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Results for “Hearing Loss, High-Frequency”

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At least 19 recordsLinked to original sources
PubMedDate not supplied

High-frequency hearing losses caused by low-frequency noises.

Human subjects were exposed to an octave-band noise for 24 hours. Temporary threshold shifts increased for the first eight hours of exposure and then were asymptotic. While threshold shifts were largest at about one-half octave above the center frequency of the noise, a second maximum was observed at higher test frequencies. The exact frequency of this second maximum decreased from 7.0 kHz, for a noise centered at 2.0 kHz, to 5.5 kHz for a noise centered at 0.5 kHz. This result could be caused by the travelling wave pattern along the cochlear partition or to the production of distortion products.

Auditory Threshold↗
PubMedDate not supplied

Animal model for the 4-kHz tonal dip.

In humans, noise exposures produce permanent hearing losses which usually begin at 4 kHz. In chinchillas, a similar pattern of hearing loss was observed following exposure for 9 or 18 days to an octave band of noise with a center frequency of 0.5 kHz. Histopathological observations of cellular degeneration showed that this exposure produced different types of damage in the basal and apical turns of the cochlea. Behavioral measures of auditory function showed that damage in the basal turn was associated with permanent threshold shifts for one to several of the high frequencies. However, moderate losses of outer hair cells commonly appeared in the apical turn without permanent threshold shifts for low-frequency tones. These findings indicate that the pure-tone audiogram may not accurately reflect the condition of the organ of Corti after noise exposure.

Animals↗
PubMedDate not supplied

Cochlear hearing loss and viral infection.

A group of about 100 consecutive patients admitted to an otorhinolaryngological outpatient department for treatment of cranial nerve affections underwent detailed neurological, audiological and laboratory examinations. Of 34 patients with hearing loss, objective signs of viral infection were found in 12. The hearing loss was sensorineural of the cochlear type, in 7 cases of the high-frequency type, in 5 cases of the low-frequency (Menière) type. Within one year after the onset of the disease the hearing loss had disappeared in all but 2 cases. Reversible dysfunction of two or more cranial nerves was found in 7 of 8 cases examined. In the cerebrospinal fluid the cell count and the total protein and gamma-globulin values were increased in most patients. Our findings indicate a reversible sensorineural hearing loss to be part of a viral-induced meningoencephalitis and cranial polyneuropathy. The mechanism of the reversible low- and high-frequency hearing loss is discussed.

Adult↗
PubMed1978

Hearing loss and cochlear pathology in the monkey (Macaca) following exposure to high levels of noise.

Eight Old World monkeys were exposed 8 h daily for 20 days to octave-band noise having center frequencies from 0.5--8 kHz at levels of 117--120 dB SPL. Two additional animals received exposures to wide-band, 120-dB SPL noise on the same schedule, and one animal was exposed to the 2-kHz octave band for 40 h continuously. Behavioral audiograms were measured throughout exposure and during a 1-month recovery period. Following recovery, the animals were sacrificed and their ears examined histologically. Monaural audiograms are presented showing initial and final TTS and PTS measured at the end of the recovery period. These are compared with complete cytocochleograms for each ear. Hair cell loss was generally restricted to the outer rows, and was reasonably well correlated with pattern of hearing loss. Some cell loss, including inner hair cells, was found in the extreme basal turn, usually without associated high-frequency hearing loss. The relationships between exposure frequency, hearing loss, and locus of cochlear pathology are discussed, as are changes in TTS during exposure.

Animals↗
PubMed1979

Follow-up of intrauterine transfused surviving children.

The long-term effects of intrauterine transfusion (IUT) are still being assessed since the procedure was first reported in 1963. Therefore, we undertook a follow-up study on the survivors of 57 infants who received IUT's between 1966 and 1975. Forty-two infants were born alive, but 15 died in the neonatal period. Overall survival was 27/57 (48%). An extensive follow-up examination was carried out at age 22 months to 10 years in 21/27 survivors. Height was below the third percentile in one child and head circumference above the mean and 2 SD in another. Of 21 children, 19 had normal vision, one was slightly myopic, and one had hyperopia. One child had unilateral high-frequency hearing loss. All had normal EEG's and none have mental retardation but 2/21 have "major" and 6/21 have "minor" neurologic signs. No evidence of passive antibody transfer was found, but minor disturbances of immunoglobulin levels were present.

