Affect Response Times Research Articles

Impact of traffic on the spatiotemporal variations of spatial accessibility of emergency medical services in inner-city Shanghai

Variability in spatial accessibility of emergency medical services has become a major concern in evaluating the quality of emergency medical services in China. Unlike some other public services, response time is critical in the provision of emergency medical services. Traffic congestion may significantly affect response time, especially in large cities. This study uses a transportation simulation model to estimate the travel time under free-flow and congested road conditions and measure the corresponding spatial accessibility of emergency medical services for various hours of a day in inner-city Shanghai. When traffic congestion is considered, the overall spatial accessibility is significantly reduced, and the effect is further magnified in certain congested areas. The results help policy makers in planning the emergency medical services resource that is sensitive to the spatiotemporal variation of its accessibility.

Aligning ambulance dispatch priority to patient acuity: A methodology

In Victoria, Australia, Emergency Medical Service (EMS) demand has increased almost 5% per annum over the past 5 years. This may adversely affect response times to time-critical patients. Additionally, >55% of cases have received Code 1 (lights/sirens) responses. Primary telephone triage occurs using the Medical Priority Dispatch System (MPDS); however, MPDS is reported to be highly sensitive, with common over-triage. The present study describes the methodology applied to better align the response allocated to MPDS determinant codes with patient acuity. Data between October 2013 and August 2014 were extracted from the Ambulance Victoria data warehouse. The decision to allocate MPDS determinant codes to a lower response priority and/or secondary triage was based on epidemiological profiling and, in some cases, expert panel review. The review identified 105 MPDS codes receiving a Code 1 response as suitable for a Code 2 (urgent) response, and 221 Code 1 or 2 codes as suitable for secondary triage. Data analysis estimated a reduction in Code 1 responses by 28%, and an increase in the secondary triage caseload by 120%. Modelling also predicted a 2.6 percentage point improvement in the proportion of Code 1 cases attended within 15 min. Analysis of a large EMS dataset supported changes to the EMS response priority for a number of MPDS determinant codes. Such changes should improve the alignment between EMS response and patient acuity, and improve response times to time-critical patients. Other EMS with electronic data could consider testing this methodology.

Correction: Transcranial direct current stimulation (tDCS) facilitates overall visual search response times but does not interact with visual search task factors.

[This corrects the article DOI: 10.1371/journal.pone.0194640.].

Cardiac Arrhythmia Simulations for Comparing Remote Telemetry Monitoring Systems

To increase the potential for timely detection of cardiac events, hospitalized patients who are at risk for critical arrhythmias are put on telemetry to continuously monitor their heart rhythm. However, telemetry monitoring systems vary widely between hospitals, there are few guidelines for decisions regarding optimal practices, and few studies have compared the efficiency of different monitoring systems. Our goal was to determine the impact of different monitoring systems on the time to detect and respond to critical cardiac events. To this end, we compared the process of communicating a critical alarm to the patient’s nurse in 2 hospitals with different monitoring systems, to determine the most efficient system. We conducted in situ unannounced simulations of cardiac arrest in the 2 hospitals to measure the response times of monitor watchers and patient care unit staff. As expected, we found response times to be shorter in the hospital that had a more direct method for monitor watchers to contact patients’ nurses. In addition to the method for communicating arrhythmias, there are many other differences between the monitoring systems in the 2 hospitals that could also have affected response times. We are using discrete event simulation to develop computer simulation models of the hospitals that will allow us to take multiple factors into account when comparing them.

Transcranial direct current stimulation (tDCS) facilitates overall visual search response times but does not interact with visual search task factors.

