presence of rollover, a previously determined indicator of retrocochlear pathology. Rollover exhibited by six subjects was an age-related phenomenon. It is suggested that normal neural degeneration concomitant with the aging process is responsible for this auditory behavior and that clinical significance of the rollover phenomenon is greatly reduced when dealing with the aged population. Implications for the use of the rollover index are also discussed.

Age Factors↗

PubMedDate not supplied

Temporal bone histopathology in deafness due to cryptococcal meningitis.

This paper reports on a patient who survived an attack of cryptococcal meningitis eight years prior to his death. A bilateral sensorineural hearing loss had been noted a short time before the patient was admitted to the hospital, and was the only complication after he recovered from the disease. Histopathologic study of the temporal bones showed a similar pattern of pathology in both ears, the most striking finding being a severe loss of spiral ganglion cells in Rosenthal's canal, and of cochlear nerve fibers in the osseous spiral lamina and internal auditory meatus. The vestibular nerve was mostly free from pathology. The organ of Corti was atrophic but the hair cell population appeared to be almost normal. A slight number of cryptococci were observed in limited areas of the cochlear and the saccular nerves in the internal auditory meatus. The severe pathology of the cochlear nerve was compatible with audiologic evaluations, which pointed to a retrocochlear lesion. Thus, this case demonstrates some characteristic aspects of cryptococcal infection of the temporal bone: The primary site of invasion was the cochlear nerve in the internal auditory meatus and the modiolus, leading to the loss of ganglion cells and nerve fibers, while the vestibular nerve appears to have been resistant to infection.

Cochlear Nerve↗