Motor dexterity is a composite measure of 2 motor tests: Purdue pegboard test and finger-tapping test.

Motor dexterity is measured bilaterally using the Purdue pegboard and an electronic tapper (Western Psychological Services, Los Angeles, California). Participants are asked to perform each test twice with each hand. The average of these 4 trials for the Purdue pegboard test represents a performance score, in number of pegs correctly inserted into the pegboard. The average of the 4 trials for the finger-tapping test represents a performance score, in number of finger taps.

The performance scores are each divided by the mean of the parent study at baseline. The values are then averaged to yield a composite measure of motor dexterity.