16 Clinical Trials for Various Conditions
The goal of this study is to investigate the finding that there are large individual differences in how participants move their eyes during active visual search. For example, some individuals tend to fixate, that is point their eyes steadily at a single location, for longer than other individuals before moving to another location. This experiment will use behavioral tasks to measure an individual's attentional and inhibitory functioning, and then see how each of these contributes to between-participant variability in eye movement behavior during visual search.
In this line of research, the researchers having participants engage in task switching between tasks which require a positive (target) template, negative (distractor) template, or neutral (non-informative) template to the cognitive control factors associated with each template type during visual search. This is a basic science study.
In this line of research, the researchers having participants engage in task switching between tasks which require a positive (target) template, negative (distractor) template, or neutral (non-informative) template to the cognitive control factors associated with each template type during visual search. This is a basic science study.
In this line of research, the researchers are utilizing an EEG measure of repeated visual stimulation, the Steady-State Visually Evoked Potential (SSVEP) to examine processing of target and distractor information during visual search. This is a basic science study.
In this line of research, we are examining whether motivation increases the utilization of target (positive) or distractor (negative) color cues to improve visual attention performance.
Using a noninvasive eye tracker, the investigators will measure how participants move their eyes to objects arrayed on a computer screen. Participants will be asked to find one element among many.
The experimenters will examine the relationship between utilization of positive (target cue) and negative (distractor cue) templates during a cued visual search task with performance on a set of measures related to executive functions associated with attentional control: shifting, updating, and inhibition.
When looking at an x-ray, radiologists are typically asked to localize a tumor (if present), and to classify it, judging its size, class, position and so on. Importantly, during this task, radiologists examine on a daily basis hundreds and hundreds of x-rays, seeing several images one after the other. A main underlying assumption of this task is that radiologists' percepts and decisions on a current X-ray are completely independent of prior events. Recent results showed that this is not true: perception and decisions are strongly biased by past visual experience. Although serial dependencies were proposed to be a purposeful mechanism to achieve perceptual stability of otherwise noisy visual input, serial dependencies play a crucial and deleterious role in the everyday task performed by radiologists. For example, an x-ray containing a tumor can be classified as benign depending on the content of the previously seen x-ray. Given the importance and the impact of serial dependencies in clinical tasks, in this proposal, the investigators plan to (1) establish, (2) identify and (3) mitigate the conditions under which serial effects determine the participants' percepts and decisions in tumor search tasks. In Aim 1, the investigators will establish the presence of serial effects in four different clinically relevant domains: tumor detection, tumor classification, tumor position and recognition speed. In Aim 2, the investigators plan to identify the specific boundary conditions under which visual serial dependence impacts tumor search in radiology. In Aim 3, once the investigators fully understand these boundary conditions in Aim 2, they will propose a series of task and stimulus manipulations to control and mitigate the deleterious effects of visual serial dependence on tumor search. As a result of these manipulations, visual search performance should improve in measurable ways (detection, classification, position, speed). Aim 3 is particularly crucial because it will allow the investigators to propose new guidelines which will greatly improve tumor recognition in x-ray images, making this task even more effective and reliable. Taken together, the proposed studies in Aim 1, 2, and 3 will allow the investigators to establish, identify, and mitigate the deleterious effect of serial dependencies in radiological search tasks, which could have a significant impact on the health and well-being of patients everywhere.
In "Mixed Hybrid Search", participants look for 3 specific target (e.g. this boot, this cat, this hat) and 3 categorical items (ANY fruit, ANY car, ANY game). In this task, participants tend to miss many categorical items. This is analogous to radiologists missing "incidental findings" when reading medical images. In this experiment, participants were given a checklist to help them to find categorical targets.
The goal is to look for qualitative differences in visual search behavior when one search is performed many times in a row compared to when multiple search tasks are intermixed. Four search tasks are tested. The target is the same in every task but the types of distractors change from task to task. In this version, observers get some degree of choice in what they are searching.
The goal is to look for qualitative differences in visual search behavior when one search is performed many times in a row compared to when multiple search tasks are intermixed. Four search tasks are tested. The target is the same in every task but the types of distractors change from task to task. In the Mixed condition, the four tasks are randomly changed from trial to trial. In the Blocked condition, each task is run as a block of 100 trials.
The goal is to look for qualitative differences in visual search behavior when one search is performed many times in a row compared to when multiple search tasks are intermixed. Four search tasks are tested. In the Mixed condition, the four tasks are randomly changed from trial to trial. In the Blocked condition, each task is run as a block of 100 trials.
EEG Measures during Visual Search Task. In this line of research, the researchers having participants receive a positive (target) template cue, negative (distractor) template cue, or neutral (non-informative) template cue. Note: This is a re-analysis of previously collected data.
In this line of research, the researchers are examining a basic science question regarding the working memory representations underlying visual search using a positive template (looking for a target) or a negative template (avoiding a distractor).
In this line of research, the researchers are examining the influence of relevance of a salient item on task performance, depending on overall task set.
The purpose of this protocol is to develop a valid, reliable, better standardized, and more efficient test of visual acuity (ability to see fine details) for use in clinical trials. Recent improvements in computer video hardware permit calibration, characterization, and accurate rendering of eye-chart-quality letters. The computer can then be used to measure acuity. The modified binary search (MOBS) testing strategy is one method of computer-based testing. This study will compare the accuracy, precision, stability and utility of the MOBS technique with the eye chart method used in the National Eye Institute's Early Treatment for Diabetic Retinopathy Study (ETDRS). The ETDRS method is currently the gold standard for acuity testing in clinical trials. Study subjects will include NEI clinic patients between 7 and 90 years of age with or without eye disease. Eye diseases include poor visual acuity, age-related macular degeneration, cataract, optic nerve abnormality, corneal abnormality, uveitis, glaucoma, other retinal or choroid abnormality, amblyopia or other eye disease. Participants will have their vision tested in each eye using both the ETDRS eye chart method and the MOBS method. The ETDRS method will require subjects to read all the letters on the chart until they can no longer see the details. For the MOBS method, they will read a single letter at a time that will appear on the computer screen. After reading each letter, a new letter will be presented that is either bigger or smaller in size. After completing the last acuity test, participants will fill out a questionnaire regarding their preference for one test type over the other.