scholarly journals Echo suppression and discrimination suppression aspects of the precedence effect

1997 ◽  
Vol 59 (7) ◽  
pp. 1108-1117 ◽  
Author(s):  
Xuefeng Yang ◽  
D. Wesley Grantham
Keyword(s):  
Precedence Effect ◽  
Echo Suppression

scholarly journals The Binaural Interaction Component of the Auditory Brainstem Response Under Precedence Effect Conditions

2020 ◽  
Vol 24 ◽  
pp. 233121652094613
Author(s):  
Kelly Dean ◽  
John H. Grose
Keyword(s):  
Auditory Brainstem Response ◽  
Interaural Time Difference ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Precedence Effect ◽  
Binaural Processing ◽  
Binaural Interaction ◽  
Brainstem Response ◽  
Echo Suppression ◽  
Interaction Component

The purpose of this study was to measure the binaural interaction component (BIC) derived from click-evoked auditory brainstem responses (ABRs) using stimuli configured to elicit the Precedence Effect. The hypothesis was that the contribution of binaural processing to echo suppression can be evidenced by a diminished or absent BIC associated with the echo. Ten normal-hearing young adults provided ABRs generated by sequences of click pairs. Results showed that BICs elicited by diotic clicks in isolation were obliterated when those diotic clicks were preceded by a click pair having an interaural time difference of 400 µs and where the interclick interval was 8.4 ms. The presence of the leading click pair increased the latency of the ABR generated by the lagging diotic click pair but did not decrease its amplitude. The results were interpreted as indicating a contribution of binaural processing at the level of the brainstem to echo suppression, at least for the conditions tested here.

Is There a Hearing Aid for the Thinking Person?

2010 ◽  
Vol 21 (09) ◽  
pp. 594-600 ◽  
Author(s):  
Ervin R. Hafter
Keyword(s):  
Hearing Aids ◽  
Verbal Memory ◽  
Hearing Aid ◽  
Reaction Times ◽  
Precedence Effect ◽  
Auditory Prosthesis ◽  
Speech In Noise ◽  
Improved Performance ◽  
Echo Suppression ◽  
Listening Strategies

Background: The history of auditory prosthesis has generally concentrated on bottom-up processing, that is, on audibility. However, a growing interest in top-down processing has focused on correlations between success with a hearing aid and such higher order processing as the patient's intelligence, problem solving and language skills, and the perceived effort of day-to-day listening. Purpose: Examination of two cases of cognitive effects in hearing that illustrate less-often-studied issues: (1) Individual subjects in a study use different listening strategies, a fact that, if not known to the experimenter, can lead to errors in interpretation; (2) A measure of shared attention can point to otherwise unknown functional effects of an algorithm used in hearing aids. Research design: In the two examples described above: (1) Patients with cochlear implants served in a study of the binaural precedence effect, that is, echo suppression. (2) Individuals identifying speech-in-noise benefit from noise reduction (NR) when the criterion was improved performance in simultaneous tests of verbal memory or visual reaction times. Conclusions: Studies of hearing impairment, either in the laboratory or in a fitting session, should include study of the complex stimuli that make up the natural environment, conditions where the thinking auditory brain adopts strategies for dealing with large amounts of input data. In addition to well-known factors that must be included in communication, such things as familiarity, syntax, and semantics, the work here shows that strategic listening can affect even how we deal with seemingly simpler requirements, localizing sounds in a reverberant auditory scene and listening for speech in noise when busy with other cognitive tasks.

scholarly journals Echolocation versus echo suppression in humans

2013 ◽  
Vol 280 (1769) ◽  
pp. 20131428 ◽  
Author(s):  
Ludwig Wallmeier ◽  
Nikodemus Geßele ◽  
Lutz Wiegrebe
Keyword(s):  
Sound Source ◽  
Spatial Information ◽  
Precedence Effect ◽  
Sound Sources ◽  
Source Discrimination ◽  
Additional Control ◽  
Acoustic Space ◽  
Echo Suppression ◽  
Listening Experiment ◽  
Blind Humans

