Journal of the American Auditory Society最新文献

The aging ear is a particularly vexing problem. This review of the literature covers much of the pertinent information and leads to some suggested research which we hope to pursue. It seems to us that research directed toward increased knowledge of the auditory blood supply and a better understanding of the function of the stria vascularis will add much to our understanding of the aging ear.

Acoustic-reflex recovery time was measured as a function of activator intensity level and duration for broad-band noise and a 500-Hz tone in 10 normal-hearing subjects. The activating signals were presented at 5 and 10 dB above individual acoustic reflex thresholds for durations ranging from 0.25 to 100 sec. Reflex-recovery times were similar across both activators and across activator intensity levels. Recovery time was relatively constant for activators of 2 sec or less and increased for longer activator durations. Portions of the results from temporary threshold shift experiments are explained on the basis of acoustic reflex recovery characteristics.

The effect of attention on auditory responses obtained with respiration audiometry was examined on twenty normal-hearing adults. Ten subjects were instructed to listen carefully for the auditory stimuli during testing, while the other ten were not instructed. The results revealed that the change in respiration resulting from sound stimuli for the instructed subjects was three times greater than for the uninstructed group during the first 11-tonal sequence. However, during the third sequence, more responses were obtained from the uninstructed subjects. There was little evidence to suggest that the respiratory changes to sound were greater in magnitude or in number as the intensity of the sound approached behavioral threshold. The results suggest that the level of attention affects the number and pattern of respiratory responses to sound.

Decompression and drainage of the endolymphatic sac is a surgical procedure which was developed to relieve vertigo and hopefully to maintain or improve hearing in patients with Meniere's disease. In this study, 16 medically diagnosed Meniere's disease patients who underwent endolymphatic sac surgery were followed audiometrically for a period of up to three years. Pre- and postoperative audiometric and other symptomatic findings were reported. Results indicated that in the greatest majority of cases hearing remained essentially unchanged or was improved. Poorer hearing was found in 26.3% of the cases for pure tones and in 15.8% of the cases for speech reception thresholds and speech discrimination scores. Due to the fluctuating nature of auditory thresholds in Meniere's disease, it was found to be essential that patients be followed postoperatively for a period of at least three years.

Tympanometry was performed under the contraction of the middle ear muscles (dynamic tympanometry). A tympanogram of lesser compliance was observed under a stapedius reflex which was produced by contralateral acoustic stimulation. In patients with reversed (downward) stapedius reflex, the dynamic tympanogram showed either a higher peak amplitude or a shift of conventional tympanogram to the negative pressure side. Voluntary contraction of the tensor tympani produced a lesser compliance with positive pressure, whereas there was an apparent increase of compliance with negative pressure in the external auditory meatus. A shift of the dynamic tympanogram to the negative pressure side was interpreted as being due to contraction of the tensor tympani muscle. Dynamic tympanometry may also be utilized as a recording of reflex decay.

Volume-conducted, short-latency auditory-evoked potentials were examined in the laboratory mouse with lesions and local recording used to localize their sources. PI corresponds in time with N1 recorded from the round window, while isolation of the eighth cranial nerve from the brainstem results in the loss of all post-PI components. PII latency agrees with that of evoked potentials recorded from the cochlear nucleus. PIII latency corresponds with that of evoked potentials from the vicinity of the contralateral superior olivary nucleus, and lesions of this and closely related contralateral structures abolish PIII from the vertex recordings. PIV is reduced in amplitude by unilateral brainstem lesions between the superior olive and the inferior colliculus. Evoked potentials and lesions localized PV to the vicinity of the lateral regions of the contralateral inferior colliculus. PVI disappeared when areas anterior to the inferior colliculi were lesioned. Although minor species differences may exist, it was concluded that the sources for PI to V in the mouse closely resemble those in the cat, and they agree well with the limited data from the human. This technique may now be applied to studies of the numerous auditory mutants of the laboratory mouse.

The English literature on the incidence of nystagmus in normal subjects and in patients with head and/or neck injuries is reviewed. The authors present a series of 202 patients with alleged vestibular trauma. The incidence of spontaneous and positional nystagmus would seem to be no greater in patients with alleged vestibular trauma than that found in the normal subjects, suggesting that these patients do not have objective evidence of vestibular trauma. Objective criteria for diagnosing vestibular abnormalities by electronystagmography are presented. At least 22% of a series of 2408 patients were found to have a functional hearing loss. The importance of looking for functional overlay in patients involved in litigation cases is stressed.

Seventy-one hearing aid users were surveyed two years after their initial fitting to determine whether they (1) wore the hearing aid(s) prescribed, (2) were satisfied with their aid(s), (3) had specific complaints about their aid(s), and (4) would recommend that a hearing-impaired friend or relative go through the same hearing aid selection process. Ninety-six percent of the respondents obtained that aid that we recommended. Eighty-eight percent were "very satisfied" or "satisfied" with the help that their aid(s) provided. Eighty-two percent would recommend that a hearing-impaired friend or relative go directly to a "hearing specialist" for assistance when selecting a hearing aid.