The Spatial Release of Cognitive Load in Cocktail Party Is Determined by the Relative Levels of the Talkers

French version of the coordinate response measure corpus and its validation on a speech-on-speech task

Since its creation, the coordinate response measure (CRM) corpus has been applied in hundreds of studies to explore the mechanisms of informational masking in multi-talker situations, but also in speech-in-noise or auditory attentional tasks. Here, we present its French version, with equivalent content to the original version in English. Furthermore, an evaluation of speech-on-speech intelligibility in French shows informational masking with similar result patterns to the original data in English. This validation of the French CRM corpus allows to propose the use of the CRM for intelligibility tests in French, and for comparisons with a foreign language under masking conditions.

Cocktail party training induces increased speech intelligibility and decreased cortical activity in bilateral inferior frontal gyri. A functional near-infrared study

The human brain networks responsible for selectively listening to a voice amid other talkers remain to be clarified. The present study aimed to investigate relationships between cortical activity and performance in a speech-in-speech task, before (Experiment I) and after training-induced improvements (Experiment II). In Experiment I, 74 participants performed a speech-in-speech task while their cortical activity was measured using a functional near infrared spectroscopy (fNIRS) device. One target talker and one masker talker were simultaneously presented at three different target-to-masker ratios (TMRs): adverse, intermediate and favorable. Behavioral results show that performance may increase monotonically with TMR in some participants and failed to decrease, or even improved, in the adverse-TMR condition for others. On the neural level, an extensive brain network including the frontal (left prefrontal cortex, right dorsolateral prefrontal cortex and bilateral inferior frontal gyri) and temporal (bilateral auditory cortex) regions was more solicited by the intermediate condition than the two others. Additionally, bilateral frontal gyri and left auditory cortex activities were found to be positively correlated with behavioral performance in the adverse-TMR condition. In Experiment II, 27 participants, whose performance was the poorest in the adverse-TMR condition of Experiment I, were trained to improve performance in that condition. Results show significant performance improvements along with decreased activity in bilateral inferior frontal gyri, the right dorsolateral prefrontal cortex, the left inferior parietal cortex and the right auditory cortex in the adverse-TMR condition after training. Arguably, lower neural activity reflects higher efficiency in processing masker inhibition after speech-in-speech training. As speech-in-noise tasks also imply frontal and temporal regions, we suggest that regardless of the type of masking (speech or noise) the complexity of the task will prompt the implication of a similar brain network. Furthermore, the initial significant cognitive recruitment will be reduced following a training leading to an economy of cognitive resources.

Discriminating between simultaneous audible alarms is easier with auditory icons

When more than one audible alarm is heard simultaneously, discrimination may be compromised. This experiment compares near-simultaneous clinical alarms in two styles, the first are the tonal 'melodies' from the 2012/2006 version of a global medical device safety standard (IEC 60601-1-8) and the second are the auditory-icon-style recommended in the 2020 version of the same standard. Sixty-six participants were required to identify the meaning and priority of four different clinical alarms for one of the two styles of alarm (between-subjects). Alarms sounded both singly and in pairs (within-subjects). Results showed that the auditory icon alarms outperformed the tonal alarms on all measures except one, both for overall accuracy (recognizing both priority and function) and for partial accuracy (recognizing priority or function but not both). The results add to the growing body of evidence supporting the use of auditory icon alarms in clinical environments.

Quantifying the Effect of Noise on Cognitive Processes: A Review of Psychophysiological Correlates of Workload

Noise is present in most work environments, including emissions from machines and devices, irrelevant speech from colleagues, and traffic noise. Although it is generally accepted that noise below the permissible exposure limits does not pose a considerable risk for auditory effects like hearing impairments. Yet, noise can have a direct adverse effect on cognitive performance (non-auditory effects like workload or stress). Under certain circumstances, the observable performance for a task carried out in silence compared to noisy surroundings may not differ. One possible explanation for this phenomenon needs further investigation: individuals may invest additional cognitive resources to overcome the distraction from irrelevant auditory stimulation. Recent developments in measurements of psychophysiological correlates and analysis methods of load-related parameters can shed light on this complex interaction. These objective measurements complement subjective self-report of perceived effort by quantifying unnoticed noise-related cognitive workload. In this review, literature databases were searched for peer-reviewed journal articles that deal with an at least partially irrelevant "auditory stimulation" during an ongoing "cognitive task" that is accompanied by "psychophysiological correlates" to quantify the "momentary workload." The spectrum of assessed types of "auditory stimulations" extended from speech stimuli (varying intelligibility), oddball sounds (repeating short tone sequences), and auditory stressors (white noise, task-irrelevant real-life sounds). The type of "auditory stimulation" was related (speech stimuli) or unrelated (oddball, auditory stressor) to the type of primary "cognitive task." The types of "cognitive tasks" include speech-related tasks, fundamental psychological assessment tasks, and real-world/simulated tasks. The "psychophysiological correlates" include pupillometry and eye-tracking, recordings of brain activity (hemodynamic, potentials), cardiovascular markers, skin conductance, endocrinological markers, and behavioral markers. The prevention of negative effects on health by unexpected stressful soundscapes during mental work starts with the continuous estimation of cognitive workload triggered by auditory noise. This review gives a comprehensive overview of methods that were tested for their sensitivity as markers of workload in various auditory settings during cognitive processing.

