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PubMed1980

[Causes of inner ear deafness; a critique of therapy (author's transl)].

In spite of recent criticisms, the diagnosis of inner ear hearing impairment is based on both pure tone thresholds and suprathreshold tests. The acoustico-facial reflex is useful only when used in conjunction with the suprathreshold tests.--Noise-induced deafness is generally confined to the higher frequencies of sound, and only exceptionally involve the middle frequencies as well. Low-tone hearing impairment may represent a partial symptom of Meniere's Disease as well as functional hearing loss. Zoster oticus produces a sensory hearing impairment but not a neural one, as might be expected from the neurotropy of the Herpes virus. Patients with socalled presbyacusis exhibit criteria of inner ear pathology which may represent a summation of different noxious agents damaging the inner ear throughout life rather than result from the physiologic process of aging. Traumatic hearing impairment seldom progresses, and usually involves central parts of the auditory pathways following blunt trauma.--We believe that uncritical therapy with vasodilating drugs is not useful in sensory hearing loss, especially if it is continued for months and if several drugs are employed at the same time. The danger of an unintended decrease in blood pressure is greater in these patients since many also suffer from hypotension which can then cause vascular insufficiency to the inner ear, similar to the "steal" effect. Therapy for inner ear hearing loss remains the responsibility of the otolaryngologist, and should still be based on proper diagnosis.

Audiometry↗
PubMed2006

Speech recognition in normal hearing and sensorineural hearing loss as a function of the number of spectral channels.

Speech recognition by normal-hearing listeners improves as a function of the number of spectral channels when tested with a noiseband vocoder simulating cochlear implant signal processing. Speech recognition by the best cochlear implant users, however, saturates around eight channels and does not improve when more electrodes are activated, presumably due to reduced frequency selectivity caused by channel interactions. Listeners with sensorineural hearing loss may also have reduced frequency selectivity due to cochlear damage and the resulting reduction in the nonlinear cochlear mechanisms. The present study investigates whether such a limitation in spectral information transmission would be observed with hearing-impaired listeners, similar to implant users. To test the hypothesis, hearing-impaired subjects were selected from a population of patients with moderate hearing loss of cochlear origin, where the frequency selectivity would be expected to be poorer compared to normal hearing. Hearing-impaired subjects were tested for vowel and consonant recognition in steady-state background noise of varying levels using a noiseband vocoder and as a function of the number of spectral channels. For comparison, normal-hearing subjects were tested with the same stimuli at different presentation levels. In quiet and low background noise, performance by normal-hearing and hearing-impaired subjects was similar. In higher background noise, performance by hearing-impaired subjects saturated around eight channels, while performance by normal-hearing subjects continued to increase up to 12-16 channels with vowels, and 10-12 channels with consonants. A similar trend was observed for most of the presentation levels at which the normal-hearing subjects were tested. Therefore, it is unlikely that the effects observed with hearing-impaired subjects were due to insufficient audibility or high presentation levels. Consequently, the results with hearing-impaired subjects were similar to previous results obtained with implant users, but only for background noise conditions.

Adult↗
PubMed1995

Vestibular function in bilateral progressive sensorineural hearing loss.

To investigate the vestibular function in patients with bilateral progressive sensorineural hearing loss, we examined 5 cases using electronystagmography. Cases 1, 2 and 3 were adult type, and Cases 4 and 5 juvenile type. All patients had dizzy spells in the early stage of the disease, and showed spontaneous nystagmus. Bilateral reduction of caloric response and very low vestibulo-ocular reflex (VOR) gain on rotation testing were observed in Cases 1, 2 and 3. Case 4 showed right canal paresis upon the caloric test and left directional preponderance upon the rotation test. Case 5 showed good responses to both tests. Optokinetic afternystagmus (OKAN) in Cases 2, 3 and 5 was not brisk, and Cases 1 and 2 showed directional preponderance of OKAN. OKAN was useful for detecting directional preponderance. We believe there are two types of this disease which correlate with vestibular function. One type is associated with high grade vestibular dysfunction while, in the other, vestibular function is reasonably good.

Adult↗
PubMed2002

Hearing loss: frequency and functional studies of the most common connexin26 alleles.

