Harrington Arthritis Research Center Study
Functional Evaluation of the DataHand® Key Entry SystemUser Experience Evaluated By Questionnaire
James B. Koeneman, Ph.D.
Harrington Arthritis Research Center, Phoenix, AZ
GOAL:
To determine if the DataHand® system is effective in reducing discomfort and/ or whether use of this alternative device provides extensive keyboard users the option to return to work.
BACKGROUND AND SIGNIFICANCE
Recent years have seen a substantial increase in the number of computers and the proportion who use them heavily [12,15]. Intensive use of keyboards result in high levels of discomfort [3] and is clearly a major factor in the incidence of cumulative musculoskeletal disorders among office workers. Repetitive stress injury in the United States has been characterized as an epidemic. From 1989 to 1990 the rate increased 23%, but among office workers it more than doubled (OSHA, Bureau of Labor Statistics).
The Bureau of Labor Statistics reports that more than 50 percent of all occupational illnesses reported in 1988 were associated with repetitive trauma. It is projected that by the year 2000, 50 percent of the work place will be at risk of developing carpal tunnel disorders (CTD). Many of these are computer users, and by the year 2000, 75 percent of all jobs will involve the use of computers. The American Academy of Orthopedic Surgeons estimates that CTDS cost $27 billion annually in medical treatment and lost income [7]. According to the U.S. Department of Labor, in 1981 CTD accounted for 18 percent of all occupational injuries; by 1988, the percentage had increased to 48 percent [3]. Law suits involving CTD also are costly. A $270 million lawsuit was filed against a supplier of word processing systems by eight journalists. Lawsuits were filed against a manufacturer of computer terminals by U. S. West telephone operators in Denver and Phoenix.
Factors characteristic of keyboard use (repetitive motions, wrist abduction and dorsiflexion, constrained posture and constant application of static forces such as are required to support and pronate the hands) are implicated in a number of studies as contributors to the rate of musculoskeletal problems in video display terminal (VDT) work. No clear determination of factors has been ascertained but there is a strong incentive to provide alternatives to the standard keyboard to reduce or eliminate these sources of stress.
In computer terminal operators there are many manifestations of CTDS. There is carpal tunnel syndrome [19], DeQuervain's tendinitis [20,9], Thoracic outlet syndrome [14], tenosynovitis [16], lateral/medial epicondylitis [13], and numerous nerve compressions. Most, if not all, of the CTDs are caused by swelling. Tendon fibers can be damaged which initiates an inflammatory response, or the synovial sheath surrounding tendons can be damaged causing inflammation. The factors which initiate the inflammation are numerous. Overload of a tendon can be a cause and external pressure to a tendon especially during tendon motion, can be a cause. The size of bony canals can predispose a person to CTD [5]. Posture and angulation of joints can put excessive pressure on tendons and tendon sheaths. Because CTDs develop over time and there can be more than one contributing factor, it is difficult to study CTD. Nevertheless there are basic postural, force and repetitive guidelines that have been proposed to reduce the incidence of CTD.
Grandjean states; "Operation of a keyboard is a mixture of dynamic and static muscle work. The fingers do mainly dynamic work and the muscles in the forearm do mainly static work. The trunk-neck- shoulder-arm area is reduced to providing a support for the limbs involved in typing." [6].
Keyboard operators seek a hand position that brings the line of the basic finger joints parallel to the keyboard rows. With the existing flat keyboard a marked pronation and ulnar abduction is necessary to ensure such hand posture [1,17].
"The strong pronation of hands operating a keyboard is associated with a considerable static load of the corresponding muscles. To relieve the degree of pronation the operator can raise the elbows. This postural adaptation decreases the static nerve tension caused by pronation, but it forces the operator to increase the ulnar abduction of the hands; this in turn can generate a static load in the shoulders" [6].
To solve the functional problems causing CTD a total systems approach must be taken to design a product system that builds on these ergonomic studies by matching the tasks to the user. There are several alternatives to conventional keyboards either on the market today or will be soon. All these alternatives are based on the conventional flat keyboard in differing configurations that attempt to address keying stress factors by including various combinations of designs to reduce wrist angles and hand pronation, provide hand support, reduce key force and/or key motion, and distribute the workload more efficiently among the fingers.
The DATAHAND system's unique design allows the user flexibility to place the "keyboard" in an individually comfortable position and allows for support to forearms with use of chair armrests.