Functional Consequences of Poor Binaural Hearing in Development: Evidence From Children With Unilateral Hearing Loss and Children Receiving Bilateral Cochlear Implants

Poor binaural hearing in children was hypothesized to contribute to related cognitive and academic deficits. Children with unilateral hearing have normal hearing in one ear but no access to binaural cues. Their cognitive and academic deficits could be unique from children receiving bilateral cochlear implants (CIs) at young ages who have poor access to spectral cues and impaired binaural sensitivity. Both groups are at risk for vestibular/balance deficits which could further contribute to memory and learning challenges. Eighty-eight children (43 male:45 female, aged 9.89  ±  3.40 years), grouped by unilateral hearing loss (n = 20), bilateral CI (n = 32), and typically developing (n = 36), completed a battery of sensory, cognitive, and academic tests. Analyses revealed that children in both hearing loss groups had significantly poorer skills (accounting for age) on most tests than their normal hearing peers. Children with unilateral hearing loss had more asymmetric speech perception than children with bilateral CIs (p < .0001) but balance and language deficits (p = .0004, p < .0001, respectively) were similar in the two hearing loss groups (p > .05). Visuospatial memory deficits occurred in both hearing loss groups (p = .02) but more consistently across tests in children with unilateral hearing loss. Verbal memory was not significantly different than normal (p > .05). Principal component analyses revealed deficits in a main cluster of visuospatial memory, oral language, mathematics, and reading measures (explaining 46.8% data variability). The remaining components revealed clusters of self-reported hearing, balance and vestibular function, and speech perception deficits. The findings indicate significant developmental impacts of poor binaural hearing in children.

Speech perception in noise: Masking and unmasking

Speech perception is essential for daily communication. Background noise or concurrent talkers, on the other hand, can make it challenging for listeners to track the target speech (i.e., cocktail party problem). The present study reviews and compares existing findings on speech perception and unmasking in cocktail party listening environments in English and Mandarin Chinese. The review starts with an introduction section followed by related concepts of auditory masking. The next two sections review factors that release speech perception from masking in English and Mandarin Chinese, respectively. The last section presents an overall summary of the findings with comparisons between the two languages. Future research directions with respect to the difference in literature on the reviewed topic between the two languages are also discussed.

Energetic and Informational Components of Speech-on-Speech Masking in Binaural Speech Intelligibility and Perceived Listening Effort

Speech perception in complex sound fields can greatly benefit from different unmasking cues to segregate the target from interfering voices. This study investigated the role of three unmasking cues (spatial separation, gender differences, and masker time reversal) on speech intelligibility and perceived listening effort in normal-hearing listeners. Speech intelligibility and categorically scaled listening effort were measured for a female target talker masked by two competing talkers with no unmasking cues or one to three unmasking cues. In addition to natural stimuli, all measurements were also conducted with glimpsed speech-which was created by removing the time-frequency tiles of the speech mixture in which the maskers dominated the mixture-to estimate the relative amounts of informational and energetic masking as well as the effort associated with source segregation. The results showed that all unmasking cues as well as glimpsing improved intelligibility and reduced listening effort and that providing more than one cue was beneficial in overcoming informational masking. The reduction in listening effort due to glimpsing corresponded to increases in signal-to-noise ratio of 8 to 18 dB, indicating that a significant amount of listening effort was devoted to segregating the target from the maskers. Furthermore, the benefit in listening effort for all unmasking cues extended well into the range of positive signal-to-noise ratios at which speech intelligibility was at ceiling, suggesting that listening effort is a useful tool for evaluating speech-on-speech masking conditions at typical conversational levels.

Benefit of binaural listening as revealed by speech intelligibility and listening effort

In contrast to the well-known benefits for speech intelligibility, the advantage afforded by binaural stimulus presentation for reducing listening effort has not been thoroughly examined. This study investigated spatial release of listening effort and its relation to binaural speech intelligibility in listeners with normal hearing. Psychometric functions for speech intelligibility of a frontal target talker masked by a stationary speech-shaped noise were estimated for several different noise azimuths, different degrees of reverberation, and by maintaining only interaural level or time differences. For each of these conditions, listening effort was measured using a categorical scaling procedure. The results revealed that listening effort was significantly reduced when target and masker were spatially separated in anechoic conditions. This effect extended well into the range of signal-to-noise ratios (SNRs) in which speech intelligibility was at ceiling, and disappeared only at the highest SNRs. In reverberant conditions, spatial release from listening effort was observed for high, but not low, direct-to-reverberant ratios. The findings suggest that listening effort assessment can be a useful method for revealing the benefits of spatial separation of sources under realistic listening conditions comprising favorable SNRs and low reverberation, which typically are not apparent by other means.