Several studies have shown that blind humans can gather spatial information through echolocation. However, when localizing sound sources, the precedence effect suppresses spatial information of echoes, and thereby conflicts with effective echolocation. This study investigates the interaction of echolocation and echo suppression in terms of discrimination suppression in virtual acoustic space. In the ‘Listening’ experiment, sighted subjects discriminated between positions of a single sound source, the leading or the lagging of two sources, respectively. In the ‘Echolocation’ experiment, the sources were replaced by reflectors. Here, the same subjects evaluated echoes generated in real time from self-produced vocalizations and thereby discriminated between positions of a single reflector, the leading or the lagging of two reflectors, respectively. Two key results were observed. First, sighted subjects can learn to discriminate positions of reflective surfaces echo-acoustically with accuracy comparable to sound source discrimination. Second, in the Listening experiment, the presence of the leading source affected discrimination of lagging sources much more than vice versa. In the Echolocation experiment, however, the presence of both the lead and the lag strongly affected discrimination. These data show that the classically described asymmetry in the perception of leading and lagging sounds is strongly diminished in an echolocation task. Additional control experiments showed that the effect is owing to both the direct sound of the vocalization that precedes the echoes and owing to the fact that the subjects actively vocalize in the echolocation task.

scholarly journals Physiological Studies of the Precedence Effect in the Inferior Colliculus of the Cat. I. Correlates of Psychophysics

1998 ◽  
Vol 80 (3) ◽  
pp. 1285-1301 ◽  
Author(s):  
Ruth Y. Litovsky ◽  
Tom C. T. Yin
Keyword(s):  
Inferior Colliculus ◽  
Free Field ◽  
Median Plane ◽  
Stimulus Level ◽  
Central Nucleus ◽  
Precedence Effect ◽  
Discharge Rates ◽  
Physiological Studies ◽  
Echo Suppression ◽  
Maximal Suppression

Litovsky, Ruth Y. and Tom C. T. Yin. Physiological studies of the precedence effect in the inferior colliculus of the cat. I. Correlates of psychophysics. J. Neurophysiol. 80: 1285–1301, 1998. The precedence effect (PE) is experienced when two spatially separated sounds are presented with such a brief delay that only a single auditory image at or toward the location of the leading source is perceived. The responses of neurons in the central nucleus of the inferior colliculus (ICC) of cats were studied using stimuli that are known to elicit the PE, focusing on the effects of changes in stimulus conditions that a listener might encounter in a natural situation. Experiments were conducted under both free-field (anechoic chamber) and dichotic (headphones) conditions. In free field, the PE was simulated by presenting two sounds from different loudspeakers with one sound delayed relative to the other. Either click or noise stimuli (2- to 10-ms duration) were used. Dichotically, the same conditions were simulated by presenting two click or noise pairs separated by an interstimulus delay (ISD) with interaural time differences (ITDs) imposed separately for each pair. At long ISDs, all neurons responded to both leading and lagging sources as if they were delivered alone. As the ISDs were shortened, the lagging response became suppressed. The ISD of half-maximal suppression varied considerably within the population of neurons studied, ranging from 2 to 100 ms, with means of 35 and 38 ms for free field and dichotic conditions, respectively. Several correlates of psychophysical findings were observed in ICC neurons: suppression was usually stronger with lower overall stimulus level and longer duration stimuli. Suppression also was compared along the azimuth and elevation in free field by placing the lagging source at (0°,0°), which is common to both axes, and the leading sources at locations along either plane that generated similar discharge rates. All neurons that showed suppression along the azimuth also did so in the elevation. In addition, there was a high correlation in the ISD of half-maximal suppression along the two planes ( r = 0.87). These findings suggest that interaural difference cues, which are robust along the horizontal axis but minimal in the median plane, are not necessary for neural correlates of the PE to be manifested. Finally, single-neuron responses did not demonstrate a correlate of build-up of suppression, a phenomenon whereby echo suppression accumulates with ongoing stimulation. This finding adds credibility to theories about the PE that argue for a “higher order” component of the PE.

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