CONTENTS:

Articles:

The WWDU (Work With Display Units) Conference as a Platform for Occupational Health and Safety in the Past-And as a WWCS (Work With Computer Systems) Conference in the Future Holger Luczak & Olaf Oehme, 379-382       Examining RULA’s Postural Scoring System With Selected Physiological and Psychophysiological Measures Leslie J.K. Fountain, 383-392       Prevention of Deep Vein Thrombosis in VDU Work Reiko Mitsuya, Yuichi Ebine, Manami Nozaki, & Kageyu Noro, 393-403       Symptoms and Clinical Findings From the Musculoskeletal System Among Operators at a Call Centre in Sweden—A 10-Month Follow-Up Study Allan Toomingas, Tohr Nilsson, Mats Hagberg, Maud Hagman, & Ewa Wigaeus Tornqvist, 405-418       Comparison Between the Strain Indicator HRV of a Head-Based Virtual Retinal Display and LC-Head Mounted Displays for Augmented Reality Olaf Oehme, Ludger Schmidt, & Holger Luczak, 419-430       Visual Strain and Lighting Preferences of VDT Users Under Different Lighting Systems Agnieszka Wolska, 431-440       Effect of Subjective and Objective Workload on Asthenopia at VDU Workplaces Thomas Stüdeli & Marino Menozzi, 441-451       An Attempt at Preventing Asthenopia Among VDT Workers Masako Omori, Tomoyuki Watanabe, Jo Takai, Hiroki Takada, & Masaru Miyao, 453-462       A New Approach to the Mouse Arm Syndrome Johan Ullman, Nils Kangas, Pia Ullman, Fredrik Wartenberg, & Mats Ericson, 463-477       The Effects of the Level of Alertness During the Rest Period on Subsequent Performance Ayako Hirose & Akihiko Nagasaka, 479-490       Reducing Musculoskeletal Discomfort: Effects of an Office Ergonomics Workplace and Training Intervention Michelle M. Robertson, Michael J. O’Neill, & Herman Miller, 491-502       Sitting Posture, Postural Discomfort, and Visual Performance: A Critical View on the Interdependence of Cognitive and Anthropometric Factors in the VDU Workplace Martina Ziefle, 503-514       Visual Costs of the Inhomogeneity of Luminance and Contrast by Viewing LCD-TFT Screens Off-Axis Martina Ziefle, Thomas Groeger, & Dietmar Sommer, 515-525       Evidence-Based Ergonomics. A Comparison of Japanese and American Office Layouts Kageyu Noro, Goroh Fujimaki, & Shinsuke Kishi, 527-538       Affective Computing—A Rationale for Measuring Mood With Mouse and Keyboard Philippe Zimmermann, Sissel Guttormsen, Brigitta Danuser, & Patrick Gomez, 539-551

Examining RULA’s Postural Scoring System With Selected Physiological and Psychophysiological Measures
Leslie J.K. Fountain

The Rapid Upper Limb Assessment (RULA) survey is a posture-sampling tool used specifically to examine the level of risk associated with upper limb disorders of individual workers. This paper examines the relationship between RULA’s postural scoring system and measures of surface electromyography (EMG), self-reports of discomfort, and job attitude questionnaires. Twenty participants each performed a 30-min typing task on a computer in 3 working postures based on RULA’s scoring system. A statistically significant difference was found only in perceived discomfort. The perceived discomfort results demonstrated that RULA was able to identify “high risk” postures. The next question we need to ask is, does perceived discomfort result in tissue damage, or does tissue damage yield discomfort?

Prevention of Deep Vein Thrombosis in VDU Work
Reiko Mitsuya, Yuichi Ebine, Manami Nozaki, & Kageyu Noro

This paper introduces preventive measures against Deep Vein Thrombosis (DVT) during Visual Display Units (VDU) work. Four experiments were conducted in order to address this issue. The effectiveness of the preventative measures was evaluated by measuring foot swelling. The results indicated that the following 3 methods would be particularly effective: (a) occasionally adopting a reclining posture with a footrest, (b) 10-min walking every 50–60 min of VDU work, and (3) stretching. In addition we predicted that taking a deep breath could sometimes be effective. DVT is likely to occur in daily life and its incidence can be related to the long-term postures associated with VDU work. This paper suggests that VDU workers should be aware of the risk of DVT and take preventative measures.

