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Biomedical subjects

W Noble

Publications and source records attributed to W Noble.

At least 19 recordsLinked to original sources
PubMed1995

Available response choices affect localization of sound.

Successful replication of an experiment by Butler and Humanski (1992) showed that listeners are able to proficiently localize sources on a lateral vertical plane on the basis of interaural differences alone. When a lateral horizontal array was included in the test setup, that finding was replicated only for a broadband signal interacting with the pinna, not for ones (lowpass and pure tone) providing only interaural differences. Cross-plane errors conforming to "cones of confusion" were observed for those latter sounds. In a second experiment, response options were made more unconstrained, which clarified the nature of the cross-plane confusions. Lowpass signals from lateral vertical plane sources tend to be heard at or close to the horizon. Measurement of cue values needs to take account of the response options available to listeners, as well as signal properties.

Adult↗
PubMed1995

Disabilities and handicaps associated with impaired auditory localization.

A questionnaire on (1) difficulties in everyday sound localization (localization disabilities), (2) limitations and disadvantages related to such disabilities (localization handicaps), and (3) everyday speech hearing disabilities was completed by 104 people with symmetrical hearing losses. Respondents considered situations when listening with and without their usual hearing aid fittings. The hearing-impaired group rated their unaided localization ability as significantly poorer than a sample with no reported hearing loss, particularly discrimination of distance. Only slight limitations on everyday activity due to localization disability were found, but disadvantage was reported in the form of experiences of confusion of sounds, of resultant loss of concentration, and of a wish to escape settings where this occurred. There was a moderate correlation between localization and speech hearing, even when hearing level was controlled for. Aided listening, whether with one or with two hearing aids, was reported as enabling significant improvements in both functions.

Adult↗
PubMed1994

Effects on sound localization of configuration and type of hearing impairment.

Localization ability of 87 bilaterally hearing-impaired listeners was tested in the horizontal and vertical planes, frontally and laterally. In those with sensorineural hearing loss, it was found that deficits in localization accuracy in different regions of auditory space could be related to different configurations of hearing loss. For example, there were associations between vertical plane discrimination and high-frequency sensitivity; and front-rear discrimination and mid-to-high-frequency sensitivity. These results agree with theoretical expectations, while the outcome overall contrasts with previous reports that localization performance is unrelated to audiometric configuration. A comparison of 13 listeners with conductive/mixed types of impairment with a sensorineural-loss group, matched for degree of loss, showed that a conductive component adds significantly to localization disturbance, particularly in the horizontal plane. The probable reason is a disturbance of low-frequency interaural time cues, and this occurs because a higher proportion of low-frequency sound is likely to be transmitted via bone conduction relative to air conduction. Correlations between hearing loss and localization are only moderate, suggesting that aspects of hearing impairment, in addition to simple attenuation, may also reduce auditory localization performance.

Adult↗
PubMed1992

Language gap.

Explore the source record for details and available documents.

Animals↗
PubMed1992

Effects of long-term bilateral and unilateral fitting of different hearing aid types on the ability to locate sounds.

Aided localization ability of 87 hearing-impaired listeners was tested for horizontal and vertical sound sources, at two signal levels, and for two orientations to the loudspeaker array (facing, sideways). Some listeners wore behind-the-ear (BTE) aids, others in-the-ear (ITE) aids. Some were bilaterally fitted, others unilaterally fitted. Listeners were tested only with types of aids and fittings that they were accustomed to wearing. The results strongly supported bilateral fitting for moderately and severely hearing-impaired listeners. However, for mildly impaired listeners, those fitted unilaterally performed as well, on average, as those fitted bilaterally. This suggests a need to consider individual listening requirements and also to provide such listeners with experience in unilaterally-aided listening before assessing the possible advantages of bilateral fitting. When hearing level was controlled, there was no overall difference in the performance of ITE and BTE aid wearers. This discrepancy with other research may be explained by measures (removal of intensity cues, permitting of head movement) designed to make the test situation more representative of real-life listening.

Adult↗
PubMed1991

Auditory localization under conditions of unilateral fitting of different hearing aid systems.

