masking condition
Recently Published Documents

The local and non local behavior of the accelerated Gisin state are investigated either before or after filtering process. It is shown that, the possibility of predicting the non-local behavior is forseen at large values of the weight of the Gisin and acceleration parameters. Due to the filtering process, the non-locality behavior of the Gisin state is predicted at small values of the weight parameter. The amount of non classical correlations are quantified by means of the local quantum uncertainty (LQU)and the concurrence, where the LQU is more sensitive to the non-locality than the concurrence. The phenomenon of the sudden changes is displayed for both quantifiers. Our results show that, the accelerated Gisin state could be used to mask information, where all the possible partitions of the masked state satisfy the masking criteria. Moreover, there is a set of states, which satisfy the masking condition, that is generated between each qubit and its masker qubit. For this set, the amount of the non-classical correlations increases as the acceleration parameter increases . Further, the filtering process improves these correlations, where their maximum bounds are much larger than those depicted for non-filtered states.

Abstract Background: To examine the progressively developed visual-search deficiency associated with Alzheimer's disease (AD).Methods: Healthy-younger adults (34), healthy-older adults (normal-aging control, NC, 30), adults with subjective cognitive decline (SCD, 14), amnestic mild cognitive impairment (aMCI, 20), or mild AD (15) participated in this study. To determine whether 1 of 4 letters presented at 4 symmetrically-located positions differed from the other 3, when the 4 letters were masked by either other randomly positioned and oriented letters or random-pixel noise. Meanwhile, eye movements were tracked.Results: In all the participants, with the stimulus-presentation time being longer, the visual-search performance improved, and both the eye interest-area first fixation duration (IFFD) and the interest-area-fixation count (IFC) increased. Particularly under the noise-masking condition, the AD group performed the worst at stimulus-presentation times between 300 and 900 ms. The aMCI group, but not the SCD group, performed worse than the NC group at the stimulus-presentation time of either 300 or 500 ms. The IFC was higher in all the patient groups than that in the NC group, and distinguishable between participants with AD and those with SCD or aMCI. Conclusions: The visual-search performance combined with eye-moment tracking under the noise-masking condition can be used for distinguishing AD from normal aging, SCD, and aMCI.

Abstract Background：To examine the progressively developed visual-search deficiency associated with Alzheimer's disease (AD).Methods: Healthy-younger adults (34), healthy-older adults (normal-aging control, NC, 30), adults with subjective cognitive decline (SCD, 14), amnestic mild cognitive impairment (aMCI, 20), or mild AD (15) participated in this study. To determine whether 1 of 4 letters presented at 4 symmetrically-located positions differed from the other 3, when the 4 letters were masked by either other randomly positioned and oriented letters or random-pixel noise. Meanwhile, eye movements were tracked.Results: In all the participants, with the stimulus-presentation time being longer, the visual-search performance improved, and both the eye interest-area first fixation duration (IFFD) and the interest-area-fixation count (IFC) increased. Particularly under the noise-masking condition, the AD group performed the worst at stimulus-presentation times between 300 and 900 ms. The aMCI group, but not the SCD group, performed worse than the NC group at the stimulus-presentation time of either 300 or 500 ms. The IFC was higher in all the patient groups than that in the NC group, and distinguishable between participants with AD and those with SCD or aMCI. Conclusions: The visual-search performance combined with eye-moment tracking under the noise-masking condition can be used for distinguishing AD from normal aging, SCD, and aMCI.