The DATAHAND system operators are not required to support their forearms and hands during keying functions. When using the DATAHAND system the operator rests his/her forearms on the chair arm with hands supported by the left and right palm supports. Operators normally type with the left and right units apart; creating a straight line from the elbow to the wrist. This also allows for small movements in arms and hands as operators shift their weight as seated. Static and dynamic forces work with, and not against, the human anatomy. Adjustments in anthropometric dimensions are accommodated by the physical design of the keying system.
The DATAHAND system potentially could reduce CTD by decreasing strike force and static loading. In addition, repetition of key strokes are mitigated by the introduction of lateral action keys in the new five-way key switch module developed for this design concept.
Although CTD has been characterized by some as a disease caused by workers compensation benefits, it has been the experience of the clinical participants in this proposal that the physical ailments are real. Sometimes recovery from treatment and incentive to use a new device can be affected by compensation and other non-medical causes.
To reduce the incidence of CTD, major changes in the work place will have to be implemented [2). The DATAHAND system's unique design offers such change. It's use offers potential change in health benefits, but also in prospective economic and organizational outcomes.
This paper presents the results of a questionnaire survey for the evaluation of the first twenty five users of the DATAHAND system device for keyed data entry.
METHOD
The initial 39 people who were shipped the DATAHAND system devices were contacted by telephone. Fourteen of the 39 people were not using the DATAHAND system due to changes in medical status, learning incentives, or incompatibility to work environments. Each of the remaining 25 people were interviewed using a survey form (questionnaire) containing more than 80 questions relating to demographics, diagnosis, history, pain assessments, alternative device usage, learning curve time frames and, ease of use. Each interview was conducted by a single researcher and was between 15 and 30 minutes in length. The results are based on the twenty-five people actually using the DATAHAND system at the time of survey.
USER PROFILE RESULTS
Answers from 25 users of the DATAHAND system were tabulated. These results include responses given by users when asked about use of conventional keyboards. Twenty-five users ranging in age from 26 to 54 (average 38.2 years) were interviewed. Nine were male, 16 were female. Types of work included programming (9), secretarial (4), numerical data entry (3), writer/publisher (3), data analysis (2), medical records (1) and training (1).
TYPE OF WORK
Medical help was sought by all but one user with the majority (13) seeking help within the first six month of symptomatology. The majority (19) reported that pain and symptoms increased gradually but six reported that the onset of symptoms was very rapid.
A pain assessment scale rating pain on a scale from 1 to 10 with 1 being the least and 10 being the greatest was used to assess pain throughout the questionnaire. Using this scale, users rated pain levels while keying on a flat keyboard at 7.7. When asked to report how long the user could use the keyboard prior to pain or symptom onset the average length of time was approximately 30 minutes. Pain when keying on a flat keyboard started at a level of 3.2 (scale 1 to 10) and increased upwards as activity continued. Nineteen reported presence of symptoms at night. Twenty-three reported presence of symptoms during the day. Symptoms were present during many normal daily activities such as driving (23), reading (20), holding children (11), telephoning and, performing household chores.
All but one user was diagnosed by a medical professional. Medical specialties for the professionals included hand surgery, orthopaedics, general practice, neurology and, homeopathy [Chart 3] with the majority of diagnosticians being hand surgeons (9) and orthopaedic surgeons (6).
Users reported numerous physical tests performed to aid diagnosis. These included nerve conduction (16), x-rays (14), electromyogram (14), Tinel's (2), Phalen's (2) and MRI (1). The most common diagnosis was carpal tunnel syndrome (10) and tendinitis (5). Other diagnosis included tenosynovitis, synovitis, and nerve compression.
DIAGNOSIS
Most users (17) have discussed hand surgery with their physician but only seven have actually had surgery.
Medications for pain management included nonsteroidal antiinflammatories (NSAID), antiinflammatories, and steroids. No clear result is available to indicate the success or failure of these therapies. Most users (20) are currently medication free.
Other methods to relieve pain and symptoms included special equipment (76%), rest (72%) and exercise (25%). The most commonly used special equipment included splints. Most users reported that none of these methods greatly reduced symptoms.