Whether transcranial direct current stimulation (tDCS) affects mental functions, and how any such effects arise from its neural effects, continue to be debated. We investigated whether tDCS applied over the visual cortex (Oz) with a vertex (Cz) reference might affect response times (RTs) in a visual search task. We also examined whether any significant tDCS effects would interact with task factors (target presence, discrimination difficulty, and stimulus brightness) that are known to selectively influence one or the other of the two information processing stages posited by current models of visual search. Based on additive factor logic, we expected that the pattern of interactions involving a significant tDCS effect could help us colocalize the tDCS effect to one (or both) of the processing stages. In Experiment 1 (n = 12), anodal tDCS improved RTs significantly; cathodal tDCS produced a nonsignificant trend toward improvement. However, there were no interactions between the anodal tDCS effect and target presence or discrimination difficulty. In Experiment 2 (n = 18), we manipulated stimulus brightness along with target presence and discrimination difficulty. Anodal and cathodal tDCS both produced significant improvements in RTs. Again, the tDCS effects did not interact with any of the task factors. In Experiment 3 (n = 16), electrodes were placed at Cz and on the upper arm, to test for a possible effect of incidental stimulation of the motor regions under Cz. No effect of tDCS on RTs was found. These findings strengthen the case for tDCS having real effects on cerebral information processing. However, these effects did not clearly arise from either of the two processing stages of the visual search process. We suggest that this is because tDCS has a DIFFUSE, pervasive action across the task-relevant neuroanatomical region(s), not a discrete effect in terms of information processing stages.

Prioritization of arbitrary faces associated to self: An EEG study.

Behavioral and neuroimaging studies have demonstrated that people process preferentially self-related information such as an image of their own face. Furthermore, people rapidly incorporate stimuli into their self-representation even if these stimuli do not have an intrinsic relation to self. In the present study, we investigated the time course of the processes involved in preferential processing of self-related information. In two EEG experiments three unfamiliar faces were identified with verbal labels as either the participant, a friend, or a stranger. Afterwards, participants judged whether two stimuli presented in succession (ISI = 1500ms) matched. In experiment 1, faces were followed by verbal labels and in experiment 2, labels were followed by faces. Both experiments showed the same pattern of behavioral and electrophysiological results. If the first stimulus (face or label) was associated with self, reaction times were faster and the late frontal positivity following the first stimulus was more pronounced. The self-association of the second stimulus (label or face) did not affect response times. However, the central-parietal P3 following presentation of the second stimulus was more pronounced when the second stimulus was preceded by self-related first stimulus. These results indicate that even unfamiliar faces that are associated to self can activate a self-representation. Once the self-representation has been activated the processing of ensuing stimuli is facilitated, irrespective of whether they are associated with the self.

Evaluating public ambulance service levels by applying a GIS based accessibility analysis approach

Ambulance vehicles are required to respond rapidly to medical emergencies. A number of factors may affect response times, most importantly the location of emergency services stations, the number of ambulance vehicles available at each station, road conditions and traffic volumes. To support spatial planning and provide input to the Integrated Development Plan of the City of Tshwane, a GIS based analysis of ambulance response time was undertaken. The purpose was to make recommendations aimed at the improved placement of stations and allocation of ambulances per station to improve service delivery through reducing the likely response times of ambulance services within the Tshwane Metropolitan area. The key input parameters used included the spatial distribution of demand (population), supply (station locations and ambulance numbers) and emergency road speeds These were tested against a provision standard of one ambulance per 30 000 people. The response target applied in suburban areas was 15 minutes but 40 minutes in low density outlying areas. The results show that the current emergency services stations’ locations are well distributed within the metropole; however, there seems to be a spatial mismatch in vehicle allocation. The paper discusses the impact of the two demand scenarios, namely: universal reliance on public ambulance services versus public ambulances only serving those without medical insurance. The paper concludes that GIS provide an extremely versatile and useful means of testing the implications of demand scenarios and standards relating to these factors of service provision and thereby contribute to better informed decision making.Keywords: Ambulance vehicles, response time, emergency services, accessibility, GIS

Effect of Social Stress on Motor Function in Older Adults: an fNIRS Investigation

