Distraction Condition Research Articles

Improve adaptive cruise control under driver distraction: Time headway compensation based on a random‐effect crash risk model

Human drivers conduct compensatory behaviour to counteract the increased risk while being distracted. This kind of compensation strategy should be learned for a safer and smart design of adaptive cruise control system (ACC). Hence, a simulator study was conducted, requiring performance visual, cognitive, and combined secondary tasks during a car following scenario. An increased time headway (THW) was found in all of the three distraction conditions, which confirmed that drivers compensated an extra THW to counteract the increased crash risk. Furthermore, crash probability models using binary logistic regression with random intercept were constructed where driver distraction and dynamic traffic situations were embodied as inputs. Results showed that crash risk increased with reduced THW, increased lead vehicle deceleration, and unopened brake light of the lead vehicle. Besides, visual-related distractions increased crash risk, while pure cognitive distraction lowered crash risk in low THW (lower than 1.8 s) condition and increased crash risk in high THW (larger than 1.8 s) condition. Based on the authors' proposed models, theoretical compensation in THW to fully counteract the increased crash risk by distraction was derived, which could be used for the design of a human-like ACC with automatic adjustment of THW setting considering driver distraction.

Associations Between Psychopathic Traits and Laboratory-Based Aggression: Moderating Effects of Provocation and Distraction.

There are two distinct combinations of psychopathic traits (primary and secondary) that have been proposed to be a function of unique cognitive-affective deficits. This study sought to use theories of psychopathy to understand the factors that exacerbate (i.e., provocation) and attenuate (i.e., distraction) aggression in individuals high in psychopathic traits in a controlled laboratory task. Male undergraduates, who scored across the range of primary and secondary psychopathic traits, completed the Taylor Aggression Paradigm (TAP; Taylor, 1967) under conditions of low and high provocation. Participants were also randomly assigned to either a distraction condition, in which they completed a distracting concurrent task, or a control condition, in which no such task was completed. Inconsistent with our prediction, results showed that regardless of condition, primary psychopathic traits were positively related to laboratory aggression. Consistent with our hypothesis, a positive association between secondary psychopathic traits and laboratory physical aggression was observed following high provocation among nondistracted participants; this association was significantly reduced among distracted participants. These results clarify the factors that contribute to aggression for individuals high in psychopathic traits and may provide directions for future intervention development.

Modeling the influence of mobile phone use distraction on pedestrian reaction times to green signals: A multilevel mixed-effects parametric survival model

Understanding and modeling the influence of mobile phone use on pedestrian behaviour is important for several safety and performance evaluations. Mobile phone use affects pedestrian perception of the surrounding traffic environment and reduces situation awareness. This study investigates the effect of distraction due to mobile phone use (i.e., visual and auditory) on pedestrian reaction time to the pedestrian signal. Traffic video data was collected from four crosswalks in Canada and China. A multilevel mixed-effects accelerated failure time (AFT) approach is used to model pedestrian reaction times, with random intercepts capturing the clustered-specific (countries) heterogeneity. Potential reaction time influencing factors were investigated, including pedestrian demographic attributes, distraction characteristics, and environment-related parameters. Results show that pedestrian reaction times were longer in Canada than in China under the non-distraction and distraction conditions. The auditory and visual distractions increase pedestrian reaction time by 67% and 50% on average, respectively. Pedestrian reactions were slower at road segment crosswalks compared to intersection crosswalks, at higher distraction durations, and for males aged over 40 compared to other pedestrians. Moreover, pedestrian reactions were faster at higher traffic awareness levels.

The influence of emotional face distractors on attentional orienting in Chinese children with autism spectrum disorder.

