The task of interpreting requires managing multiple tasks simultaneously, but how this practice of multitasking may contribute to the nonverbal domain of executive functioning has been explored in only a few studies, and little is known about the Event-related Potentials (ERP) neural correlates of this potential advantage. To fill this gap, we conducted an ERP study asking consecutive interpreting students and bilingual controls to perform a psychological refractory period (PRP) dual-task, comprising an auditory (Task 1) and a visual (Task 2) discrimination task. They were performed separately or together, the performance differences between which, i.e., dual-task costs, served as indices of coordination. Smaller costs for interpreting students in either or both tasks are considered an interpreter advantage in coordination, and those confined to Task 2 further indicate an advantage in bottleneck switching. The latter was exactly observed in stimulus-locked lateralized readiness potential (LRP) onset latency, suggesting such an advantage was probably due to efficient switching from the response selection of one task to that of the other at the bottleneck stage of dual-task processing. Smaller dual-task costs of stimulus-locked LRP onset latency thus constitute the neural correlates of the interpreter advantage in coordination.

Despite extensive discussions on interpreter advantages in nonverbal abilities/skills, the advantage in coordination remains underexplored, with little evidence from interpreting students across different training stages. To fill the gap, the present study conducted two experiments with the Psychological Refractory Period dual-task consisting of two discrimination tasks presented either alone or together. Smaller dual-task costs in Task 1 and/or Task 2 are considered indices for better coordination (with smaller costs restricted to Task 2 further suggesting better bottleneck coordination). Experiment 1, focusing on the intermediate training stage, revealed a bottleneck coordination advantage for interpreting students over controls, which differs from the task instantiation and/or bottleneck access advantage found for professional interpreters in Strobach et al. (2015). Experiment 2, focusing on the beginning stage, revealed no group differences between controls and interpreting students with less/more training (Experiment 2a/2b respectively), suggesting no evidence for an interpreter advantage in coordination. Developmental changes are discussed.

Introduction: In the clinical settings, emergency physicians are faced with situations that require multitasking such as interacting with other team members, documentation and utilization of computer resources whiles ensuring competency on a particular trauma skill. The purpose of this study was to assess the effect of multitasking on cognitive load when learning a common trauma skill. Methods: Sixteen students who had no previous experience with the one-handed square knot were randomly assigned to one of the two groups: practice and non-practice groups. A pre-recorded instructional video of a one-hand knot tying was presented to all participants. Next, the practice group completed a single session of 10 trials of the one-hand knot tying using a benchtop simulator, while the non-practice group did not. All returned a week later for a transfer task on a different simulator. On trials 1, 4, 7,10 and during the transfer performance the participants performed under dual task conditions, where they were asked to focus on the knot-tying task, but also to react as fast as possible to the illumination of an incandescent light bulb by pressing a foot pedal. Subjective ratings of mental effort, and reaction time to the visual stimulus were used as indices of cognitive load. Results: A repeated measure ANOVA showed a significant effect of dual task on subjective measure of mental effort (F(4, 28) = 10.35, p = .001, ω = .60) and reaction time (F(4, 28) = 7.93, p = .001, ω = .53), with plots indicating cognitive load plateaued by the 7th trial. Conclusion: These findings highlights the number of trials necessary to attain a level of proficiency in a basic trauma skill such as the one-hand knot tying, ease the level of cognitive load and possibly enhance transfer to more challenging tasks.

The purpose of this study was to investigate the effects of pediatric traumatic brain injury (TBI) on verbal and visual-spatial working memory (WM). WM tasks examined memory span through recall of the last item of a series of stimuli. Additionally, both verbal and visual-spatial tests had a dual-task condition assessing the effect of increasing demands on the central executive (CE). Inhibitory control processes in verbal WM were examined through intrusion errors. The TBI group (n = 73) performed more poorly on verbal and visual-spatial WM tasks than orthopedic-injured children (n = 30) and non-injured children (n = 40). All groups performed more poorly on the dual-task conditions, reflecting an effect of increasing CE load. This effect was not greater for the TBI group. There were no group differences in intrusion errors on the verbal WM task, suggesting that problems in WM experienced by children with TBI were not primarily due to difficulties in inhibitory control. Finally, injury-related characteristics, namely days to follow commands, accounted for significant variance in WM performance, after controlling for relevant demographic variables. Findings suggest that WM impairments in TBI are general rather than modality-specific and that severity indices measured over time are better predictors of WM performance than those taken at a single time point. (JINS, 2012, 18, 29–38)

This research compares the performance of a sample of non-litigating participants with severe brain injury on both the WMT and TOMM under conditions of (1) full effort, (2) distraction, or (3) simulated malingering. The study included 60 participants with a severe brain injury and used restricted randomization to assign participants to the groups. Following Craik (1982) an auditory distraction task was used during the learning phase of each test in the distraction group, while a scenario adapted from Tombaugh (1997) was used to encourage simulation of memory impairment in the simulated malingering group. The results of this study clearly showed that while both tests demonstrated excellent sensitivity, the false positive rates for the WMT were significantly greater than those for the TOMM. It was concluded that the so-called “effort” components of the WMT required more cognitive capacity than was previously believed. (JINS, 2008, 14, 1074–1080.)

The present study examined dual-task performance in elders with cognitive impairments and normal controls. The participants (N = 60; M age = 84.6) were recruited from residential facilities and the community. They were assigned to one of three groups: (1) cognitive impairment; (2) residential facility control; (3) community control. Two different dual-task conditions were comprised of simple tests that are presumably processed via separate perceptual modalities: 1 visual–manual and 1 auditory–verbal. The first condition consisted of a visual cancellation test and an auditory digit span. The second condition was comprised of an alternate form of the visual cancellation test and letter fluency. MANOVA examined the effect of cognitive status (3-level independent variable) on 3 indices of dual-task performance (letter fluency, digit span, visual cancellation). Analyses controlled for age, education and performance on each test when performed alone. The results revealed that the cognitive impairment group incurred significantly greater dual-task costs compared to both control groups. Furthermore, as was evident from discriminant function analyses, the dual-task measures were very accurate and better than the traditional neuropsychological measures at discriminating elders with cognitive impairments from normal controls. (JINS, 2004, 10, 230–238.)

The roles of N100 and the early and late negative difference (Nd) waveforms in selective attention were investigated with primary simulated flying and secondary dichotic listening tasks. Twenty highly trained participants performed the two tasks together, either while detecting secondary task deviant tones in one ear and ignoring tones in the other ear (dual condition) or while ignoring the tones in both ears (ignore condition). The amplitude of the N100–P200 complex in both the dual-task and ignore conditions was reduced equally in the attended and unattended ear by the introduction of the primary task. In the dual-task condition, the amplitude of the late Nd but not the early Nd was reduced by a combination of the introduction of the primary task and an increase in its difficulty. P300 showed the same amplitude pattern as the late Nd. We propose that the reduction in N100–P200 amplitude reflects an automatic gating mechanism. The dissociation of the early and late Nd suggests that the latter is not modality specific. The question is raised whether the late Nd is more closely associated with P300 than with the early Nd.

The n-back task was hypothesized to be a dual task, permitting the imposition of parametrically increasing attentional and working memory demands, while keeping constant the demands of an embedded matching subtask. Visual targets were presented for 200 ms every 2.2 s at pseudorandomly varying positions on a computer screen. Participants were required to remember the most recent 0, 1, 2, or 3 positions and responded with a choice button push to whether the current target position matched the position presented n items previously. P300 peak latency was constant across n-back tasks, reflecting constant perceptual and cognitive demands of the matching subtask. P300 peak amplitude decreased with increasing memory load, reflecting reallocation of attention and processing capacity away from the matching subtask to working memory activity. These data support a dual-task nature of the n-back, which should be considered when employing this paradigm.

Prominent apathy and/or irritability are frequently observed among individuals infected with the human immunodeficiency virus (HIV). Although these symptoms often occur as part of a mood disorder, compelling evidence suggests that they may occur independently of depression in neurologic disease/disorder. The current study examined the prevalence of both apathy and irritability among a sample of HIV-infected individuals and explored the degree to which these neuropsychiatric (NP) phenomena were associated with performance on neurocognitive measures thought to be sensitive to the potential CNS effects of HIV-1. Clinician-administered rating scales assessing apathy and irritability were administered to 65 HIV-seropositive (HIV+) and 21 HIV-seronegative (HIV−) participants who also completed a dual-task reaction time paradigm and the Stroop task. NP disturbance was significantly more prevalent among HIV+ participants compared with HIV− controls and was associated with specific neurocognitive deficits suggestive of executive dysfunction. Relative to both HIV− controls and to neuropsychiatrically intact HIV+ participants, those HIV+ individuals with evidence of prominent apathy and/or irritability showed deficits in dual-task, but not single-task, performance and on the interference condition of the Stroop. Unexpectedly, NP disturbance did not show a robust relationship with HIV disease stage. These results suggest that the presence of prominent apathy and/or irritability among HIV+ individuals may signify greater HIV-associated CNS involvement. In HIV/AIDS, the disruption of frontal–subcortical circuits may be a common mechanism causing both executive dysfunction and NP disturbance. (JINS, 2000, 6, 336–347.)