Stress has adverse impacts on mental and physical health and quality of life, especially in older adults. Stress can impair cognitive function including short and long-term memory, and this functional declines can further be associated with decreased neuromuscular performance (Mehta & Parasuraman, 2014) and increased fatigability (Keller-Ross et al., 2014). Since older adults are more susceptible to the effect of stress because their limited mobility caused by aging can worsen under stress (Noven at al., 2014), it is important to examine the effect of acute stress on neuromuscular function in older adults. In the present study, we tested the effect of social stress on neuromuscular function of both upper and lower extremity in older adults before and after a short bout of social stress. Thirty participants (15 males, 15 females, mean age: 73.3 (5.6) yrs) performed ten trials of submaximal voluntary contraction at 30% of their maximum voluntary contraction force level before and after the Trier Social Stress Test (TSST) session. Handgrip and knee extension motor performance was measured on separate days. TSST consisted of five minutes speech and five minutes serial arithmetic subtraction tasks. We measured force steadiness and electromyography (EMG) of working muscles to evaluate motor function. Additionally, electrocardiogram (ECG), the Visual Analogue Scale of Stress (VAS), and salivary cortisol were collected to evaluate the effect of the TSST. Neural activation pattern changes of prefrontal and sensorimotor area during exercise and TSST sessions was recorded using functional Near Infrared Spectroscopy (fNIRS). To confirm whether the TSST session increased stress level in our participants, we first analysed the stress metrics. Heart rate increased during the TSST and returned to prestress level instantly after the TSST session. Perceived stress level using the VAS increased after TSST. While not significant, salivary cortisol level increased after the TSST session. Findings indicate that handgrip force steadiness improved after the TSST session, whereas knee extension force steadiness remained unchanged. On the other hand, handgrip EMG root mean square (RMS) did not change after stress while knee extension EMG RMS was found to increase. Neural activation during handgrip exercise increased at the left motor area, and neural activation during knee extension increased at the left sensory area after the TSST session. Change of heart rate and VAS indicates that participants’ stress level was increased after stress and the improved motor performance during handgrip exercise after the stress is consistent with a previous study that reported increased memory function after stress in older adults (Pulopulos et al., 2015). However, the differential effects of stress based on upper or lower extremity indicates increased sensitivity of certain motor tasks to social stress than other. While social stress is known to affect response time but not memory function (Guez et al., 2016), different spatial activation pattern between handgrip and knee extension exercises observed in the present study suggest that different neural strategies were adapted to compensate for the effects of acute social stress to maintain motor performance.

Response Inhibition Is Facilitated by a Change to Red Over Green in the Stop Signal Paradigm.

Actions are informed by the complex interactions of response execution and inhibition networks. These networks integrate sensory information with internal states and behavioral goals to produce an appropriate action or to update an ongoing action. Recent investigations have shown that, behaviorally, attention is captured through a hierarchy of colors. These studies showed how the color hierarchy affected visual processing. To determine whether the color hierarchy can be extended to higher level executive functions such as response execution and inhibition, we conducted several experiments using the stop-signal task (SST). In the first experiment, we modified the classic paradigm so that the go signals could vary in task-irrelevant color, with an auditory stop signal. We found that the task-irrelevant color of the go signals did not differentially affect response times. In the second experiment we determined that making the color of the go signal relevant for response selection still did not affect reaction times(RTs) and, thus, execution. In the third experiment, we modified the paradigm so that the stop signal was a task relevant change in color of the go signal. The mean RT to the red stop signal was approximately 25 ms faster than to the green stop signal. In other words, red stop signals facilitated response inhibition more than green stop signals, however, there was no comparative facilitation of response execution. These findings suggest that response inhibition, but not execution, networks are sensitive to differences in color salience. They also suggest that the color hierarchy is based on attentional networks and not simply on early sensory processing.

Stimulus recognition occurs under high perceptual load: Evidence from correlated flankers.