The current study examined how emotional faces impact on attentional control at both involuntary and voluntary levels in children with and without autism spectrum disorder (ASD). A non-face single target was either presented in isolation or synchronously with emotional face distractors namely angry, happy and neutral faces. ASD and typically developing children made more erroneous saccades towards emotional distractors relative to neutral distractors in parafoveal and peripheral conditions. Remote distractor effects were observed on saccade latency in both groups regardless of distractor type, whereby time taken to initiate an eye movement to the target was longest in central distractor conditions, followed by parafoveal and peripheral distractor conditions. The remote distractor effect was greater for angry faces compared to happy faces in the ASD group. Proportions of failed disengagement trials from central distractors, for the first saccade, were higher in the angry distractor condition compared with the other two distractor conditions in ASD, and this effect was absent for the typical group. Eye movement results suggest difficulties in disengaging from fixated angry faces in ASD. Atypical disengagement from angry faces at the voluntary level could have consequences for the development of higher-level socio-communicative skills in ASD.

Cognitive load and the effectiveness of distraction for acute pain in children.

Distraction tasks that place continuous, high demand on executive resources have been shown to reduce pain intensity and pain unpleasantness ratings in some healthy adult samples. We examined the effects of a high-demand 'working memory' 1-back task compared to a low-demand 'motor control' task on pain intensity and unpleasantness ratings in healthy children. Additionally, dispositional mindfulness was examined to explore the mechanisms of distraction on the affective processing of pain. Fifty-seven children (9-13years old) experienced three randomly presented heat levels (not painful, slightly painful, moderately painful) during two distraction conditions involving different levels of cognitive load (a high load 'working memory' task and a low load 'motor' control task) in counter-balanced order. Children completed measures of dispositional mindfulness, and attentional control and emotional control. As predicted, children's pain intensity and pain unpleasantness ratings were lower in the high load condition compared to the low load condition. These differences were amplified in the moderately painful heat trials. In contrast with predictions, dispositional mindfulness did not significantly predict the effectiveness of distraction. Dispositional mindfulness was significantly related to measures of children's attentional and emotional control abilities; however, an exploratory serial mediation model did not produce significant indirect or overall effects to suggest a strong influence of mindfulness on the effectiveness of distraction. Results demonstrate that distraction that places higher demand on executive resources is more effective for acute pain management for children. Further research is needed to explore cognitive and affective moderators of the effectiveness of distraction for children. This study is one of the first to demonstrate that working-memory engagement can attenuate pain intensity and pain unpleasantness in children aged 9-13. The findings suggest that distraction tasks used in clinical settings for moderately painful medical procedures may benefit more children if they are adequately demanding of cognitive resources.

Support for an inhibitory model of word retrieval

Word retrieval may involve an inhibitory process in which a target word is activated and related words are suppressed. In the current functional magnetic resonance imaging (fMRI) study, we examined the inhibition of language processing cortex by the left dorsolateral prefrontal cortex (DLPFC) during word retrieval using an anagram-solving paradigm. Participants were presented with a distractor that was read aloud followed by a to-be-solved anagram. Distractor types were defined relative to orthographic overlap with the subsequent anagram solution and included related words with one letter different (e.g., “gripe” for the anagram of “price”), related pseudo-words, and unrelated words (i.e., all five letters were different). The anagram solution reaction time was slower in both the related word and related pseudo-word distractor conditions as compared to the unrelated word distractor condition, which can be attributed to greater inhibition following related distractors. The contrast of related words and unrelated words produced one activation in the left DLPFC, a region that has been associated with memory inhibition. To identify the regions that were negatively correlated with activity in the left DLPFC for related distractors, we conducted a functional connectivity analysis between this left DLPFC region and the rest of the brain. We found negatively correlated activity between the DLPFC and language processing cortex for the related word distractor condition (and the related pseudo-word distractor condition at a relaxed threshold). These findings suggest that that the left DLPFC may inhibit related word (and pseudo-word) representations in language processing cortex.

Improving the safety of distracted pedestrians with in-ground flashing lights. A railway crossing field study

