摘要:

Neurochemistry of the auditory system has become one of the fastest growing areas in the study of audition. Many recent advances have implications for not only the basic auditory researcher but also the clinician. This article introduces some of the fundamentals of auditory neurochemistry as well as some recent developments. Also highlighted are some of the studies that appear to have current and future clinical significance.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Central auditory function was assessed in 15 patients with multiple sclerosis (MS) to determine whether the demyelinating lesions resulted in disruption of temporal processing. Auditory evoked potential (AEP) recordings included all three latency regions: Auditory brain stem responses (ABRs), midlatency responses (MLRs), and long-latency responses (LLRs). Two psychophysical tasks thought to involve temporal processing were used: a monaural-processing task (gap-detection) and a binaural-processing task (masking level difference; MLD). Further, AEP abnormalities and psychophysical performance deficits were related to lesion location, based on magnetic resonance imaging (MRI) scans. Reduced MLDs were seen in six MS subjects. Abnormal MLDs were always accompanied by abnormal ABRs and MLRs, and compared to subjects with normal MLDs, the subjects with abnormal MLDs were more likely to have bilateral abnormalities in the AEPs. Further, MLR indices of abnormal binaural interaction appeared to be specifically related to the psychophysical measure of binaural processing. The MRI data of these patients indicated widespread involvement of the auditory pathway. MS subjects with abnormal MRI signals restricted to levels caudal to the lateral lemniscus did not have abnormal MLDs. Gap-detection thresholds were more resistant to the effects of the demyelinating lesions; only two subjects had abnormal gap-detection thresholds. These subjects had extensive AEP abnormalities (bilaterally, in all three latency regions). The gap-detection thresholds wete most specifically related to abnormalities of the LLRs. In addition, the subjects with elevated gap-detection thresholds were the only ones with a prolonged interval between the ABRs and MLRs. Thus, efficient neural conduction between the upper brain stem and auditory cortex appears to be crucial for normal monaural temporal processing. The results indicate that demyelinating lesions can cause deficits in temporal processing in the central auditory pathway. However, auditory temporal processing is not a unitary phenomenon since abnormalities at different levels of the auditory system disrupt different types of temporal processing. Finally, abnormal psychophysical performance was not seen in all subjects with AEP and MRI evidence of involvement of the auditory pathway; rather, these psychophysical measures appeared to be sensitive to disruption only in specific portions of the auditory system.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

On-line computer methods were developed and evaluated for automated hearing testing with auditory brain stem responses (ABR). The system contained (1) a response recognition unit which recognized the presence or absence of an ABR response and (2) a threshold tracking unit which adjusted stimulus intensity and determined the ABR threshold. Two methods, one nontemplate (variance ratio) and one template (cross-correlation), were evaluated for response recognition while three threshold tracking methods were explored: clinical, Békésy, and PEST (parameter estimation by sequential testing). Both response recognition and threshold tracking units were evaluated by computer simulations for on-line operation using a standard set of experimentally recorded ABRs. The results indicated that while all the response recognition methods were reasonably accurate, their on-line use resulted in significant differences in test efficiency due to differences in tracking methods.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The Hearing Handicap Inventory for the Elderly (HHIE) was modified for use with younger hearing-impaired adults (< 65 years of age). Similar to the HHIE, the Hearing Handicap Inventory for Adults (HHIA), is a 25-item self-assessment scale composed of two subscales (emotional and social/situational). Replacement questions from the HHIE which form the HHIA focus on the occupational effects of hearing loss. For 67 hearing-impaired adults, the HHIA demonstrated high internal consistency reliability and a low standard error of measurement. Audiometric correlates of the HHIA revealed weak, yet statistically significant relationships with pure-tone sensitivity and supra-threshold word recognition ability. These findings support the use of self-report handicap measures with adults in that audiometric measures alone are insufficient in describing a patient's reaction to their hearing loss.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The psychometric properties of a tinnitus handicap questionnaire are reported. There were two phases in this study. In Phase I, 87 questions were administered to 100 tinnitus patients. From their responses, 59 items that were either redundant, insensitive, or had low item-total correlations were eliminated. In Phase II, the resulting 27-item questionnaire was administered to 319 patients. Fifty-three of these patients also completed psychological and psychophysical measures that were used to validate the questionnaire. A factor analysis of patients' responses revealed a three-factor structure. These three factors appeared to reflect the physical, emotional, and social consequences of tinnitus (Factor I), hearing ability of the patient (Factor 2), and the patients' view of tinnitus (Factor 3). Although the 27-item questionnaire had high internal consistency reliability and validity as reflected by correlations with life satisfaction and depression scales, it is recommended that only the items on the Factor 1 and the Factor 2 subscales be scored because of the low internal consistency reliability of the Factor 3 subscale. This questionnaire can be used to compare a patient's tinnitus handicap with the norm, identify specific areas of handicaps, and to monitor a patient's progress with particular treatment programs.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

