Evaluation of Robotic-Assisted Carotid Artery Stenting in a Virtual Model Using Motion-Based Performance Metrics.

PURPOSE: Robotic-assisted carotid artery stenting (CAS) cases have been demonstrated with promising results. However, no quantitative measurements have been made to compare manual with robotic-assisted CAS. This study aims to quantify surgical performance using tool tip kinematic data and metrics of precision during CAS with manual and robotic control in an ex vivo model. MATERIALS AND METHODS: Transfemoral CAS cases were performed in a high-fidelity endovascular simulator. Participants completed cases with manual and robotic techniques in 2 different carotid anatomies in random order. C-arm angulations, table position, and endovascular devices were standardized. Endovascular tool tip kinematic data were extracted. We calculated the spectral arc length (SPARC), average velocity, and idle time during navigation in the common carotid artery and lesion crossing. Procedural time, fluoroscopy time, movements of the deployed filter wire, precision of stent, and balloon positioning were recorded. Data were analyzed and compared between the 2 modalities. RESULTS: Ten participants performed 40 CAS cases with a procedural success of 100% and 0% residual stenosis. The median procedural time was significantly higher during the robotic-assisted cases (seconds, median [interquartile range, IQR]: 128 [49.5] and 161.5 [62.5], p=0.02). Fluoroscopy time differed significantly between manual and robotic-assisted procedures (seconds, median [IQR]: 81.5 [32] and 98.5 [39.5], p=0.1). Movement of the deployed filter wire did not show significant difference between manual and robotic interventions (mm, median [IQR]: 13 [10.5] and 12.5 [11], p=0.5). The postdilation balloon exceeded the margin of the stent with a median of 2 [1] mm in both groups. Navigation with robotic assistance showed significantly lower SPARC values (-5.78±3.14 and -8.63±3.98, p=0.04) and higher idle time values (8.92±8.71 and 3.47±3.9, p=0.02) than those performed manually. CONCLUSIONS: Robotic-assisted and manual CAS cases are comparable in the precision of stent and balloon positioning. Navigation in the carotid artery is associated with smoother motion and higher idle time values. These findings highlight the accuracy and the motion stabilizing capability of the endovascular robotic system. CLINICAL IMPACT: Robotic assistance in the treatment of peripheral vascular disease is an emerging field and may be a tool for radiation protection and the geographic distribution of endovascular interventions in the future. This preclinical study compares the characteristics of manual and robotic-assisted carotid stenting (CAS). Our results highlight, that robotic-assisted CAS is associated with precise navigation and device positioning, and smoother navigation compared to manual CAS.

Summative Usability Assessments of STAR-Vote: A Cryptographically Secure e2e Voting System That Has Been Empirically Proven to Be Easy to Use.

BACKGROUND: From the project's inception, STAR-Vote was intended to be one of the first usable, end-to-end (e2e) voting systems with sophisticated security. To realize STAR-Vote, computer security experts, statistical auditors, human factors (HF)/human-computer interaction (HCI) researchers, and election officials collaborated throughout the project and relied upon a user-centered, iterative design and development process, which included human factors research and usability testing, to make certain the system would be both usable and secure. OBJECTIVE: While best practices in HF/HCI methods for design were used and all apparent usability problems were identified and fixed, summative system usability assessments were conducted toward the end of the user-centered design process to determine whether STAR-Vote is in fact easy to use. METHOD AND RESULTS: After collecting efficiency, effectiveness, and satisfaction measurements per ISO 9241-11's system usability criteria, an analysis of the data revealed that there is evidence for STAR-Vote being the most usable, cryptographically secure voting system to date when compared with the previously tested e2e systems: Helios, Prêt à Voter, and Scantegrity. CONCLUSION AND APPLICATION: STAR-Vote being one of the first e2e voting systems that is both highly usable and secure is a significant accomplishment, because tamper-resistant voting systems can be used in U.S. elections to ensure the integrity of the electoral process, while still ensuring that voter intent is accurately reflected in the cast ballots. Moreover, this research empirically shows that a complex, secure system can still be usable-meaning that implemented security is not an excuse for poor usability.

A new and automated method for objective analysis of detrusor rhythm during the filling phase.