Symptoms and Clinical Findings From the Musculoskeletal System Among Operators at a Call Centre in Sweden—A 10-Month Follow-Up Study
Allan Toomingas, Tohr Nilsson, Mats Hagberg, Maud Hagman, & Ewa Wigaeus Tornqvist

The musculoskeletal health among 57 operators at 1 call centre in Sweden was studied with 10 monthly follow-ups, parallel to a reference group of 1,226 professional computer users in other occupations. Operators at this call centre were more symptom-loaded than the other professional computer users in spite of their younger age and shorter exposure to computer work. Symptoms were long-lasting or recurrent. Muscle tenderness and nerve affections in the neckshoulder region were the most common specific findings and diagnoses at medical examination of incident symptom cases. More extensive studies should be done on the working conditions and health status among call centre workers.

Comparison Between the Strain Indicator HRV of a Head-Based Virtual Retinal Display and LC-Head Mounted Displays for Augmented Reality
Olaf Oehme, Ludger Schmidt, & Holger Luczak

Augmented Reality uses Head Mounted Displays (HMD) to overlay the real word with additional virtual information. Virtual Retinal Displays (VRD), a new display technology, no longer requires Liquid Crystal Displays (LCD). VRD technology addresses the retina directly with a single laser stream of pixels. There are no studies on the user’s informational strain in this new VRD technology. Various papers have shown that Heart Rate Variability (HRV) is a valid indicator for the user’s informational strain. An empirical test revealed no difference in the user’s HRV between VRD technology and LCD technology. Consequently, there seems to be a comparable user informational strain regarding the display types.

Visual Strain and Lighting Preferences of VDT Users Under Different Lighting Systems
Agnieszka Wolska

Lighting influences users’ visual strain and well-being. Therefore creating lighting that ensures visual work conditions do not result in visual fatigue is a preventive activity. The aim of the study was to model different lighting systems for visual display terminal (VDT) work and to determine their influence on users’ visual strain and preferences. The results of the study showed that visual fatigue was lowest for indirect and compound lighting systems. On the other hand, in general, direct lighting realized by “dark-light” luminaires was the most preferred lighting system. Some interesting differences related to age, gender, and VDT work experience were found. On the basis of the obtained results lighting designers can be provided with some guidance.

Effect of Subjective and Objective Workload on Asthenopia at VDU Workplaces
Thomas Stüdeli & Marino Menozzi

An ergophthalmological tool has been developed to investigate effects of subjective and objective workload on work-related visual complaints (asthenopia). In field studies on different visual display unit (VDU) workplaces effects of objective and subjective workload, work intensity, and work breaks (5–9 min/hour) could be found. It could be shown that during the first hours of VDU work, asthenopic complaints have the tendency to follow effective workload. With increasing working time the effect of a general and visual fatigue overlaps other reported visual complaints in the majority of cases.

An Attempt at Preventing Asthenopia Among VDT Workers
Masako Omori, Tomoyuki Watanabe, Jo Takai, Hiroki Takada, & Masaru Miyao

We report the results of 3 surveys of visual display terminal (VDT) users who took a minibreak during which they viewed a stereoscopic image of a repeating parallel pattern showing planets. The single image stereogram method employed is called Stretch EyeTM, and we evaluated the effects of Stretch EyeTM on asthenopia. An accommodative relaxation of about 1 D was observed in participants while they were gazing at the image. The employees of 2 information technology companies were evaluated according to a visual analogue scale (VAS) for subjective symptoms of asthenopia and eyesight. The results showed that Stretch EyeTM was effective in easing visual fatigue due to VDT work and it improved eyesight under working conditions.

A New Approach to the Mouse Arm Syndrome
Johan Ullman, Nils Kangas, Pia Ullman, Fredrik Wartenberg, & Mats Ericson

OBJECTIVES: The study validates a new computer mouse concept. The tested device is a small mouse with a pivoting pen-shaped handle. The hypothesis behind the design is the assumptions that the pen grip requires less static tension than the normal mouse grip and that fine-motor, high precision tasks normally are done with finger movements with forearm at rest.
METHODS: Four muscles were monitored with electromyography (EMG) during work with a new mouse and with a traditional mouse.
RESULTS: EMG activity was significant lower, in M. pronator teres—46%, M. extensor digitorum—46%, M. trapezius—69%, and M. levator scapulae—82%, during work with the new mouse as compared to the traditional mouse.
CONCLUSION: Altering the design of the computer mouse can significantly reduce muscular tension.