A dominant account of selective attention, perceptual load theory, proposes that when attentional resources are exhausted, task-irrelevant information receives little attention and goes unrecognized. However, the flanker effect-typically used to assay stimulus identification-requires an arbitrary mapping between a stimulus and a response. We looked for failures of flanker identification by using a more-sensitive measure that does not require arbitrary stimulus-response mappings: the correlated flankers effect. We found that flanking items that were task-irrelevant but that correlated with target identity produced a correlated flanker effect. Participants were faster on trials in which the irrelevant flanker had previously correlated with the target than when it did not. Of importance, this correlated flanker effect appeared regardless of perceptual load, occurring even in high-load displays that should have abolished flanker identification. Findings from a standard flanker task replicated the basic perceptual load effect, with flankers not affecting response times under high perceptual load. Our results indicate that task-irrelevant information can be processed to a high level (identification), even under high perceptual load. This challenges a strong account of high perceptual load effects that hypothesizes complete failures of stimulus identification under high perceptual load. (PsycINFO Database Record

Age-Related Differences of Individuals' Arithmetic Strategy Utilization with Different Level of Math Anxiety.

The present study used the choice/no-choice method to investigate the effect of math anxiety on the strategy used in computational estimation and mental arithmetic tasks and to examine age-related differences in this regard. Fifty-seven fourth graders, 56 sixth graders, and 60 adults were randomly selected to participate in the experiment. Results showed the following: (1) High-anxious individuals were more likely to use a rounding-down strategy in the computational estimation task under the best-choice condition. Additionally, sixth-grade students and adults performed faster than fourth-grade students on the strategy execution parameter. Math anxiety affected response times (RTs) and the accuracy with which strategies were executed. (2) The execution of the partial-decomposition strategy was superior to that of the full-decomposition strategy on the mental arithmetic task. Low-math-anxious persons provided more accurate answers than did high-math-anxious participants under the no-choice condition. This difference was significant for sixth graders. With regard to the strategy selection parameter, the RTs for strategy selection varied with age.

RE-STORM: REAL-TIME ENERGY EFFICIENT DATA ANALYSIS ADAPTING STORM PLATFORM

It is necessary to model an energy efficient and stream optimization towards achieve high energy efficiency for Streaming data without degrading response time in big data stream computing. This paper proposes an Energy Efficient Traffic aware resource scheduling and Re-Streaming Stream Structure to replace a default scheduling strategy of storm is entitled as re-storm. The model described in three parts; First, a mathematical relation among energy consumption, low response time and high traffic streams. Second, various approaches provided for reducing an energy without affecting response time and which provides high performance in overall stream computing in big data. Third, re-storm deployed energy efficient traffic aware scheduling on the storm platform. It allocates worker nodes online by using hot-swapping technique with task utilizing by energy consolidation through graph partitioning. Moreover, re-storm is achieved high energy efficiency, low response time in all types of data arriving speeds.it is suitable for allocation of worker nodes in a storm topology. Experiment results have been demonstrated the comparing existing strategies which are dealing with energy issues without affecting or reducing response time for a different data stream speed levels. Finally, it shows that the re-storm platform achieved high energy efficiency and low response time when compared to all existing approaches.

The Effects of Grids on Web Surveys Completed with Mobile Devices

Question grids are common on Web surveys, and studies show that grids can affect how respondents complete surveys. However, there is little research that investigates the effects of grids on Web surveys completed on mobile devices. In this article, we evaluate the effects of question grids on response quality and measurement error for surveys taken on phones or tablets. Our study draws on a probabilistic Web survey. The survey included an experiment in which respondents were assigned to one of three question format conditions: one large grid, two small grids, or single item per page. We analyze how question grids affect response times and nondifferentiation as well as explore the interaction effects between grids and devices. Reductions in time associated with question grids were greater for surveys completed on mobile devices as opposed to those completed on computers. Likewise, the increases in nondifferentiation associated with question grids were greater for surveys completed on mobile devices. We find that effects of question grids on responses in Web surveys can differ across devices, and so researchers should be cautious of using grids on Web surveys as more people opt to do surveys on phones or tablets.

The Things You Do: Internal Models of Others' Expected Behaviour Guide Action Observation.