INTRODUCTION: There is growing acceptance that the detrusor muscle is not silent during the filling phase of the micturition cycle but displays low-amplitude phasic contractions that have been associated with urinary urgency. Unfortunately, there is currently no standardized methodology to quantify detrusor rhythm during the filling phase. Therefore, the purpose of this study was to develop an automated computer algorithm to analyze rat detrusor rhythm in a quick, accurate, and reproducible manner. MATERIALS AND METHODS: Strips of detrusor smooth muscle from rats (n = 17) were placed on force transducers and subjected to escalating doses of PGE2 to generate contractile rhythm tracings. An automated computer algorithm was developed to analyze contractile frequency, amplitude, and tone on the generated rhythm tracings. Results of the automated computerized analysis were compared to human (n = 3) interpretations. Human interpreters manually counted contractions and then recounted the same data two weeks later. Intra-observer, inter-observer, and human-to-computer comparisons were performed. RESULTS: The computer algorithm quantified concentration-dependent changes in contractile frequency, amplitude, and tone after administration of PGE2 (10(-9)-10(-6)M). Concentration-response curves were similar for all contractile components with increases in frequency identified mainly at physiologic concentrations of PGE2 and increases in amplitude at supra-physiologic concentrations. The computer algorithm consistently over-counted the human interpreters, but with less variability. Differences in inter-observer consistency were statistically significant. CONCLUSIONS: Our computerized algorithm accurately and consistently identified changes in detrusor muscle contractile frequency, amplitude, and tone with varying doses of PGE2. Frequency counts were consistently higher than those obtained by human interpreters but without variability or bias. Refinements of this method may allow for more standardized approach in the study of pharmacologic agents on filling phase rhythmic activity.

Fourier transform analysis of rabbit detrusor autonomous contractions reveals length dependent increases in tone and slow wave development at long lengths.

PURPOSE: Bladder wall muscle (detrusor) develops low amplitude rhythmic contractions. Low amplitude rhythmic contraction activity is increased in detrusor from patients with overactive bladder. In this in vitro study we used fast Fourier transforms to assess the length dependence of low amplitude rhythmic contraction components. MATERIALS AND METHODS: Rabbit detrusor strips were placed in a muscle bath between 2 clips to adjust length and record isometric tension. Tissues stretched from 70% to 130% of a reference muscle length at 10% increments were allowed to develop low amplitude rhythmic contractions at each length for 20 minutes. Low amplitude rhythmic contraction data were analyzed using fast Fourier transforms and represented by a frequency rather than a time spectrum. RESULTS: Based on fast Fourier transform analysis summarized by signal peaks within specific frequency ranges, rabbit low amplitude rhythmic contraction waveforms were divided into 1 tonic and 2 phasic components, defined as A0 + A1F1 + A2F2, where A0 is a length dependent basal tonic component that increases linearly, A1F1 is a slow wave with a length dependent specific amplitude (A1) and a length independent constant frequency (F1) of approximately 11.2 Hz, and A2F2 is a fast wave with a length dependent amplitude (A2) and frequency (F2) of approximately 0.03 Hz. CONCLUSIONS: Fast Fourier transform analysis revealed that rabbit low amplitude rhythmic contractions consist of a basal tonic component plus 2 phasic components. The amplitude of all 3 components was length dependent. The frequency of the fast component was not length dependent and the slow component was absent at short muscle lengths, developing only at muscle lengths beyond that producing a maximum active contraction.

The environmental basis of memory.

Memory should make more available things that are more likely to be needed. Across multiple environmental domains, it has been shown that such a system would match qualitatively the memory effects involving repetition, delay, and spacing (Schooler & Anderson, 2017). To obtain data of sufficient size to study how detailed patterns of past appearance predict probability of being needed again, we examined the patterns with which words appear in large two data sets: tweets from popular sources and comments on popular subreddits. The two data sets show remarkably similar statistics, which are also consistent with earlier, smaller studies of environmental statistics. None of a candidate set of mathematical models of memory do well at predicting the observed patterns in these environments. A new model of human memory based on the environmental model proposed by Anderson and Milson (1989) did better at predicting the environmental data and a wide range of behavioral studies that measure memory availability by probability of recall and speed of retrieval. A critical variable in this model was range, the span of time over which an item occurs, which was discovered in mining the environmental data. These results suggest that theories of memory can be guided by mining of the statistical structure of the environment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Haptic Feedback Based on Movement Smoothness Improves Performance in a Perceptual-Motor Task.