PERFORMANCE RESULTS
Twenty-two users reported the primary reason for switching to the DATAHAND® system to be the result of a medical condition. Fifteen (63%) reported that the impact of their medical condition on their job performance resulted in risk of career loss while eight (23%) reported the impact to reduce productivity. [Chart 51 When asked to rate the level of concern for job/career loss on a scale of one to ten (ten the highest) the users reported an average of 7.1 for concern. One participant reported that the use of the DATAHAND® system had saved his/her job.
Pain assessment, using the pain scale of 1 to 10 with 10 being the highest, when keying on a standard flat keyboard is reported at a level of 7.7 but was somewhat reduced (6.1) just prior to use of the DATAHAND® system. This may be attributed to change of work habits or use of special equipment such as splints, wrist rests, and voice recognition systems. However, pain assessment scores upon first use of the DATAHAND® system drop to 4.3 (44% and 29% change respectively) and further drop to 2.2 (48% change) when asked to assess pain now. [Chart 6 and 6A].
DISCOMFORT BY INDIVIDUAL USER
The DATAHAND® system users surveyed reported length of time of use to be an average of 3.3 months with daily use of 4.4 hours on average. Sixteen (64%) reported reduction of symptoms while six (24%) stated that the symptoms had not changed and one reported increased symptomatology. First recognition of reduction of symptoms occurred in an average of 7.4 days from first use of the DATAHAND® system. Of the seven reporting swelling as a symptom, five reported that the swelling had gradually reduced with the use of the DATAHAND® system.
Other questions related to learning curves and productivity when using the DATAHAND® system device. Data is inconclusive due to length of usage time. The DATAHAND® system's design places all but four keys in the standard QWERTY positions, but incentive to learn something new and the retraining of muscle memories is necessary for most touch typists. Most users (22) reported reaching comfort in use after 2.6 weeks, but also reported that while keying speed did not appear to equal flat keyboard speed it would only be a matter of time before it did equal or exceed it. Three users reported that their word per minute speed is greater on the DATAHAND® system than on the flat keyboard. Fourteen users have chosen to use the DATAHAND® system exclusively, while eleven task share with flat keyboards. The most common reason for task sharing is use of multiple computers.
SUMMARY
This preliminary study indicates that the DATAHAND® system is potentially a viable alternative to traditional keyboard devices. The initial pain reduction demonstrated is impressive. This questionnaire is the first step - it establishes a baseline. The DATAHAND® system warrants more extensive and longer term review. The DATAHAND® system's unique design may also provide help for other categories of users with problems such as arthritis, spinal injury, or blindness.
Repetitive stress injury incidents continue to be a significant problem for people who make intensive use of keyboards. Studies including objective measurements such as strength evaluations, surface electromyography to identify muscle dysfunction, postural asymmetry, and functional outcomes, and vibrometry are in progress. Periodic evaluations to assess long term use are needed. For people with hand pathology such as Carpal Tunnel Syndrome and tendinities, the DATAHAND® system design offers much needed support and may provide the opportunity for continued job security.
REFERENCES
ACKNOWLEDGEMENT'SAyoub, M.A., Ergonomic Deficiencies: Ill. Root Causes and Their Correction, J. of Occupational Medicine, 32, 5 (1990) pp. 455-460. Ayoub, M.A., Wittels, N.E., Cumulative trauma disorders, International Reviews of Ergonomics, 2 (1989) pp. 217-272 Barrer, S.J., Gaining the Upper Hand on Carpal Tunnel Syndrome, Occupational Health and Safety, Jan 1991, Vol 60 No. 1, p. 38. Ferrell, W.R., Knight, L.W., Koeneman, J.B. (1992). Preliminary Test and Evaluation of DataHand®@) (A keyboard alternative designed to prevent musculoskeletal disorders and to improve performance). Ergonomics & Safety Conference Proceedings. Gordon, C., et al Wrist Ration Correlation with Carpal Tunnel Syndrome in Industry, Am. 1. Phys. Med Rehabil., 67 (1988) pp. 270-272. Grandjean, E., Fitting the Task to the Man: A Textbook of occupational Ergonomics, 4th ed., (1988) Taylor & Francis, London. Joyce, M., Ergonomics will Take Center Stage During '90s and into New