Mutations in the GJB2 gene, encoding the gap-junction channel protein connexin 26, account for the majority of recessive forms and some of the dominant cases of deafness. Here, we report the frequency of GJB2 alleles in the Italian population affected by hearing loss and the functional analysis of six missense mutations. Genetic studies indicate that, apart from the common 35delG, only few additional mutations can be detected with a significant frequency in our population. Transfection of communication-incompetent HeLa cells with Cx26 missense mutations revealed three distinct classes of functional deficits in terms of protein expression, subcellular localisation and/or functional activity. Moreover, the M34T mutant acted as a dominant inhibitor of wild-type Cx26 channel activity when the two proteins were co-expressed in a manner mimicking a heterozygous genotype. These data support the hypothesis of a functional role for M34T as a dominant allele and represent a further step towards a complete understanding of the role of GJB2 in causing hearing loss.

Alleles↗
PubMed2003

Gentamicin perfusion vestibular response and hearing loss.

OBJECTIVE: To compare hearing results as a function of vestibular ablation in the treatment of Ménière's Disease, using gentamicin perfusion. STUDY DESIGN: A retrospective review of patients with Ménière's Disease treated by gentamicin perfusion of the inner ear via the MicroWick device. SETTING: A tertiary otologic referral center. PATIENTS AND INTERVENTIONS: The charts of patients treated with gentamicin perfusion via the MicroWick between the years 1998 and 2000 were reviewed. The results for patients with functional hearing in the affected ear were analyzed and were compared with the results in patients without functional hearing. MAIN OUTCOME MEASURES: Audiologic and vestibular test results as well as subjective symptoms. RESULTS: There were 45 patients who met the inclusion criteria. The averages for speech discrimination score and pure tone average before treatment were 92% and 38 dB, and after treatment were 82% and 47 dB. Patients were divided into two groups: Group 1 (20 patients), less than 75% ice air caloric reduced vestibular response (RVR); Group 2 (25 patients), those who reached greater than 75% ice air caloric RVR. There were 8 patients (17.6%) with persistent vertigo; 7 were from Group 1, and 1 was from Group 2, which was statistically significant (p = 0.007)wwww. The pure tone average dropped an average of 3 dB for Group 1 and 15 dB for Group 2. The difference in hearing loss between the two groups was statistically significant (p = 0.01). CONCLUSION: This study suggests that there is a correlation between the degree of vestibular ablation, the control of vertigo, and the risk of hearing loss. Patients with functional hearing seem to have a similar success rate for vertigo control, compared with patients who already had lost functional hearing before treatment. Future investigation may determine if less than 100% RVR, but greater than 75% RVR, is an alternative end point with adequate vertigo control and reduced risk of hearing loss.

Administration, Topical↗
PubMed1993

The effects of long-term cochlear hearing loss on the functional organization of central auditory pathways.

We have developed an animal model of neonatal high-frequency cochlear hearing loss to investigate the long-term effects on the central auditory pathways. Specifically, we have induced basal cochlear lesions in newborn kittens using the ototoxic aminoglycoside, amikacin. We have monitored the consequent auditory threshold elevations using auditory brainstem evoked responses (ABR) to tone pip stimuli. In the mature animal we have mapped tonotopic (cochleotopic) representation in primary auditory cortex (AI) using standard micro-electrode recording techniques, and we show that this map becomes massively re-organized. In particular, one frequency area that corresponds to the high frequency cut-off slope of the subject's audiogram appears to become greatly expanded, in some cases to take up 75% of AI surface. In general, the development of normal cochleotopic or tonotopic representation in cortex appears to depend upon the integrity of ascending sensory input from the cochlea particularly during early stages of development. With the clinician in mind, we discuss our findings in relation to practical issues.

Acoustic Stimulation↗
PubMed1993

Organic thresholds and functional components in experimentally simulated exaggerated hearing loss.

Previous studies on the relationship between functional overlays and underlying organic hearing levels in nonorganic hearing loss (NOHL) have relied upon the clinical resolution of the nonorganic portion of the loss. This study involved the first use of subjects with sensorineural losses in a simulated NOHL experiment. This is important because most adults with NOHLs have underlying sensorineural losses. Different configurations of the experimentally simulated functional components (the difference between the exaggerated and real thresholds) as a function of frequency were associated with (a) normal hearing; (b) losses becoming abruptly worse at 4000 Hz, and (c) sloping losses, respectively. Thus, the simulation data corroborate the observations made using clinical patients with resolved NOHLs, and provide further support for the notion that these patients typically employ a strategy involving the use of an internalized loudness-based anchor on a within-ear basis to generate their exaggerated audiograms. Moreover, the outcome of this study reveals the limitations of restricting the subjects used in simulated NOHL experiments to normal hearing individuals, and highlights the importance of using hearing impaired groups in future experimental simulations of nonorganic hearing losses.

