The Computer Voice Stress Analyzer (CVSA®) was born out of a need to improve the measurement of psychophysiological associated with deception. In 1970, Olaf Lippold discovered the muscle “microtremor.” Based upon this discovery, three former U.S. Army officers formed Dektor Counterintelligence and Security, Inc. and created a technology to measure the “Lippold tremor” in the human voice. This became the first Voice Stress Analysis (VSA) tool.

NITV Federal Services’ founder, Charles Humble, refined this technology and debuted the CVSA in 1988. This device also measures psychophysiological changes in response to direct questions, but unlike the polygraph, it focuses solely on changes in voice frequency controlled by involuntary muscles. In other words, there is no way for a human to control the reactions measured by the CVSA. Using only a microphone and the CVSA instrument, the results are charted to indicate stress associated with “deception” or “no deception.” With the CVSA, there are no inconclusive results as there are with the polygraph.

In field and lab studies, the CVSA has proven to have higher accuracy rates than the polygraph. Professor James Chapman (Professor Emeritus, Former Director of Forensic Crime Laboratory, State University of New York at Corning) and Marigo Stathis (neuro-cognitive scientist and research analyst) conducted a study that showed “of the 329 confession possibilities, 92.1% of the CVSA examinations produced a ‘Stress Indicated’ result, and 89% of those resulted in validated confessions.” And in “96.4% of interviews conducted, where the CVSA indicated stress, suspects made self-incriminating confessions.”


  • No known countermeasures and extremely high accuracy rate, very low error rate, no inconclusive results.
  • Ease of use, shorter examination time required, strong portability, and requires only a microphone attached to the interview subject.
  • Adaptability of use for analyzing pre-recorded materials or use over phone or Internet.
  • Many polygraph examiners have transferred their skills in truth verification analysis to the CVSA.


  • Less well-known than the polygraph.
  • Polygraph organizations have campaigned for over 40 years to dissuade polygraph examiners from switching to the CVSA.

Addressing Many Polygraph Issues with Innovative Technology

The CVSA®II has solved many of the problems relating to the polygraph. Scientific research and advancements in digital technology have allowed for more adaptive uses of CVSA truth verification technology, more accurate results, and data that is easier to comprehend than the polygraph system.

Credit: NITVFS