Voice Stress Analysis


Unlike polygraph examinations, Voice Stress Analysis (VSA) testing does not require electrodes, wires, cables, sensors, or blood pressure cuffs. Instead, a computer like the one pictured above, uses software that detects and measures certain aspects of a suspect’s voice, such as voice frequencies that react abnormally to psychological stress at the moment when the person speaks. These fluctuations – physiological tremors – are controlled by the Central Nervous System (CNS), and occur in stressful situations. The computer analyzes and records the varying frequencies.


Computer image of a voice stress analysis

Interpretation of the peaks:


A sharp, high peak indicates very little, if any, stress.


A flattened, wide peak indicates stress and a possible lie.

VSA testing is used in a variety of areas, such as law enforcement, human resources, counter-intelligence, intelligence, and screening and security clearances.

*    *    *

Bulletin Board

* I’m pleased to say that I was able to present this topic today, because we had another safe week for police officers. No officer deaths were reported.

– Be sure to stop by Terry Odell’s blog today for another Homicide-Hussey story. They’re great!


– My online Writers Police Academy will soon be up and running. It’s the next best thing to attending a real police academy! More details soon.

From the wire…

Associated Press

COLUMBUS, Ohio — Drivers better buckle up or pay the price: More cash-strapped states want to give law enforcement officers the authority to pull over motorists just for not wearing their seat belts.

Albuquerque Journal

BOSQUE FARMS, N.M. — The mayor is reaching into his own pocket to help with unexpected expenditures in the Police Department.

Mayor Wayne Ake has told the village’s clerk-administrator, Gayle Jones, to take his salary for the remainder of the fiscal year and give it to the Police Department.

Associated Press

PHILADELPHIA — A private prison transportation company lost an attempted-murder suspect somewhere between Florida and Pennsylvania, leading to a search for the cuffed and shackled inmate and drawing complaints that such companies are poorly regulated.

6 replies
  1. Lee Lofland
    Lee Lofland says:

    Carrie – Thanks for stopping by. I’m sure you’ll understand when I say that we cannot offer legal advice on this site. We are not attorneys. I would suggest, however, that you do consult with a reputable attorney to discuss your situation.

    There are many types of VSA’s on the market. Some utilize lapel mics, while others are even capable of working over a cellphone transmission. Without knowing the type you used I’d have no way of knowing where its mic would be best positioned. Although, I’d think the positioning really wouldn’t matter as long as it was basically in the same place during the entire test.

  2. Carrie Bote
    Carrie Bote says:

    I’m curious of how a voice analysis test is performed. I took one months ago and was told to my face that I was a liar and should come clean to make it easier on myself. My reply was ” One day you will apologize for calling me a liar to my face”. I was told before the test that they have had problems with the machine but believed it to be okay. My question is…… Where does the microphne go, on the desk or do I hold it to my lips? I have been accused of sexually molesting my 2 grandsons, that we have had guardianship of since 2003. In Oct. 2008, the courts decided it was time that the mother got the boys back, disreguarding that the boys had been placed in state custody during her 45 days temp. custody and she had tested positive for drugs. We wouldn’t even be going through this if the boys had not been placed with the mother. Beside all of this I could talk forever it seems. I really need to have my question answered PLEASE. Thankyou for your time and hope to hear from you soon.

  3. Bobby M
    Bobby M says:

    Glad to see that there’s nothing to report for Friday’s Heroes.

    I look forward to the on-line Police Academy, Lee. I’m sure there’ll be people from Mayberry there somewhere.

  4. Terry
    Terry says:

    Another ‘safe’ week. Excellent.
    I had to take a voice stress test as part of my Civilian Police Academy alumni qualification (we’re often asked to volunteer, and as such, have to be vetted almost the same as any regular civilian employee). It was fascinating, and the examiner let me look at the response graphs after I told him I was a writer.

    When I took the test, I wrote my experiences for my blog — if you happen to be over there for the stories detective Mark Hussey is sharing, you might want to look for that post as well. It was Jan. 29, 2008 (not this year). The direct link is

    I don’t know if that’ll translate to a clickable link here.

  5. Carla F
    Carla F says:

    Happy Dancing, not just ‘cuz it’s Friday but because there’s nothing to report in Friday’s Heroes!

    And yes, we’re a little nervous here in the Philly ‘Burbs over that escaped suspect. The officers referred to him as “Houdini”. I’ll be sure to keep my car and house doors locked. Bad enough there’s an arsonist loose in Coatesville.

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