Introduction: Current signage at intersections is designed for attentive pedestrians who are looking ahead. Such signage may not be sufficient when distracted by smartphones. Illuminated in-ground LED lights at crossings are an innovative solution to alert distracted pedestrians. Method: We conducted a field study at a railway crossing equipped with in-ground lights to assess whether distracted pedestrians (N = 34, Mean age 33.6 ± 8.6 years) could detect these lights and how this impacted on their visual scanning and crossing behaviour. This involved a 2 × 3 repeated measures design exploring the impact of the presence (treatment) or absence (control) of in-ground lights (treatment) at a crossing, and a distractor task presented through a mobile device (none, visual, and audio) on eye movements recorded using an eye tracker, and verbal reporting of when participants detected the lights. Results: Participants engaged in the distraction tasks as evidenced by their accuracy and reaction times in all conditions. With both the audio and visual distraction tasks, participants looked at the in-ground LEDs and detected their activation as accurately as when not distracted (95%). While most participants detected the lights at their activation, visual distraction resulted in 10% of the detections occurring as participants entered the rail corridor, suggesting effectiveness in gaining pedestrians’ attention. Further, participants were significantly less likely to check for trains when visually distracted (70%), a 10% reduction compared to the no or audio distractor conditions (80% and 78% respectively). The introduction of the in-ground lights resulted in appropriate scanning of the rail tracks (77% and 78% for the visual and auditory distractor tasks respectively) similar to that of non-distracted participants for the crossing without lights (80%). Conclusions: Our findings indicate that illuminated in-ground lights could be useful in attracting the attention of distracted pedestrians at railway level crossings, and possibly at other road intersections. Practical Applications: Illuminated in-ground lights can be installed at rail and road intersections with known pedestrian distraction as a countermeasure. Further research is necessary to understand their long-term effects.

The Deficit of Early Selective Attention in Adults With Sluggish Cognitive Tempo: In Comparison With Those With Attention-Deficit/Hyperactivity Disorder.

Sluggish cognitive tempo (SCT) is a cluster of attentional symptoms characterized by slow information processing and behavior, distractibility, mental confusion, absent-mindedness, and hypoactivity. The present study aimed to compare early and late selective attention in the information processing speed of adults with SCT to those with attention-deficit/hyperactivity disorder (ADHD) and adults without any attentional problems. The participants were screened using Barkley Adult ADHD Rating Scale-IV and divided into the following groups: SCT (N = 24), ADHD (N = 24), and controls (N = 25). All participants completed the irrelevant distractor task measuring early and late selective attention under load condition (low vs. high) and distractor condition (no-distractor vs. distractor). The inefficiency index was calculated by subtracting the reaction time of no-distractor condition of correct trials from the reaction time of distractor condition to control the impact of accuracy. Upon analysis, the SCT group showed a lower efficiency compared to the ADHD group under high load, while the ADHD group showed lower efficiency under low load than high load. This meant that the ADHD group had increased efficiency of selective attention with higher load, while the SCT group had low efficiency of selective attention even under high loads. These results suggest that the symptoms of “slow” or “distracted” in SCT could be attributed to the reduced speed and efficiency of selective attention in early information processing and the problem can be pronounced in situations with distractors. The results of the study imply that the attention-deficit-like symptoms shown in those with SCT and ADHD can be distinguished in specific stage of information processing.

Prediction of Navigational Decisions in the Real-World: A Visual P300 Event-Related Potentials Brain-Computer Interface

ABSTRACT Despite the widespread availability of portable neuroimaging systems, current applications of brain-computer interfaces (BCI) have largely remained confined to laboratory and clinical settings. In order to develop BCI that will assist individuals across a wide range of everyday life behaviors, it is critical to test paradigms that have been successful in highly controlled setups within the frame of real-world environments. In the present study, a visual P300 paradigm was used to elicit neural responses reflective of decision making within the frame of real-world navigation. Participants (n = 8) were equipped with a tablet and a mobile EEG system while navigating through university corridors. Upon reaching an intersection, participants were presented with left and right arrows flashing on the tablet (and additional non-directional stimuli in the distractor condition). Neural responses elicited by the presentation of such stimuli (Event-Related Potentials) were recorded along with the participant’s navigational decisions. The participants completed two separate sessions to collect data for both the training and testing of an offline BCI system aimed at predicting their navigational decisions based on the extraction of event-related potentials features. Single-trial classification accuracy reached 59.6% (up to 72.3% when classifying group averages of six trials). Individual classification results were contrasted with single-trial analysis. Results are discussed in terms of their implications for the design of real-world BCI applications, and several recommendations to improve experimental protocols are proposed.