The spatial localization function of hearing-impaired listeners, usually fitted bilaterally with BTE, ITE or ITC devices, was tested under conditions of unilateral fitting of each of their own hearing aids, and unilateral fitting of stock versions of each of the other types. For the BTE wearers average localization accuracy and individual variability were not greatly changed when wearing only their left ear device, compared with bilateral aided performance. In ITE wearers, unilateral fitting in either ear led to somewhat poorer performance than bilateral. In the ITC wearers unilateral fitting produced inconsistent outcomes. Both BTE and ITE wearers fared poorly when fitted unilaterally with stock forms of devices 'foreign' to them, whereas ITC wearers did not show such a contrasting outcome. A group of non-impaired listeners showed severe disruption of localization under unilateral BTE and ITC hearing aid conditions, and to a lesser extent with ITEs. Results for the hearing-impaired listeners are interpreted in terms of adaptation to different usage patterns, with BTE wearers suggested as having adapted to their own systems unilaterally as well as bilaterally.

Auditory Threshold↗
PubMed1990

The effect of various hearing protectors on sound localization in the horizontal and vertical planes.

Listeners were tested under free head/torso movement conditions, using a brief pulsed broadband noise signal presented from any 1 of 20 loudspeakers in two intersecting hemicircumferential arrays: one in the horizontal plane, one in the vertical. The listeners' task was to judge the whereabouts of each signal while listening in normal, open-ears conditions or while wearing various types of standard or electronic earmuffs or compressible foam earplugs. Results showed that listeners could accomplish the task successfully in normal (open-ear) conditions. Results using earplugs, nonelectronic earmuffs, and two types of dichotic (dual microphone) electronic earmuffs showed decrements in performance similar to each other. These decrements took the general form of loss of appreciation of the vertical plane and of front-rear differences in the horizontal plane. Lateral discrimination was blurred but otherwise intact. Of two diotic (single microphone) electronic earmuffs, one completely disrupted localization function and the other came close to it.

Auditory Perception↗
PubMed1990

A comparison of different binaural hearing aid systems for sound localization in the horizontal and vertical planes.

Three groups of hearing-impaired listeners who had been fitted binaurally with behind-the-ear (BTE), in-the-ear (ITE), or in-the-ear-canal (ITC) hearing aids were tested on spatial localization function for sources in the frontal horizontal and vertical planes. No significant differences in unaided performance were observed between the groups, nor between that and aided performance in the BTE and ITE wearers. ITC wearers, by contrast, showed a deterioration in aided over unaided performance. From observations of performance when each group wore temporary fittings of the other two types of system, and from the performance of a non-impaired control group, it appears that the performance decrement for the ITC wearers was due to their own particular systems although specific reasons for this decrement could not be identified. In all conditions, aided and unaided, vertical plane localization was markedly disrupted in all the hearing impaired groups. It was also disrupted, to a lesser but still substantial extent, in aided conditions for the non-impaired listeners.

Adult↗
PubMed1989

Staff carriage of epidemic methicillin-resistant Staphylococcus aureus.

Twenty-six nurses were repeatedly screened for carriage of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) immediately before and after duty periods in which they solely attended six patients widely colonized with two EMRSA strains distinguishable by plasmid analysis. EMRSA carriage was detected in 13 nurses. Three EMRSA carriage patterns emerged: transient carriage in 12 nurses, when the EMRSA was isolated from noses or fingers of nurses after duty but was gone before their next day's duty; short-term nasal carriage, seen on occasion in 4 of these 12 nurses, when EMRSA carriage was detected on two consecutive screens; and persistent nasal carriage, seen in 1 nurse only, when the EMRSA was seen on more than two consecutive occasions. All but one of these incidents of carriage could be explained by close patient, rather than environmental, exposure and occurred despite an intensive control programme. Transient or short-term carriage in nurses probably resulted in transfer of the EMRSA between patients. Staff decontamination should be considered following a period of cohort nursing of EMRSA patients, especially if staff members are shortly to nurse unaffected patients. Our findings may explain some of the difficulties in controlling EMRSA.

Air Microbiology↗
PubMed1987

Auditory localization in the vertical plane: accuracy and constraint on bodily movement.

In two preliminary experiments, listeners were instructed to limit increasingly the movement of their heads and/or bodies while attempting to localize narrow bands of noise centered on 2.3 or 8.3 kHz. With increasing constraint on movement, the high-frequency band was incorrectly perceived as elevated above the horizon. The low-frequency band, when actually elevated above the horizon, was not so regularly perceived incorrectly as being below the horizon, a finding inconsistent with a previous report. A third experiment, which more closely replicated the task conditions and strategies of the previous study, did tend to reveal the anomalous low-frequency error. The error is explicable as a default response to which listeners whose sensitivity to the vertical dimension, in general, appears imperfect are prone. From various reports, it emerges that about 25% of presumed normally hearing people exhibit this insensitivity.