Predictions allow humans to manage uncertainties within social interactions. Here, we investigate how explicit and implicit person models–how different people behave in different situations–shape these predictions. In a novel action identification task, participants judged whether actors interacted with or withdrew from objects. In two experiments, we manipulated, unbeknownst to participants, the two actors action likelihoods across situations, such that one actor typically interacted with one object and withdrew from the other, while the other actor showed the opposite behaviour. In Experiment 2, participants additionally received explicit information about the two individuals that either matched or mismatched their actual behaviours. The data revealed direct but dissociable effects of both kinds of person information on action identification. Implicit action likelihoods affected response times, speeding up the identification of typical relative to atypical actions, irrespective of the explicit knowledge about the individual’s behaviour. Explicit person knowledge, in contrast, affected error rates, causing participants to respond according to expectations instead of observed behaviour, even when they were aware that the explicit information might not be valid. Together, the data show that internal models of others’ behaviour are routinely re-activated during action observation. They provide first evidence of a person-specific social anticipation system, which predicts forthcoming actions from both explicit information and an individuals’ prior behaviour in a situation. These data link action observation to recent models of predictive coding in the non-social domain where similar dissociations between implicit effects on stimulus identification and explicit behavioural wagers have been reported.

Effects of Adjacent Vehicles on Judgments of a Lead Car During Car Following.

Two experiments were conducted to determine whether detection of the onset of a lead car's deceleration and judgments of its time to contact (TTC) were affected by the presence of vehicles in lanes adjacent to the lead car. In a previous study, TTC judgments of an approaching object by a stationary observer were influenced by an adjacent task-irrelevant approaching object. The implication is that vehicles in lanes adjacent to a lead car could influence a driver's ability to detect the lead car's deceleration and to make judgments of its TTC. Displays simulated car-following scenes in which two vehicles in adjacent lanes were either present or absent. Participants were instructed to respond as soon as the lead car decelerated (Experiment 1) or when they thought their car would hit the decelerating lead car (Experiment 2). The presence of adjacent vehicles did not affect response time to detect deceleration of a lead car but did affect the signal detection theory measure of sensitivity d' and the number of missed deceleration events. Judgments of the lead car's TTC were shorter when adjacent vehicles were present and decelerated early than when adjacent vehicles were absent. The presence of vehicles in nearby lanes can affect a driver's ability to detect a lead car's deceleration and to make subsequent judgments of its TTC. Results suggest that nearby traffic can affect a driver's ability to accurately judge a lead car's motion in situations that pose risk for rear-end collisions.

Implicit acquisition of tone-suffix connections in L2 learners of Swedish

Swedish native speakers (NSs) unconsciously use tones realized on word stems to predict upcoming suffixes during speech comprehension. The present response time study investigated whether relatively proficient second language (L2) learners of Swedish have acquired the underlying association between tones and suffixes without explicit instruction, internalizing a feature that is specific to their L2. Learners listened to sentences in which the tone on the verb stem either validly or invalidly cued the following present or past tense inflection. Invalidly cued suffixes led to increased decision latencies in a verb tense identification task, suggesting that learners pre-activated suffixes associated with stem tones in a manner similar to NSs. Thus, L2 learners seemed to have acquired the tone-suffix connections through implicit mechanisms. Correctly cued suffixes were associated with a smaller processing advantage in the L2 group relative to NSs performing the same task; nevertheless, results suggest a tendency for increasingly native-like tone processing with cumulative language experience. The way suffix type affected response times also indicates exposure-related effects.

Comparison of consultation–liaison psychiatry services for inner-city, district or regional general hospitals using a common tool: Does one size fit all?

