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At least 307 records · Page 17Linked to original sources
PubMed1992

Comparison of clinical and real-life judgments of loudness discomfort.

The purpose of this study was to determine the relationship between the loudness discomfort level (LDL) and real-life impressions of loudness discomfort. LDLs were measured with an established procedure for a variety of stimuli including FM tones, speech noise, and stimuli recorded from two real-life environments, in two groups of subjects. Sound pressure level distributions were measured in each of two environments at the time of subject recruitment, and LDLs were subsequently measured. LDLs were then compared to the sound pressure levels measured in each environment, and to the impressions of loudness discomfort which subjects reported through the use of a questionnaire. Results indicated large discrepancies between LDLs and judgments of loudness discomfort in real-life environments. The LDL does not appear to be an accurate predictor of subjects' impression of loudness discomfort and may not be appropriate for setting the SSPL of hearing aids.

Adult↗
PubMed2005

Specific findings in distortion product otoacoustic emissions and growth functions with chronic tinnitus.

Chronic tinnitus has a very high prevalence in industrialized countries. Latest studies found chronic tinnitus in 4% of the German population, with almost 2% suffering severely in their daily life. Because no curative therapeutic approach is available--neither pharmacological nor surgical--the main focus lies in treatments that enhance the habituation of tinnitus. Habituation occurs in almost 50% of affected patients as a normal process, leading to a complete compensation. This finding is based on the ability of the auditory perception to habituate random noise and focus on important acoustic information. According to our audiological data, 90% of tinnitus patients have deficits in inner-ear function as a generator of tinnitus, mainly in the outer hair cells. This occurrence can be verified by registration of distortion products of otoacoustic emissions. Thus, the main origin of tinnitus is peripheral, and most patients suffer from accompanying hearing loss, even though it is sometimes mild or subjectively not even noticed. In almost 50% of our patients, we find hyperfunction of outer hair cells, again recorded via distortion products of otoacoustic emissions and their growth functions. Normal efferent reduction of distortion products through contralateral acoustic stimulation does not take place in most tinnitus patients. This finding shows that central auditory functions are also disturbed in chronic tinnitus patients, leading to reduced efferent effects on the hair cells and thus impeding habituation. Tests to verify these more central pathological findings have yet to be developed. We have data on diminished ability to distinguish stimuli from random noise by bilateral sound processing: The so-called bilateral masking difference test results are pathological in almost 30% of patients suffering from chronic tinnitus. We concluded from our audiological data that chronic tinnitus is primarily a cochlear dysfunction, but habituation is impeded by accompanying or consecutive deficits of the central auditory pathway. Regarding therapeutic approaches, these central functions can be trained by hearing therapy, as we know from patients' rehabilitation.

Adolescent↗
PubMed2005

[Otoacoustic emissions and recruitment].

INTRODUCTION: Typical high frequency hearing loss is accompanied by an exaggerated response to loudness as the sound level exceeds your elevated thresholds. This exaggerated response to sound levels is termed "recruitment". Recruitment is a paradoxical phenomenon present in hearing losses due to cochlear damage. Loudness recruitment is usually present to some degree as measured on the SISI. There have been many explanation connected this phenomena so far. It has been suggested that otoacoustic emissions might be more sensitive in assessment of changes to the cochlea caused by noise than pure tone audiometry. MATERIAL AND METHODS: In the present study results of the short increment sensitivity index test (SISI), DPOAE as well as slope of DPOAE input/output (I/O) function were compared before and after noise exposure. The I/O function plots DPOAE amplitude as a function of the level of the primary tones, for the progressively increasing stimulus levels (from 45 to 70 dB SPL) for the frequencies 1, 2, 3, 4, 6, 8 kHz. From 40 patients between 18-21 years, 30 ears were extracted with cochlear lesions and good hearing. RESULTS: Both, PTA and DPOAEs amplitude showed in this group significant reduction due to noise exposure. Slopes of the DPOAE I/O function were depended on stimulus levels. For the low intensity stimuli levels (45-55 dB SPL) we obtained DP I/O amplitude value worse than before noise exposure. When stimulus level was above 55 dB SPL for the frequencies (1, 2, 3, 4, 6, 8 kHz) the amplitude and DP I/O slope was higher than before noise exposure. We did not notice that phenomena in persons without cochlear lesions. CONCLUSIONS: Our results showed that in examination group with cochlear lesion I/O DP amplitude was higher using stimulus level above 55 dB SPL. This notice can be otoacoustic recruitment phenomena.

Acoustic Stimulation↗
PubMed2006

[Recruitment in presbycusis].

Presbycusis is characterised by a sensorineural hearing loss, mainly in high frequencies, symmetrical and progressive and poor understanding. Recuritment, typical in cochlear hearing loss, would be present in cases of sensorial presbycusis which runs mainly in cochlear pathologies. We analyse variables and their possible interrelations with recruitment in 241 presbycusic patients.

Aged↗
PubMed2006

[A clinical study of pyridoxine treatment for pervasive developmental disorders with hypersensitivity to sound].

In our earlier study we conducted a randomized, placebo-controlled, triple blind trial, and showed that pyridoxine treatment of pervasive developmental disorders with expressive verbal disorders and hypersensitivity to sound as significantly effective in improving VIQ scores. This study analyzed the long-term changes of the subjects. We confirmed that their VIQ scores improved over time. An analysis of the reports of their daily life provided by their parents and teachers showed that the children's hypersensitivity to sound was also improved. They became able to adjust to their daily life at home and school without any panic. Our results indicate there are PDD subgroups whose expressive language capabilities and hypersensitivity to sound can be improved by pyridoxine treatment.

