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Results for “Recruitment Detection, Audiologic”

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PubMed1981

Acoustic neuromas. Diagnostic efficiency of various test combinations.

In the majority of diagnostic tests usually used in the search for acoustic tumors, there is a large difference in the outcome between patients with and without tumors. Because of a possible coherence between the tests applied, a statistical analysis of this connection was performed with the aid of a logistic model. The best single investigation used to differentiate between patients with and without tumors was tomography of the internal acoustic meatus. This examination was used in combination with the differential caloric test and the alternate binaural loudness balance recruitment test to differentiate completely between patients with and without tumors. Results of other examinations did not contribute significantly to the differentiation between patients with and without tumors. This factor did not render the other examinations superfluous because the analysis was valuable only in patients with a hearing level better or equal to 80 dB. By applying the other tests, information was obtained on pressure conditions in the internal acoustic meatus and possible difficulties at surgery, as well as information about the size of the tumor.

Audiometry, Pure-Tone↗
PubMed1993

Use of alprazolam for relief of tinnitus. A double-blind study.

OBJECTIVE: To systematically test the effectiveness of alprazolam as a pharmacological agent for patients with tinnitus. DESIGN: Prospective, placebo-controlled, double-blind study. PATIENTS: Forty adult patients with constant tinnitus who had experienced their tinnitus for a minimum of 1 year and who resided in the Portland, Ore, metropolitan area. Twenty patients were randomly assigned to the experimental group and 20 to the control group. RESULTS: Seventeen of 20 patients in the experimental (alprazolam) group and 19 of the 20 in the placebo (lactose) group completed the study. Of the 17 patients receiving alprazolam, 13 (76%) had a reduction in the loudness of their tinnitus when measurements were made using a tinnitus synthesizer and a visual analog scale. Only one of the 19 who received the placebo showed any improvement in the loudness of their tinnitus. No changes were observed in the audiometric data or in tinnitus masking levels for either group. Individuals differed in the dosages required to achieve benefit from the alprazolam, and the side effects were minimal for this 12-week study. CONCLUSIONS: Alprazolam is a drug that will provide therapeutic relief for some patients with tinnitus. Regulation of the prescribed dosage of alprazolam is important since individuals differ considerably in sensitivity to this medication.

Adult↗
PubMed1980

The graph of loudness recruitment (ABLB-test).

The ABLB-test compares the subjective loudness in patients with unilateral sensorineural hearing loss. The graph of this comparison of loudness at different suprathreshold intensities is of interest for understanding the function of the hair cells.

Auditory Threshold↗
PubMed1988

Evolution of recruitment at different frequencies during the development of endolymphatic hydrops in the guinea pig.

The study of human temporal bones has identified endolymphatic hydrops as a common feature of several diseases. In particular it is systematically found in those bones removed from patients with premortem Menière's disease. Menière's disease is known to induce sensorineural pathology with recruitment, which changes with the evolution of the hearing loss, and is suspected to induce a cochlear conductive loss by a possible increase in static pressure of endolymph. Amplitude/intensity functions of sensorineural responses can reflect recruitment and/or conduction loss. Experimentally induced hydrops in animals provokes cochlear physiological alterations, some of which closely resemble certain features of Menière's disease. In the present study using a guinea-pig animal model, we have examined amplitude/intensity functions at the round window for cochlear microphonics (RWCM), summating potentials (RWSP) and action potentials (CAP) at different stages of hearing loss in experimentally induced hydrops. During the period of fluctuating thresholds there was reduction of maximal RWCM amplitude, no change in RWSP and recruitment on the CAP. At a later stage when the audiogram was flat and fluctuations were no longer seen, RWCM remained unchanged. At this time RWSP could show recruitment while CAP amplitudes at all intensities were reduced, indicating either a cochlear conductive loss and/or a general depression of neural activity.

Animals↗
PubMed2003

[Hyperacusis, phonophobia, and recruitment. Abnormal deviations of hearing associated with hypersensitivity to sound].

Hypersensitivity to sound is a common description of distinct nosological phenomena of peripheral and central hearing disorders, which are characterized by intense suffering from the acoustic environment. One can distinguish between recruitment accompanying inner ear hearing loss, hyperacusis with a general hypersensitivity to sound of any frequency, and phonophobia as an anxious sensitivity towards specific sound largely independent of its volume. While recruitment can be described as a peripheral reaction caused by a lack of outer hair cell moderation, hyperacusis and phonophobia represent disturbances of central auditory processing without peripheral pathology, often combined with psychosomatic reactions. Due to insufficient efferent inhibition, hyperacusis often follows psychovegetative exhaustion. In cases of phonophobia, peripheral and efferent hearing functions are usually intact, but certain learning (conditioning) processes lead to development of specific reactions and avoidance patterns to certain content-related acoustic stimuli. This article describes those different phenomena with regard to their clinical appearance, diagnostics, and possibilities for therapy.

