Beverly Jaeger

Comparison of Simulator Sickness Using Static and Dynamic Walking Simulators

Findings from the Simulator Sickness Questionnaire (SSQ) evaluated several factors related to the physiological effects of immersive virtual environments (IVE) exposure. Subjects conducted locomotion activities within a selected IVE by traversing a three-dimensional computer hallway setting using either a mouse-driven static simulator or a treadmill-operated dynamic simulator system. Two levels of rendered visual detail were also compared for their SSQ effects. Simulator Sickness Questionnaire analyses reveal an effect of gender such that the females were significantly more affected by simulator activities than the male subjects. Length of time in the simulator was also found to have a significant physiological effect on the participants in the tested range of 13–23 minutes of exposure. Longer time intervals were associated with significantly greater symptoms of simulator sickness and perceived discomfort. A comparison of scores between distance judgment and movement production activities produced no significant results, leading to the conclusion that the task objectives were not different from one another in simulator effects on the participants. Individuals who used the static simulator were significantly more affected than those with similar exposure times in the dynamic simulator. Analysis of two levels of detail in the IVEs revealed a tendency for more richly textured imagery to yield higher Total Severity SSQ scores with nearly significant differences. In accordance with previously established simulator sickness profiles, the static simulator pattern of symptoms resembled those of visually-dependant IVEs (cybersickness), while the dynamic simulator symptomology was more analogous to that of motion-based IVEs (classic simulator sickness).

Optic flow and geometric field of view in a driving simulator display

This article reports on a study that used a driving simulator to display conditions of high and low optic flow. The study included 30 drivers who were requested to produce vehicle speeds of either 30 or 60 mph with the geometric field of view at 25, 55, or 85 visual degrees. Drivers overestimated the production of 30 by 20 mph. It was also found that the production of speed was highly dependent on the geometric field of view. These results suggest that optic flow presented in a driving simulator display does not correspond with optic flow found in real-world driving.

MEASURING DIVIDED-ATTENTION CAPABILITY OF YOUNG AND OLDER DRIVERS

A divided-attention task was used to measure the ability of young and older drivers to obtain information from an in-vehicle display. Performance with the in-vehicle display was compared with performance with information superimposed on the driving scene. Ten young and 10 older drivers drove on a curvy road by using a fixed-based driving simulator. Older drivers were less accurate in obtaining information from the in-vehicle display, the average lane-position error of older drivers was greater, and older drivers spent more time driving outside their lanes. These results suggest that the use of in-vehicle displays, in their present configuration, is not appropriate for older drivers. When viewing information superimposed on the driving scene, older drivers were much more accurate and controlled their vehicles better. This indicates that the poor performance of older drivers with the in-vehicle display was due to vision-related changes, such as longer eye accommodation times, rather than cognitive processes.

The Effect of Driving Environments on Simulator Sickness

In order to be an effective tool for driver evaluation and education, driving simulators need to be better designed to reduce simulator sickness. This study investigated driving in four environments (country, suburban, city, and curves) using a simulator. When driving on straight roads (city and suburban environments) subjects reported less simulator sickness then driving in the city environment (which included left and right turns) and on curves. A mini-SSQ was used to measure the accumulation of simulator sickness over trials. From trial 1 to trial 5, reported simulator sickness increased linearly. From trial 5 through 8, the rate of increase in simulator sickness decreased. We suggest that the rapid and distorted optic flow experienced while executing turns and driving on curves in driving simulators makes a substantial contribution to simulator sickness.

DRIVING PERFORMANCE OF NOVICE AND EXPERIENCED DRIVERS IN LANE-CHANGE SCENARIOS

Using a virtual reality driving simulator, the behavior of 12 novice and 12 experienced drivers was recorded during three right-to-left lane-change scenarios. The first scenario had no vehicles in the left lane, the second had one rear-approaching vehicle in the left lane, and the third had three vehicles approaching from the rear left lane. Each lane-change maneuver was composed of 1) a preparatory period, 2) the actual steering initiative from the right lane to the left lane, and 3) a post-lane change period and was to be accomplished while maintaining a specified highway velocity. Lane deviation data showed that novice drivers had significantly more variance in lane position during the preparatory and post-lane change periods than experienced drivers. Novice drivers also spend significantly less time looking at the vehicles speedometer and mirrors. This study suggests that virtual reality driving simulators may be useful in helping novice drivers acquire the skills necessary for safe lane change maneuvers.

Toward Monitoring Parkinson's Through Analysis of Static Handwriting Samples: A Quantitative Analytical Framework

Detection of changes in micrographia as a manifestation of symptomatic progression or therapeutic response in Parkinsons disease (PD) is challenging as such changes can be subtle. A computerized toolkit based on quantitative analysis of handwriting samples would be valuable as it could supplement and support clinical assessments, help monitor micrographia, and link it to PD. Such a toolkit would be especially useful if it could detect subtle yet relevant changes in handwriting morphology, thus enhancing resolution of the detection procedure. This would be made possible by developing a set of metrics sensitive enough to detect and discern micrographia with specificity. Several metrics that are sensitive to the characteristics of micrographia were developed, with minimal sensitivity to confounding handwriting artifacts. These metrics capture character size-reduction, ink utilization, and pixel density within a writing sample from left to right. They are used here to “score” handwritten signatures of 12 different individuals corresponding to healthy and symptomatic PD conditions, and sample control signatures that had been artificially reduced in size for comparison purposes. Moreover, metric analyses of samples from ten of the 12 individuals for which clinical diagnosis time is known show considerable informative variations when applied to static signature samples obtained before and after diagnosis. In particular, a measure called pixel density variation showed statistically significant differences (

Quantitative assessment of a therapeutic exercise in mitigating micrographia associated with Parkinson's disease

p < 0.05

Objective Quantitative Assessment of Movement Disorders Through Analysis of Static Handwritten Characters

) between two comparison groups of remote signature recordings: earlier versus recent, based on independent and paired t-test analyses on a total of 40 signature samples. The quantitative framework developed here has the potential to be used in future controlled experiments to study micrographia and links to PD from various aspects, including monitoring and assessment of applied interventions and treatments. The inherent value in this methodology is further enhanced by its reliance solely on static signatures, not requiring dynamic sampling with specialized equipment.

Control Design for a Hand Tremor Suppression Pen

Parkinsons disease (PD) is the second most common neurodegenerative disorder. The debilitating nature of this medical condition can negatively impact use of the upper limb for tasks such as handwriting, which affects daily lives of many PD patients. A two-week self-administrated handwriting therapeutic exercise protocol, Amplified Air Writing (AAW), has been conducted by six PD subjects who have demonstrated micrographia symptoms, to investigate its influence on their writing samples. To study handwriting changes, several computerized metrics developed by our group to quantify micrographia were implemented. Metric results demonstrate significant temporary improvement for post-AAW handwriting performance; cursive samples especially show clear benefits for the subjects. Therefore, this self-administrated AAW exercise has potential to impart benefits on a larger PD population in their handwriting.

A novel quantitative assessment method to detect effects of essential tremor on static handwriting

Movement disorders associated with Essential Tremor (ET) and Parkinson’s disease (PD) can negatively impact use of the upper limb for many precision tasks, including handwriting. Both ET and PD can be assessed through clinical tests which are, however, relatively subjective. This assessment approach possesses inherent logistical and resolution limitations. To address this, here we present objective computerized metrics intended to assess and quantify the extent to which static writing samples display the effects of ET and PD. Specifically, these metrics are tested in their ability to measure tremor by comparing unaffected writing samples with those affected by artificially induced tremor on healthy subjects, and also by comparing healthy writing samples with symptomatic writing samples collected from PD patients reporting micrographia. Our findings indicate that the presented metrics can be utilized for assessment, leading to a toolset capable of objectively monitoring static handwriting changes associated with symptom variations in ET and/or PD patients.Copyright