Adult↗
PubMed2003

The functional age of hearing loss in a mouse model of presbycusis. I. Behavioral assessments.

Presbycusis is a common form of hearing loss that progresses from high to low frequencies with advancing age. C57BL/6J mice experience a rapid progression of presbycusis-like hearing deficits and thus provide a convenient animal model for evaluating behavioral, physiological and anatomical correlates of the disorder. Previous studies of C57BL/6J mice have relied on short-term observations of age-matched subject groups to reconstruct a time course for auditory pathologies. Such statistical approaches are weakened by the variability of hearing thresholds in young mice and the inconsistent timing of degenerative effects in older mice. The present study was designed to resolve these ambiguities by tracking the hearing abilities of individual C57BL/6J mice from age 16 weeks until the onset of hearing loss in specific listening conditions. Testing at frequencies of 8 and 16 kHz in quiet confirmed the high-to-low frequency progression that is characteristic of presbycusis. Often the hearing loss developed in two phases, one gradual and the other abrupt. Testing in noise revealed deficits that were first manifested as threshold instability and then an increased susceptibility to masking. These changes occurred before hearing loss in quiet. CBA/CaJ mice did not show significant loss during a similar period of observation. Our findings provide a well-ordered chronology for isolating the functional consequences of multiple cochlear pathologies that arise during the time course of presbycusis. This neurobehavioral assessment is termed the functional age of hearing loss. Neuroanatomical assessments of behaviorally characterized C57BL/6J mice are presented in the companion paper [Hear. Res. 183 (2003) 29-36].

Acoustic Stimulation↗
PubMed1992

Eustachian tube function in sudden hearing loss and in healthy subjects.

The relationship between sudden hearing loss and an ipsilateral patulous tube was tested in our Eustachian tube laboratory. Fifty patients suffering from sudden hearing loss were examined by the pressure chamber impedance method, giving objective data on Eustachian tube function. Results were compared to those obtained from 56 healthy volunteers in a preceding investigation. Our investigation did not show any associations between patulous tube syndrome and sudden hearing loss, as had been claimed by several authors previously. There was even indication of a decreased patency of Eustachian tube in our patients in active and passive tubal tests. We could demonstrate a high reproducibility of values obtained by our method, indicating that results are representative in healthy persons as well as in patients. In a case report the importance of objective diagnostic methods in differential diagnostics of Eustachian tube pathology is emphasized.

Ear, Middle↗
PubMed1990

Speech recognition ability of children with unilateral sensorineural hearing loss as a function of amplification, speech stimuli and listening condition.

The purpose of this investigation was to examine three types of audiological recommendations [unaided, CROS (contralateral routing of signals) and personal FM system] and their impact upon speech recognition ability of children with unilateral sensorineural hearing loss. Each of these recommendations was tested under three listening conditions encountered in a classroom [monaural direct (MD), monaural indirect (MI), midline signal/omnidirectional noise (MS/ON)] with two types of speech materials (Nonsense Syllable Test and an American English adaptation on the Bamford-Kowal-Bench Sentence Lists). These experimental conditions were simulated in a classroom, recorded on audiotape, and played back to subjects under headphones to control such factors as signal-to-noise ratio, earmold fit, and head shadow effects. Six school-age children with unilateral hearing losses between 56 and greater than 120 dB HL (PTA) were evaluated using a repeated measures design. The children experienced the most listening difficulty in the MI condition when they were unaided. The CROS aid improved speech recognition in this condition but degraded speech recognition in the MD condition. The FM system was the only audiological recommendation to produce uniformly high speech recognition scores across all listening conditions with both types of speech materials. Implications for the audiological management of unilaterally hearing-impaired children in the classroom are discussed.

Child↗
PubMed2002

Plastic changes in the central auditory system after hearing loss, restoration of function, and during learning.

