摘要:

Many studies have documented the decline in auditory function with age. We broaden that data base in this the first of a series of reports emanating from the auditory testing of the Framingham cohort during biennial exam 18. The results of the auditory questionnaire, hearing sensitivity, acoustic compliance measures, and word recognition tests obtained from 1662 men and women in their 60th through 90th decades are presented. Pure-tone thresholds increased with age but the rate of change with age did not differ by gender even though men had poorer threshold sensitivity. Maximum word recognition ability declined with age more rapidly in men than in women and was poorer in men than in women at all ages. Acoustic compliance and middle ear pressure did not vary with gender or age. Acoustic reflex thresholds to a contralat-era1 stimulus at 1 kHz increased slightly with age, more in women than in men; ipsilateral acoustic reflex thresholds did not vary with age or gender. Hearing aids were being used in only 10% of subjects likely to benefit from amplification.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

In a longitudinal and an age cohort comparing study the influence of aging and occupational noise exposure on hearing sensitivity was studied. The participants of the hoi study e studied at 70, 75, and 79 years of age. Seventy year old men exposed to occupational noise had 10 to 15 dB poorer hearing in the high frequency range than nonexposed men. The difference in hearing acuity decreased with increasing age. The differences between exposed and nonexposed older persons was no longer significant at age 79. In women there were no differences in hearing sensitivity between those exposed to noise and those not exposed to noise. Men not exposed to noise had 10 to 15 dB poorer hearing at 4 kHz compared with women of the same age also not exposed to noise.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The purpose of this investigation was to examine three types of audiological recommendations [unaided, CROS (contralateral routing of signals) and personal FM system] and their impact upon speech recognition ability of children with unilateral sensorineural hearing loss. Each of these recommendations was tested under three listening conditions encountered in a classroom [monaural direct (MD), monaural indirect (MI), midline signal/omnidirectional noise (MS/ON)] with two types of speech materials (Nonsense Syllable Testand an American English adaptation on theBamford-Kowal-Bench Sentence Lists). These experimental conditions were simulated in a classroom, recorded on audiotape, and played back to subjects under headphones to control such factors as signal-to-noise ratio, earmold fit, and head shadow effects. Six school-age children with unilateral hearing losses between 56 and >120 dB HL (PTA) were evaluated using a repeated measures design. The children experienced the most listening difficulty in the MI condition when they were unaided. The CROS aid improved speech recognition in this condition but degraded speech recognition in the MD condition. The FM system was the only audiological recommendation to produce uniformly high speech recognition scores across all listening conditions with both types of speech materials. Implications for the audiological management of unilaterally hearing-impaired children in the classroom are discussed.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

