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Biomedical subjects

R H Margolis

Publications and source records attributed to R H Margolis.

At least 37 records · Page 2Linked to original sources
PubMed1994

Tympanometric evaluation of middle ear function in children with otitis media.

Current tympanometry instruments allow a quantitative approach to the evaluation of middle ear function in children with otitis media. Conventional 226-Hz tympanograms can be characterized by static admittance, tympanometric width (gradient), tympanometric peak pressure, and equivalent volume. Multifrequency tympanograms obtained with probe frequencies ranging from 226 to 2,000 Hz appear to be sensitive to sequelae of otitis media that are not detected by conventional tympanometry or audiometry.

Acoustic Impedance Tests↗
PubMed1994

Identification of hearing loss in children with otitis media.

Hearing loss is the most common complication of otitis media. Hearing loss secondary to otitis media has increasingly been associated with significant developmental and educational problems. However, not enough is known about the peripheral auditory effects of otitis media. The young age of most children affected by otitis media makes detailed audiologic assessment challenging. This paper presents a brief synopsis of audiologic strategies that may be employed to assess the hearing status of infants and children with otitis media with effusion. Data pertaining to the risk of hearing loss recurrence after tympanostomy tube insertion are presented from a prospective longitudinal study of hearing in children with chronic otitis media with effusion.

Audiometry, Pure-Tone↗
PubMed1993

Acute otitis media with transient sensorineural hearing loss. A case study.

A patient had acute otitis media with transient sensorineural hearing loss. Early symptoms included otalgia, progressive sensorineural hearing loss, and tinnitus with inflammation of the tympanic membrane. During the second week a conductive component emerged resulting in a 60-dB mixed loss in the 2- to 4-kHz region. The conductive component lasted 15 days while the sensorineural hearing loss recovered more slowly, with complete recovery at 6 months. Audiologic measures included conventional and extended high-frequency audiometry, 226-Hz and multifrequency tympanometry, binaural speech recognition, auditory brain-stem response, and psychoacoustic tuning curves.

Acoustic Impedance Tests↗
PubMed1993

Detection of hearing impairment with the acoustic stapedius reflex.

The acoustic stapedius reflex (ASR) is the sound-evoked contraction of the stapedius muscle. The ASR is mediated by a neural network, receiving its afferent input from the VIIIth cranial (auditory) nerve and sending its efferent output to the VIIth cranial (facial) nerve. Several centers in the brain stem comprise the central portion of the reflex pathway. The stapedius muscle in each ear responds to ipsilateral, contralateral, and binaural stimulation. The normal ASR threshold is 90 to 95 dB SPL for tones and 70 to 75 dB SPL for wideband noise. In ears with sensorineural hearing loss, ASR thresholds are elevated more for wideband noise than for tones. These bandwidth-related changes form the basis for detection of hearing loss from ASR data. A number of methods have been proposed which differ in the nature of the outcome. Some try to quantitatively estimate hearing loss, whereas others categorize outcomes as pass or fail. In general, methods that attempt quantitative estimation of hearing loss do so at the expense of higher error rates. With adequate recording techniques, the ASR has been shown to effectively detect hearing losses exceeding 30 dB in adult subjects. Although ASR recording in newborns requires a higher probe frequency than the commonly used 226 Hz, ASR thresholds in newborns appear to be similar to those in adults. Limited information exists on the use of the ASR for detection of hearing loss in the infant population. With adequate attention to methodological requirements of testing infants, the ASR may offer a cost-effective method for the early detection of hearing loss.

Acoustic Stimulation↗
PubMed1993

The effect of middle ear pressure on transient evoked otoacoustic emissions.

To determine the effect of middle ear pressure on transient evoked otoacoustic emissions (TEOAEs), emissions were recorded in ears with tympanometric peak pressures < or = -100 daPa and audiometric thresholds < or = 30 dB HL at 500 through 2000 Hz. TEOAEs were alternately recorded at ambient pressure and at the tympanometric peak pressure. As demonstrated for the 14 ears tested, equalization of the middle ear pressure increased TEOAE amplitude. Reproducibility was similarly improved in 12 of 14 ears. Unequalized middle ear pressure attenuated low frequency emissions more than high frequency emissions. These amplitude and spectrum differences were consistent with previously reported observations of the effects of ear canal pressure on otoacoustic emissions. Results suggest that unequalized middle ear pressure may increase the occurrence of false positive failures, if otoacoustic emission testing is used for hearing screenings without consideration of middle ear pressure.

Acoustic Impedance Tests↗
PubMed1993

Multifrequency tympanometry in normal adults.

