Wingz Ergonomic Computer Keyboard An overview of research leading to a new keyboard design

Transcription

1 Wingz Ergonomic Computer Keyboard An overview of research leading to a new keyboard design Advanced Research Computers Inc. March 2011 Abstract The Wingz Smartkeyboard is an advance in computer keyboard design, combining beneficial hand and wrist position with modern multi-touch display technology. This paper discusses research findings supporting the use of correct hand and wrist position to reduce inter-carpal tunnel pressure in the prevention of Musculoskeletal disorders (MSDs), such as carpal tunnel syndrome, and repetitive strain injuries (RSI). The wireless Wingz computer keyboard includes a multi-touch display screen which replaces and extends the functionality of the computer mouse. The keyboard contains a choice of fully functional operating systems including Windows Mobile, Android, Apple ios, as a gateway to thousands of software applications. Additional keyboard features include: WiFi, telephony capabilities, high definition pico projector and anti-bacterial surfaces. The cost savings resulting from a solid ergonomic program can be substantial. Using numbers derived from modern studies on injury rates and using a hypothetical company employing 500 computer users as an example, a 10 percent reduction in repetitive strain injuries and symptoms would yield an annual savings of $700,000. Using the Wingz ergonomic keyboard provides computer users with a healthy and productive workplace, but is good for the bottom line as well. Page 1 of 6

2 The Scope and Costs of RSI The costs associated with repetitive strain injury (RSI) to businesses are increasing; in 2006 the federal Occupational Safety & Health Administration (OSHA) estimates them to be between $15 billion and $20 billion per year in the United States. The Washington State Department of Labor and Industries, reports the following: The magnitude, cost and burden of work-related musculoskeletal disorders (WMSDs) are enormous. From , there were 380,485 Washington state accepted workers' compensation state fund claims for nontraumatic soft tissue musculoskeletal disorders of the neck, back and upper extremity. These claims resulted in $2.9 billion in direct costs, and 26.9 percent of all state fund workers' compensation claims. Of WMSD claims during this time period, 32.4% were compensable with an average of 123 lost time days per compensable claim. Translating this to a hypothetical company of 500 computer users, a 10 percent reduction in repetitive strain injuries and symptoms would yield an annual savings of $700,000 in claims. Keyboard Research findings Split keyboards A 2008 study funded by the National Institute of Health (NIH) and published in the Orthopedic Research Society Journal by Dr Rempel et al, Effect of Wrist Posture on Carpal Tunnel Pressure while Typing 1 provides a review of research and guidelines for keyboard makers. a physiological basis to support the findings of two randomized intervention studies of fixed split keyboards.2,3 Both intervention studies found that the use of a fixed split keyboard reduced hand discomfort and pain when compared to a conventional keyboard. One of the studies was a 6 month trial of patients with carpal tunnel syndrome and tendonitis.2 In a separate laboratory study, the fixed split keyboard reduced wrist extension, ulnar deviation, and pronation in comparison to a conventional keyboard.1 Hand and Wrist Position and Carpal Tunnel Pressure Based on human and animal studies, one mechanism for the development or aggravation of carpal tunnel syndrome may involve the sustained elevation of the fluid pressure inside the carpal tunnel.5 Patients with carpal tunnel syndrome typically have elevated carpal tunnel pressures in comparison to healthy controls.6 Animal studies support the concept of a pressure threshold for nerve injury.7 Carpal tunnel pressure is influenced by wrist posture,6,8,9,10 forearm posture, finger posture,8 and fingertip force.11,12 Specifically, carpal tunnel pressure increases with forearm rotation from 45 of pronation,10, 11 and wrist deviation from neutral, especially in wrist extension. 8 The findings of this study suggest that the keyboard and workstation be adjusted to avoid wrist extension greater than 30 and radial deviation greater than 15 when using a computer for long hours. Wrist extension can be reduced by positioning the keyboard at or lower then elbow height. Ulnar deviation can Page 2 of 6

3 be reduced by using a split keyboard, but it should be noted that a large keyboard opening angle may lead to radial deviation, which should be avoided.1 Wingz Keyboard Design The Wingz keyboard is based on a continuous curved arc design, enabling the correct arm and hand position while typing. A multi-touch display is embedded in the center of the split curved keyboard. The multi-touch display is a fully functional mobile computer supporting standard smartphone software applications. Curved Keyboard Wrist Angle 45 degrees The photo below shows a user with wrist angle markers to illustrate the Wingz keyboard providing the correct wrist angle of 45 degrees while typing, research has proven this position to be the lowest internal carpal tunnel pressure.1,8,9,10 Page 3 of 6

