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posted 02-15-2008 10:07 AM
Has anyone used the Lafayette finger cuff in place of the blood pressure cuff? It is a less intrusive alternative, but would like to know if it functions as well as the BP cuff.
posted 02-15-2008 10:35 AM
I use both. The cardio appears to be more responsive over all. I would add to my collection of apparatus' but not disregard or replace any component.
posted 02-15-2008 10:36 AM
The farther you get from the source (heart), the more the signal is reduced (oversimplified, I know). Therefore, I don't think it's possible for it to function as well as the BP cuff. (Lafayette's is just an infant cuff used on the finger.) With that said, I've used it, and I've found it to (appear to, anyhow) work. I wouldn't use it unless there was a problem making it the best alternative.
The jury is still out on them, meaning the research is still underway (last I knew).
I found (just through my own experimentation) the Limestone finger cuff to be superior. It was easier to get a tracing - a good tracing (again, apparently), and it uses less pressure.
In short, it seems to work, yes, but I wouldn't replace the arm cuff for no real reason quite yet.
posted 02-15-2008 12:34 PM
Call me mean, but I like the cuff on the arm, because it tells the subject they are taking at test and its serious.
I run it at 65mm, which is always less than the normal BP of 120/80.
I don't endorse complaints about discomfort, and circumvent whining by advising in advance that approx 1/2 the people who take polygraphs find their hand will fall asleep, but its not mechanically possible for the cuff to completely cut of the circulation. Nobody's arm has ever fallen off during a polygraph test, and there is not pile of arms anywhere in the office.
A problem, for me, with the finger cuff involves discussion about testing sequences that exceed the present # of minutes and relevant questions. RQs beyond 4 will become mathematically unmanageable. No matter how tempting it is, to simply count points, the future of polygraph scoring is statistical analysis, and that becomes really complicated when more questions are added. I am not convinced that adding more questions, beyond the present 4 RQs, would add any utility or accuracy. More questions simply means more complicated variance.
r\
------------------ "Gentlemen, you can't fight in here. This is the war room." --(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)
posted 02-15-2008 01:28 PM
Let's not forget the states that require us to collect a cardio even if we don't use it, for example, when conducting CITs / GKTs. A finger cuff is a nice way to meet the requirements and yet run half-a-dozen CITs without having to wait on the cuff.
I once tested a guy who had "some scars" on his upper arms from an incident in which he was bound and almost killed. I didn't look at them until after I got wacky cardio tracings, and I learned my definition of scars and his were different. His scars were as wide as my arms!
posted 02-15-2008 03:29 PM
Excellent points Ray. I tell my examinees the same thing, "you may experience tingling in the arm, but that is normal and no one has ever lost an arm or been taken to the hospital." They seem to accept that explanation.
posted 02-15-2008 04:38 PM
Also, with people who are extremely big---via obesity or steroid use, puting the cuff on the wrist or ankle suffices. I would imagine a finger cuff tracing would be loaded with autonomic twitching, especially with older examinees.
posted 02-16-2008 07:18 AM
FYI, that's a photoshop job gang---the stripes on the wall just above and behing his left shoulder are also "thickened"----a byproduct of the distort/enlargen photoshop job. Funny pic though---especially since the new steroid revalation regarding Barry Bond's "positive drop" from 2001.
posted 02-16-2008 07:38 AM
I just did a Barak pic to demonstrate---see the distortion around the background? I didn't clean this pic up, but I could scarcely do so even with time as I distorted too much.Web is loaded with distorted pics---always look at the immediate background for good detective work.
I grew his ears, shrunk his forehead, grew his neck, shrunk his shoulders, and stretched his smile. It makes him look younger, less experienced. Political enemies do such tricks --although with far more subdtly--to distort their opponent's images on the web.
[This message has been edited by stat (edited 02-16-2008).]
Polygraph Place Bulletin Board
posted 02-15-2008 10:07 AM
posted 02-15-2008 03:29 PM
