摘要:

The interaction of the head with a sound impinging upon it has a direct effect on the sound as it is seen at the port of the hearing aid microphone. While other investigators have evaluated this effect in terms of changes in the frequency response of the hearing aid, this investigation sought to evaluate the significance of the effect in terms of the intelligibility of speech presented in a noisy background. The three typical locations of a hearing aid microphone were simulated with a high-fidelity probe-tube microphone placed around the right ear of KEMAR. The locations were: over the ear, behind the ear, and in the ear. An earmold was kept in the ear at all times. Speech and noise were presented to the microphone and recorded on tape for presentation to normally hearing subjects. The results indicated that so long as the hearing aid microphone is located on the head, around the ear, no one location is better than any other for speech intelligibility.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Immittance procedures and medical evaluation based on case history and otoscopy were administered to 115 youngsters from a large pediatric practice. Using ASHA immittance guidelines, a reasonable 73% overall agreement was achieved between immittance and medical recommendations of “pass,” “at risk,” and “fail/treat.” When using medical findings as the criterion, there were three definite cases of under-referral (false negatives) and five over-referrals (false positives) in this sample group.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Acoustic reflex patterns were reviewed for 100 patients suspected of having cochlear otosclerosis (group 1) and 73 patients with confirmed stapedial otosclerosis and conductive hearing losses of less than 5 years duration (group 2). Three abnormal reflex patterns were exhibited by these patients “negative on/off,” “no response when the probe was in the affected ear,” and “no response when the stimulus was in affected ear.” Results showed that the negative on/off pattern was equally as common for the two subject groups. The “no response” patterns were more common for the early stapedial otosclerosis group. The presence of acoustic reflex patterns classically associated with stapedial otosclerosis in patients with cochlear otosclerosis leads us to predict that some degree of stapedial fixation is common in many cases of cochlear otosclerosis. Based upon these findings, the presence of the negative on/off pattern in patients with mild sensorineural hearing loss, excellent speech discrimination, and a family history of hearing loss, is now considered indicative of cochlear otosclerosis.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The purpose of this study was to evaluate the effects of various cut-off frequencies on low-pass filtered speech discrimination test results obtained from children. Two groups of children, one presumed to have normal auditory perception and the other with auditory learning diabilities, were tested. Phonetically Balanced Kindergarten word list words were low-pass filtered at 1000 Hz, 750 Hz, and 500 Hz. The results indicate a clear separation of groups for the 1000 Hz filtered condition only. The implications of these preliminary test findings are discussed.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Auditory brain stem responses were elicited by unfiltered clicks as well as 500-Hz and 1000-Hz tone-pips with and without high-pass noise masking, from normal hearing subjects and from patients with high-frequency hearing losses. The responses elicited by tone-pips were similar in configuration to the familiar click-evoked responses. When presented in quiet, the latencies of responses elicited by tone-pips (i.e. wave V latency) were identical, or close to those evoked by clicks, suggesting common origins on the basilar membrane. With the addition of high-pass filtered white noise mixed with the tone-pips, wave V latency shifted, suggesting responses originating from apical low-frequency regions. This procedure yielded a good approximation of audiograms obtained from the same subjects. The unfiltered clicks inferred hearing sensitivity in the 2000 to 4000 Hz range, the masked tone-pips closely reproduced thresholds at 500 Hz and 1000 Hz.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The auditory brain stem response (ABR) and the auditory middle response (AMR) were simultaneously recorded in 19 normal adults and 29 patients with hearing loss. The test was performed using tone pips at 0.5, 1, 2, and 4 kHz with intensity levels of 0,10, 20, and 30 dB above the individual's behavioral threshold. A wide pass-band of 0.5 Hz to 3 kHz was used for recording the response. The typical waveform of the response provided six peaks that were successively labeled as P10, N15, P20, N25, P35, and N45. P10was a large positive deflection in the ABR. N15-P20-N25, P35, and N45corresponded to the Na peak complex, Pa, and Nb of the AMR, respectively. Of all components recorded, P10was detected most consistently. However, because N25and P35of the AMR also gave important information for the assessment of hearing, simultaneous recording of the ABR and AMR is considered a useful clinical technique for estimating hearing in normal as well as in hearing-impaired subjects.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Standard audiometric transducers, such as the TDH-49, produce an electrical artefact which interferes with the recording of the early auditory evoked potentials. The sources of these artefacts have been identified as the capacitive and inductive coupling of the transducer and its leads to the recording electrodes. Artefacts were recorded using an artificial head with an M,-C, electrode array for 500- and 3-kHz tone pips and positive, negative, and alternating polarity clicks at Peak Equivalent Sound Pressure Levels from 60 dB (positive click and 3-kHz tone pip) to 90 dB (alternating polarity click). The artefacts grew linearly with increases in intensity. Shifts in the Visual Detection Threshold of the artefacts produced by various conditions of shielding the transducer and its leads were explored. Acceptable reductions in artefact magnitude were obtained by enclosing the transducer in either an aluminum or mu-metal case connected through a braided-wire shield of the transducer leads to earth ground. Lesser reductions were achieved by the use of antiphase cancellation. The combination of the latter and the aluminum and mu-metal cases did not produce greater shifts in the visual detection threshold than the use of the aluminum and mu-metal cases alone. The fabrication of a pair of shielded enclosures is described and data are presented which show that they do not adversely affect the acoustic output of the headphones.

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1981

数据来源: OVID