Listening Effort in Cochlear Implant Users: The Effect of Speech Intelligibility, Noise Reduction Processing, and Working Memory Capacity on the Pupil Dilation Response

Purpose: This study aimed to evaluate the effect of speech recognition performance, working memory capacity (WMC), and a noise reduction algorithm (NRA) on listening effort as measured with pupillometry in cochlear implant (CI) users while listening to speech in noise. Method: Speech recognition and pupil responses (peak dilation, peak latency, and release of dilation) were measured during a speech recognition task at three speech-to-noise ratios (SNRs) with an NRA in both on and off conditions. WMC was measured with a reading span task. Twenty experienced CI users participated in this study. Results: With increasing SNR and speech recognition performance, (a) the peak pupil dilation decreased by only a small amount, (b) the peak latency decreased, and (c) the release of dilation after the sentences increased. The NRA had no effect on speech recognition in noise or on the peak or latency values of the pupil response but caused less release of dilation after the end of the sentences. A lower reading span score was associated with higher peak pupil dilation but was not associated with peak latency, release of dilation, or speech recognition in noise. Conclusions: In CI users, speech perception is effortful, even at higher speech recognition scores and high SNRs, indicating that CI users are in a chronic state of increased effort in communication situations. The application of a clinically used NRA did not improve speech perception, nor did it reduce listening effort. Participants with a relatively low WMC exerted relatively more listening effort but did not have better speech reception thresholds in noise.

Coping with syntactic complexity in English–Chinese sight translation by translation and interpreting students.

This study approaches syntactic complexity from a relative point of view and examines how translation and interpreting students cope with relative clauses and passive constructions, two exemplifications of syntactic complexity in English–Chinese sight translation. A group of students (N = 23) took part in the study. The study consisted of three parts: an English reading span test, a sight translation task, and a baseline reading task. During the sight translation task, the participants sight translated English sentences with different degrees of structural asymmetry into Chinese in the single sentence context and the discourse context. During the baseline reading task, they silently read the English sentences and answered the comprehension questions. The participants' eye movements in the sight translation and baseline reading tasks were recorded as indicators of cognitive load. Three major findings were generated: (1) Syntactic complexity resulted in a significant increase in cognitive load during the sight translation task. The syntactic aspects of the target language were activated during the initial stage of comprehension, which favoured the parallel view of translation. (2) Although sight translation became more time efficient due to wider contexts, a larger amount of contextual information did not make word-based processing less effortful, as indicated by more fixations and the longer regression path duration in the discourse context. (3) No correlations were found between reading span and cognitive load in addressing syntactical complexity.

The role of working memory capacityin interpreting performance

This study aims to examine the relationship between working memory (WM) capacity and the performance of student interpreters defined as the quality of their interpreting output. To measure WM capacity, we administered Korean and English reading span tasks, and an operation span task. The WM scores were analysed for correlation with simultaneous interpreting (SI) and consecutive interpreting (CI) scores. The results were mixed: (1) the CI score showed no correlation with any of the WM span tasks and (2) the SI score correlated with only one WM span task, the operation span task. Given that the participants received shorter training in SI than in CI, we can tentatively conclude that interpreting performance is influenced more by WM capacity when the interpreter performs a less familiar type of interpreting. Further research is needed to find out why the reading span tasks and the operation span task showed different relationships with SI.

Individual Differences in Disqualifying Monitoring Underlie False Memories Across Different Paradigms

The current study leveraged experimental and individual differences methodology to examine whether false memories across differing tasks arise from a common cause. Participants completed multiple false memory (DRM and memory conjunction), working memory (operation and reading span), and source monitoring (verbal and picture) tasks. Memory discriminability in the DRM and memory conjunction tasks loaded onto a single (general) factor and were unaffected by warnings provided at encoding. Consistent with previous research, source monitoring ability fully mediated the relation between working memory and false memories. Moreover, individuals with higher source monitoring ability were better able to recall contextual information from encoding to correctly reject lures. These results suggest that there are stable individual differences in false remembering across tasks. The commonality across tasks may be due, at least in part, to the ability to effectively use disqualifying monitoring processes.

Working memory and lexical ambiguity resolution in Cantonese Chinese

The present study examined how working memory functions in the underlying mechanism of the lexical disambiguation process (in activation approach or in inhibition approach). We recruited sixty native Cantonese listeners to participate in two experimental tasks: (a) a Cantonese-version reading span task to measure their working memory (WM) capacity and (b) a standard cross-modal priming task to measure the lexical disambiguation time. The results revealed that (1) the underlying mechanism of the disambiguation process seemed favorable for an inhibition approach and (2) the frequency of the individual meanings of the ambiguous words and the numbers of their meanings might interact with the WM capacity during lexical access, particularly for the low-WM span group.

White Matter Integrity Correlates of the Reading Span

Although working memory (WM) is crucial for intellectual abilities, not much is known about its brain underpinnings, especially the structural connectivity. We used diffusion tensor imaging (DTI) to look across the whole brain for the white matter integrity correlates of the individual differences in the reading span (verbal WM capacity during reading) in healthy adults. Right-handed healthy native Russian speakers (N = 67) underwent DTI on a 3T Philips Ingenia scanner. Verbal WM was assessed with the Daneman-Carpenter reading span test (Russian version). Fractional anisotropy maps from each participant were entered into the group tract-based spatial statistics analysis with the reading span as a covariate; the results were TFCE-corrected. After taking into account effects of age, sex, education and handedness, reading span positively correlated with the white matter integrity in multiple sites: the body, the genu and the splenium of corpus callosum; bilateral corona radiata (anterior, posterior, and superior); bilateral superior longitudinal fasciculus; several tracts in the right hemisphere only, including the internal and external capsule; bilateral superior parietal and frontal white matter. Although the left hemisphere is central for verbal processing, we revealed the important role of the right hemisphere white matter for the verbal WM capacity. Our finding indicates that larger verbal working memory span may originate from additional processing resources of the right hemisphere.

White Matter Integrity in the Right Hemisphere Correlates with the Reading Span

Although working memory (WM) is crucial for intellectual abilities, not much is known about its brain underpinnings, especially the structural connectivity. We used diffusion tensor imaging (DTI) to look across the whole brain for the white matter integrity correlates of the individual differences in the reading span (verbal WM capacity during reading) in healthy adults. Right-handed healthy native Russian speakers (N = 47) underwent DTI on a 3T Philips Ingenia scanner. Verbal WM was assessed with the Daneman-Carpenter reading span test (Russian version). Fractional anisotropy maps from each participant were entered into the group tract-based spatial statistics analysis with the reading span as a covariate; the results were TFCE-corrected. Reading span positively correlated with the white matter integrity in several sites of the right hemisphere: the body and the splenium of corpus callosum; the posterior limb of internal capsule; posterior corona radiata; and superior parietal white matter. Although the left hemisphere is central for verbal processing, we revealed the important role of the right hemisphere white matter for the verbal WM capacity. Our finding indicates that larger verbal working memory span may originate from additional processing resources of the right hemisphere.