4 Curved Keyboard Radial Deviation 0-10 Degrees The photo below shows a user with wrist angle markers and wrist deviation (black line) to illustrate the Wingz keyboard promotes the correct wrist radial deviation of 0-10 degrees proven to be the position of lowest internal carpal tunnel pressure. 1,8,9,10 Replacing the Computer Mouse A study of carpal tunnel pressure during computer mouse use reported an increase in pressure with button pressing compared to just resting the hand on the mouse.12 A touch display embedded in the keyboard eliminates the hazard of button pressing finger tip pressure. The photo below comparing approximately 5-10 degrees, internal pressure) 9,11,12. approximately 45 degrees, pressure) 1,8,9,10. wrist pronation while mousing with left hand at (this position has proven increased carpal tunnel To wrist angle on keyboard with left and at (this position has proven lowest carpal tunnel Page 4 of 6

5 Hazards of Mouse use Carpal tunnel pressures measured while performing mousing tasks were found to attain a level of concern. Active use of the mouse elevated the pressure in the carpal tunnel to ~ 30 mmhg. Prolonged pressure of this magnitude has been associated with altered nerve function and structure in human and animal nerve studies (Hargens et al. 1979, Lundborg et al. 1983, Powell and Myers 1986, Dahlin et al. 1987) as well as eliciting symptoms of carpal tunnel syndrome when induced in the carpal tunnel (Lundborg et al. 1982). These changes in tissue physiology may be the first step in a cascade of events that lead to carpal tunnel syndrome (Dahlin et al. 1987, Rempel 1995). Mousing, in general, promotes a fully pronated forearm. Forearm rotation has been shown to affect carpal tunnel pressure (Rempel et al. 1998, Werner et al. 1997). Smartkeyboard Applications The photos below show the software applications available for the Wingz keyboard. Standard smartphone applications and custom function applications can be displayed on the multi-touch display screen. Conclusions The Wingz computer keyboard is based on laboratory research to identify the root causes of wrist injuries. Wingz ergonomic keyboard provides computer users with a healthy and productive keyboard, which is good for worker health and company bottom line as well. Page 5 of 6

6 Related Links and References Washington State Department of Labor and Industries MSD information: Ergoweb Inc. s ergonomic success stories: Future Industrial Technologies press release, Carpal Tunnel Syndrome Reaching Epidemic Proportions, Jan. 18, 2005: The Typing Injury FAQ: 1. J Orthop Res September ; 26(9): doi: /jor Effect of Wrist Posture on Carpal Tunnel Pressure while Typing 1,2) David M. Rempel, 3)Peter J. Keir, 4) Joel M. Bach 1 Department of Medicine, University of California, San Francisco, California 2 Department of Bioengineering, University of California, Berkeley, California 3 Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada 4 Orthopaedic Biomechanics Labs, Department of Orthopaedics, University of Colorado Health Sciences, Center, Denver, Colorado 2. Tittiranonda P, Rempel D, Armstrong T, et al. Effect of four computer keyboards in computer users with upper extremity musculoskeletal disorders. Am J Ind Med 1999;35: [PubMed: ] 3. Moore, JS.; Swanson, N. The effect of alternative keyboards on musculoskeletal symptoms and disorders. Proceedings of the Human Computer Interaction International Conference; Crete p Rempel D, Barr A, Brafman D, et al. The effects of six keyboard designs on wrist and forearm postures. Appl Ergonomics 2007;38: Rempel D, Dahlin L, Lundborg G. Pathophysiology of nerve compression syndromes: response of peripheral nerves to loading. J Bone Joint Surg (Am) 1999;81: [PubMed: ] Rempel et al. Page 5 J Orthop Res. Author manuscript; available in PMC 2009 March Seradge H, Jia YC, Owens W. In vivo measurement of carpal tunnel pressure in the functioning hand. J Hand Surg (Am) 1995;20: [PubMed: ] 7 Diao E, Shao F, Liebenberg E, et al. Carpal tunnel pressure alters median nerve morphology and function in a dose-dependent manner: A rabbit model for carpal tunnel syndrome. J Orthop Res 2005;23: [PubMed: ] 8 Keir PJ, Bach JM, Rempel DM. Effects of finger posture on carpal tunnel pressure during wrist motion. J Hand Surg 1998;23: Werner R, Armstrong TJ, Bir C, et al. Intracarpal canal pressures: the role of finger, hand, wrist and forearm position. Clin Biomech 1997;12: Keir PJ, Bach JM, Hudes M, et al. Guidelines for wrist posture based on carpal tunnel pressure thresholds. Human Factors 2007;49: [PubMed: ] 11. Rempel D, Keir PJ, Smutz WP, et al. The effects of static fingertip loading on carpal tunnel pressure. J Orthop Res 1997;15: [PubMed: ] 12. Keir PJ, Bach J, Rempel D. Effects of computer mouse design and task on carpal tunnel pressure. Ergonomics 1999;42: [PubMed: ] Page 6 of 6