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Biomedical subjects

David L Strayer

Publications and source records attributed to David L Strayer.

11 recordsLinked to original sources
PubMed2006

Understanding the long-term effects of species invasions.

We describe here the ecological and evolutionary processes that modulate the effects of invasive species over time, and argue that such processes are so widespread and important that ecologists should adopt a long-term perspective on the effects of invasive species. These processes (including evolution, shifts in species composition, accumulation of materials and interactions with abiotic variables) can increase, decrease, or qualitatively change the impacts of an invader through time. However, most studies of the effects of invasive species have been brief and lack a temporal context; 40% of recent studies did not even state the amount of time that had passed since the invasion. Ecologists need theory and empirical data to enable prediction, understanding and management of the acute and chronic effects of species invasions.

Animals↗
PubMed2006

Drug delivery as control task: improving performance in a common anesthetic task.

OBJECTIVE: To conceptualize delivery of anesthesia as a control task, similar to control tasks in nonmedical domains, and to evaluate how presentation of new information and feedback affects task performance. BACKGROUND: In anesthesia, integrated monitors that show intravenous drug and effect-site concentrations in a patient currently do not exist. However, using real-time displays of intravenous anesthetic concentrations and effects could significantly enhance intraoperative clinical performance. Pharmacological models are available to estimate past, present, and future drug concentrations in the brain and to predict the drug's physiological effects. A display that integrates pharmacological models and visualizes drug concentrations was developed and tested to see if this drug display significantly improved clinical performance. METHOD: Thirty-three anesthesiologists with different levels of expertise administered anesthesia to simulated patients in a high-fidelity patient simulator. The experimental group used a drug display that visualized drug concentrations in real time, whereas the control group administered drugs without this information. RESULTS: Anesthesiologists using the drug display achieved better hemodynamic control of the simulated patient than did the control group. Similarly, the drug display enabled anesthesiologists to wake up and reanimate the patient faster. CONCLUSION: Visual feedback of drug concentrations leads to superior performance in the delivery of anesthesia. Drug delivery can be conceptualized within a control theoretical framework. Finally, the drug display has significant clinical potential to increase patient safety. APPLICATION: Clinical performance in delivering anesthesia depends on feedback. By providing this feedback, the drug display supports clinicians' ability to more precisely and safely administer anesthesia.

Anesthetics↗
PubMed2006

A comparison of the cell phone driver and the drunk driver.

OBJECTIVE: The objective of this research was to determine the relative impairment associated with conversing on a cellular telephone while driving. BACKGROUND: Epidemiological evidence suggests that the relative risk of being in a traffic accident while using a cell phone is similar to the hazard associated with driving with a blood alcohol level at the legal limit. The purpose of this research was to provide a direct comparison of the driving performance of a cell phone driver and a drunk driver in a controlled laboratory setting. METHOD: We used a high-fidelity driving simulator to compare the performance of cell phone drivers with drivers who were intoxicated from ethanol (i.e., blood alcohol concentration at 0.08% weight/volume). RESULTS: When drivers were conversing on either a handheld or hands-free cell phone, their braking reactions were delayed and they were involved in more traffic accidents than when they were not conversing on a cell phone. By contrast, when drivers were intoxicated from ethanol they exhibited a more aggressive driving style, following closer to the vehicle immediately in front of them and applying more force while braking. CONCLUSION: When driving conditions and time on task were controlled for, the impairments associated with using a cell phone while driving can be as profound as those associated with driving while drunk. APPLICATION: This research may help to provide guidance for regulation addressing driver distraction caused by cell phone conversations.

Adult↗
PubMed2006

Lack of impairment in patients with Parkinson's disease on an object-based negative priming task.

12 nondemented patients with Parkinson's disease (M age = 67.3) and 12 normal control participants were administered an object-based attention task that enabled examination of both negative and positive priming. Unlike previous studies in which spatial-based attention tasks were used, results of the present study indicated that the patients displayed negative and positive priming not different from those shown by controls. These results suggest that certain object-based attentional processes may not be impaired in patients with Parkinson's disease.

Aged↗
PubMed2005

Invasion success of vertebrates in Europe and North America.

Species become invasive if they (i) are introduced to a new range, (ii) establish themselves, and (iii) spread. To address the global problems caused by invasive species, several studies investigated steps ii and iii of this invasion process. However, only one previous study looked at step i and examined the proportion of species that have been introduced beyond their native range. We extend this research by investigating all three steps for all freshwater fish, mammals, and birds native to Europe or North America. A higher proportion of European species entered North America than vice versa. However, the introduction rate from Europe to North America peaked in the late 19th century, whereas it is still rising in the other direction. There is no clear difference in invasion success between the two directions, so neither the imperialism dogma (that Eurasian species are exceptionally successful invaders) is supported, nor is the contradictory hypothesis that North America offers more biotic resistance to invaders than Europe because of its less disturbed and richer biota. Our results do not support the tens rule either: that approximately 10% of all introduced species establish themselves and that approximately 10% of established species spread. We find a success of approximately 50% at each step. In comparison, only approximately 5% of native vertebrates were introduced in either direction. These figures show that, once a vertebrate is introduced, it has a high potential to become invasive. Thus, it is crucial to minimize the number of species introductions to effectively control invasive vertebrates.