In many training scenarios, and in surgery in particular, feedback is provided to the trainee after the task has been performed, and the assessment is often qualitative in nature. In this paper, we demonstrate the effect of real-time objective performance feedback conveyed through a vibrotactile cue. Subjects performed a mirror-tracing task that requires coordination and dexterity similar in nature to that required in endovascular surgery. Movement smoothness, a characteristic associated with skilled and coordinated movement, was measured by spectral arc length, a frequency-domain measure of smoothness. The smoothness-based performance metric was encoded as a vibrotactile cue displayed on the user's arm. Performance on the mirror tracing task with smoothness-based feedback was compared to position-based feedback (where the subject was alerted when they moved outside the path boundary) and to a no vibrotactile feedback control condition. Subjects receiving smoothness-based feedback altered their task completion strategies, resulting in faster task completion times, but their accuracy was slightly worse overall than the other two groups. In procedures such as endovascular surgery, the reduction of procedure time that could be achieved with smoothness-based feedback training may be advantageous, despite the fact that accuracy was inferior to that observed with no feedback or position-based feedback.

Comparing Manual and Robotic-Assisted Carotid Artery Stenting Using Motion-Based Performance Metrics.

Carotid artery stenting (CAS) is a minimally invasive endovascular procedure used to treat carotid artery disease and is an alternative treatment option for carotid artery stenosis. Robotic assistance is becoming increasingly widespread in these procedures and can provide potential benefits over manual intervention, including decreasing peri- and post-operative risks associated with CAS. However, the benefits of robotic assistance in CAS procedures have not been quantitatively verified at the level of surgical tool motions. In this work, we compare manual and robot-assisted navigation in CAS procedures using performance metrics that reliably indicate surgical navigation proficiency. After extracting guidewire tip motion profiles from recorded procedure videos, we computed spectral arc length (SPARC), a frequency-domain metric of movement smoothness, average guidewire velocity, and amount of idle tool motion (idle time) for a set of CAS procedures performed on a commercial endovascular surgical simulator. We analyzed the metrics for two procedural steps that influence post-operative outcomes. Our results indicate that during advancement of the sheath to the distal common carotid artery, there are significant differences in SPARC (F(1, 22.3) = 6.12, p = .021) and idle time (F(1, 22.6) = 6.26, p = .02) between manual and robot-assisted navigation, as well as a general trend of lower SPARC, lower average velocity, and higher idle time values associated with robot-assisted navigation for both procedural steps. Our findings indicate that significant differences exist between manual and robot-assisted CAS procedures. These are quantitatively detectable at the granular-level of physical tool motion, improving the ability to evaluate robotic assistance as it grows in clinical use.

Comparing vector-based and Bayesian memory models using large-scale datasets: User-generated hashtag and tag prediction on Twitter and Stack Overflow.

The growth of social media and user-created content on online sites provides unique opportunities to study models of human declarative memory. By framing the task of choosing a hashtag for a tweet and tagging a post on Stack Overflow as a declarative memory retrieval problem, 2 cognitively plausible declarative memory models were applied to millions of posts and tweets and evaluated on how accurately they predict a user's chosen tags. An ACT-R based Bayesian model and a random permutation vector-based model were tested on the large data sets. The results show that past user behavior of tag use is a strong predictor of future behavior. Furthermore, past behavior was successfully incorporated into the random permutation model that previously used only context. Also, ACT-R's attentional weight term was linked to an entropy-weighting natural language processing method used to attenuate high-frequency words (e.g., articles and prepositions). Word order was not found to be a strong predictor of tag use, and the random permutation model performed comparably to the Bayesian model without including word order. This shows that the strength of the random permutation model is not in the ability to represent word order, but rather in the way in which context information is successfully compressed. The results of the large-scale exploration show how the architecture of the 2 memory models can be modified to significantly improve accuracy, and may suggest task-independent general modifications that can help improve model fit to human data in a much wider range of domains. (PsycINFO Database Record

Learning to achieve perfect timesharing: architectural implications of Hazeltine, Teague, and Ivry (2002).

E. Hazeltine, D. Teague, and R. B. Ivry have presented data that have been interpreted as evidence against a central bottleneck. This article describes simulations of their Experiments 1 and 4 in the ACT-R cognitive architecture, which does possess a central bottleneck in production execution. The simulation model is capable of accounting for the emergence of near-perfect timesharing in Experiment 1 and the detailed data on the distribution of response times from Experiment 4. With practice, the central bottleneck in ACT-R will be reduced to a maximum of 50 ms (1 production cycle) and can often be much less, depending on timing of stages and variability in their times. The authors also show, with a mathematical analysis of E. Hazeltine et al.'s Experiment 2, that the expected dual costs for these kinds of highly practiced tasks will be small in many circumstances, often under 10 ms.

