Use of intraoperative auditory brainstem responses to guide prosthesis positioning.
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Evoked Potentials, Auditory, Brain Stem↗
Biomedical subjects
J L Yanz
Publications and source records attributed to J L Yanz.
The computerized audiology clinic.
Computer-assisted audiologic testing is undergoing a transition from laboratory settings to audiology clinics, resulting in increased accuracy, efficiency, and sophistication in the evaluation and treatment of patients. The computerized clinic also offers superior information storage and analysis capabilities and increasingly significant economic advantages. Implementation of new test techniques with software modification, rather than expensive new electronic instrumentation, is an advantage unique to the computer-based audiologic system. Decisions regarding the selection from a variety of system architecture designs and human interface schemes are critically important and unique to this new technology. The replacement of traditional audiometric instruments with computer-controlled systems will accelerate as system sophistication increases and cost continues to decrease.
Ambulatory Care Facilities↗
Speech recognition threshold in noise: effects of hearing loss, frequency response, and speech materials.
Speech recognition threshold (SRT) was measured in quiet and in noise for normal-hearing subjects and subjects with high-frequency sensorineural hearing loss. For the hearing-impaired subjects, SRT in quiet approximated the amount of hearing loss in the frequency region of importance for each of two sets of speech materials--spondees and monosyllables. With changes in frequency response of the stimulus delivery system, SRT shifted differentially for spondees and monosyllables. The speed, reliability, and apparent sensitivity of the SRT in quiet and noise to frequency response characteristics make it a potentially useful tool for hearing aid evaluation if speech materials appropriate to both the hearing loss configuration and the frequency response of amplification are chosen.
Adult↗
The questionable relation between cochlear pigmentation and noise-induced hearing loss.
Some evidence has suggested that susceptibility to noise-induced hearing loss may be inversely proportional to the amount of melanin in the cochlea. However, published data have not been consistent in demonstrating this relation, and some results may be contaminated by lack of genetic control in experimental animals. In this investigation, noise-induced hearing loss was evaluated in pigmented and albino C57BL/6J mice that differed only in their ability to produce melanin. Surface-recorded electric responses to sound were used to assess auditory sensitivity. Results indicated no difference between the two groups either in pre-exposure thresholds or in magnitude of noise-induced threshold shift.
Animals↗
Age effects in susceptibility to noise-induced hearing loss.
Several studies in recent years have suggested that susceptibility to noise-induced hearing loss is influenced by an animal's age at the time of acoustic overstimulation. In the present experiment an attempt was made to learn more about age effects by integrating into a single study observations of the initial effects of noise exposure and the time course of postexposure threshold changes. Mice were exposed to noise at one of two ages (18 or 28 days). The threshold of the auditory compound action potential was estimated from the scalp-recorded electrical response immediately after the exposure and again at 5- and 30-days postexposure. These measures were compared with identical measures from yoked control subjects to determine the effects of noise exposure. Results indicate an interaction of age with exposure intensity and postexposure interval. Specifically, an age effect is seen only at the higher of two exposure intensities and only after a 30-day postexposure interval. Individual data suggest further that the existence of an age effect is determined not by the initial postexposure threshold shift, but rather by subsequent changes in threshold following exposure.
Age Factors↗
The application of the theory of signal detection to the assessment of speech perception.
Traditional audiological measures of speech recognition ability have failed to correlate well with self-assessments of communication difficulty. In this tutorial, an approach to the evaluation of speech perception is described that uses quantities derived from the theory of signal detection. The basics of the theory are reviewed briefly, and its relevance to communication processes is discussed. The measures of performance accuracy and decision criterion provided by the theory of signal detection offer a way of quantifying the ability of a listener to assess the accuracy of his or her own identifications of spoken messages. It is hoped that these quantities will provide new information about communication processes and help to characterize communication difficulties encountered in everyday life.
Audiometry, Speech↗
Comparison of speech perception skills in young and old listeners.
A companion paper (Yanz. 1984, Ear Hear. 5, 64-71) has described an approach to the quantification of speech perception using measures derived from the theory of signal detection (TSD). The present experiment uses this approach to compare speech perception in young and old listeners in terms of the traditional word recognition score (%C), the ability to assess the accuracy of one's own identifications [P(A)], and the decision criterion used in that assessment (B). Monosyllables were presented in a background of broadband noise at two signal-to-noise ratios (S/N), 0 dB and 5 dB. Subjects recorded their identification of each test item and then rated their confidence in that identification on a six-point scale. Results indicated that in this particular task, neither %C nor B differed between the two age groups, but both quantities varied with S/N. P(A) was the same for the two groups at S/N = 0 dB but differed at S/N = 5 dB. The young group showed significant improvement in P(A) from the 0-dB to the 5-dB S/N condition, while old subjects showed no change. These results suggest that young subjects are more able than older subjects to adapt to and take advantage of an improvement in the acoustic environment.
Adult↗
An ear-canal electrode for the measurement of the human auditory brain stem response.
A new electrode has been developed and evaluated for the measurement of the human auditory brain stem response (ABR). The goal of the electrode design was to enhance the amplitude and clarity of wave I without sacrificing wave V. The electrode consists of a foam rubber ear-plug through which a fine stainless steel wire has been threaded to make contact with the wall of the external auditory canal (EAC). The ABR measured between vertex and EAC was compared with that measured between vertex and mastoid. Results indicate that the vertex-to-EAC configuration yields a larger wave I than the vertex-to-mastoid configuration, with no loss in size or clarity of wave V.
Acoustic Stimulation↗
Self-assessment of communication skills: toward the development of a new speech audiometric tool.
This investigation was carried out in an effort to characterize differences between groups of normal-hearing and hearing-impaired listeners on a speech perception test based on the theory of signal detection (TSD). TSD allows the quantification of two performance measures designed to evaluate listeners' ability to assess the accuracy of their own identifications and their level of confidence in the self-assessment task. It is hoped that these measures will provide a meaningful way to quantify communication skills beyond the percent correct word recognition score routinely measured in the audiology clinic. Nonparametric indices of self-assessment ability and confidence level, P(A) and B, respectively, were measured for ten normal-hearing and ten hearing-impaired subjects at two signal-to-noise ratios (S/N). In addition, percent correct word recognition scores (%C) were measured. Results indicated that %C differed across groups and across S/Ns. In contrast, P(A) and B differed as a function of S/N but did not differ between hearing-impaired and normal-hearing groups.
Adult↗
Age-dependent changes in susceptibility to ototoxic hearing loss.
Several species undergo age-dependent changes in susceptibility to noise-induced and drug-induced hearing loss. In this experiment 18-day-old mice were given 200 mg/kg kanamycin plus varying doses of bumetanide (20, 30 or 40 mg/kg). Thresholds of the scalp-recorded compound action potential of the auditory nerve indicated that diuretic doses of 30 and 40 mg/kg produced significant loss of hearing sensitivity. Thirty-eight-day-old mice were then treated with 200 mg/kg kanamycin plus 40 mg/kg bumetanide and demonstrated no loss of hearing sensitivity. These results confirm the existence of age-dependent changes in susceptibility to ototoxic hearing loss in mice. Furthermore, the treatment, consisting of two injections on the same day, offers promise as a means of defining the critical period of susceptibility in greater detail than has been possible with aminoglycosides alone.
Aging↗