Examining driver distraction in the context of driving speed: An observational study using disruptive technology and naturalistic data

Considering the number of people who have been involved in crashes associated with driver distractions, it is important to understand the characteristics of distracted driving on public roadways. While experiments have indicated that driver distractions are associated with slower driving speeds, the methodologies tend to have limited external validity. Observational studies are often conducted under limited circumstances – be it time or location. Therefore, in order to better understand the nature of driver distractions, the authors investigated the relationships between driving speed, posted speed limits, and phone handling frequency through naturalistic driving data obtained (via disruptive technology) from 8,240 mobile application users on state-maintained highways throughout Texas. As a measure of manual distractions, a phone handling rate (PHR; times/hours driven) was calculated based on phone rotations. Within-subject comparisons were drawn for driving speed and posted speed limits under normal driving conditions and distracted conditions. The analysis revealed a strong negative correlation between PHR and driving speed (rs = -0.87). Paired t-tests revealed significantly lower driving speeds (p = 0.000 < 0.01, d = -0.48, η = 0.69) and posted speed limits (p = 0.000 < 0.01, d = -0.20, η = 0.42) during phone handling events when compared to driving without phone handling. On average, users drove 3.26 mph slower in distracted conditions than in undistracted conditions. Driving speed had a larger effect size than posted speed limits. The findings were in line with existing theories and experiments as well as other observational studies conducted at fixed locations. Although this research did not reveal causal relations, it is noteworthy that speed reduction with manual distractions was observed under real road conditions. Spatial analyses are recommended to conduct in order to paint a more thorough picture of speed reduction, its relationship to space, and crash risks related to distracted driving.

The neural basis underlying impaired attentional control in problematic smartphone users

As a portable media device that enables ubiquitous access to friends and entertainment, smartphones are inextricably linked with our lives. Although there is growing concern about the detrimental effect of problematic smartphone use on attentional control, the underlying neural mechanisms of impaired attentional control in problematic smartphone users (PSU) has yet to be investigated. Using a modified cognitive conflict task, we examined behavioral performance in the presence of distracting words during functional magnetic resonance imaging in 33 PSU and 33 control participants (CON). Compared with the CON group, the PSU group demonstrated impaired performance that was accompanied by constantly enhanced but not differentiated activation in the frontoparietal regions across all conditions, regardless of distractor saliency. The inferior parietal lobule (IPL) activation in the PSU group, in particular, showed an association with performance deficits in the distractor conditions. Furthermore, the PSU group exhibited decreased functional connectivity of the right IPL with the right superior temporal gyrus of the ventral attention system in the attention-demanding condition relative to the easiest condition, which was associated with the severe dependence on smartphone use. Our findings suggest that greater distractibility in the PSU group during the attentional control task may be associated with inefficient recruitment of the ventral attention network involved in bottom-up attentional processing, as indicated by hyperactivation but less coherence within the network. The present study provides evidence for understanding the neural mechanisms underlying the impaired ability to keep attention from being oriented to task-irrelevant stimuli observed in PSU.

Effect of Distractors on Sustained Attention and Hyperactivity in Youth With Attention Deficit Hyperactivity Disorder Using a Mobile Virtual Reality School Program

Objective: This study examined whether distractors in virtual reality (VR) environment affected the attention and hyperactivity in children and adolescents with ADHD. Method: A total of 40 students (21 ADHD, 19 controls) aged between 9 and 17 years participated in this study. A rapid visual information processing task utilizing VR (VR-RVP) was performed under two conditions (no-distractor and distractor condition). Task performance and head movement during each condition were compared, and additional analyses were conducted after grouping participants into two developmental stages. Results: Children with ADHD performed comparably to the controls under the distractor condition, but had poorer performance under the no-distractor condition. They displayed more head movement under the distractor condition than in the no-distractor condition. Conclusion: VR is possibly a useful tool for investigating the effect of distractors on individuals with ADHD, and children with ADHD are more vulnerable to a low-level stimulation situation than normal children in VR.

Reconsidering the ability of the stimulus unique features to capture attention: Evidence from change blindness and visual search paradigms.