Anxiety↗
PubMed2000

[Categorical loudness scaling within the scope of hearing aid management].

The loudness perception of patients with hearing aids was measured with a one-stage category loudness scaling procedure. Data were obtained from 102 ears and were studied primarily in older patients who represented the majority of patients with hearing disorders evaluated in our department. In all, 75% of the patients were older than 45 years and had a mean age of 58 years. The reduction of dynamics at high frequencies was considered to be typical for age-related hearing disorders and was easily quantified with loudness scaling. Findings demonstrated that prediction of recruitment was not possible from pure-tone thresholds or even together with uncomfortable loudness levels, since the slopes of the level-loudness functions revealed a high interindividual variability. In contrast, the desired compression ratio can be easily calculated with data from the loudness scaling. In this study the loudness perception of patients with mainly non-linear hearing aids fitted with customary procedures was evaluated. The benefit from the hearing aids was proven with the outcome from the loudness scaling, with testing also allowing for a better fitting of the aids.

Adult↗
PubMed1999

Topodiagnostic assessment of occupational noise-induced hearing loss using distortion-product otoacoustic emissions compared to the short increment sensitivity index test.

Because the efforts needed to produce an "automatic audiogram" by means of distortion-product otoacoustic emissions (DPOAE) are still experimental, their capacity to produce objective topodiagnostic information must still be defined. In the present study results of the short increment sensitivity index testing (SISI) test in 97 patients with noise-induced hearing loss (NIHL) were compared with those of a DP-gram. Pure tone, speech and impedance audiometry, SISI tests and DPOAE measurements were performed on all patients. SISI was measured in both ears of 93 patients and unilaterally in 4 patients. SISI was also determined at two frequencies in 46 patients. Six measurements were rejected because of conductive hearing losses in adjacent frequencies. In all, 230 measurements could be compared. After classifying topodiagnostic results of the SISI test and DP-gram into cochlear, inconclusive and retrocochlear lesions, statistically significant correlations were found and differences were noted in only 18% of cases. Findings demonstrated the superiority of DPOAE to the SISI test in obtaining topodiagnostic information about inner ear disease.

Acoustic Impedance Tests↗
PubMed1990

Neural representation of sound amplitude in the auditory cortex: effects of noise masking.

Single auditory cortical neurons express their sensitivity to the amplitude of a preferred-frequency tone pulse as either a monotonic, saturating intensity profile or as a non-monotonic, bell-shaped intensity function. In the presence of continuous, wideband noise masking, the tone intensity profile is displaced toward higher tone levels. The magnitude of the tone threshold adjustments brought about by increments in noise level very closely match the elevations in noise amplitude. The mechanisms underlying the threshold adjustments likely include neural adaptation. This is because the tone threshold shifts seen in the spike count data are paralleled by spike latency data, and because recovery of tonal sensitivity following noise offset proceeds in a negatively-accelerating fashion. In some instances, the slope of the masked tone intensity profile is greater than that for unmasked tones. For masked tone levels evoking submaximal responses, this has the consequence that cortical responses to masked tones are somewhat more salient than those for unmasked tones of comparable suprathreshold level. These observations bolster our understanding of the psychophysics of noise-masking in normal listeners, and they provide a partial explanation of the difficulty shown by patients with temporal lobe lesions in discriminating signals in noise.

Animals↗
PubMed1984

Responses elicited from medial superior olivary neurons by stimuli associated with binaural masking and unmasking.

The responses of binaural neurons of the medial superior olive were measured as a function of interaural temporal differences for tones and as a function of signal-to-noise ratio under homophasic and antiphasic masking conditions. The degree of neural response synchrony to the frequency of the signal was related to the degree of behavioral detectability of the signal in the homophasic, but not the antiphasic masking condition. For the antiphasic condition, a decrease in discharge rate resulted from the addition of the signal to the noise, similar to the decrease which occurred when interaural temporal differences were introduced in the tonal stimuli. The results are compatible with a model in which interaural temporal-difference information arriving over monaural afferents in the form of synchronized impulses is mapped into a place code by a neural coincidence-detection device. Several differences were noted between the responses to tones found in the present experiment and those reported by others. These differences were attributed mainly to differences among the experimental procedures in use among the various reporting laboratories.

Animals↗
PubMed1994

Binaural processing after corrected congenital unilateral conductive hearing loss.

