BCIA Instrumentation & Technology 3

Question 1

What does a notch filter specifically remove from a biofeedback signal?

Accepted Answer

A narrow frequency band, typically 60 Hz power line noise

Answer

A notch filter eliminates a very narrow frequency range, most commonly 60 Hz in North America, to reduce power line interference.

Question 2

Temperature biofeedback sensors (thermistors) measure which physiological variable?

Accepted Answer

Peripheral skin temperature reflecting vasodilation

Answer

Thermistors placed on fingers or hands measure peripheral skin temperature, which reflects sympathetic-mediated vasoconstriction or vasodilation.

Question 3

What is the function of an analog-to-digital (A/D) converter in biofeedback equipment?

Accepted Answer

Converts continuous physiological signals into discrete digital values for computer processing

Answer

The A/D converter samples the continuous analog biosignal at regular intervals and encodes each sample as a digital number for software processing.

Question 4

Ground electrodes in biofeedback systems serve what primary function?

Accepted Answer

They provide an electrical reference point that reduces common-mode noise

Answer

A ground electrode establishes a stable reference voltage, helping the differential amplifier reject environmental electrical interference.

Question 5

In HRV biofeedback, the R-R interval refers to the time between which features of the ECG?

Accepted Answer

R peaks (QRS complexes)

Answer

The R-R interval is the time between successive R peaks in the QRS complex, and its variability is the basis of HRV analysis.

BCIA - Biofeedback Certification International Alliance Practice Test