Pre-procedural antibiotics for endoscopic urological procedures: Initial experience in individuals with spinal cord injury and asymptomatic bacteriuria.

OBJECTIVE: The objective of this study was to compare the safety, efficacy, quality-of-life impact, and costs of a single dose or a longer course of pre-procedural antibiotics prior to elective endoscopic urological procedures in individuals with spinal cord injury and disorders (SCI/D) and asymptomatic bacteriuria. DESIGN: A prospective observational study. SETTING: Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA. PARTICIPANTS: Sixty persons with SCI/D and asymptomatic bacteriuria scheduled to undergo elective endoscopic urological procedures. INTERVENTIONS: A single pre-procedural dose of antibiotics vs. a 3-5-day course of pre-procedural antibiotics. OUTCOME MEASURES: Objective and subjective measures of health, costs, and quality of life. RESULTS: There were no significant differences in vital signs, leukocytosis, adverse events, and overall satisfaction in individuals who received short-course vs. long-course antibiotics. There was a significant decrease in antibiotic cost (33.1 ± 47.6 vs. 3.6 ± 6.1 US$, P = 0.01) for individuals in the short-course group. In addition, there was greater pre-procedural anxiety (18 vs. 0%, P < 0.05) for individuals who received long-course antibiotics. CONCLUSION: SCI/D individuals with asymptomatic bacteriuria may be able to safely undergo most endoscopic urological procedures with a single dose of pre-procedural antibiotics. However, further research is required and even appropriate pre-procedural antibiotics may not prevent severe infections.

An integrated theory of the mind.

Adaptive control of thought-rational (ACT-R; J. R. Anderson & C. Lebiere, 1998) has evolved into a theory that consists of multiple modules but also explains how these modules are integrated to produce coherent cognition. The perceptual-motor modules, the goal module, and the declarative memory module are presented as examples of specialized systems in ACT-R. These modules are associated with distinct cortical regions. These modules place chunks in buffers where they can be detected by a production system that responds to patterns of information in the buffers. At any point in time, a single production rule is selected to respond to the current pattern. Subsymbolic processes serve to guide the selection of rules to fire as well as the internal operations of some modules. Much of learning involves tuning of these subsymbolic processes. A number of simple and complex empirical examples are described to illustrate how these modules function singly and in concert.

Toward more usable electronic voting: testing the usability of a smartphone voting system.

OBJECTIVE: The goal of this research was to assess the usability of a voting system designed for smart-phones. BACKGROUND: Smartphones offer remote participation in elections through the use of pervasive technology. Voting on these devices could, among other benefits, increase voter participation while allowing voters to use familiar technology. However, the usability of these systems has not been assessed. METHOD: A mobile voting system optimized for use on a smartphone was designed and tested against traditional voting platforms for usability. RESULTS: There were no reliable differences between the smartphone-based system and other voting methods in efficiency and perceived usability. More important, though, smartphone owners committed fewer errors on the mobile voting system than on the traditional voting systems. CONCLUSION: Even with the known limitations of small mobile platforms in both displays and controls, a carefully designed system can provide a usable voting method. Much of the concern about mobile voting is in the area of security; therefore, although these results are promising, security concerns and usability issues arising from mitigating them must be strongly considered. APPLICATION: The results of this experiment may help to inform current and future election and public policy officials about the benefits of allowing voters to vote with familiar hardware.

Unified theories of cognition.

Unified theories of cognition (UTCs) offer an alternative to the modal 'divide and conquer' methodology within cognitive science and attempt to address the full range of cognitive activity within a single theoretical framework. These theories, also termed 'cognitive architectures' are generally computational in nature and are intended to model, at some degree of fidelity, human cognition in a broad range of tasks. This style of research has numerous advantages, not the least of which being that the actual human cognitive system is itself an integrated system and many important tasks require bringing integrated capabilities to bear. There are also drawbacks, particularly dealing with the incompleteness of the knowledge base in cognitive science and the difficulty of evaluating such theories. Three architectures are profiled, each one representing a different 'home' discipline: from AI, Soar; from cognitive psychology, Adaptive Control of Thought-Rational; and from neuroscience, Leabra. Future directions for UTCs include expansion into branches of cognition not already well represented, such as spatial cognition, and increasing attention to cognitive moderators such as emotion and fatigue. Overall, this is a powerful research strategy that is likely to remain an important part of cognitive science for the foreseeable future. WIREs Cogn Sci 2012, 3:431-438. doi: 10.1002/wcs.1180 For further resources related to this article, please visit the WIREs website.