Blood Cell Count↗
PubMed1977

Amikacin therapy of exacerbations of Pseudomonas aeruginosa infections in patients with cystic fibrosis.

Amikacin, a new semisynthetic aminoglycoside antibiotic with activity against Pseudomonas aeruginosa, was used to treat 22 acute exacerbations of chronic pulmonary infections in 18 patients with cystic fibrosis. Patients ranged from 5 to 32 years of age and had mucoid P. aeruginosa isolated from sputum. The amikacin dose was usually 7.5 mg/kg every eight hours but was increased to 10 mg/kg and/or carbenicillin was added in selected cases depending on clinical course. Although P. aeruginosa was not eliminated from our patients' sputum except in two cases, there was a good clinical response in 19 of 22 courses. Significant improvement in chest x-ray films, spirometry, or arterial oxygen tension was documented in 11 of 17 courses. One instance of serum creatinine level elevation could not be attributed to this antibiotic. Two patients showed minimal (15 dB) unilateral high-frequency hearing loss on serial audiograms. Activity against many gentamicin-resistant strains and high blood levels are among the attractive properties of amikacin. Amikacin is clinically effective in treating Pseudomonas-associated pulmonary infections complicating cystic fibrosis.

Acute Disease↗
PubMed1976

Phase I clinical trial of combined therapy with vinblastine (NSC-49842), bleomycin (NSC-125066), and cisdichlorodiammineplatinum(II)( NSC-119875).

Seventeen patients with various histologic types of incurable malignant disease were treated with a combination of vinblastine, bleomycin, and cis-dichlorodiammineplatinum(II). Creatinine and blood urea nitrogen elevations were noted but were not of a severe degree. White blood cell and platelet count depressions were seen and appeared to be cumulative, though not life-threatening. Tinnitus and high-frequency hearing loss were noted. Tumor regression was seen in one patient with adenocarcinoma of the lung and in one patient with a testicular tumor. This appears to be a manageable drug combination with frequent monitoring of renal, hematopoietic, pulmonary, and auditory function. A phase II study establishing the therapeutic efficacy of this combination in advanced testicular neoplasms now appears to be indicated.

Adult↗
PubMedDate not supplied

High-frequency consonant word discrimination lists in hearing aid evaluation.

A summary of the results shows that with 5 of the 9 subjects the high-frequency consonant scores indicated the same aid for the patient that the NU-6 scores indicated. In 2 cases the NU-6 indicated amplification was appropriate whereas the high-frequency consonant scores indicated amplification was not appropriate. Obviously, the high-frequency consonant scores should be considered supplemental to the NU-6 scores and not as a replacement for the NU-6. The combination of the NU-6 and the high-frequency consonant results for Subject 1 may indicate that the patient should have received further counseling and should have been taught how to communicate more effectively without an aid. The high-frequency consonant scores obtained by 2 of the subjects indicated different aids than the ones indicated by the NU-6 test and the patient preference. Perhaps the reason the patient chose an aid other than the one that would most benefit him was that he was most comfortable with the aid that allowed him to hear in the manner to which he was accustomed, even if he did not do as well with it. If a person had become accustomed to not hearing the high-frequency sounds, an aid that suddenly allowed him to hear those sounds might disturb him. The addition of high-frequency amplification might have made speech sound foreign to him. It would have been much easier for him to choose the aid that he was most comfortable with.(ABSTRACT TRUNCATED AT 250 WORDS)

Hearing Aids↗
PubMed1978

Evaluation of frequency-following potentials in man: masking and clinical studies.

