ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Electrical auditory brain stem responses (EABR) and electrical middle latency responses (EMLR) were recorded from patients who had received the Nucleus multichannel cochlear implant system. Twenty-five sequential patients had either intraoperative or outpatient EABR testing. We also recorded EMLRs from several outpatients. EABR results were consistent among all patients tested. Wave V mean latencies were the shortest (3.82 msec) for the most apical electrode (E20) and increased slightly for the medial (E12) and basal (E5) electrodes (3.94 and 4.20 msec, respectively). Absolute latencies for all EABR component waves were observed to be 1 to 1.5 msec shorter than typical acoustic auditory brain stem response (ABR) mean latencies. We have examined the relationships between patients' EABR/EMLR and their behavioral responses to electrical stimulation. Generally, the behavioral threshold and comfort current levels were lower than the predicted values based on EABR/EMLR findings. This observation may be due in part to psychophysical loudness differences noted for pulse rates of 10 to 500 pulses per second in some of the patients that we have studied in greater detail.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Comparisons were made of the ABR latencies of tinnitus (T) and nontinnitus (NT) patient groups balanced for age and gender and matched for acoustic reflex threshold (ART)s, 1000 to 4000 Hz and 4000 Hz auditory thresholds, and normal hearing. In the ART match, prolongations of wave I [t(94) = 4.42, p <0.001], wave III [f(94) = 2.72, p <0.011, and wave V [t(94) = 3.32, p <0.011 and the III-V interval [t(94) = 2.48, p <0.02) were seen in T subjects. Wave I in 1 to 4 kHz matched [2(62) = 3.13, p <0.0051 and normal-hearing subjects [r(30) = 2.58, p <0.01] was prolonged in T females. The utility of using wave I as a diagnostic indicator for tinnitus in females is discussed.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Auditory brain stem responses (ABRs) of 33 high risk, full term or near term newborns with transient elevation of ABR threshold (transient group) were compared with those of normal infants (normal group) and high-risk infants with known conductive (conductive group) and known sensorineural hearing loss (sensorineural group). ABRs of infants in the transient group initially were not significantly different from those of the conductive group in terms of wave I latency, wave V latency, and the slope of the latency-intensity (L-I) function of wave V. In Infants with transient unilateral threshold elevation, significantly shorter inter-peak latencies were recorded in the affected ear than in the ear that passed. This finding has been previously described in infants with conductive disorders. On follow-up, ABRs in the transient group closely resembled those of the normal group with respect to the same measures. Otologic histories in the transient group were unremarkable in the majority of cases. Increased slope of the L-1 function in infants with confirmed conductive disorders was an unexpected finding. Previous studies of patients with conductive loss had not revealed a significant deviation from normal for this measure. An age interaction for the effect might explain the discrepancy between this and previous studies.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Clinical auditory brain stem response latency measures are conventionally evaluated for abnormality by reference to normative laboratory values in standard deviation units. This note suggests that the directionality of the test hypothesis should be considered when the clinical ABR is evaluated for abnormality at a predetermined level of confidence.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Several hearing aid prescription procedures specify frequency gain functions in terms of the desired levels of amplified speech. The most direct method for verifying hearing aid fittings based on these procedures requires a measurement of amplified speech in the ear canal. This paper describes the evaluation of a probe microphone measurement procedure designed to measure amplified speech to verify hearing aid fittings using the MSUv3 prescription procedure. With minor modifications, the same protocol could be used with other prescriptive procedures. Hearing aids were fitted to a group of subjects with sensorineural hearing impairment. Data derived from the fittings were analyzed to assess several issues relating to the procedure itself and to prescriptive fittings in general. The main results were: (1) with over the ear hearing aids, most prescriptions can be matched with an RMS error of 5 dB or less through the frequency range from 500 to 2500 Hz; (2) even though actual fittings usually do not perfectly correspond with their prescriptions, differences among frequency gain prescriptions are preserved in hearing aid fittings if the RMS error of the fitting is 5 dB or less; (3) if sound field stimuli presented to the hearing aid are precisely controlled, an in situ output verification method produces valid results; (4) when hearing aids are fitted with gain similar to that prescribed by the MSUv3 procedure, the maximum comfortable speech input level is typically about 72 dB; (5) the SSPLSO prescription generated by the MSUv3 procedure overestimates desired SSPLSO by 7 dB on average.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The optimal frequency response slope, from the low frequencies (250 or 500 Hz) to 2000 Hz, was estimated for each of 46 severely or profoundly hearing-impaired adults. The estimates were derived from paired comparison judgments of speech filtered to simulate different frequency response conditions, from home trials and ratings of different tone settings of high-powered, behind-the-ear hearing aids, and for 28 subjects, from speech recognition testing. The estimated optimal response, expressed as the slope from 250 to 2000 Hz and as the slope from 500 to 2000 Hz, was compared with the response prescribed by the National Acoustic Laboratories (NAL) procedure and its relationship to audiometric variables was analyzed. Insertion gain was measured for the preferred volume setting with the best frequency response. Preferred gain was typically about 10 dB higher than the NAL prescribed gain. Considering these results in relation to other data, it appears that the “half-gain” rule ceases to apply when HTL exceeds about 70 dB. The estimated optimal frequency response agreed with the NAL response for some subjects but relatively more low frequencies were required for between a third and half of the subjects, depending upon how frequency response is expressed. Generally, more low frequencies were required if HTL at 2000 Hz exceeded 95 dB, whereas the NAL response was usually appropriate for other cases.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The ability to perceive for suprasegmental and eight segmental speech pattern contrasts was measured on 16 adult cochlear implantees using the Nucleus multichannel prosthesis with either FO-F2 (n = 9) or FO-Fl-F2 (n = 7) coding. The results of this study indicated the following: (1) The Nucleus device provided significant access to the majority of suprasegmental and segmental speech contrasts. (2) Both one- and two-format coding strategies provided good access to speech pattern contrasts. (3) Considerable intersubject differences in performance were observed, but there was no evidence to suggest that these were related to either processing scheme. (4) Although the accessibility of speech contrasts varied, the pattern of perceptual performance was interpreted in terms of an acoustic/phonetic hierarchy. (5) The Speech Pattern Contrast (SPAC) test appears to be a practical procedure for analyzing the perception of phonologically salient information about the suprasegmental and segmental components of speech.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The Quantified Denver Scale of Communication Function (QDS) is a 25 item questionnaire developed to measure communication difficulties in adults with hearing impairment. This study reassessed the constructs, reliability, and validity of the scale, and developed a 5 item short version. The QDS was administered to 238 elderly individuals (137 with and 101 without hearing loss). Factor analysis using this sample identified only two subscale constructs as opposed to four originally proposed constructs. The validity of the new revised two-construct model was verified by four independent investigators who labeled the two constructs as measuring self isolation and communication function. The internal reliability of the revised scale was 0.97 and of both construct subscales was 0.95. Overall test-retest reliability was 0.73. Validity examined by comparing the revised scale with another well-known handicap measure, the Hearing Handicap Inventory for the Elderly, was adequate: overall scale correlations were 0.73 and subscale correlations ranged from 0.64 to 0.72. The accuracy of the revised QDS for discriminating between individuals with and without hearing loss was 73%. Stepwise discriminant analysis generated a 5 item short version scale which contained two questions from the long communication subscale and three from the long self-isolation subscale. The accuracy of the short QDS was 74%. We conclude that the revised QDS is a reliable and valid scale that can be used to assess self isolation and communication function in elderly individuals with hearing loss, and that a new 5 item short version performs as well as the original 25 item scale.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID