Secondary Task Conditions Research Articles

Effector-specific improvements in action prediction in left-handed individuals after short-term physical practice

Research has established the influence of short-term physical practice for enhancing action prediction in right-handed (RH) individuals. In addition to benefits of physical practice for these later assessed perceptual-cognitive skills, effector-specific interference has been shown through action-incongruent secondary tasks (motor interference tasks). Here we investigated this experience-driven facilitation of action predictions and effector-specific interference in left-handed (LH) novices, before and after practicing a dart throwing task. Participants watched either RH (n = 19) or LH (n = 24) videos of temporally occluded dart throws, across a control condition and three secondary-task conditions: tone-monitoring, RH or LH force monitoring. These conditions were completed before and after physical practice throwing with the LH. Significantly greater improvement in prediction accuracy was shown post-practice for the LH- versus RH-video group. Consistent with previous work, effector-specific interference was shown, exclusive to the LH-video group. Only when doing the LH force monitoring task did the LH-video group show secondary task interference in prediction accuracy. These data support the idea that short-term physical practice resulted in the development of an effector-specific motor representation. The results are also consistent with other work in RH individuals (showing RH motor interference) and hence rule out the interpretation that these effector specific effects are due to the disruption of more generalized motor processes, thought to be lateralized to the left-hemisphere of the brain.

The Effects of Auditory Working Memory Task on Situation Awareness in Complex Dynamic Environments: An Eye-movement Study.

This study investigated the effect of auditory working memory task on situation awareness (SA) and eye-movement patterns in complex dynamic environments. Many human errors in aviation are caused by a lack of SA, and distraction from auditory secondary tasks is a serious threat to SA. However, it remains unclear how auditory working memory tasks affect SA and eye-movement patterns. Participants (n = 28) were randomly allocated to two groups and received different periods of visual search training (short versus long). They subsequently completed a situation awareness measurement task in three auditory secondary task conditions (without secondary task, auditory calculation task, and auditory 2-back task). Eye-movement data were collected during the situation awareness measurement task. The auditory 2-back task significantly reduced overall SA, Level 1 SA, dwell times, and total percentage of fixation time on task-related areas of interests in the SA measurement task. Overall SA and Level 3 SA were not reduced by the auditory 2-back task in individuals in the longer visual search training time condition. Auditory working memory load impairs SA in the perception and projection stage; however, greater experience can overcome impairment of SA in the projection stage. This study provided possible approaches to preventing loss of SA: (1) improving crew members' communication skills to ensure the accurate and clear transmission of information, reducing the difficulty of processing information, and (2) providing targeted cognitive training tailored to each pilot's level of experience.

Boring But Demanding: Using Secondary Tasks to Counter the Driver Vigilance Decrement for Partially Automated Driving.

We investigated secondary-task-based countermeasures to the vigilance decrement during a simulated partially automated driving (PAD) task, with the goal of understanding the underlying mechanism of the vigilance decrement and maintaining driver vigilance in PAD. Partial driving automation requires a human driver to monitor the roadway, but humans are notoriously bad at monitoring tasks over long periods of time, demonstrating the vigilance decrement in such tasks. The overload explanations of the vigilance decrement predict the decrement to be worse with added secondary tasks due to increased task demands and depleted attentional resources, whereas the underload explanations predict the vigilance decrement to be alleviated with secondary tasks due to increased task engagement. Participants watched a driving video simulating PAD and were required to identify hazardous vehicles throughout the 45-min drive. A total of 117 participants were assigned to three different vigilance-intervention conditions including a driving-related secondary task (DR) condition, a non-driving-related secondary task (NDR) condition, and a control condition with no secondary tasks. Overall, the vigilance decrement was shown over time, reflected in increased response times, reduced hazard detection rates, reduced response sensitivity, shifted response criterion, and subjective reports on task-induced stress. Compared to the DR and the control conditions, the NDR displayed a mitigated vigilance decrement. This study provided convergent evidence for both resource depletion and disengagement as sources of the vigilance decrement. The practical implication is that infrequent and intermittent breaks using a non-driving related task may help alleviate the vigilance decrement in PAD systems.

Distraction pattern classification and comparisons under different conditions in the full-touch HMI mode

Understanding driver distraction patterns is an important part of human–machine interaction (HMI), which is beneficial for the development of control strategies in human–machine co-driving systems. However, comparatively few studies have focused on driver distraction patterns. To address this issue, this study proposes a framework to characterize distraction patterns using glance behavior and manual behavior, and classifies distraction patterns into: aggressive, moderate, and conservative patterns based on real road experiments. Subsequently, differences in distraction behavior and effects on lateral vehicle control ability across distraction pattern groups, as well as distraction behavior differences exhibited by drivers in the same distraction pattern group under different conditions, are analyzed. Firstly, the results show that the aggressive distraction patterns have a smaller number of eyes-off-road (NoEOR) incidences but longer mean single eyes-off-road time (MSEORT), maximum single eyes-off-road time (MaxEORT) and a higher percentage of long eyes-off-road (PoLEOR) incidences than the other patterns. There are slight differences in the single eyes-off-road times (EORTs) between the conservative and moderate patterns and in the manual behavior for the aggressive and moderate distraction patterns. Secondly, the same distraction pattern exhibited by drivers for different road and secondary task conditions has differences in terms of the behavioral performance. Finally, there is few differences in the lateral motion of a vehicle with different distraction patterns. Surprisingly, the standard deviation of the steering wheel angle (SDSWA) is the smallest in the aggressive distraction pattern.

Perceptual Learning of Noise-Vocoded Speech Under Divided Attention.

Speech perception performance for degraded speech can improve with practice or exposure. Such perceptual learning is thought to be reliant on attention and theoretical accounts like the predictive coding framework suggest a key role for attention in supporting learning. However, it is unclear whether speech perceptual learning requires undivided attention. We evaluated the role of divided attention in speech perceptual learning in two online experiments (N = 336). Experiment 1 tested the reliance of perceptual learning on undivided attention. Participants completed a speech recognition task where they repeated forty noise-vocoded sentences in a between-group design. Participants performed the speech task alone or concurrently with a domain-general visual task (dual task) at one of three difficulty levels. We observed perceptual learning under divided attention for all four groups, moderated by dual-task difficulty. Listeners in easy and intermediate visual conditions improved as much as the single-task group. Those who completed the most challenging visual task showed faster learning and achieved similar ending performance compared to the single-task group. Experiment 2 tested whether learning relies on domain-specific or domain-general processes. Participants completed a single speech task or performed this task together with a dual task aiming to recruit domain-specific (lexical or phonological), or domain-general (visual) processes. All secondary task conditions produced patterns and amount of learning comparable to the single speech task. Our results demonstrate that the impact of divided attention on perceptual learning is not strictly dependent on domain-general or domain-specific processes and speech perceptual learning persists under divided attention.

Visuospatial working memory and obstacle crossing in young and older people

Obstacle crossing requires visuospatial working memory to guide the trailing leg trajectory when vision in unavailable. Visuospatial working memory, as assessed with neuropsychological tests, declines with age, however, this remains to be investigated functionally in obstacle crossing. There is also evidence that visuospatial encoding during a secondary task interferes with balance control during stepping and walking in older people. Here, we studied the interaction effects of age by delay (study 1) and age by secondary visuospatial task (study 2) conditions on obstacle clearance in a visuospatial working memory -guided obstacle crossing task. Healthy young adults aged 19 to 36 years (n = 20 in study 1 and n = 17 in study 2) and healthy older adults aged 66 to 83 years (n = 29 in study 1 and n = 21 in study 2) were instructed to step over an obstacle with their leading leg and straddle it for a delay period before completing the crossing with their trailing leg. In study 1, two obstacle height conditions (12 cm, 18 cm) and two delay durations (20 s, 60 s) were presented in random order. In study 2, participants were required to attend to either no secondary task (control), a visuospatial secondary (star movement) task, or a nonspatial secondary (arithmetic) task, while straddling the obstacle for a delay duration of 20 s, at obstacle heights of 12 cm and 18 cm, randomly presented. Trailing leg kinematics (mean and variability of maximum toe clearance over the obstacle) were determined via motion capture. There were no statistically significant age by delay or age by secondary task interactions. In study 1, toe clearance variability was significantly greater in young adults and increased with increasing delay duration in both groups. In study 2, compared with the control condition, toe clearance variability was significantly greater in the non-spatial secondary task condition but not in the visuospatial condition. Contrary to our hypotheses, these findings suggest that young and older adults alike can store an obstacle representation via visuospatial working memory for durations of at least 60 s and use this information to safely scale their trailing leg over an obstacle. However, the increase in trailing leg toe clearance variability with delay duration suggests that obstacle representation starts to deteriorate even within the first 20 s regardless of age. The finding that undertaking a concurrent arithmetic task impaired visuospatial working memory-guided obstacle clearance suggests a potential increased risk of tripping during obstacle crossing while dual-tasking in both young and older people.

Survival processing effect in memory under semantic divided attention.

Past research demonstrated enhanced memory for information encoded with relevance to a survival scenario compared to a control scenario, an effect referred to as the survival processing effect in memory. This effect has been explained by a proximate mechanism hypothesis (i.e., survival processing enables deep elaborative processing that promotes memory). In support of this hypothesis, past research found that, during encoding, the survival processing effect was largely intact under a perceptual or low-load secondary task condition but eliminated under a high-load secondary task condition. To test semantic encoding as a possible proximate mechanism, the current study assesses the impact of high-load and low-load divided attention tasks that require semantic processing of digits on the survival processing effect. Seventy-two young adults rated words for their relevance to two survival scenarios (i.e., grassland and mountain) and one non-survival control scenario (i.e., cruise), while completing a concurrent high-load or low-load semantic digit-monitoring task. No survival processing effect was found in either condition. The results suggest that semantic encoding probably serves as a proximate mechanism for the survival processing effect in memory. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Patterns in transitions of visual attention during baseline driving and during interaction with visual–manual and voice-based interfaces

Voice interfaces reduce visual demand compared with visual-manual interfaces, but the extent depends on design. This study compared visual demand during baseline driving with driving while using voice or manual inputs to place calls with Chevrolet MyLink, Volvo Sensus, or a smartphone. Mean glance duration and total eyes-off-road-time increased when using manual input compared with baseline driving; only eyes off road time increased with voice input. Confusion matrices developed with hidden Markov modelling characterise the similarity of glance sequences during baseline driving and while making phone calls. Glance sequences with the MyLink voice interface were misclassified as baseline driving more frequently than the other voice interfaces. Conversely, glance sequences with the Sensus and smartphone voice interfaces were more often misclassified as manual phone calling. Thus, the MyLink voice interface not only reduced the overall visual demand of placing calls, but produced glance patterns more similar to driving without another task. Practitioner Summary: The attention map and confusion matrix methodologies provide ways of characterising similarities and differences in glance behaviour across secondary task conditions, complementing traditional temporally based metrics (e.g. mean glance duration, long duration glances) while addressing some of the limitations of total-eyes-off-road-time (TEORT) for comparing secondary task behaviour to baseline driving.

Individual factors that influence task performance on a stepladder in older people

Ladder falls are a common cause of injury in the domestic setting, particularly among older adults. There is a need, therefore, to understand contributing factors of safe and effective ladder use in this group. This study investigated associations between individual human factors (vision, lower and upper limb sensation, upper limb control, strength, balance, cognitive function and psychological status) with task performance on a ladder (time to climb a household stepladder and change a light bulb) under single and secondary cognitive task conditions in 104 older adults. Measures of upper limb control, strength, balance, cognitive processing speed and psychological domains were significantly associated with ladder task completion time in the single task condition; with the addition of executive function and global cognition significantly associated with ladder task completion time in the dual task condition. Knee extension strength, upper limb bimanual coordination, cognitive processing speed and fear of falling were found to be robust predictors of ladder task completion times. These findings help identify individuals with greater ladder use ability and presumably lower fall risk. This work can guide ladder fall interventions, such as strength and balance training, ladder design and targeted safety instructions.

The evaluation of dual-task conditions on static postural control in the older adults: a systematic review and meta-analysis protocol

BackgroundIn postural stability evaluation, the dual-task concept is often adopted in order to create a more challenging situation. The dual-task consists of performing simultaneously two tasks, a primary static or dynamic motor task and an additional secondary cognitive task. Usually, a multitask condition leads to a reduction in the postural control performance, especially in older adults. Considering the wide spectrum of secondary task conditions existing in scientific literature, the present manuscript aims to write a peer-reviewed protocol that will be used in a systematic review and meta-analysis performed to identify the effects of different secondary tasks conditions in a population of older adults during static postural stability.MethodsThe study will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and for this manuscript, the PRISMA Protocol. PICOS criteria (population, intervention, comparison, outcomes, study design) will be also followed. The population examined will be healthy older adults over 60 years of age and all quantitative, qualitative, and mixed methods study design will be included. Original articles will be also included if written in English, while no restriction criteria will be applied to the country of origin. Instead, reviews, meta-analysis, abstracts, citations, scientific conferences, opinion pieces, books, books reviews, statements, letters, editorials, non-peer reviewed journals articles, and commentaries will be excluded. The research of literature will be performed using PubMed, Web of Science, and Scopus with words related to the topic. From each included study, information previously agreed will be extracted and inserted into a spreadsheet and a narrative synthesis containing summary tables and graphs will describe the articles taken in examination. Furthermore, a meta-analysis will be performed to establish which DT condition has a greater effect following the Hedges and Olkin approach, extension of Glass’ method and Cohen’s d will be calculated.DiscussionThe present manuscript wants to provide the protocol that will be used in the systematic review and meta-analysis with the intent to inform the researchers and professionals about the dual-task condition effects. Such will lead future investigations in using the most appropriate dual-task condition.Systematic review registrationPROSPERO CRD42018116597.

Modeling Driver Take-Over Reaction Time and Emergency Response Time using an Integrated Cognitive Architecture

Drivers’ take-over reaction time in partially automated vehicles is a fundamental component of automated vehicle design requirements, and take-over reaction time is affected by many factors such as distraction and drivers’ secondary tasks. This study built cognitive architecture models to simulate drivers’ take-over reaction time in different secondary task conditions. Models were built using the queueing network-adaptive control of thought rational (QN-ACTR) cognitive architecture. Drivers’ task-specific skills and knowledge were programmed as production rules. A driving simulator program was connected to the models to produce prediction of reaction time. Model results were compared with human results in both single-task and multi-task conditions. The models were built without adjusting any parameter to fit the human data. The models could produce simulation results of take-over reaction time similar to the human results in take-over conditions with visual or auditory concurrent tasks, as well as emergency response time in a manual driving condition. Overall, R square was 0.96, root mean square error (RMSE) was 0.5 s, and mean absolute percentage error (MAPE) was 9%. The models could produce simulation results of reaction time similar to the human results from different task conditions. The production rules are plausible representations of drivers’ strategies and skills. The models provide a useful tool for the evaluation of take-over alert design and the prediction of driver performance.

Effect of Distance Increase of External Focus of Attention on Tracking Task Learning Under Secondary Task Condition

ObjectivesNumerous studies have demonstrated that using an external focus of attention significantly enhances motor skill performance. However, limited research has been carried out on increasing the distance of an external focus of attention. Therefore, the main purpose of the present study is to determine whether learning tracking task is affected by different attentional focuses.MethodsA sample of 42 participants, after taking a pre-test, were divided randomly into three groups, including distal external group (DEG), proximal external group (PEG), and control group (COG). Proximal external focus group received instructions concerning near body movements; distal external focus group received instructions on the effect of movements in the environment, and control group did not receive any instructions. The participants practiced the tracking task in four blocks of four trials under their own condition of attention. Then, after 48 hours, they participated in a delay retention test under secondary task condition (auditory).ResultsThe results indicated that distal external focus group learned the tracking task better than proximal external focus group (P > 0.05), however, control group learned the tracking task less effectively than the other groups.ConclusionsThese findings suggest that increasing the distance of an external focus of attention improves tracking task learning, especially under secondary task, because secondary task condition enhances attention resources and shifts focus of attention to the external environment.

The Use of Vibrotactile Feedback During Dual-Task Standing Balance Conditions in People With Unilateral Vestibular Hypofunction

People with unilateral vestibular hypofunction (UVH) would have increased postural sway and slower reaction times while using vibrotactile feedback (VTF) during dual-task conditions compared with age-matched controls. VTF has been shown to improve real-time balance performance in persons with vestibular disorders. Future use of this technology outside of the laboratory environment as a real-time balance aid requires that using VTF during dual-tasking scenarios be studied. Nine people with UVH and nine age-matched controls participated in a study focused on assessing the effects of a secondary cognitive task and sensory integration conditions on the root-mean-square of center of pressure (RMS COP) while using VTF. Reaction times from the secondary cognitive task were used to assess the effects of VTF, and sensory integration conditions on the attention required to perform the task. The results showed that there was no group difference between individuals with UVH and age-matched controls on balance performance while using VTF during dual-task conditions. Using VTF significantly degraded the reaction time performance in both groups, and the participants with UVH had slower reaction times compared with controls. People with UVH showed the ability to use VTF to control balance during dual-task conditions, but more attentional resources were needed to perform the secondary cognitive tasks while using VTF.

Effect of Distance Increase of External Focus of Attention on Tracking Task Learning Under Secondary Task Condition

Objectives: Numerous studies have demonstrated that using an external focus of attention significantly enhances motor skill performance. However, limited research has been carried out on increasing the distance of an external focus of attention. Therefore, the main purpose of the present study is to determine whether learning tracking task is affected by different attentional focuses. Methods: A sample of 42 participants, after taking a pre-test, were divided randomly into three groups, including distal external group (DEG), proximal external group (PEG), and control group (COG). Proximal external focus group received instructions concerning near body movements; distal external focus group received instructions on the effect of movements in the environment, and control group did not receive any instructions. The participants practiced the tracking task in four blocks of four trials under their own condition of attention. Then, after 48 hours, they participated in a delay retention test under secondary task condition (auditory). Results: The results indicated that distal external focus group learned the tracking task better than proximal external focus group (P > 0.05), however, control group learned the tracking task less effectively than the other groups. Conclusions: These findings suggest that increasing the distance of an external focus of attention improves tracking task learning, especially under secondary task, because secondary task condition enhances attention resources and shifts focus of attention to the external environment.

STOPPING OF TASK-SWITCHING IN PATIENTS WITH OBSESSIVE-COMPULSIVE DISORDER (OCD)

Introduction Inhibition and attentional switching both play central role in theorizing about cognitive impairments in OCD. The aim of the present study was to investigate inhibition and shifting abilities within a single experimental task. A new ‘inhibition-of-switching’ task was designed with minimal memory load suitable for patients under medication. The goal of this task was to simulate a real life situation, where following consecutive successful execution of a simple algorithm, participants need to change to another algorithm in order to respond adequately to new stimuli configurations. However, a further difficulty could be if the response must be inhibited for the same stimuli configuration on the next encounter with it. We hypothesized that OCD patients along with slower switching performance, will have difficulties in inhibiting previously adequate switching responses, making more false alarm type errors. Methods Twenty-six properly diagnosed OCD patients and twenty-six healthy adults matched in age and education undertook an inhibition-of-switching task in two conditions. 1) Single task condition: two digits appeared on a computer screen, and subjects had to press the right or the left-arrow key under the bigger number, and 2) Secondary task conditions: here the participants’ primary task was identical with the single task condition, whereas their secondary task was to press the up-arrow key if the two presented digits were identical. Furthermore, participants had an inhibition rule for the secondary task, they needed to respond only on every second time encountering with identical digits. To assess the memory performance, subjects completed the Digit Span Forward and Backward Tasks and the Prospective Retrospective Memory Questionnaire (PRMQ). Statistical analyses were performed using mixed analysis of variance and two-tailed t-tests. Results We found that secondary task instruction produced significantly more cost in terms of reaction time during the execution of primary task for OCD patients compared to a healthy control group. However, there was no difference in switching cost in terms of reaction time between the two groups, suggesting that OCD patients had no difficulty with changing one stimuli-based response algorithm to another one. Additionally, OCD patients made significantly more false alarm type errors in the secondary task, and there was a significant positive correlation between the number of false alarm type errors and the prospective memory subscale scores of the PRMQ in the OCD group. Conclusion These results suggest that OCD patients experience difficulties during inhibition-of-switching task, and here we propose that these difficulties originate from over-monitoring of secondary task stimuli during execution of primary task and disinhibition of activated out-of-date responses. We argue that over-activated intentions go together with a response inhibition deficit, and these two factors together contribute to the higher rate of perseverative errors.

Task Integration Facilitates Multitasking.

The aim of this study was to investigate multi-task integration in a continuous tracking task. We were particularly interested in how manipulating task structure in a dual-task situation affects learning of a constant segment embedded in a pursuit-tracking task. Importantly, we examined if dual-task effects could be attributed to task integration by varying the structural similarity and difficulty of the primary and secondary tasks. In Experiment 1 participants performed a pursuit tracking task while counting high-pitched tones and ignoring low-pitched tones. The tones were either presented randomly or structurally 250 ms before each tracking turn. Experiment 2 increased the motor load of the secondary tasks by asking participants to tap their feet to the tones. Experiment 3 further increased motor load of the primary task by increasing its speed and having participants tracking with their non-dominant hand. The results show that dual-task interference can be moderated by secondary task conditions that match the structure of the primary task. Therefore our results support proposals of task integration in continuous tracking paradigms. We conclude that multi-tasking is not always detrimental for motor learning but can be facilitated through task-integration.

Driving and Multitasking: The Good, the Bad, and the Dangerous.

Previous research has shown that multitasking can have a positive or a negative influence on driving performance. The aim of this study was to determine how the interaction between driving circumstances and cognitive requirements of secondary tasks affect a driver's ability to control a car. We created a driving simulator paradigm where participants had to perform one of two scenarios: one with no traffic in the driver's lane, and one with substantial traffic in both lanes, some of which had to be overtaken. Four different secondary task conditions were combined with these driving scenarios. In both driving scenarios, using a tablet resulted in the worst, most dangerous, performance, while passively listening to the radio or answering questions for a radio quiz led to the best driving performance. Interestingly, driving as a single task did not produce better performance than driving in combination with one of the radio tasks, and even tended to be slightly worse. These results suggest that drivers switch to internally focused secondary tasks when nothing else is available during monotonous or repetitive driving environments. This mind wandering potentially has a stronger interference effect with driving than non-visual secondary tasks.

The useful field of view assessment predicts simulated commercial motor vehicle driving safety

ABSTRACTObjective: The Useful Field of View (UFOV) assessment, a measure of visual speed of processing, has been shown to be a predictive measure of motor vehicle collision (MVC) involvement in an older adult population, but it remains unknown whether UFOV predicts commercial motor vehicle (CMV) driving safety during secondary task engagement. The purpose of this study is to determine whether the UFOV assessment predicts simulated MVCs in long-haul CMV drivers.Method: Fifty licensed CMV drivers (Mage = 39.80, SD = 8.38, 98% male, 56% Caucasian) were administered the 3-subtest version of the UFOV assessment, where lower scores measured in milliseconds indicated better performance. CMV drivers completed 4 simulated drives, each spanning approximately a 22.50-mile distance. Four secondary tasks were presented to participants in a counterbalanced order during the drives: (a) no secondary task, (b) cell phone conversation, (c) text messaging interaction, and (d) e-mailing interaction with an on-board dispatch device.Results: The selective attention subtest significantly predicted simulated MVCs regardless of secondary task. Each 20 ms slower on subtest 3 was associated with a 25% increase in the risk of an MVC in the simulated drive. The e-mail interaction secondary task significantly predicted simulated MVCs with a 4.14 times greater risk of an MVC compared to the no secondary task condition. Subtest 3, a measure of visual speed of processing, significantly predicted MVCs in the email interaction task. Each 20 ms slower on subtest 3 was associated with a 25% increase in the risk of an MVC during the email interaction task.Conclusions: The UFOV subtest 3 may be a promising measure to identify CMV drivers who may be at risk for MVCs or in need of cognitive training aimed at improving speed of processing. Subtest 3 may also identify CMV drivers who are particularly at risk when engaged in secondary tasks while driving.

ID 428 – Effect of cognitive task on the maintaining of postural stability in patients with type 2 diabetes mellitus and peripheral neuropathy

Objective To investigate the effect of cognitive task on the postural stability of patients with type 2 diabetes mellitus and peripheral neuropathy (DPN). Methods Thirty DPN patients (aged between 55 and 65 years) and 20 matched controls took part in the investigations.The postural stability was evaluated by static posturography, during upright quiet stance with eyes closed on stable or on foam support without a secondary cognitive task condition and combined with counting backwards in steps of seven aloud or silently. Results Stabilizing effect of cognitive task on the postural stability during stance on stable support was observed, while an impaired postural stability during counting aloud than counting silently on foam support were observed. Conclusions Results indicate that control of body sway and cognitive functioning are not independent systems and a significant effect of dual cognitive task on the postural stability of patients with DPN are established and related to the difficulty of cognitive task. Count aloud focused attention on preventing errors and together with changing the proprioceptive information during stance on foam support lead to depletion the possibilities to keeping the equilibrium.

How do drivers behave during indecision zone maneuvers?

Yellow signal indications at intersections are well-known to be a contributor to traffic crashes. This study examined drivers’ behavior during yellow signal indication (i.e., indecision zone) maneuvers. Data from a driving simulator study was used, which included drivers’ performance data when they encountered a yellow signal indication at intersections under different secondary-task conditions. This study calculated drivers’ likelihood to go through a yellow signal indication and examined factors that are related to drivers’ decision making on intersection traversing. The results showed that drivers’ decision on stopping or not at a yellow signal indication was associated with different variables including age, distraction, pedal conditions, and time to stop line. Distracted drivers’ insensitive behavior was also captured from the significant interaction effect between time to stop line and distraction conditions, which implied that intersection related crash risk may increase when drivers were distracted.