Traditionally the auditory system was considered a hard-wired sensory system; this view has been challenged in recent years in light of the plasticity of other sensory systems, particularly the visual and somatosensory systems. Practical experience in clinical audiology together with the use of prosthetic devices, such as cochlear implants, contributed significantly to the present view on the plasticity of the central auditory system, which was originally based on data obtained in animal experiments. The loss of auditory receptors, the hair cells, results in profound changes in the structure and function of the central auditory system, typically demonstrated by a reorganization of the projection maps in the auditory cortex. These plastic changes occur not only as a consequence of mechanical lesions of the cochlea or biochemical lesions of the hair cells by ototoxic drugs, but also as a consequence of the loss of hair cells in connection with aging or noise exposure. In light of the aging world population and the increasing amount of noise in the modern world, understanding the plasticity of the central auditory system has its practical consequences and urgency. In most of these situations, a common denominator of central plastic changes is a deterioration of inhibition in the subcortical auditory nuclei and the auditory cortex. In addition to the processes that are elicited by decreased or lost receptor function, the function of nerve cells in the adult central auditory system may dynamically change in the process of learning. A better understanding of the plastic changes in the central auditory system after sensory deafferentation, sensory stimulation, and learning may contribute significantly to improvement in the rehabilitation of damaged or lost auditory function and consequently to improved speech processing and production.

Animals↗
PubMed2003

The functional age of hearing loss in a mouse model of presbycusis. II. Neuroanatomical correlates.

This report relates patterns of age-related outer hair cell (OHC) loss to auditory behavioral deficits in C57BL/6J mice. Hair cell counts were made from serial sections of the cochlear partition in three subject groups representing young (2-3 months), middle (8-9 months), and old ages (12-13 months). The cochlear location of OHC counts was determined from three-dimensional computerized reconstructions of the serial sections. Comparisons of the topographic distribution of surviving OHCs across the subject groups confirmed an orderly base-to-apex progression of cochlear degeneration that is well known in this mouse strain. All mice appeared to follow the same progression of OHC loss, although subjects showed considerable variation in the rate at which they advanced through a uniform sequence of structural changes. Behavioral implications of the magnitude and location of OHC loss were investigated by correlating the histological status of individual mice with sound detection thresholds from the same subjects [Hear. Res. 183 (2003) 44-56]. The analysis revealed regionalized patterns of OHC loss that were correlated with frequency-dependent changes in hearing thresholds, and validates the use of 'functional age' as an indicator of age-related cochlear degeneration and dysfunction. In the absence of physiologically defined cochlear frequency maps for C57BL/6J mice, these structure-function correlation techniques offer an alternative approach for linking anatomical results to hearing abilities.

Age Factors↗
PubMed2000

[Clinical study of time-shift evoked potentials].

Quick change of the interaural time difference (ITD) generates moving sound stimuli. Specific biphasic event-related potentials called "time-shift evoked potentials (TSEPs)" can be recorded when this moving sound is given. The results of TSEPs in various types of hearing loss were analyzed in comparison with auditory brainstem response (ABR) and slow vertical response (SVR) in order to evaluate clinial applicability of TSEPs. Firstly, the detection threshold of TSEPs was established in groups of patients with low tone sensorineural hearing loss and with steep high tone sensorineural hearing loss. The usefulness of TSEPs was then evaluated in patients with retrocochlear hearing loss and with functional deafness. The patients with retrocochlear hearing loss were divided into 2 subgroups, one with auditory nerve disorder and the other with cortical disorder. It was found that TSEPs participate in the transference of auditory time-factors. They reflect the function of not only the auditory nerve and brainstem which form major components of ABR, but also the central nervous system superior to the inferior colliculus. TSEPs could be recorded in most patients with functional deafness and are more useful for its diagnosis than using the conventional directional hearing test. It is concluded that TSEPs is useful as a clinical test for detection of cortical disorder and functional deafness.

Acoustic Stimulation↗
PubMedDate not supplied

Hearing loss and auditory function in sickle cell disease.

