CPE CPE Instrument Technology 1 — Questions and Answers
Question 1: What component of a polygraph instrument measures changes in respiratory patterns?
- Pneumograph (Correct answer)
- Galvanograph
- Cardio cuff
- Plethysmograph
Correct answer: Pneumograph
The pneumograph consists of corrugated rubber tubes placed around the thorax and abdomen to record respiratory changes during a polygraph examination.
Question 2: Which polygraph component records electrodermal activity (skin conductance)?
- Cardio cuff
- Pneumograph
- Galvanic skin response sensor (Correct answer)
- Plethysmograph
Correct answer: Galvanic skin response sensor
The galvanic skin response (GSR) sensor, also called the electrodermal activity sensor, measures changes in skin conductance caused by sweat gland activity.
Question 3: What does the cardiorespiratory channel on a computerized polygraph system primarily measure?
- Blood oxygen levels
- Relative blood pressure and pulse rate changes (Correct answer)
- Core body temperature
- Respiratory CO2 levels
Correct answer: Relative blood pressure and pulse rate changes
The cardiorespiratory channel measures relative changes in blood pressure and pulse rate using an inflated cuff typically placed on the upper arm.
Question 4: In computerized polygraph systems, what is the typical minimum sampling rate recommended for accurate physiological data capture?
- 25 Hz
- 50 Hz (Correct answer)
- 100 Hz
- 200 Hz
Correct answer: 50 Hz
A minimum sampling rate of 50 Hz (50 samples per second) is generally recommended by the American Polygraph Association for computerized polygraph systems to ensure accurate data capture.
Question 5: Which sensor placement on a computerized polygraph records finger pulse volume?
- Cardio cuff
- Plethysmograph (Correct answer)
- Pneumograph
- EDA electrode
Correct answer: Plethysmograph
The plethysmograph, typically a photoplethysmograph clipped to a finger, measures volumetric changes in blood flow to detect pulse and vascular activity.
Question 6: What is the purpose of the 'artifact channel' available in some computerized polygraph systems?
- Recording ambient room temperature
- Detecting and documenting subject movement (Correct answer)
- Measuring examiner stress levels
- Logging audio from the interview
Correct answer: Detecting and documenting subject movement
The artifact channel uses a motion sensor (often a seat pad or accelerometer) to detect and document physical movements by the subject that could affect the tracings.
CPE CPE Instrument Technology 1
What component of a polygraph instrument measures changes in respiratory patterns?