Multifrequency tympanograms were recorded from 56 ears of 28 normal-hearing adult subjects to obtain normative data and to determine abnormal criteria for tympanometric measures. Static admittance, tympanometric width, and tympanometric peak pressure at 226 Hz were analyzed along with eight different estimates of the resonant frequency of the middle ear. Based on test-retest reliability and normal distribution characteristics, preferred methods for clinical estimation of resonant frequency were determined. The sweep pressure mode (ear canal pressure is swept while probe frequency is held constant) is preferred for detection of abnormally high resonant frequencies. The sweep frequency mode (probe frequency is swept while ear canal air pressure is held constant) is preferred for identification of abnormally low resonant frequencies. Compensation for ear canal volume at +200 daPa was preferred over other compensation methods for estimation of middle ear resonant frequency.

Acoustic Impedance Tests↗
PubMed1993

Just noticeable differences for intensity and their relation to loudness.

The present study examines the relation between the form of the loudness function and the size of the intensity just noticeable difference (jnd). The hypothesis that equal loudnesses at any given sound frequency yield equal-intensity jnd's was examined. In addition, Hellman et al.'s [J. Acoust. Soc. Am. 82, 448-453 (1987)] experiment, which showed that jnd's are independent of the slope of the loudness function was replicated. Threshold shifts and altered loudness-balance functions for 1-kHz tones were produced by using backgrounds of narrow- or wideband noise. The two types of background noise produced intersecting points on loudness-balance functions at which intensity jnd's were obtained. Intensity jnd's were also obtained at equal-loudness levels (corresponding to 30, 40, 50, and 60 dB SL in the unmasked ear) under each of the two noise conditions and in quiet. The results indicate that tones of equal loudness produce approximately equal jnd's and that there is no apparent relation between the slope of the loudness-balance functions and the size of the intensity jnd.

Acoustic Stimulation↗
PubMed1993

Effects of otitis media on extended high-frequency hearing in children.

Extended high-frequency (EHF) hearing was studied in children with and without histories of chronic or recurrent otitis media (OM). The EHF thresholds were found to have good test-retest repeatability. Children with OM histories had poorer EHF hearing than children without OM histories. The EHF hearing in OM children appeared to be related to OM severity. Children with residual tympanometric abnormalities had poorer EHF hearing than OM children with normal middle ear function. The results suggest evidence for middle ear and inner ear components of EHF hearing losses in children with OM.

Acoustic Impedance Tests↗
PubMed1993

Tympanic and transtympanic electrocochleography in acoustic neuroma and vestibular nerve section surgery.

Eighth nerve action potential (AP) amplitudes and latencies and cochlear microphonic (CM) amplitudes were compared using tympanic and transtympanic electrocochleography (ECOG) in two patient groups. Tympanic ECOG was performed with a wick electrode placed on the tympanic membrane (TM). Transtympanic ECOG was performed with a needle electrode placed on the promontory of the anesthetized patient. Eighteen subjects were tested by tympanic ECOG as part of a preoperative assessment for either acoustic neuroma removal or transection of the vestibular portion of the eighth cranial nerve. Surgery occurred within 1 week of the preoperative evaluation. Intraoperative auditory monitoring was performed using transtympanic ECOG. Baseline recordings were compared to the preoperative tympanic ECOG data. Stimuli were condensation and rarefaction clicks and tone bursts, presented by an insert earphone. As expected, the two methods resulted in essentially identical response latencies and large amplitude differences, although the response amplitudes were extremely variable. The AP amplitude and the CM amplitude did not increase by the same factor with the transtympanic (TT) electrode compared to the tympanic electrode. On comparison of preoperative and intraoperative response amplitudes with regard to stimulus polarity, tympanic electrocochleography appears to be a useful method of gathering preliminary information on the status of the patient's auditory system. In this study, tympanic ECOG was found to have some predictive value when trying to ascertain the best intraoperative monitoring situation.

Acoustic Stimulation↗
PubMed1992

A clinical profile of otitis media.

An otitis media with effusion algorithm developed by Paradise et al and tested by Cantekin et al has become the basis for many studies of otitis media. However, a two-point scale algorithm (otitis media with effusion-no otitis media with effusion) may be too ambitious (ie, low specificity) and too optimistic (ie, absence of fluid does not necessarily mean normal ear). We propose a four-point profile that characterizes the condition of the middle ear, and we report the validation of the profile against findings at myringotomy. Statistically, a four-point scale profile would substantially increase powers of statistical tests, compared with a two-point scale algorithm (in studies of the same size), when used to study changes of the middle-ear condition over time or to compare treatment effects.

Acoustic Impedance Tests↗
PubMed1992

A comparison of acoustic reflex and auditory brain stem response screening of high-risk infants.