Auditory Perception↗
PubMed1987

Generation 04 sodium slides and generation 04 reference fluid evaluated for use with the Ektachem 400 Analyzer.

Evaluation of a new generation of sodium slides and reference fluid for use with the Kodak Ektachem 400 Analyzer demonstrated improved performance in generation 04 over the previous generation 03 slide for sodium determinations. A decrease in between-replicate imprecision and a correction of the "serum" assigned values of the calibrators used to calibrate the slide used with the reference fluid account for the improvement. When generation 04/Ektachem results (y) were compared with results obtained with a Beckman ion-selective electrode (x), linear regression statistics were: slope = 0.88, y-intercept = 15.4 mmol/L, and Syx = 2.1 mmol/L. The average fixed bias in comparison with the Beckman electrode decreased from +1.9 mmol/L with generation 03 to -0.6 mmol/L with generation 04 materials. Random error is indicated by a decrease in Syx from 2.8 mmol/L for generation 03 to 2.1 mmol/L for generation 04. Application of Deming's regression, a more accurate portrayal of the generation 04 sodium data set, produces a slope of 1.0 and a y-intercept of -0.6 mmol/L.

Humans↗
PubMed1985

Occupational deafness: the continuing challenge of early German and Scottish research.

Systematic studies in occupational deafness were first carried out in the late 19th century, in America, Germany, Russia, and Scotland. The studies by Gottstein and Kayser, in 1881 in Germany, and by Barr, in 1886 in Scotland, are identified as the two principal landmarks. The physicians who carried them out should be seen as occupying a place in the mainstream of development of industrial medicine. Gottstein and Kayser's study of personnel in a railway works reflected a contemporary concern about railway safety; Barr's, of boilermakers, a feeling for the difficulties in hearing in the everyday world experienced by the victims of occupational deafness. Barr's evaluation of such difficulties through self-report, we argue, reveals more of the quality of hearing handicap than the present century's apparently objective tests. Both studies relied on occupation-based epidemiology, which was able to identify occupational deafness, distinguish its etiology, and locate the site of its pathology. We argue that occupation-based epidemiology has since been neglected in favour of dose-response epidemiology to the detriment of research in occupational deafness and in industrial medicine generally. Dose-response epidemiology seems the more scientific but, in practice, it is afflicted by even more uncertainty than occupation-based epidemiology. To compound the uncertainty, there are two incompatible mathematical expressions for the dose-response relation for noise, both separately enshrined in legislation in various parts of the world. We conclude by advocating more secondary research in industrial medicine. Barr points us to a further topic for such research, the place of temporary threshold shift in the development of knowledge about occupational deafness as a problem for industrial medicine.

Germany↗
PubMed1985

Accuracy, latency, and listener-search behavior in localization in the horizontal and vertical planes.

Thirty-six listeners localized continuous filtered noise bursts centered on 2.3 or 8.3 kHz under normal listening conditions or while wearing earmuffs. The noise bursts were from any one of 20 loudspeakers, 18 degrees apart, visible to the listeners, and arranged in the horizontal and vertical planes. Listeners were free to move, while remaining seated, throughout all trials. The noise bursts were terminated by the listeners. Measures of accuracy and latency showed that earmuff listening had a significant effect whereas, overall, signal frequency had no significant effect. There was, however, an apparent downward shift of the 2.3-kHz signals presented above the midline in the vertical plane. Analysis of video records of listeners' behavior revealed a strong tendency for initial orientation by head or eye movement to correlate with final response, even when both were inaccurate. The paradigm adopted in this latter aspect of the study illustrates an "ecological" approach to the study of auditory phenomena.

Acoustic Stimulation↗
PubMed1983

Hearing, hearing impairment, and the audible world: a theoretical essay.

In contrast to traditional understandings about hearing, based on physics and physiology, the ecological model permits development of a perspective on hearing in relation to the audible features and characteristics of the real, day-to-day world. An ecological account, furthermore, addresses the perceiver's role more adequately, allowing the description of 'hearing acts' typically undertaken in relation to the audible world. The affordances or utilities of the audible world for the normally hearing perceiver having been understood - and the most crucial affordance is ongoing sustainment of social selves - a model of the hearing-impaired actor is advanced that incorporates the concept of 'management of spoiled identity'. The implications for practitioners' attitudes in assessment and rehabilitation are discussed.

Attention↗