Adolescent↗
PubMedDate not supplied

[Amplitude and time characteristics of latent auditory evoked potentials in occupational hearing disorders with and without the recruitment phenomenon].

Cortical evoked potentials (CEP) of workers exposed to industrial noise were recorded by an Amplaid MK-6 unit (Italy). They suffered from neurosensory hypoacusis with or without the recruitment phenomenon. The results were compared with those derived from patients with neurosensory hypoacusis of vascular origin, aggravated by the recruitment phenomenon, and in the cortical structures of the hearing organ in the case of neurosensory hypoacusis of both vascular and noise origin. Increase of the N2 with observations made on normal controls who were not exposed to industrial noise. CEP were found to give reliable information about changes peak latency may be used for differential diagnosis of neurosensory hypoacusis of vascular or noise origin. Decrease of the P2--N2 amplitude in response to 1 kHz stimulation may also help discriminate neurosensory hypoacusis of vascular or noise origin.

Acoustic Stimulation↗
PubMed1990

How much do we gain by gain control in hearing aids?

This paper considers three rationales for the use of automatic gain control (AGC) in hearing aids, and particularly multi-channel AGC. One rationale is to restore loudness relations among the acoustical elements of speech to what they would be for a normal ear. At present, there seems to be little evidence to support the idea that such loudness relations are critical for speech intelligibility. A second rationale is to reduce the effects of narrowband interfering sounds. This may be applicable in some restricted situations, but not in many others. The third rationale, the one considered here to be most important, is to ensure that all of the important elements in speech are comfortably audible. This can be achieved using two forms of AGC: slow-acting AGC operating on the whole speech signal, to compensate for variations in overall sound level from one situation to another; and fast-acting (syllabic) compression acting independently in a number of bands, to compensate for differences in level of acoustical elements within speech. To reduce spectral and temporal distortions introduced by the syllabic compression, the number of bands should be small (probably two or three) and the amount of compression should be the minimum required to ensure that all of the important elements in speech are audible. It is concluded that gain control can be useful for increasing user comfort and for ensuring the audibility of speech sounds. It is not likely to restore impaired hearing to normal for most patients, but may usefully be employed in conjunction with other forms of signal processing.

Equipment Design↗
PubMed1990

[Contribution to the study of the perfect pitch].

Absolute pitch (AP) is the ability to name a note without any reference, since relative pitch (RP) needs for a previous and known tone to be able of such a recognition. We suggest that AP is due to both environmental features and physiological particularity. From the responses of 263 musicians including 169 AP we observed that for AP musical environment in childhood was better, and younger the age of instrumental beginning than for RP. The study of otoacustic emissions evoked by a supraliminar stimulation in 183 musicians ears including 68 AP showed that the echo was significantly greater in case of AP than in case of RP.

Adult↗
PubMed1989

Decruitment and abnormal auditory adaptation.

1. Factual findings related to decruitment have been presented. 2. Decruitment is considered to be a manifestation of eighth nerve involvement indicating abnormal adaptation. 3. Loudness match as a quick screening test may be applied in cases of suspected abnormal auditory adaptation.

Adaptation, Physiological↗
PubMed1978

The influence of attack time and release time on speech intelligibility. A study of the effects of AGC on normal hearing and hearing impaired subjects.

Automatic gain control may be used in hearing aids intended for different types and degrees of hearing loss; to average the levels, to reduce the dynamics of speech or to set the maximum output level of the hearing aid without adding nonlinear distortion. Our study concerns hearing impaired listeners with recruitment. A group of normal hearing subjects was used as a control group. The compression was introduced over a laboratory unit. The compression ratio was set to 30:5 dB. A fixed ratio between the attack time and the release time, tr = 200 x ta, was used. The values used varied from 0.05 to 5 ms for ta and 10 - 1000 ms for tr. The speech material was nonsense syllables of the CVC type presented with S/N = 60 dB and S/N = 5 dB. With S/N = 5 dB a significant deterioration of the discrimination of the nonsense syllables was found at time constant combination ta = 5 ms and tr = 1000 ms. No statistically significant difference in discrimination was found between the different combinations of attack and release times for the S/N = 60 dB condition neither for the normal hearing nor for the hearing impaired group.

Hearing Aids↗
PubMed1978

Comparison of normal and impaired hearing. I. Loudness, localization.

Impaired hearing is characterized by high thresholds and reduced loudness. Loudness, however, may quickly recover as it increases rapidly from an elevated threshold. This rapid growth, known as loudness recruitment, is a sign of cochlear impairment and is generally not seen in conductive or retrocochlear impairment. Loudness recruitment means that the hard-of-hearing person detects small changes in intensity near his elevated threshold but he probably does no better than a normal listener at the same SPLs. Recruitment is often accompanied by reduced loudness summation, which means that the loudness of a band of noise does not increase as much with increasing bandwidth as in normal hearing. This reduced summation of loudness is probably why the cochlearly impaired ear has nearly the same threshold for the acoustic reflex to pure tones as to wide-band noise, whereas the normal ear has a much lower threshold to wide-band noise. Corresponding differences between normal and impaired hearing are not found in auditory localization. Rather, the evidence suggests that persons with residual hearing learn to localize sounds reasonably well. Even the inability of many hearing impaired persons to understand a speaker in a noisy environment may result more from a failure of frequency analysis rather than of localization.

Auditory Threshold↗