An issue in the measurement of bone conduction sensitivity is the placement of the bone vibrator. The effect of bone vibrator position on the amplitude and phase of the received signal was investigated using a cancellation technique. This technique involves canceling the signal delivered by the bone vibrator with a signal delivered acoustically via an earphone. At cancellation, the acoustic signal is equal in amplitude but opposite in phase to the bone-conducted signal. Results showed that the amplitude of the received signal did not vary significantly with bone vibrator position close to the center of the forehead whereas the phase of the received signal was critically dependent on bone vibrator position. Substantial intersub-ject differences were observed in the variation of phase with bone vibrator position. The precision of measurement using the cancellation technique was found to be high.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The precedence effect in sound localization involves presenting identical sounds (e.g., clicks) from pairs of matched speakers situated on opposite sides of a subject's head, with the clicks from one speaker preceding those from the other by a short interval. With appropriate delays, normal subjects perceive a fused image which originates from the side of the leading speaker. This test was administered to 24 patients with multiple sclerosis (MS). Separate tests involving speaker delays ranging from 0 msec (simultaneous presentation) to 8 msec were presented. At 0 msec delay, normal subjects perceived the fused image to be located halfway between the two speakers; at progressively longer delays, the image was perceived closer to the leading speaker. In contrast to normal subjects, a large proportion of the MS subjects exhibited difficulties with the task. The discrimination deficit was limited to delays below 1 msec, suggesting a problem involving an increased threshold for lateralizing the fused image away from midline toward the side of the leading speaker. The neural instability produced by de-myelination in MS patients might account for this pattern of results.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Auditory brain stem responses evoked with click stimuli of varying repetition rates (11, 31, 51, and 91 clicks/sec) and intensities but judged as being equally loud as three reference loudness levels (90, 80, and 70 phons) were examined in normal-hearing listeners. Analysis of wave component latencies and amplitudes indicated that loudness level changes are reflected in the brain stem response. However, the combined influence of stimulus rate and intensity was greater than that of perceived loudness level. It was concluded that the auditory brain stem response does not provide a direct link to loudness perception.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The frequency of the resonance peak of the external auditory canal was measured in 250 children aged 3 to 12 years. The mean resonance peak frequency was greatest in the younger age groups (3089 Hz in 4 year olds, range 2298 to 3763) and then decreased with age until 7, the age at which adult values were reached. Children less than 7 years of age have mean resonance frequencies significantly different from adults, suggesting that the “adult” length of external auditory canal is not reached until the age of 7. This alteration in resonance frequency with age may have practical implications by affecting the insertion gain of hearing aid systems in children.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The insertion gain preferred by a group of 26 moderately hearing-impaired, elderly hearing-aid users was investigated in everyday listening situations. The subjects used monaural behind-the-ear aids, carefully fitted according to a prescription formula of the half-gain type, validated and used at National Acoustic Laboratories, Australia. The fitting was checked with real-ear measurements of insertion gain and reviewed at one or more follow-up sessions. The subjects were strictly instructed to try the recommended volume control setting before reporting which setting they preferred. The prescription significantly overestimated preferred gain by about 7 dB. No correlation could be detected between prescribed versus preferred gain differences and the amount of previous hearing-aid use or the degree of subjective hearing problems.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

This study examined the effect of external microphone reference placement on peak sound pressure level (pSPL) and measurement variability. Nine normal subjects were seated in a double-walled sound suite, 1 m and 0° azimuth from a wall-mounted speaker. Digitized Gaussian noise was presented at 80 dB pSPL with a 500 msec duration and was measured through a probe tube microphone assembly. Replicated measurements were made at five locations external to the pinna. They were: anterior-superior and posterior-superior positions simulating hearing aid microphone placement (locations 1 and 2) and 2, 4, and 6 cm lateral to the lateral edge of the pinna (locations 3,4, and 5). Means, standard deviations, and ranges were compared, and statistical analyses were performed. The highest pSPL values were recorded lateral to the pinna, and the lowest values were obtained at the simulated hearing aid positions. ANOVAs indicated a main effect for pSPL, and post hoc testing demonstrated a significant difference between the posterior-superior and 2 cm lateral to the pinna positions. Variability was largest at the posterior-superior and 6 cm positions, and lowest 2 cm from the pinna. From this study, we concluded that pSPL and variability are both important criteria for selecting an optimal reference microphone site and both can affect the accuracy of ear canal measurements. A reference site 2 cm from the pinna eliminates attenuation of the signal and is the least variable site.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Pitch scaling was assessed for 10 normal-hearing listeners and 8 patients who use the Ineraid multichannel cochlear implant. For two patients who were excellent users of the prosthesis, pitch increased over a wide range of frequencies (100 Hz to 2333–3000 Hz). For three patients who were above average users of the prosthesis, pitch increased with frequency over a smaller range (100 Hz to 1200–2300 Hz). For three patients who demonstrated poor word recognition ability, pitch increased with frequency over a very small range (100 Hr to 600–1000 Hz). These results suggest that differences in speech understanding among patients who use the Ineraid may be accounted for, in part, by the range of pitch available through the implant.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID