BCIA Instrumentation & Technology 2

Question 1

What type of sensor is used to measure skin conductance (EDA) in biofeedback?

Accepted Answer

Ag/AgCl electrodes

Answer

Silver/silver chloride (Ag/AgCl) electrodes are the standard for measuring electrodermal activity due to their stable half-cell potential.

Question 2

A photoplethysmograph (PPG) sensor measures peripheral blood flow using which method?

Accepted Answer

Light absorption changes in tissue

Answer

PPG sensors shine light into tissue and detect changes in light absorption caused by pulsatile blood volume changes.

Question 3

In biofeedback instrumentation, what does 'common mode rejection ratio' (CMRR) indicate?

Accepted Answer

How well the amplifier rejects signals common to both inputs

Answer

A high CMRR indicates the amplifier effectively cancels electrical interference that appears equally on both input leads.

Question 4

Respiration biofeedback transducers most commonly use which mechanism?

Accepted Answer

Strain gauge or piezoelectric stretch sensor

Answer

Strain gauge or piezoelectric sensors attached to a chest or abdominal belt detect respiratory excursion through mechanical stretch.

Question 5

What is the primary advantage of using wireless biofeedback sensors during ambulatory sessions?

Accepted Answer

They allow monitoring in natural environments without restricting movement

Answer

Wireless sensors enable ambulatory biofeedback, letting clinicians assess and train physiology in real-world settings without tethering the client.

BCIA - Biofeedback Certification International Alliance Practice Test