JHE Polygraph examiners use a laptop computerized Lafayette polygraph instrument.

The Lafayette Computerized Polygraph Instrument is used to determine the relative physiological changes with the examinee's body. Three physiological responses are measured:

1. Respiratory rate: Two rubber tubes filled with air, called pneumographs are placed around the examinee's chest and abdomen. When the chest or abdominal muscles expand, the air inside the tubes is displaced. The digital or computerized polygraph employs transducers to convert the energy of the displaced air into electronic signals.

2. Blood pressure / heart rate: A blood pressure cuff is placed around the examinee's upper arm. Tubing runs from the cuff to the polygraph. In the computerized polygraph these signals are converted into electrical signal by transducers.

3. Galvanic skin response: this is a measurement of sweat on your fingertips. Fingerplates, called galvanometers, are attached to two of the examinee's fingers. These plates measure the skin's ability to conduct electricity. When the skin is hydrated, it conducts electricity much more easily that when it is dry.