The Effects of the Level of Alertness During the Rest Period on Subsequent Performance
Ayako Hirose & Akihiko Nagasaka

Effects of an office ergonomics workplace and training intervention on workers’ knowledge and self-reported musculoskeletal pain and discomfort were investigated. An instructional systems design process was used to develop an office ergonomics training program and the evaluation tools used to measure the effectiveness of the training program on workers’ office ergonomics knowledge and skills. It was hypothesized that the training and workplace intervention would allow the worker to more effectively use their workplace through increased office ergonomics knowledge and skills. Following the intervention, there was a significant increase in workers’ office ergonomics knowledge and awareness. Self-reported work-related musculoskeletal disorders significantly decreased for the group who had a workplace change and received ergonomic training relative to a workplace change-only group and a no intervention control group.

Reducing Musculoskeletal Discomfort: Effects of an Office Ergonomics Workplace and Training Intervention
Michelle M. Robertson, Michael J. O’Neill, & Herman Miller

Effects of an office ergonomics workplace and training intervention on workers’ knowledge and self-reported musculoskeletal pain and discomfort were investigated. An instructional systems design process was used to develop an office ergonomics training program and the evaluation tools used to measure the effectiveness of the training program on workers’ office ergonomics knowledge and skills. It was hypothesized that the training and workplace intervention would allow the worker to more effectively use their workplace through increased office ergonomics knowledge and skills. Following the intervention, there was a significant increase in workers’ office ergonomics knowledge and awareness. Self-reported work-related musculoskeletal disorders significantly decreased for the group who had a workplace change and received ergonomic training relative to a workplace change-only group and a no intervention control group.

Sitting Posture, Postural Discomfort, and Visual Performance: A Critical View on the Interdependence of Cognitive and Anthropometric Factors in the VDU Workplace
Martina Ziefle

The study focuses on individual and standard visual display unit (VDU) workplaces with respect to performance and muscular load. Three different work settings were realized: The workplace was either adjusted to individual preferences or to the European standard. The third condition mirrored exactly the individual setting, however participants were told that it was set according to another standard. Dependent variables were visual performance in a search task, the rated muscular load, and individual preferences. Results show that both individual work settings yielded a superior performance as compared to the standard. However, performance and muscular comfort improved when participants knew they had adjusted the workplace. Apparently, VDU users follow a intuitive rationale adjusting their work setting minimizing muscular load and optimizing performance.

Visual Costs of the Inhomogeneity of Luminance and Contrast by Viewing LCD-TFT Screens Off-Axis
Martina Ziefle, Thomas Groeger, & Dietmar Sommer

In this study the anisotropic characteristics of TFT-LCD (Thin-Film-Transistor-Liquid Crystal Display) screens were examined. Anisotropy occurs as the distribution of luminance and contrast changes over the screen surface due to different viewing angles. On the basis of detailed photometric measurements the detection performance in a visual reaction task was measured in different viewing conditions. Viewing angle (0°, frontal view; 30°, off-axis; 50°, off-axis) as well as ambient lighting (a dark or illuminated room) were varied. Reaction times and accuracy of detection performance were recorded. Results showed TFT’s anisotropy to be a crucial factor deteriorating performance. With an increasing viewing angle performance decreased. It is concluded that TFT’s anisotropy is a limiting factor for overall suitability and usefulness of this new display technology.

Evidence-Based Ergonomics. A Comparison of Japanese and American Office Layouts
Kageyu Noro, Goroh Fujimaki, & Shinsuke Kishi

There is a variety of alternatives in office layouts. Yet the theoretical basis and criteria for predicting how well these layouts accommodate employees are poorly understood. The objective of this study was to evaluate criteria for selecting office layouts. Intensive computer workers worked in simulated office layouts in a controlled experimental laboratory. Eye movement measures indicate that knowledge work requires both concentration and interaction. Findings pointed to one layout as providing optimum balance between these 2 requirements. Recommendations for establishing a theoretical basis and design criteria for selecting office layouts based on work style are suggested.

Affective Computing—A Rationale for Measuring Mood With Mouse and Keyboard
Philippe Zimmermann, Sissel Guttormsen, Brigitta Danuser, & Patrick Gomez

Emotions are an increasingly important factor in Human-Computer Interaction (HCI). Up to the present, emotion recognition in HCI implies the use of explicit or intrusive methods, for example, video cameras or physiological measurements. We are developing and evaluating a method for the measurement of affective states through motor-behavioral parameters from standard input devices (mouse and keyboard).