Abstract Background：To examine the progressively developed visual-search deficiency associated with Alzheimer's disease (AD).Methods: Healthy-younger adults, healthy-older adults (normal-aging control, NC), adults with subjective cognitive decline (SCD), amnestic mild cognitive impairment (aMCI), or mild AD participated in this study. To determine whether 1 of 4 letters presented at 4 symmetrically-located positions differed from the other 3, when the 4 letters were masked by either other randomly positioned and oriented letters or random-pixel noise. Meanwhile, eye movements were trackedResults: In all the participants, with the stimulus-presentation time being longer, the visual-search performance improved, and both the eye interest-area first fixation duration (IFFD) and the interest-area-fixation count (IFC) increased. Particularly under the noise-masking condition, the AD group performed the worst at stimulus-presentation times between 300 and 900 ms. The aMCI group, but not the SCD group, performed worse than the NC group at the stimulus-presentation time of either 300 or 500 ms. The IFC was higher in all the patient groups than that in the NC group, and distinguishable between participants with AD and those with SCD or aMCI. Conclusions: The visual-search performance combined with eye-moment tracking under the noise-masking condition can be used for distinguishing AD from normal aging, SCD, and aMCI.

Objective This research investigated whether the psychoacoustics of simultaneous masking, which are integral to a model-checking-based method, previously developed for detecting perceivability problems in alarm configurations, could predict when IEC 60601-1-8-compliant medical alarm sounds are audible. Background The tonal nature of sounds prescribed by IEC 60601-1-8 makes them potentially susceptible to simultaneous masking: where concurrent sounds render one or more inaudible due to human sensory limitations. No work has experimentally assessed whether the psychoacoustics of simultaneous masking accurately predict IEC 60601-1-8 alarm perceivability. Method In two signal detection experiments, 28 nursing students judged whether alarm sounds were present in collections of concurrently sounding standard-compliant tones. The first experiment used alarm sounds with single-frequency (primary harmonic) tones. The second experiment’s sounds included the additional, standard-required frequencies (often called subharmonics). T tests compared miss, false alarm, sensitivity, and bias measures between masking and nonmasking conditions and between the two experiments. Results Miss rates were significantly higher and sensitivity was significantly lower for the masking condition than for the nonmasking one. There were no significant differences between the measures of the two experiments. Conclusion These results validate the predictions of the psychoacoustics of simultaneous masking for medical alarms and the masking detection capabilities of our method that relies on them. The results also show that masking of an alarm’s primary harmonic is sufficient to make an alarm sound indistinguishable. Application Findings have profound implications for medical alarm design, the international standard, and masking detection methods.

AbstractThe neural representation and perceptual salience of tonal signals presented in different noise maskers were investigated. The properties of the maskers and signals were varied such that they produced different amounts of either monaural masking release, binaural masking release, or a combination of both. The signals were then presented at different levels above their corresponding masked thresholds and auditory evoked potentials (AEPs) were measured. It was found that, independent of the masking condition, the amplitude of the P2 component of the AEP was similar for the same stimulus levels above masked threshold, suggesting that both monaural and binaural effects of masking release were represented at the level of P2 generation. The perceptual salience of the signal was evaluated at equal levels above masked threshold using a rating task. In contrast to the electrophysiological findings, the subjective ratings of the perceptual signal salience were less consistent with the signal level above masked threshold and varied strongly across listeners and masking conditions. Overall, the results from the present study suggest that the P2 amplitude of the AEP represents an objective indicator of the audibility of a target signal in the presence of complex acoustic maskers.

