While there is no definite evidence that keyboard use can cause or aggravate carpal tunnel syndrome, “The study found that carpal tunnel pressure is influenced by wrist posture during typing and, independently, by the act of typing.” [1]
The mere “activity of touch typing increases carpal tunnel pressure above the pressure associated with just holding hands suspended over the keyboard at the same wrist posture.” [1]
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
- decreasing the slope of the keyboard
- decreasing the keyboard thickness.
- using a split keyboard.
- using a forearm support surface, or raising the keyboard height relative to the chair. (questionable)
“Ulnar deviation can 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]
“These findings may provide guidelines to keyboard designers and to clinicians for the management of patients with carpal tunnel syndrome who use a keyboard at work or home.” [1]
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