ObjectiveConsultation–liaison psychiatry (CLP) services vary in terms of structure, function and responsiveness. It is not known whether evaluation measurements can be meaningfully compared across different CLP services to assess value and efficiency. The aim was to develop and test a common tool for measuring process and outcome measures in CLP. MethodsA data collection tool was developed using the literature and consultation with CLP clinicians. The tool was used to prospectively gather referral data, response times, health utilisation data and functional outcomes for individuals referred over seven months to three different CLP teams, servicing inner city, district and regional areas. ResultsThe structure, staffing, liaison attachments and scope of practice varied between the services. The regional CLP service attended seven hospitals and had the highest referral rate and largest inpatient population pool. The three services received referrals for similar reasons and made similar diagnoses. Multimodal management was the norm, and CLP facilitated follow-up arrangements upon discharge. Only the district CLP service saw all emergency referrals within an hour. Age and need for an interpreter did not affect response times. ConclusionDespite local differences in geography, CLP roles, hospital and community mental health service pathways and patient populations, the CLP data collection tool was applicable across sites. Staff resourcing and referral demand are key determinants of CLP response times.

Automatic imitation? Imitative compatibility affects responses at high perceptual load.

Imitation involves matching the visual representation of another's action onto the observer's own motor program for that action. However, there has been some debate regarding the extent to which imitation is "automatic"-that is, occurs without attention. Participants performed a perceptual load task in which images of finger movements were presented as distractors. Responses to target letter stimuli were performed via finger movements that could be imitatively compatible (requiring the same finger movement) or incompatible with the distractor movements: In this common stimulus-response compatibility manipulation, the stimulus set comprises images of the response movements, producing an imitative compatibility effect. Attention to the distractor movements was manipulated by altering perceptual load through increasing the number of nontarget letter stimuli. If imitation requires attention, then at high perceptual load, imitative compatibility should not affect response times. In contrast, imitative compatibility influenced response times at high perceptual load, demonstrating that distractor movements were processed. However, the compatibility effect was reversed, suggesting that longer response times at high perceptual load tap into an inhibitory stage of distractor movement processing. A follow-up experiment manipulating temporal delay between targets and distractor movements supported this explanation. Further experiments confirmed that nonmovement distractor stimuli in the same configuration produced standard perceptual load effects and that results were not solely due to effector compatibility. These data suggest that imitation can occur without attention. (PsycINFO Database Record

Data trimming procedure can eliminate bilingual cognitive advantage.

Bilingualism and its cognitive impacts have drawn increasing interest. Recently, inconsistencies in the findings have raised discussions on what might have caused such discrepancies and how evidence should be evaluated. This review tries to shed new light onto the reasons for the inconsistencies by taking a novel perspective. Motivated by the finding that bilingualism affects response time distribution profiles, particularly findings that suggest bilinguals have fewer long responses, we investigated the relation between maximum response times allowed/included in the analysis of an experiment and the finding of a bilingual advantage. We reviewed 68 experiments from 33 articles that compared monolingual and bilingual speakers' performance in three commonly used non-verbal interference tasks (Simon, Spatial Stroop and Flanker). We found that studies that included longer responses in their analysis were more likely to report a bilingualism effect. We conclude that seemingly insignificant details such as the data trimming procedure can have a potential impact on whether an effect is observed. We also discuss the implication of our findings and suggest the usefulness of more fine-grid analytical procedures.

The Effect of Experience on Response Time When Judging Synthesized Voice Quality

The purpose of this study was to determine the effect of level and type of experience on response time and the number of replays needed when judging voice quality. This was a within-subjects group design. Speech-language pathologists, singing voice teachers, speech-language pathology graduate students with and without experience with a voice client, graduate students who have completed a voice pedagogy course, and inexperienced listeners (n=60) rated stimuli with systematically altered measurements of jitter, shimmer, and noise-to-harmonics ratio (NHR) on a visual analog scale ranging from mild to severe for overall severity, roughness, breathiness, strain, and pitch. Response time (in seconds) and number of replays were recorded during the experiment. Results showed that experienced listeners took the most time when rating the stimuli. Stimuli with two altered acoustical components also yielded longer response times compared with the stimuli with one altered acoustical component. Finally, level and type of experience had some effect on the number of replays for each stimulus during the rating task. In conclusion, experience does affect response time when judging voice quality and the number of replays during voice quality rating tasks. Continued research is needed regarding the reasons for extended time and replays as per experience so as to enhance future training protocols.