In Experiment 1 (change blindness), participants received either intermixed or blocked presentations of two visual stimuli that contained several common (X) and unique (A or B) features. On the critical trial after exposure, the stimulus AX was presented but included an unexpected visual event (a change in the size of a stimulus feature). We found that participants readily detected the change when it involved an A-unique feature that had been preexposed intermixed. However, if the change involved an A-unique feature preexposed in blocks, or an X-common feature (preexposed either intermixed or in blocks), the level of the detections considerably decreased. In Experiment 2, after either intermixed or blocked preexposure to AX and BX, all the participants were instructed to search for an unrelated visual target item. In the distractor condition, during the development of the search task, the A-unique feature emerged at an unpredictable location that was different to that occupied by this feature during the preexposure. In the control condition, the target was presented on its own during the entire task. The presence of the A-unique feature only produced a detrimental effect on search performance when the AX and BX had been preexposed intermixed. These results are discussed as indicative of the intermixed preexposure schedule enhancing the ability of the stimulus unique features to capture involuntary attention. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Altered Vergence Eye Movements and Pupil Response of Patients with Alzheimer's Disease and Mild Cognitive Impairment During an Oddball Task.

Alzheimer's disease (AD) is characterized by progressive deterioration of cognitive functions and may be preceded by mild cognitive impairment (MCI). Evidence shows changes in pupil and vergence responses related to cognitive processing of visual information. Here we test the hypothesis that MCI and AD are associated with specific patterns in vergence and pupil responses. We employed a visual oddball task. In the distractor condition (80%of the trials), a blue stimulus was presented whereas in the target condition (20%of trials) it was red. Participants (23 Controls, 33 MCI patients, and 18 AD patients) were instructed to press a button when a target appeared. Participants briefly converged their eyes 200 ms after stimulus presentation. In controls, this transient peak response was followed by a delay response to targets but not to distractor stimuli. In the patient groups, delay responses to distractors were noticed. Consequently, the differential vergence response was strong in the control group, weak in the MCI group, and absent in the AD group. Pupils started to dilate 500-600 ms after the appearance of a target but slightly contracted after the presentation of a distractor. This differential pupil response was strongest in the AD group. Our findings support the idea of a role of vergence and pupil responses in attention and reveal altered responses in MCI and AD patients. Further studies should assess the value of vergence and pupil measurements as an objective support tool for early diagnosis of AD.

Messages beyond the phone: Processing variable message signs while attending hands-free phone calls

We examined the effects of different types of cognitive distraction coming from a hands-free phone conversation on the processing of information provided by variable message signs (VMS), on driving performance indicators, and on a physiological index of mental effort (heart rate). Participants drove a route in a driving simulator and had to respond to VMS messages under three conditions: no-distraction, visuospatial distraction (attending phone calls with questions inducing visuospatial processing), and conceptual distraction (attending phone calls with questions requiring semantic memory). Results showed more errors responding to VMS messages in the visuospatial distraction condition. In addition, both types of questions increased the intraindividual variability of response distances and the heart rate, as compared to the no-distraction condition. These results provide new evidence that talking on a hands-free phone entails costs in the processing of traffic information (in particular, text messages displayed on VMS) and it increases the driver’s cognitive effort. Interestingly, the cognitive distraction had no effect on the driver’s control of the vehicle speed or lateral position. Therefore, the effects of potential risk factors can critically vary among the different driving subtasks due to modulatory factors, such as the level of attentional task demands (relatively high in the processing of messages on VMS, but relatively low in controlling the speed and lateral position of the vehicle in quiet traffic conditions). In consequence, the current paper provides new evidence to discuss hands-free phone policies and highlights the importance of designing technological countermeasures to prevent drivers missing critical information displayed on VMS.

