NEC VERSA 4000 Manual page 80

Although some studies have shown an association between
increasing hours of keyboard use and the development of
some musculoskeletal disorders, it is still unclear whether
working at a computer causes such disorders. Some doctors
believe that using the keyboard and mouse may aggravate
existing musculoskeletal disorders.
Some people are more susceptible to developing these
disorders due to pre-existing conditions or psychosocial
factors (see "Pre-existing Conditions and Psychosocial
Factors" later in the appendix).
To reduce your risk of developing these disorders, follow
the instructions in this appendix. If you experience
discomfort while working at your computer or afterwards,
even at night, contact a doctor as soon as possible. Signs of
discomfort might include pain, tenderness, swelling,
burning, cramping, stiffness, throbbing, weakness, soreness,
tingling and/or numbness in the hands, wrists, arms,
shoulders, neck, back, and/or legs.
NOTE
using your notebook computer as your primary
computer system at your home or office, note the
following recommendations:
use a separate, external keyboard attached to
your notebook computer
use a separate, external monitor attached to
your notebook computer.
A-2 Setting Up a Healthy Work Environment
To increase your comfort and safety when