This investigation was undertaken to explore the feasibility of screening for hearing impairment in an intensive care nursery population with a combined acoustic stapedius reflex-ABR approach. Acoustic reflex threshold measurements (AR) were made on intensive care nursery patients in an existing ABR screening program. Pass-fail results were determined for the two methods, separately and in combination. AR screening identified all 10 ears that failed the ABR screen. The cost savings of screening with a combined AR-ABR approach was determined for various pass-fail criteria. The results suggest that the AR-ABR approach can produce a significant cost savings without compromising the sensitivity and specificity of the screening program.

Acoustic Impedance Tests↗
PubMed1992

A look at ear canal changes with jaw motion.

Two procedures were used with one subject to examine changes in the ear canal with jaw motion. Silicone ear impressions were examined to measure the effect of jaw position. Magnetic resonance imaging was used to define the three-dimensional structure of the canal and visualize key underlying tissue. Results showed that inexpensive impressions can detail changes in the cartilaginous region of the canal. Approximately a 25% change in this subject's ear canal with different jaw positions was observed in the anterior/posterior plane with essentially no change in the superior/inferior plane. This is likely related to asymmetric stress from action of the mandibular condyle on neighboring cartilaginous tissue. Solutions to jaw motion-induced feedback problems are suggested.

Ear Canal↗
PubMed1992

Short-term poststimulatory response characteristics of the human acoustic stapedius reflex: monotic and dichotic stimulation.

Two experiments were performed to study short-term poststimulatory response characteristics of the human acoustic stapedius reflex in the time and intensity domains. In experiment 1, monotic magnitude-intensity functions (MIFs) were obtained for a 20-ms test stimulus preceded by a conditioning stimulus varying in duration (20, 50, 100, 500 ms) and level (-10, 0, +10 dB re: stapedius-reflex threshold) and temporally separated from the test stimulus by various interstimulus intervals (ISIs) (0, 20, 50, 100, 500 ms). Experiment 2 was similar in design except that conditioner and test stimuli were presented dichotically and fewer ISIs were used. Both experiments demonstrated that a prior conditioning stimulus produced significant increases in test-stimulus response magnitude. These poststimulatory effects were characterized by complex interactions among stimulus variables (conditioner duration, conditioner level, and interstimulus interval) with similar interactions occurring for both monotic and dichotic stimuli. A simple superposition effect of the responses to the conditioner and test stimulus does not account for the effect of prior stimulation since responses often exceeded the sum of the responses to the conditioner and the test stimulus alone.

Acoustic Stimulation↗
PubMed1992

Effect of ear-canal air pressure on evoked otoacoustic emissions.

The effect of ear-canal air pressure on click-evoked otoacoustic emissions was measured for pressures ranging from 200 to -200 daPa and stimulus levels ranging from 60-90 dB PeSPL. Positive and negative ear-canal pressures (relative to ambient pressure) reduced the emission amplitude by 3-6 dB. A spectral analysis of the emissions revealed that the effect of ear-canal air pressure is that of a high-pass filter with a cutoff frequency of 2600 Hz and a slope of 4 dB/oct. The spectral changes are the expected effect of an increase in stiffness of the middle ear and were independent of pressure polarity and click level. Ear-canal air pressure substantially reduced the reproducibility of the emission waveform, in many cases rendering the emission indistinguishable from background noise. The implication of these findings for hearing screening applications is that a high false alarm rate may occur in normal-hearing patients with intratympanic air pressures that are significantly different from ambient pressure.

Adult↗
PubMed1992

Tympanic electrocochleography for evaluation of endolymphatic hydrops.

There has been increased interest in electrocochleography for the diagnosis and intraoperative monitoring of patients with endolymphatic hydrops. Attention has been focused on the determination of the summating potential:action potential (SP:AP) ratio from alternating polarity clicks. Review of this technique at the University of Minnesota led to a reevaluation of the usual interpretation of these recordings. Separate examination of the rarefaction and condensation click recordings provides insight into abnormal response patterns. Cases are presented to illustrate a variety of normal and abnormal patterns including abnormal differences in the latency of condensation and rarefaction-click-generated action potentials, increased summating potential, uncanceled cochlear microphonic, and reduced action potential and summating potential amplitudes. These response categories may be useful in understanding the pathophysiology of Meniere's disease.

Acoustic Stimulation↗
PubMed1992

Tympanic electrocochleography: normal and abnormal patterns of response.

Electrocochleography has been widely used in human and animal studies of endolymphatic hydrops. A variety of response patterns have been reported in normal and hydropic ears. Recent clinical studies have focused almost exclusively on the amplitude ratio of the summating potential (SP) and action potential (AP) derived from alternating polarity click responses. In this report normal response patterns are described with a tympanic membrane electrode employing condensation, rarefaction and alternating polarity clicks and tone burst stimulation. A variety of response abnormalities are described in patients with suspected endolymphatic hydrops. The exclusive use of alternating polarity clicks is not adequate to reveal the nature of these abnormalities.

Acoustic Stimulation↗
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↗