Trail Making B. This test assesses visual conceptual and visual motor tracking. The subject is given a hand held tablet with a stylus and is presented with a grid containing randomly positioned numbers and letters, which are to be connected in alternating numerical and alphabetical order by them tapping with the stylus (ie 1 - A - 2 - B - 3 - C and so on.) The test score is the time taken to tap all the letters and numbers on the screen in the correct order.