UNLABELLED: Sickle cell disease was first reported in 1910 by J. Herrick, and since then, various associated conditions and complications have been described. Sickle cell disease is a hereditary disorder characterized by abnormality of the hemoglobin in the red blood cell. During periods of decreased oxygen tension in the red blood cell's environment, the abnormal hemoglobin within the red blood cell polymerizes and causes it to assume its sickled shaped. This morphological change and its associated physiological changes drastically reduce the ability of red blood cells to navigate and deliver oxygen throughout the body. Sickle cell disease is a significant health problem affecting 1 in 400 African-Americans in the United States. One in 10 African-Americans in the United States has sickle cell trait. A variety of hemoglobinapathies are classified as sickle cell disease. Variants that simultaneously occur with hemoglobin S in high frequency are hemoglobins C and beta Thalassemia, and less frequently hemoglobin E. Sickle cell disease is characterized by chronic hemolytic anemia, end-organ damage, a heightened susceptibility to infections, and intermittent episodes of vascular occlusion causing both acute and chronic pain. Neurological symptoms are frequent in patients diagnosed with sickle cell disease. Considering the vaso-occlusive nature of sickle cell disease, the potential for auditory damage is not unexpected. However, the incidence of subjective hearing impairment among sickle cell anemia subjects is very low; therefore, the interest in hearing loss associated with the disease is not in its symptomatology, but in its pathogenesis. The relationship between sickle cell anemia and hearing loss is documented, but little is known about the relationship. Numerous investigations have assessed peripheral auditory sensitivity with a wide disparity of results. In the article, we will discuss: In view of the diversity of results and speculative etiology presented here and in the literature, the relationship between sickle cell anemia, auditory sensitivity, and auditory function warrants additional investigation. LEARNING OUTCOMES: As a result of this activity, the participant will read descriptions of the genetic and pathophysiological characteristics of sickle cell disease. The participant will examine evidence of the prevalence of hearing loss and auditory dysfunction in the sickle cell population, as well as the overall hearing health risk for sickle cell patients in comparison to the risk for the normal hemoglobin population. The participant will examine a model for appropriate audiological assessment of treatment of patients with sickle cell disease.

Anemia, Sickle Cell↗
PubMed2004

Inferred basilar-membrane response functions for listeners with mild to moderate sensorineural hearing loss.

Psychophysical estimates of cochlear function suggest that normal-hearing listeners exhibit a compressive basilar-membrane (BM) response. Listeners with moderate to severe sensorineural hearing loss may exhibit a linearized BM response along with reduced gain, suggesting the loss of an active cochlear mechanism. This study investigated how the BM response changes with increasing hearing loss by comparing psychophysical measures of BM compression and gain for normal-hearing listeners with those for listeners who have mild to moderate sensorineural hearing loss. Data were collected from 16 normal-hearing listeners and 12 ears from 9 hearing-impaired listeners. The forward masker level required to mask a fixed low-level, 4000-Hz signal was measured as a function of the masker-signal interval using a masker frequency of either 2200 or 4000 Hz. These plots are known as temporal masking curves (TMCs). BM response functions derived from the TMCs showed a systematic reduction in gain with degree of hearing loss. Contrary to current thinking, however, no clear relationship was found between maximum compression and absolute threshold.

Adult↗
PubMed2006

Assessment of school functioning among Israeli Arab children with hearing loss in the primary grades.

The study examined school functioning of Israeli Arab children with hearing impairment (HI) who were included in regular education classrooms, in comparison to their classmates with normal hearing (NH). Ninety-three children (60 NH and 33 HI), grades 1-6, participated. Teachers evaluated the children using the Arabic version of the Screening Instrument for Targeting Educational Risks (SIFTER; Anderson, 1989); they also reported children's achievement levels in Arabic and mathematics. Results demonstrated that the HI children's functioning was lower than that of the NH children. Children with unilateral and minimal hearing losses had lower functioning than those with more severe hearing loss. As grade level increased, functioning decreased among HI children. Use of the SIFTER was beneficial in detecting children with difficulties. Regular, ongoing SIFTER use and appropriate follow-up on the results may better enable each child to perform optimally in class.

Arabs↗
PubMed1981

Effect of sensorineural hearing loss on the stapedius reflex growth function in the elderly.

The effect of sensorineural hearing loss upon stapedius reflex growth functions was studied in the elderly. The reflex activators were pure tones (500, 1000, and 2000 Hz) and broadband noise; reflex magnitude was expressed in decibels relative to static acoustic impedance. When expressed in decibels relative to reflex threshold, the mean growth functions of the elderly were reduced compared to previous data for young subjects [Silman, Popelka, and Gelfand, J. Acoust. Soc. Am. 64, 1406--1411 (1978)] and the noise functions differed in terms of both shape and magnitude. When expressed in SPL, the mean growth functions of the normal hearing elderly demonstrated saturation at high activator levels, whereas saturation was not observed in the mean growth functions of the hearing loss subjects. In the normal elderly, saturation was found to be frequency dependent. The saturation effect is discussed in terms of energy integration of the reflex response in the aging ear.

Acoustic Stimulation↗