Binaural processing was measured in a series of tests in patients before and after surgery to correct congenital unilateral conductive hearing losses. Data are presented from 19 patients between the ages of 6 and 33 years that had an abnormal external and/or middle ear on one side but normal hearing in the other ear. Surgery improved thresholds an average of 36 dB HL (from 56 to 20 dB HL). Patients were tested pre- and postoperatively for interaural temporal difference limens, alternate and simultaneous loudness balances, sound localization, binaural detection thresholds, and speech perception in noise. There was statistically significant improvement after surgery in all tests, and the amount of improvement varied along a continuum that appears to be related to the simplicity of the task. For example, most postoperative patients had normal or near-normal performance in a test of interaural temporal difference limens, while almost all had difficulty localizing sounds. Neither binaural performance (before or after surgery) nor the improvement in performance was correlated with age, pure-tone thresholds, or asymmetry. Limited available data show no significant changes in performance from four weeks to over 24 weeks after surgery. In conclusion, binaural ability following corrective surgery exists in varying degrees in these tasks, suggesting different effects of abnormal early experience on different aspects of binaural hearing.

Adolescent↗
PubMed2002

Medial olivocochlear bundle activation and perceived auditory intensity in humans.

In order to test the hypothesis of a role of cochlear efferent activity in intensity perception in humans, loudness functions, loudness integration, and loudness summation were measured in the absence and in the presence of contralateral noise in normal-hearing subjects. Additionally, relationships with the effect of the noise on evoked otoacoustic emissions (EOAEs) were tested, and comparisons with vestibular neurotomy patients were performed. Overall, the results failed to demonstrate significant effects of contralateral noise stimulation on loudness functions and loudness integration. Furthermore, no significant differences were found in vestibular neurotomy patients. A significant effect of contralateral noise on loudness summation was noted, but was not related to the effect on otoacoustic emissions. The present results fail to support the notion that efferent influences onto the cochlear compression have a significant perceptual effect.

Acoustic Stimulation↗
PubMed1998

Differential recruitment of high frequency wavelets (600 Hz) and primary cortical response (N20) in human median nerve somatosensory evoked potentials.

Human median nerve somatosensory evoked potentials contain a burst of high-frequency (600 Hz) wavelets superimposed on the primary cortical response (N20). These presumably reflect highly-synchronized repetitive thalamic and/or intracortical population spike bursts and are diminished in non-REM sleep with N20 persisting. Here the burst/N20 relation in awake subjects was examined by using eight different intensities of electric median nerve stimuli. In all subjects the amplitude recruitment of both N20 and burst could be modeled adequately as a sigmoidal function of stimulus intensity. While 8/10 subjects showed a parallel recruitment, 2/10 subjects required significantly higher stimulation intensities for burst than for N20 recruitment. This dampened burst recruitment possibly reflects slight vigilance fluctuations in open-eyed awake subjects; a further increase of burst thresholds could explain the burst attenuation when entering shallow sleep.

Adult↗
PubMed2004

A revised model of loudness perception applied to cochlear hearing loss.

We previously described a model for loudness perception for people with cochlear hearing loss. However, that model is incompatible with our most recent and most satisfactory model of loudness for normal hearing. Here, we describe a loudness model that is applicable to both normal and impaired hearing. In contrast to our earlier model for impaired hearing, the new model correctly predicts: (1) that a sound at absolute threshold has a small but finite loudness; (2) that, for levels very close to the absolute threshold, the rate of growth of loudness is similar for normal ears and ears with cochlear hearing loss; (3) the relation between monaural and binaural threshold and loudness; (4) recent measures of equal-loudness contours. Like the earlier model, the new model can account for the loudness recruitment and reduced loudness summation that are typically associated with cochlear hearing loss.

Cochlea↗
PubMed2002

Permanent sensorineural hearing loss following spinal anesthesia.

A 25-year-old female developed permanent, fluctuating sensorineural hearing loss (SNHL), disabling vertigo, and tinnitus following an uneventful spinal anesthesia for cesarean section. At her first visit to the ear-nose-throat (ENT) department approximately 2 months postoperatively, pure-tone thresholds revealed profound SNHL on the right side whereas thresholds were within normal limits on the left side. The recruitment score (SISI) was 95% at 2000 Hz on the right side. Directional preponderance towards the right and the right canal paresis were evidenced by bithermal caloric testing. At follow ups the pure tone thresholds have shown some improvement, but fluctuating SNHL, disabling vertigo attacks, and tinnitus have remained. These findings imply a cochlear pathology causing endolymphatic hydrops possibly induced by lumbar puncture for spinal anesthesia.

Adult↗