Animals↗
PubMed2004

Conversation disrupts change detection in complex traffic scenes.

A set of studies examined the effects of cognitive distraction on visual scanning and change detection in natural traffic scenes. Experiment 1 found that a naturalistic hands-free phone conversation could disrupt change detection, thereby degrading the encoding of visual information and increasing the frequency of undetected changes. Data also revealed a tendency for conversation to impair knowledge-driven orienting of attention in older adults. Experiment 2 found that an attentive listening task produced no such effects. Actual or potential applications of this research include the design of displays and interventions to minimize the effects of cognitive distraction on human performance.

Accidents, Traffic↗
PubMed2004

Profiles in driver distraction: effects of cell phone conversations on younger and older drivers.

Our research examined the effects of hands-free cell phone conversations on simulated driving. We found that driving performance of both younger and older adults was influenced by cell phone conversations. Compared with single-task (i.e., driving-only) conditions, when drivers used cell phones their reactions were 18% slower, their following distance was 12% greater, and they took 17% longer to recover the speed that was lost following braking. There was also a twofold increase in the number of rear-end collisions when drivers were conversing on a cell phone. These cell-phone-induced effects were equivalent for younger and older adults, suggesting that older adults do not suffer a significantly greater penalty for talking on a cell phone while driving than compared with their younger counterparts. Interestingly, the net effect of having younger drivers converse on a cell phone was to make their average reactions equivalent to those of older drivers who were not using a cell phone. Actual or potential applications of this research include providing guidance for recommendations and regulations concerning the use of mobile technology while driving.

Accidents, Traffic↗
PubMed2003

Cell phone-induced failures of visual attention during simulated driving.

This research examined the effects of hands-free cell phone conversations on simulated driving. The authors found that these conversations impaired driver's reactions to vehicles braking in front of them. The authors assessed whether this impairment could be attributed to a withdrawal of attention from the visual scene, yielding a form of inattention blindness. Cell phone conversations impaired explicit recognition memory for roadside billboards. Eye-tracking data indicated that this was due to reduced attention to foveal information. This interpretation was bolstered by data showing that cell phone conversations impaired implicit perceptual memory for items presented at fixation. The data suggest that the impairment of driving performance produced by cell phone conversations is mediated, at least in part, by reduced attention to visual inputs.

Adolescent↗
PubMed2002

Negative priming in patients with Parkinson's disease: evidence for a role of the striatum in inhibitory attentional processes.

Patients with Parkinson's disease (PD) and normal controls (NCs) performed a negative priming task. NCs displayed the normal pattern of negative priming in that relative to a control condition they were slower to identify a target within a stimulus array when it had been a distractor in the previous array. PD patients did not display any evidence of negative priming. In contrast, both PD patients and NCs displayed statistically the same level of spatial priming and response repetition cost. Regression analyses indicated that although symptom severity, symptom characteristics, and global cognitive functioning were not reliable predictors of negative priming or spatial priming in PD patients, greater symptom severity and poorer global cognitive functioning were associated with less response repetition cost. The possible role of the striatum in negative priming, spatial priming, and response repetition cost is discussed.

Aged↗
PubMed2002

Development and evaluation of a graphical anesthesia drug display.

BACKGROUND: Usable real-time displays of intravenous anesthetic concentrations and effects could significantly enhance intraoperative clinical decision-making. Pharmacokinetic models are available to estimate past, present, and future drug effect-site concentrations, and pharmacodynamic models are available to predict the drug's associated physiologic effects. METHODS: An interdisciplinary research team (bioengineering, architecture, anesthesiology, computer engineering, and cognitive psychology) developed a graphic display that presents the real-time effect-site concentrations, normalized to the drugs' EC(95), of intravenous drugs. Graphical metaphors were created to show the drugs' pharmacodynamics. To evaluate the effect of the display on the management of total intravenous anesthesia, 15 anesthesiologists participated in a computer-based simulation study. The participants cared for patients during two experimental conditions: with and without the drug display. RESULTS: With the drug display, clinicians administered more bolus doses of remifentanil during anesthesia maintenance. There was a significantly lower variation in the predicted effect-site concentrations for remifentanil and propofol, and effect-site concentrations were maintained closer to the drugs' EC(95). There was no significant difference in the simulated patient heart rate and blood pressure with respect to experimental condition. The perceived performance for the participants was increased with the drug display, whereas mental demand, effort, and frustration level were reduced. In a post-simulation questionnaire, participants rated the display to be a useful addition to anesthesia monitoring. CONCLUSIONS: The drug display altered simulated clinical practice. These results, which will inform the next iteration of designs and evaluations, suggest promise for this approach to drug data visualization.

Anesthesia, Intravenous↗