The frequency-following potential (FFP) can have applicability in the assessment of hearing-impaired subjects only if it can be shown that its generation is initiated by neurons which have low best frequencies (2.0 kHz or lower). This study presents results from five subjects with high frequency hearing losses and three subjects with normal hearing. Using 500 Hz tone bursts in the presence of continuous noise of various configurations, it has attempted to determine how in normal hearing subjects, the amplitude and latency of the FFP may be affected. Recordings of the FFP in the presence of noise and wave forms from hearing imparied subjects provide evidence that the FFP is initiated in the cochlea largely by neurons whose best frequencies are 2.0 kHz or lower. Hearing impaired subjects may exhibit 'deviant' responses to tone bursts. These FFP responses may be related to peculiarities of the hearing loss and provide, therefore, a potential means for assessing the temporal viability of the low frequency channels of the auditory neuraxis.

Auditory Perception↗
PubMedDate not supplied

Conservation of hearing in acoustic neurilemmoma excision.

Conservation of hearing in acoustic neurilemmoma surgery is possible by the suboccipital route. The hearing preservation prognosis decreases as the size of the cerebellopontine angle neoplasm increases. Von Recklinghausen disease spells a poor prognosis for hearing. Some hearing was retained in seven of ten patients with preoperative hearing. Three patients retained postoperative hearing levels and speech sound discrimination equal to preoperative levels. One patient had a progressive high-frequency sensorineural hearing loss in the nontumor ear and was fitted with a hearing aid for the postoperative ear; he now has successful binaural hearing function. Gentle technique, microhemostasis, special instrumentation, and well-developed surgical craft are essential for preserving the microstructures necessary for hearing. Furthermore, the suboccipital approach for neurilemmomas less than 2 cm gives good surgical exposure and a reasonable chance to save hearing.

Audiometry↗
PubMed1979

Subclinical effects of chronic increased lead absorption--a prospective study. II. Results of baseline neurologic testing.

This report summarizes the results of baseline neurologic testing in a group of apparently healthy workers from a secondary lead smelter and a group of controls from nearby aluminum processing plants. The test battery included a standard neurologic examination nerve conduction measurements, quantitative oculomotor function tests and detailed audiologic studies. Lead workers and controls were intermixed so that the examiners were unaware of the status of any individual being tested. Although the lead workers reported significantly more neurologic symptoms than the controls, relatively few differences were found on quantitative neurologic testing. Decreased deep tendon reflexes occured more frequently in the lead workers than in the controls (22% vs. 11%) but the difference was of borderline significance (p=0.06) and other signs of peripheral neuropathy occurred with equal frequency in both groups. The mean motor conduction velocity and sensory latency measurements were not significantly different in the lead workers and in the controls and, of the six oculomotor function measurements, only the mean accuracy of saccadic eye movements was significantly (p less than 0.01) different in the two groups. High frequency hearing loss occurred with equal frequency and severity in both groups, consistent with the level of noise exposure in the lead and control plants.

Absorption↗
PubMed1975

[The prognosis of the noise-induced permanent hearing-loss (author's transl)].

Basing on a microscopic study the question was explored whether a TTS is found in the high-frequency range after exposure to a low-frequency tone or not. Such a depression is demonstrable after several registrations with automatic audiometry. This depression is significantly higher in the average of normal-hearing persons than in noise-resistant men (having a normal threshold after working in noise for many years). Also after the exposure the spikes of the Békésy-audiogram are significantly smaller in the noise-resistant men than in the control-group. Paying attention to both parameters the significance is 1%. Therefore the investigation of the high-frequency-range after exposure to a low-frequency tone seems to be a method of prediction of PTS.

Audiometry↗
PubMedDate not supplied

The case for small fenestra stapedectomy.

Eight hundred stapedectomies were analyzed to evaluate the long-term results with four prostheses. It was concluded that limitation of fenestra size played a most important part in the outcome of stapedectomy, especially in regard to the preservation of high-frequency bone conduction response over prolonged periods. Other advantages deriving from small fenestra stapedectomy included significantly fewer fistulae and severe sensorineural losses.

Fistula↗