Effects of mild cognitive impairment on brain function during distracted driving

AbstractBackgroundDriving is an integral part of daily life. The complex, multi‐faceted nature of driving makes it vulnerable to the effects of pathological aging on the brain. Studies have shown that patients with mild cognitive impairment (MCI) maintain safe driving in routine circumstances, however there is limited examination of the effects of MCI in more challenging driving scenarios, such as distracted driving. In addition, little is known about how distraction may disrupt the brain networks that are involved in safe driving for patients with MCI. This is the first study to combine functional magnetic resonance imaging (fMRI) with an MRI‐compatible driving simulator to study the effect of distraction on driving‐related brain activity in healthy and MCI cohorts.MethodsThis study used fMRI and an MRI‐compatible driving simulator to measure brain activity during driving in 30 patients with MCI and 30 age and sex‐matched control participants. Patients were diagnosed using the criteria defined by the National Institute on Aging‐Alzheimer’s Association. In the simulator, participants were required to respond to a distracting true or false question while driving. Parametric maps of brain activity were calculated using one‐sample t‐tests, which were cluster‐size thresholded to adjust for multiple comparisons.ResultsBoth groups displayed consistent recruitment of the bilateral frontal, parietal, temporal and occipital lobes during the distracting condition (Figure 1). Patients with MCI exhibited more extensive positive activation in the bilateral superior temporal lobes and the middle and inferior frontal lobes. Although patients with MCI did not commit more driving errors, they displayed impairment by not answering the true or false questions (p &lt; 0.001) and by taking longer to complete turns (p &lt; 0.001).ConclusionsDuring distracted driving, patients with MCI significantly altered their behaviour to safely complete the driving task. The observed increased recruitment of the frontal lobes among patients may be reflective of the compensatory cognitive effort exerted to maintain task performance. MCI may result in changes in driving behaviour, which are exacerbated in challenging driving situations. These findings suggest that subtle changes in measures of driving behaviour may be signs of significant MCI‐related alterations in driving networks of the brain.

A comparison of workload demands imposed by different types of distracted walking tasks and its effect on gait

A growing body of research has found that distracted walking is a safety concern due to reduced situation awareness and the possibility of compromised gait performance. Distraction tasks, such as texting, browsing social media, and playing games, differ in terms of their physical and cognitive demands. However, few studies have examined whether there are differences in how physical and cognitive demands impact gait. The goal of this paper is to evaluate workload differences between four distraction tasks that represent common smartphone functions and may differ in terms of physical and cognitive demands: 1) No distraction, 2) Reading, 3) Tapping, 4) N-Back. We characterized the workload differences using three methods, a subjective workload assessment (NASA-TLX) and two physiological workload measures, pupil width and blink rate. Our results suggest that the chosen distraction tasks differ in their workload demands. While, a preliminary analysis of descriptive gait parameters failed to find significant differences between the distraction conditions, further analysis of more complex gait measures may be required to understand differences between physical and cognitive demands.

The Role of Alpha Power in the Suppression of Anticipated Distractors During Verbal Working Memory.

As working memory (WM) is limited in capacity, it is important to direct neural resources towards processing task-relevant information while ignoring distractors. Neural oscillations in the alpha frequency band (8-12Hz) have been suggested to play a role in the inhibition of task-irrelevant information during WM, although results are mixed, possibly due to differences in the type of WM task employed. Here, we examined the role of alpha power in suppression of anticipated distractors of varying strength using a modified Sternberg task where the encoding and retention periods were temporally separated. We recorded EEG while 20 young adults completed the task and found: (1) slower reaction times in strong distractor trials compared to weak distractor trials; (2) increased alpha power in posterior regions from baseline prior to presentation of a distractor regardless of condition; and (3) no differences in alpha power between strong and weak distractor conditions. Our results suggest that parieto-occipital alpha power is increased prior to a distractor. However, we could not find evidence that alpha power is further modulated by distractor strength.

Arousal-Biased Competition Explains Reduced Distraction by Reward Cues Under Threat

