摘要:

Color imaging brain mapping techniques were applied to the middle latency response in 40 normal-hearing, neurologically intact adults. Stimuli included 9/sec and 41/sec clicks and 500 and 2000 Hz tone bursts. Wave Na had no specific focus of activity while wave Pa was largest in amplitude over the vertex and frontal lobes. Variables such as the baseline from which amplitude measures are made (prestimulus versus preceding wave) and reference electrode (ipsilateral mastoid versus C7) were assessed. The preceding trough (Na) yielded a more precise measure of Pa amplitude than the prestimulus baseline. The reference electrode location did not influence the topography of wave Pa, although response amplitudes were significantly larger with the noncephalic reference. Two averaging strategies were assessed: (1) averaging the entire pre- and poststimulus epoch point for point across individuals and (2) averaging the voltage of Pa at the latency of Pa for each individual. The z statistic was evaluated as a means for identifying clinically encountered abnormalities. The use of this measure was found to be problematic because such an analysis assumes normally distributed data while Pa amplitude approximates a gamma distribution. The z statistic may be more appropriate for the analysis of interhemi-spheric differences, which have a normal distribution with a mean close to zero. Responses obtained to 500 Hz stimuli tended to be larger than 2000 Hz-elicited responses. Of interest clinically, is that Pa amplitude was largest at electrode location Fz. The scalp topography and subsequent conclusions regarding 9 versus 41/sec responses differed depending on the data analysis strategy used, emphasizing the importance of these strategies. Future directions for this technology were discussed.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The interactive effects of gender, age, and degree of sensori-neural hearing loss on the absolute latency of wave V of the auditory brain stem response were analyzed in 325 subjects with cochlear loss. Norms based on these data were then applied to an analysis of the wave V latencies of 87 subjects with retrocochlear loss. Results in the cochlear group revealed interactions between gender and age and between gender and degree of hearing loss. The interactive effect between gender and degree of loss was observed for wave V, but not for waves III or I. Separate gender norms for absolute wave V latency, based on empirical boundaries encompassing 99% of the cochlear group, resulted in a 90% correct identification rate in the 87 subjects with retrocochlear lesion.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

This paper considers the problem of determining the performance of test protocols, i.e., combinations of diagnostic tests. Two techniques are developed which provide quantitative measures of performance. First, protocol performance can be calculated from clinical data. This technique is simple and straightforward. The primary limitation is that the necessary clinical data may not be available. A second technique is developed to predict protocol performance based on (1) protocol design, (2) individual test performance, and (3) test correlation. This second technique is applied to two types of audiological protocols: those to determine retrocochlear site-of-lesion, and those to identify hearing loss in newborns. Both techniques provide information essential to the design and selection of test protocols. The ability to predict performance is extremely important because clinical studies to evaluate protocols can take years to complete, or may be impractical.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The behavior of spontaneous otoacoustic emissions (SOAEs) is affected by external stimuli. A series of experiments was conducted with 25 normal-hearing subjects to explore multiple and bilateral SOAEs, frequency and amplitude drift of SOAEs, suppression functions and existence regions for distortion products generated by the interaction of SOAEs and external tones.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Two studies were performed in which hearing-impaired subjects responded to the Connected Speech Test (CST). In experiment 1, 40 subjects, divided into four groups according to extent and configuration of hearing loss, responded to the CST version 1 (CSTv1). This version of the test consisted of 57 passages of connected speech: 48 test passages and 9 practice passages. It was developed on the basis of data for normal-hearing listeners. Performance of hearing-impaired listeners for the CSTv1 revealed that, although the passages were equal in average intelligibility for normal hearers, they were not equally intelligible for hearing-impaired persons. Based on results of data analyses, the 57 passages were reconstituted into 28 pairs of passages: 24 test pairs and 4 practice pairs. The pairs were equal in average intelligibility for both normal and hearing-impaired listeners. This form of the test was named the CST version 2 (CSTv2). In experiment 2, an additional 23 hearing-impaired subjects responded to the CSTv2. Critical differences and the slope of the signal to babble ratio (SBR) function were determined for the CSTv2 for hearing-impaired listeners. When two CSTv2 pairs were used per score, the 95% critical difference for hearing-impaired subjects was about 15.5 rationalized arcsine units (rau). The mean SBR function slope for hearing-impaired listeners was 8.5 rau/dB. Comparing the critical difference with the SBR function slope, it may be seen that, for hearing-impaired listeners, differences in intelligibility equivalent to a 2 dB change in SBR can be detected with CST scores based on mean performance across two passage pairs.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The diagnostic performance of the Hearing Handicap Inventory for the Elderly—Screening Version (HHIE-S) was evaluated against five definitions of hearing loss in 178 elderly subjects screened in primary care. Hearing loss was assessed by puretone audiometry. Using a score of greater than 8 as a cut point, the HHIE-S had sensitivities ranging from 53 to 72% and specificities ranging from 70 to 84% with the different definitions. The HHIE-S receiver-operating characteristics and likelihood ratios were similar regardless of hearing loss definition used. The HHIE-S is a valid, robust test for identifying hearing-impaired elderly, irrespective of the audiometric definition used to finally diagnose hearing difficulties.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Data concerning hearing aid monitoring practices and hearing aid malfunction were collected for three groups of mainstreamed hearing-impaired children: 248 children receiving services from itinerant teachers of the hearing impaired, 43 who participated in a study involving extensive psychoeducational evaluation, and 10 children who attended a 6 week residential treatment program in which hearing aid function was checked at least twice each day. Comparisons of the three data sets revealed that even conscientious parental and professional monitoring practices prove inadequate. As a result, it is hypothesized that children must take active roles in the monitoring process. A program to help children develop hearing aid monitoring skills is outlined.

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1988

数据来源: OVID