This study compared the intelligibility of speech delivered via three transducers: a TDH-39 earphone, a Pracitronic KH 70 bone vibrator, and a Radioear 6-72 bone vibrator. CID W-1 spondees were presented to normal-hearing listeners via each transducer over a range of intensity levels. Functions relating the percentage of spondees correctly identified to stimulus level were similar for the three transducers, and notably, their slopes were comparable. This suggests that it is appropriate to use the W-1 word lists to determine speech reception thresholds (SRTs) with the KH 70 and 6-72 bone vibrators, even though these word lists were originally developed for testing by air conduction. Our subjects also identified NU-6 monosyllabic words equally well for each transducer when the words were delivered at 40 d6 above SRT. This result suggests that it is also valid to deliver the NU 6 speech test via the two types of bone vibrators.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Test and re-test high-frequency (10–20 kHz) thresholds were obtained for 200 ears of 100 normally hearing (0.25–8 kHz) young adults (18–28 years old) using a Beltone 2000 audiometer and Sennheiser HD 250 earphones referenced to sound pressure levels developed in a Bruel and Kjaer flat-plate coupler. Normative high-frequency thresholds could not be recommended for clinical use due to the very large intersubject threshold variability. This occurred even though test versus re-test thresholds were not significantly different (p >0.05) at any frequency. However, comparisons of the test minus re-test threshold for individual ears were within a clinically acceptable range of 210 dB for at least 95% of the ears at each frequency. Future research should concern intrasubject threshokl reliability and variability rather than specifying intersubject normative thresholds.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The time course for reacquisition of spondee word recognition was examined for 27 patients who use the Ineraid cochlear. implant. At 1 month postfitting, test scores ranged from 0 to 84% correct. The median score was 10% correct. At 22 to 28 months postfitting, the scores ranged from 0 to 100% correct. The median score was 56% correct. The rate of improvement in spondee recognition varied greatly within the sample. Most patients continued to extract new information from the electrically evoked representation of the speech signal over a period of a year or more.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We report the restoration of binaural hearing in an 88-year-old man who was experiencing significant communication difficulties. His preoperative air conduction thresholds had revealed a pure-tone average of 55 dB for the left ear and 107 dB for the right, and he was dissatisfied with the benefits provided by his BICROS hearing aid arrangement that had been fitted to his left ear. The combined effects of surgery and a hearing aid offered a 70 to 80 dB improvement for his right ear and restored the communication advantages of binaural hearing.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

ABR evaluations were completed for 36 adults (18 males, 18 females) having normal hearing sensitivity and for 91 adult patients having various degrees of sensorineural hearing loss. Amplitudes of waves I and V were compared for ear canal (TIPtrode™) electrode and mastoid electrode recordings. lnterpeak intervals (1–III, III–V, and I–V) were determined and upper 95% confidence limits defined for normative data. In general, amplitude of wave I was larger when TIPtrodes were used. Wave V amplitude was nearly identical for the two electrodes. Wave I was identified more frequently for TIPtrode than for mastoid recordings of ABR waveforms for the sensorineural hearing loss subjects.

ISSN:0196-0202    

出版商:OVID    

年代:1990

数据来源: OVID