On the correlation between motion data captured from low-cost gaming controllers and high precision encoders.

Gaming controllers are attractive devices for research due to their onboard sensing capabilities and low-cost. However, a proper quantitative analysis regarding their suitability for use in motion capture, rehabilitation and as input devices for teleoperation and gesture recognition has yet to be conducted. In this paper, a detailed analysis of the sensors of two of these controllers, the Nintendo Wiimote and the Sony Playstation 3 Sixaxis, is presented. The acceleration and angular velocity data from the sensors of these controllers were compared and correlated with computed acceleration and angular velocity data derived from a high resolution encoder. The results show high correlation between the sensor data from the controllers and the computed data derived from the position data of the encoder. From these results, it can be inferred that the Wiimote is more consistent and better suited for motion capture applications and as an input device than the Sixaxis. The applications of the findings are discussed with respect to potential research ventures.

Using computational cognitive modeling to predict dual-task performance with sleep deprivation.

OBJECTIVE: The effects of fatigue on multiple-task performance were explored through computational cognitive modeling. BACKGROUND: Fatigue typically has a negative impact on human performance. Biomathematical models exist that characterize the dynamics of human alertness, but the link between alertness and in situ performance on specific tasks is tenuous. Cognitive architectures offer a principled means of establishing that link. METHOD: We implemented mechanisms for fatigue, which produce microlapses in cognitive processing, into an existing model, adaptive control of thought-rational, and validated the performance predictions with Bratzke, Rolke, Ulrich, and Peters' data on fatigue and multiple-task performance. RESULTS: The microlapse model replicated the human performance results very well with zero free parameters, although the fit was improved when we allowed two individual differences parameters to vary. CONCLUSION: Increased frequency of microlapses as a result of fatigue provides a parsimonious explanation for the impact of fatigue on dual-task performance and is consistent with previous research. APPLICATION: Our results illustrate how using biomathematical models of fatigue in conjunction with a cognitive architecture can result in accurate predictions of the effects of fatigue on dual-task performance. Extending and generalizing this capability has potential utility in any safety-critical domain in which fatigue may affect performance.

Task structure and postcompletion error in the execution of a routine procedure.

OBJECTIVE: To replicate a successful laboratory slip-class error paradigm and, more importantly, to further understand the underlying causes of errors made in that paradigm. BACKGROUND: Routine procedural errors are facts of everyday life but have received limited controlled empirical study, despite the sometimes severe consequences associated with such errors. This research concerns one such error, postcompletion error (M. D. Byrne & S. Bovair, 1997), which is a lapse that occurs after the main goal of a task has been satisfied. METHOD: In the two experiments conducted, participants were trained to criterion on a routine procedural task and were then brought back to the lab for a later session or sessions in which performance on task execution was measured. In the second experiment, a variety of motivational manipulations, retraining, and task redesign were compared. RESULTS: Experiment 1 demonstrated a substantial reduction of error rate generated by a simple design change (alteration of when feedback about goal completion occurred). Furthermore, the reduction in error rate came with no penalty in terms of overall speed of performance. Experiment 2 showed that this more appropriate design is superior to motivationally oriented interventions, retraining, and even midtask redesign. As in Experiment 1, Experiment 2 revealed no speed-accuracy tradeoff. CONCLUSION: These experiments provide evidence that controlled laboratory studies of slip-class errors can be meaningful and highlight the centrality of cognitive factors (particularly goal structure) in such errors. APPLICATION: Potential applications include design of interfaces and their related procedures as well as error-mitigation techniques.

Returning human factors to an engineering discipline: expanding the science base through a new generation of quantitative methods--preface to the special section.

Newell and Card (1985) warned the human factors community that the way to deal with scientists, engineers, and designers was not through the use of platitudes or by advocating the empirical testing of an infinity of design alternatives but, rather, through the use of predictive and reliable quantitative techniques. As the scope and scale of the issues that the human factors community was asked to consider expanded, the tool chest of quantitative methods seemed to diminish. That situation appears to be changing. As the papers in this special section show, the science base and techniques available for applying that science through use of quantitative formalisms have progressed. The pendulum is swinging back, and human factors engineers are in the ascendance. Engineering quantitative formal models of human performance is the wave of the present and represents an important part of the future of our profession.