BackgroundUnder ‘cocktail party’ listening conditions, healthy listeners and listeners with schizophrenia can use temporally pre-presented auditory speech-priming (ASP) stimuli to improve target-speech recognition, even though listeners with schizophrenia are more vulnerable to informational speech masking.MethodUsing functional magnetic resonance imaging, this study searched for both brain substrates underlying the unmasking effect of ASP in 16 healthy controls and 22 patients with schizophrenia, and brain substrates underlying schizophrenia-related speech-recognition deficits under speech-masking conditions.ResultsIn both controls and patients, introducing the ASP condition (against the auditory non-speech-priming condition) not only activated the left superior temporal gyrus (STG) and left posterior middle temporal gyrus (pMTG), but also enhanced functional connectivity of the left STG/pMTG with the left caudate. It also enhanced functional connectivity of the left STG/pMTG with the left pars triangularis of the inferior frontal gyrus (TriIFG) in controls and that with the left Rolandic operculum in patients. The strength of functional connectivity between the left STG and left TriIFG was correlated with target-speech recognition under the speech-masking condition in both controls and patients, but reduced in patients.ConclusionsThe left STG/pMTG and their ASP-related functional connectivity with both the left caudate and some frontal regions (the left TriIFG in healthy listeners and the left Rolandic operculum in listeners with schizophrenia) are involved in the unmasking effect of ASP, possibly through facilitating the following processes: masker-signal inhibition, target-speech encoding, and speech production. The schizophrenia-related reduction of functional connectivity between the left STG and left TriIFG augments the vulnerability of speech recognition to speech masking.

Purpose The study investigates whether auditory information affects the nature of intrusion and reduction errors in reiterated speech. These errors are hypothesized to arise as a consequence of autonomous mechanisms to stabilize movement coordination. The specific question addressed is whether this process is affected by auditory information so that it will influence the occurrence of intrusions and reductions. Methods Fifteen speakers produced word pairs with alternating onset consonants and identical rhymes repetitively at a normal and fast speaking rate, in masked and unmasked speech. Movement ranges of the tongue tip, tongue dorsum, and lower lip during onset consonants were retrieved from kinematic data collected with electromagnetic articulography. Reductions and intrusions were defined as statistical outliers from movement range distributions of target and nontarget articulators, respectively. Results Regardless of masking condition, the number of intrusions and reductions increased during the course of a trial, suggesting movement stabilization. However, compared with unmasked speech, speakers made fewer intrusions in masked speech. The number of reductions was not significantly affected. Conclusions Masking of auditory information resulted in fewer intrusions, suggesting that speakers were able to pay closer attention to their articulatory movements. This highlights a possible stabilizing role for proprioceptive information in speech movement coordination.

People who stutter (PWS) presumably pay excessive attention to monitoring their speech, possibly exacerbating speech fluency. Using a reading comprehension task, we investigated whether or not PWS devote excessive attention to their speech. Methods Eleven PWS and 11 people who do not stutter (PNS) read passages in silent and oral reading conditions with and without noise masking, then answered comprehension questions. For PWS, auditory noise masking and silent reading would presumably divert their attention away from their speech. Results The comprehension performance of PWS was lower in the oral-no-masking condition than the oral-masking and silent-no-masking conditions. In contrast, there were no significant differences in the comprehension performance of PNS between the four conditions. Conclusions PWS had poor comprehension when listening to their speech, suggesting excessive attention to speech and limited attention to concurrent cognitive tasks.

Purpose This study was designed to test two hypotheses about apraxia of speech (AOS) derived from the Directions Into Velocities of Articulators (DIVA) model (Guenther et al., 2006): the feedforward system deficit hypothesis and the feedback system deficit hypothesis. Method The authors used noise masking to minimize auditory feedback during speech. Six speakers with AOS and aphasia, 4 with aphasia without AOS, and 2 groups of speakers without impairment (younger and older adults) participated. Acoustic measures of vowel contrast, variability, and duration were analyzed. Results Younger, but not older, speakers without impairment showed significantly reduced vowel contrast with noise masking. Relative to older controls, the AOS group showed longer vowel durations overall (regardless of masking condition) and a greater reduction in vowel contrast under masking conditions. There were no significant differences in variability. Three of the 6 speakers with AOS demonstrated the group pattern. Speakers with aphasia without AOS did not differ from controls in contrast, duration, or variability. Conclusion The greater reduction in vowel contrast with masking noise for the AOS group is consistent with the feedforward system deficit hypothesis but not with the feedback system deficit hypothesis; however, effects were small and not present in all individual speakers with AOS. Theoretical implications and alternative interpretations of these findings are discussed.