Century, Occupational Health and Safety, (1991). Kelly, Charles(1994).Gadgets designed to be 'user friendly'. The Arizona Republic, January3, 1994. Keon-Cohen,B.DeQuervain's Disease, J. of Bone and joint Surgery, 33B l (l951) pp.96-99. Knight, L.W., Koeneman, J.B., Ferrell, W.R. (1991). Evaluation of the DataHand® key entry system for physically challenged users. RESNA Conference Proceedings 1991. Koeneman, J.B. (1991). A Biomechanical Comparison of DataHand® and Conventional Data Entry. Harrington Arthritis Research Center Report, (1991) March 25. Kominsky, R. (1991). Computer use in the United States: 1989 (Current Population Reports, Special Studies Series P-23, No. 171). US Department of Commerce, Bureau of Census. Kurppa, K., Waris, P., Rokkanen, P., Tennis Elbow: Lateral Elbow Pain Syndrome, Scandinavian J. of Work, Environment and Health, 5 (1979a) Supplement 3 pp. 15-18. Lascelle, R.G., Mohr, P.D., Neary, D., Bloor, K., The Thoracic Outlet Syndrome, Brain, 100 (1977) pp. 601-612. Louis Harris & Associates (1989). Office environment index (A survey for Steelcase, Inc.) No. Louis Harris & Associates Luopajarvi, T., Kourinka, I., Virolainen, N., Homlmberg, M., Prevalence of Tenosynovitis and Other Injuries of the Upper Extremities in Repetitive Work, Scandinavian J. of Work, Environment and Health, 5 (1979) Supplement 3, pp. 48-55. Nakasko, M., Grandjean, E., Huntinh, W., Grierer, R., Studies on Ergonomically
Designed Alphanumeric Keyboards, Human Factors, 27,2 (1985) pp. 175-187.Sauter, S.L., Schleifer, L.M., & Knutson, S.J. (1991). Work posture, workstation design, and musculoskeletal discomfort in a VDT data entry task. Human Factors, 33(2),151-168. Silverstein, B.A., Find, L.J., Armstrong, T.J., Occupational Factors and Carpal Tunnel Syndrome, Am. J. Ind. Med., 11 (1 987) pp. 343-358. Wilson, R.N., Wilson, S.(1957), Tenosynovitis in Industry, Practitioner, (1978) pp. 612-625.
Funding for this project was provided by Industrial Innovations, Inc, of Scottsdale, AZ.
Janet
S. Kaiser
Harrington
Arthritis Research Center
1800
E. Van Buren
Phoenix,
AZ 85018
(602)
254-0377
About the Authors
The Harrington Arthritis Research Center is a non-profit organization internationally recognized for the breadth of its scope in medical and development and testing services. The Center maintains a position on the leading edge of orthopedic research based on its close association with clinical orthopedics and manufacturers.
Although highly regarded for both basic and applied research, the Harrington Center is thoroughly focused on real world problems. The Center has introduced numerous publications and presentations before the scientific community.
Drawing on a multidisciplinary staff, the Center owes its success to employing the expertise of highly trained specialists in orthopedics, rheumatology, histology/histomorphometry, engineering and computer sciences. The Center is affiliated with the St. Luke Medical Hospital in Phoenix, Arizona. It has conducted research with and for Fortune 500 companies, as well as NASA.
James
B. Koeneman, Ph.D.
Dr.
Koeneman is head of bio-engineering Harrington Arthritis Research Center,
including Mechanical Testing and Experimental Stress Analysis, Design and
Analytical Stress Analysis (CAD and FEM), Motion Analysis, and Image Analysis.
He has been involved in bioengineering research since 1965 and has administered
major grants from the National Institute of Health and the Flinn
Foundation,
as well as numerous corporate research programs.
The Society for the Advancement of Materials & Process Engineering named Dr. Koeneman the 58th fellow out of 1 1,000 members. He has received international recognition as an expert in the field of bioengineering research and numerous honors and awards. His Ph.D. is in Mechanical Engineering. He has an M.S. in Bioengineering, and a B.S.M.E. in Mechanical Engineering.
Janet
Kaiser, B.S.
Janet
Kaiser is an independent consultant with extensive experience in scientific,
computer-based data research and analysis. She has been a part of numerous
medical and biomechanical-based surveys, including management of a sophisticated,
time-oriented American Rheumatism Association Medical Information System
(ARAMIS) database where she had responsibility for data collection, assessment,
analysis and result reporting in collaboration with four other centers
in the US and Canada. Janet served as a Research Associate at Harrington
from 1983 to 1988 and continues to collaborate on projects to date. She
is a published author of abstracts as well as an assistant for contributors
to numerous books.
END