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Temporal change in bimanual interkeypress intervals and self-reported symptoms during continuous typing
Huey-Wen Liang1, Yaw-Huei Hwang, Fu-Han Chang
1Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan, ROC.
Journal of Occupational Rehabilitation
|October 3, 2008
Summary
Continuous typing causes fatigue and discomfort, with right-hand interkeypress intervals (IKIs) shortening over time while left-hand IKIs lengthen. Typing speed remained consistent despite increased pain.
Area of Science:
- Ergonomics
- Human-Computer Interaction
- Occupational Health
Background:
- Continuous typing can lead to mental and muscular fatigue, contributing to musculoskeletal discomfort.
- Understanding temporal changes in typing symptoms and interkeypress intervals (IKIs) is crucial for ergonomic assessments.
Purpose of the Study:
- To describe temporal changes in symptoms and IKIs for each hand during prolonged typing.
- To examine the effects of demographics and time on typing IKIs.
Main Methods:
- 24 skilled typists performed a 90-minute continuous typing task.
- Collected data included self-reported pain/fatigue, typing speed, accuracy, and IKIs using VDTlog software.
- Generalized estimating equation (GEE) analysis explored demographic and temporal effects on IKIs.
Main Results:
- Pain and fatigue increased significantly after 60 and 90 minutes of typing, with common complaints in eyes, upper back, and wrists.
- Average typing speed and accuracy remained consistent throughout the 90-minute session.
- Right-hand IKIs shortened in the final 10 minutes, while left-hand IKIs lengthened during the last 10 minutes of each 30-minute interval.
Conclusions:
- Continuous typing affects left and right-hand IKIs differently over time.
- Right-hand IKIs decrease with prolonged typing, particularly in the last 10 minutes.
- Left-hand IKIs increase as typing sessions progress, despite stable typing speed and observed increases in perceived pain and fatigue.
