Calibration Flashcards

According to APA standards, after completing instrument calibration, the examiner should document:

Answer: All calibration steps, settings, and any anomalies observed, as part of the case record

APA standards require that calibration procedures and results be documented as part of the complete case record to support quality assurance and legal defensibility.

A polygraph examiner is using a portable instrument in a field setting and notices the cardio cuff pressure is dropping gradually between questions. The most appropriate action is:

Answer: Re-inflate the cuff to the correct pressure before the next relevant question

Gradual cuff deflation reduces the quality of cardiovascular recordings, so re-inflating to the correct pressure before diagnostic questions is necessary to maintain data integrity.

The 'time constant' of an amplifier in a polygraph instrument affects which aspect of the recorded signal?

Answer: The rate at which the tracing returns to baseline after a slow deflection

The time constant determines how quickly a DC-coupled amplifier's output returns toward baseline after a sustained deflection, affecting the appearance of slow physiological changes.

When calibrating the electrodermal channel, an examiner uses a fixed resistor to simulate a known skin resistance value. This is an example of:

Answer: External or electrical calibration using a reference standard

Using a fixed resistor as a reference simulates a known electrical value, allowing the examiner to verify that the electrodermal channel's output is accurate and repeatable.

A polygraph examiner switches from one brand of electrodermal gel to another before an examination. What calibration-related concern does this raise?

Answer: Different gels have different ionic concentrations that can shift baseline skin conductance readings

Electrodermal gel formulations differ in ionic concentration and viscosity, which can alter baseline conductance values and may require recalibration of the GSR channel.

During the calibration phase, the examiner asks the subject to hold their breath briefly. The expected observable change in the cardiovascular tracing is:

Answer: A detectable change in inter-beat interval or amplitude reflecting cardiorespiratory interaction

Breath-holding affects thoracic pressure and venous return, producing detectable changes in cardiac inter-beat interval and pulse amplitude via cardiorespiratory coupling.

Which of the following scenarios would render a polygraph calibration invalid and require the examiner to recalibrate before proceeding?

Answer: The instrument is moved to a different room between calibration and testing

Moving the instrument can displace sensors, change environmental electrical interference, and alter operating conditions, necessitating a fresh calibration in the new location.