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Biomedical subjects

S Silman

Publications and source records attributed to S Silman.

44 records · Page 3Linked to original sources
PubMed1979

The effects of aging on the stapedius reflex thresholds.

The acoustic reflex thresholds for broadband noise and 500-, 1000-, and 2000-Hz activating signals were measured in a group of young normal hearing adults and a group of elderly normal hearing subjects. The results indicated that the acoustic reflex thresholds for tonal activating signals in the young subjects were similar to those in the elderly subjects. However, the acoustic stapedius reflex thresholds for broadband noise activating signals is significantly higher in the elderly subjects than in the young. These differences were explained in light of Bredburg's findings [Acta Otolaryngol. Suppl. 236, 1--135 (1968)] regarding degeneration of outer hair cells as a function of aging.

Acoustic Stimulation↗
PubMed1978

Some observations in a case of acoustic neuroma.

The subject was a 47-year-old male with a moderate asymmetrical sensorineural hearing loss that initially presented cochlear signs except for positive stapedius reflex results. Over the course of only five weeks, he developed the audiological constellation of retrocochlear involvement. The retrocochlear results were confirmed by the removal of an acoustic tumour. The results highlight the importance of audiological monitoring and reflex measures in the identification of acoustic neuromas. Several observations provide insight into the apparent relationship between loudness and the stapedius reflex. The findings are discussed with reference to a proposed extension of Borg's recent theory that elevated reflex thresholds and reflex decay reflect differing degrees of the eighth nerve destruction.

Auditory Threshold↗
PubMed1978

Effect of sensorineural hearing loss on acoustic stapedius reflex growth functions.

The growth function of the acoustic stapedius reflex was measured in subjects with normal hearing and sensorineural hearing loss of cochlear origin. The effects of age and magnitude of hearing loss were controlled. Activating stimuli were 500, 1000, and 2000 Hz tones and broadband noise. Stapedius muscle activity was inferred from acoustic impedance measures in the contralateral ear. The mean growth functions for tones were essentially linear in log-log plots with the rate of growth equal for the two groups. The mean growth function for the noise signal was curvilinear for the normal hearing groud had linear for the hearing loss group. Comparison of slope functions derived from the fitted data indicated that the rate of reflex growth for the noise signal, over a limited range above reflex threshold, is greater in ears with cochlear lesions than normal ears. For higher level noise signals, however, the rate of reflex growth is similar for normal and pathological ears. The effect of a cochlear lesion on the input-output function of the cochlea for both tonal and noise stimuli is to maintain the rate of reflex growth but shift the function along the intensity axis of a tonal signal and the response axis for a noise signal.

Acoustic Impedance Tests↗
PubMedDate not supplied

Usage of CROS and IROS hearing aids by patients with bilateral high-frequency hearing loss.

Responses to a hearing aid usage questionnaire were received from 128 patients with high-frequency sensorineural hearing loss fitted monaurally with contralateral routing of signals (CROS) or ipsilateral routing of signals (IROS) hearing aids. Functional benefits were demonstrated by wearing the instruments 8 to 9 hr/day, use of the aids about 60% of the time in communicative situations, subjective benefit judgements of 5 to 9 on a 10-point scale, improved subjective sound localization, and improved clarity of speech with the hearing aids. Although CROS and IROS fittings could not be separated on the basis of these factors, considerably more complaints were reported by the CROS wearers, and many of these related to auditory factors. Both CROS and IROS fittings appear to be effective approaches to the patient with high-frequency hearing loss. However in light of the fewer complaints by the IROS group, and the fact that a large proportion of the CROS complaints related to the amplified signal, IROS appears to be the preferable of the two. The exception involves cases requiring high gain so that CROS might be employed to reduce acoustic feedback.

Consumer Behavior↗
PubMedDate not supplied

The collapsed earmold phenomenon.

This paper describes the collapsed earmold phenomenon resulting from a wide bore earmold. The collapse was alleviated by a simple modification of the earmold (cutting of its most medial 1/6 of an inch).

Air Pressure↗
PubMedDate not supplied

Functional hearing loss and its relationship to resolved hearing levels.

The nature of functional hearing loss was retrospectively studied with respect to hearing sensitivity after resolution of the nonorganic components in 63 adults with bilateral exaggerated losses (126 ears). The configuration of the functional components (difference between the functional and resolved thresholds) was found to be related to that of the resolved hearing levels. The size of the functional overlay was essentially the same across the audiometric frequency range when the hearing was actually normal or if there was only mild loss. In cases of precipitously sloping high-frequency losses, the magnitude of the functional overlay became dramatically smaller for the impaired frequencies than for lower frequencies where hearing was normal or only mildly impaired. Moderate and severe losses represented a transitional situation, in which the functional components became gradually smaller with increasing frequency. Subjects with different resolved hearing in each ear (e.g., mild loss in one ear and a precipitous loss in the other) demonstrated nonorganic overlays that were consistent with the actual hearing levels for each respective ear. The findings suggest the use of an internalized, loudness level-based anchor by subjects with functional losses: the test signal must sound as loud as the anchor at each frequency in order for an exaggerated threshold response to be volunteered at that respective frequency. The pure-tone audiometric configuration and amount of functional loss at least in bilateral cases is thus consistently accounted for on the basis of known and explainable auditory factors.

Adult↗
PubMedDate not supplied

Temporal summation in acoustic reflex growth functions.

Acoustic reflex growth functions for pure tone activators of 500, 1000 and 2000 Hz and a broad-band noise (BBN) were obtained with activator durations of 20, 200 and 1000 msec (10 msec rise/decay) in four young, normal subjects. The lowest reflex thresholds were obtained for the 1000 msec activators, followed by 200 msec and then 20 msec. The reflex growth functions revealed lower reflex magnitudes for the shorter duration activators. When normalized to account for temporal summation at reflex threshold, reflex magnitude growth was similar among the three durations at 500 Hz, slower for 20 msec than for 200 and 1000 msec at 1000 Hz, and became progressively slower with decreasing duration from 1000 to 200 to 20 msec at 2000 Hz. When expressed in SPL, the BBN growth functions reasonably resembled those at 2000 Hz. No particular pattern was revealed for the normalized BBN growth functions.

Adult↗