A recent University of Pittsburgh cross-sectional study found that when performing computer keyboarding tasks, individuals with Rheumatoid Arthritis (RA) expend greater energy, assume work methods that may exacerbate their condition, and are less productive compared to those without RA.
Specifically, the investigation found that those with RA:
- Used greater force when striking the keys
- Assumed a fixed hand/finger position
- Did not use a wrist/palm rest
- Utilized two or fewer fingers to strike a key
Greater age and greater distal upper extremity structural changes were strongly associated with these work methods.
The authors concluded that workstation modifications to reduce the impact of hand structural changes on typing style would greatly benefit those with RA. Suggestions included angled keyboards, adjustable wrist/palm rests, keyboard keys with low activation demand, training in touch typing (for those with minor structural changes), and voice activation software (for those with marked structural changes).
The Bottom Line – How This Applies To Ergonomists
This study provides another example of how an ergonomist can contribute to workplace productivity. RA is a relatively common condition and may be a silent contributor to a company’s overhead. With a good analysis, an appropriate worksite modification could generate an extremely favorable return.
Further, with the expansion of those qualified under the ADA, an ergonomist could help a company avoid legal liability by assisting an employee suffering from this condition.
For practitioners with a limited clinical background, this study provides an awareness of what to anticipate when performing an ergonomic assessment of a computer user who suffers from Rheumatoid Arthritis.
Other Key Points
Hand structural changes associated with RA include degrees of carpal subluxation, metacarpophalangeal volar subluxation, hand swan neck deformity, and wrist ulnar deviation. Suggested hand functional changes have included decreased hand strength and reduced dexterity.
Research studies referenced by the authors show that among those who were diagnosed with RA, 23% had early cessation of work within 1 to 3 years of clinical identification and 35% within 10 years.
Striking a computer key requires a combination of hand stability and mobility. When operating a standard keyboard, the 3rd, 4th, and 5th metacarpophalangeal joints assume extended positions to about 75% of their full range with an accompanying 30% maximum voluntary muscle contraction of finger extensors.
Research Method
The 45 study volunteers with RA came from the University of Pittsburgh Medical Center Arthritis Network Research Registry. The non-RA comparison group was comprised of 29 University of Pittsburgh faculty, staff and students. Fifty-six was the average age of the RA cohort while the non-RA cohort averaged 47 years of age.
Those within the RA cohort had their right and left distal upper extremity structural changes evaluated/classified as none, mild to moderate, or severe. The left and right sided assessments were added to produce a Severity of Structural Changes Score that ranged from 2 to 6.
All participants completed a questionnaire to determine if they had completed a touch typing training course (more than half of each group had taken a course).
After positioning the computer and chair in a comfortable position, the subjects typed a standard paragraph.
The postures and behaviors while performing computer keyboard motions were video recorded and assessed using the Keyboard-Personal Computer Style Instrument. This evaluation method records the postures/behaviors of three keyboarding characteristics: static posture, dynamic posture and tension/force.
Productivity was measured/calculated by keyboarding speed, gross accuracy, and net speed.
Access:
This entire study can be freely acquired at:
http://www.springerlink.com/content/k84k4q07m47k7728/?p=1330f8890436491cb6fea1e9a9a0009e&pi=6
Article Title: The Association Between Rheumatoid Arthritis Related Structural Changes in Hands and Computer Keyboard Operation
Publication: The Journal of Occupational Rehabilitation, 20:59-68, 2010
Authors: N A Baker, N P Gustafson, and J Rogers
This article originally appeared in The Ergonomics Report™ on 2010-05-24.