Anxiety has consistently been found to potentiate the attentional processing of physically salient stimuli. However, a recent study demonstrated that experimentally-inducing anxiety reduces attentional capture by previously reward-associated stimuli, suggesting that anxiety does not globally increase distractibility but rather its influence depends on the nature of the eliciting stimulus. To decipher how the processing of threat interacts with the processing of visual reward cues, we probed the neural mechanisms of oculomotor capture by previously reward-associated stimuli with and without the threat of unpredictable electric shock (blockwise manipulation, within-subjects), combining the value-driven attentional capture paradigm with the translational threat of shock paradigm in an fMRI study. Our eye-movement data replicated prior behavioral findings demonstrating an interaction between threat and distractor condition, with oculomotor capture by previously reward-associated distractors being reduced under threat. In our neuroimaging data, significant main effects of threat and distractor condition on stimulus-evoked blood-oxygen-level-dependent (BOLD) activation were evident in the extrastriate visual cortex, frontal eye field, intraparietal sulcus, and caudate tail, collectively referred to as the value-driven attention network (VDAN). In addition, we found an interaction between distractor condition and threat within each region of the VDAN. Surprisingly, the direction of this interaction was opposite that of the behavioral interaction, with the previously reward-associated distractor evoking especially strong neural activation under threat. Our neuroimaging data are consistent with the Arousal-Biased Competition (ABC) model of information processing in the visual system, although our corresponding behavioral results suggest that, at least under certain circumstances involving reward cues, such biased competition can be leveraged to facilitate more efficient ignoring at the level of eye movements. Our findings inform our understanding of value-driven attention, emotion-attention interactions, and mechanisms of signal suppression.

Mapping of Posterior Talar Dome Access through Standard Posteromedial and Posterolateral Approaches With or Without an External Fixator Distraction: A Match-paired Cadaveric Study

Category:Trauma; Ankle; OtherIntroduction/Purpose:Posterior talar body fractures (AO/OTA 81.1.B/C) are rare injuries that present unique challenges in their access to the treating surgeon. Accessibility to this structure has been investigated extensively in the context of osteochondral lesion interventions, normally requiring perpendicular access to perform operative procedures. However, techniques in gaining this access regarding fracture repair, requiring only adequate visualization, has not been described in literature. Generally, a pre-operative decision is made between a posterior, soft-tissue based approach or a peri-articular osteotomy, which is associated with comparatively higher morbidity and complication rates. The aim of this study is to evaluate the accessible area of the talar dome via two standard posterior approaches (posteromedial; PM, and posterolateral; PL) with and without external fixator distraction.Methods:Eight male through-knee matched-paired cadaveric legs (mean age: 49.0 +- 14.6; mean BMI: 24.5+- 3.9 kg/m2) were included in this study. A standard PM or PL approach was performed using a randomized crossover design for surgical sequences. The accessible area without distraction was initially outlined by drilling a 1.6-mm Kirschner wire around the periphery of the visualized talus. Five millimeters of distraction, confirmed with fluoroscopy, was then applied to the specimens using an external fixator. The accessible area was again marked using the same method. The tali specimens were then explanted and imaged using a Micro-CT scanner to acquire 3 dimensional reconstructions. The accessible area was calculated as a percentage of the total talar dome surface area. The Mann-Whitney U test was used to compare the reported areas among the two surgical approaches, where the Wilcoxon signed rank test was utilized to compare values among distracted and non-distracted conditions.Results:In reference, the average total surface area of the talus is 16.94 +- 2.47 cm2. No statistically significant differences were found among match-paired specimens (p=0.63). The PM approach allowed access to 17.1% (11.1 to 23.6%, SD 5.4) of the talar dome surface without distraction and 29.3% (20.0 to 38.6%, SD 8.6) of the talar dome surface with distraction. The PL approach provided access to 7.4% (4.7 to 11.8%, SD 3.1) and 17.0% (11.0 to 26.1%, SD 6.5) of the talar dome surface with and without distraction, respectively. A statistically significant difference was observed in talar dome accessibility among distracted and non- distracted conditions in both surgical approaches (p=0.008). Additionally, the PM approach provided significantly more access to the talar dome relative to the PL approach (p=0.043).Conclusion:This matched-paired cadaveric study provides roadmap that can assist in the pre-operative planning of talar dome access in the treatment of talar body and posterior tubercle fractures. We found no advantage to a PL approach over a PM approach to access these challenging fractures. Additionally, added distraction using an external fixator consistently increased visualization of the talar dome by a magnitude of at least 40% greater than the non-distracted conditions. These methods can be applied clinically to gain appropriate access to the talar dome, allowing fracture repair.