Has anyone ever had this come up before? I have some case law from intermediate appellate courts that say minor variations aren't going to make the results of the test admissible. I also plan on arguing that any potential variation in the way the test was performed would go to weight not admissibility.

If anybody has any suggestions or if anyone has briefed the issue before, I would appreciate it. We have a close knit defense bar and I don't want to stamp this issue out quickly so I'm not going to suppression hearings every other day.

I think it would depend on what the variations in the test administration were. Variations that would not affect the reliability of the test are one thing, but others such as speed the stimulus is moved is another. Do you know what the variations from the NHTSA manual the defense is arguing are?

I've watched the video our officer and the speed of the stimulus is the only thing we can think of. According to a report by a Dr. Burns, variations in stimulus speed wouldn't cause a false positive, if anything they would cause a false negative.

Do you know of a case that speaks directly to stimulus speed?

If the officer moves the stimulus too fast they will not induce nystagmus but they may actually miss seeing it. If the stimulus is held at maximum deviation for too long it can cause fatigue nystamgus.

Our DWI Case Law Update cites many cases addressing the admissibility of HGN, beginning on page 56.

Here's a link:
http://www.tdcaa.com/sites/def...aw_update_120621.pdf