During a battery of tests that I took for ADHD/LD, there was a computerized test that was to test for impulsivity. A variety of letters would pop up on the screen and the test was to only click the "target" letter. The test monitored reaction time and ability to sort out the nonessential letters from the target letters and correctly hit the right ones. I think the results are pretty accurate from computer tests such as these but I still don't think that the tests can completely replace the tests administered by a human administrator.