The American Heritage® Dictionary of the English Language, 4th Edition
adj. Of or relating to movement or muscular activity associated with mental processes, especially affects, as in psychomotor slowing associated with depression.
adj. Of or pertaining to the function of muscles under the control of the mind
Word Usage
"Every two hours during the day, the researchers tested the subjects' ability to sustain attention with what's known as the psychomotor vigilance task, or P.V.T., considered a gold standard of sleepiness measures."