The principle
Observing body signals in real time
Breathing, heart activity, skin conductance, skin temperature and muscle tension change continuously. Many of these functions are regulated by the autonomic nervous system and happen largely outside conscious awareness.
During biofeedback, sensors record a selected signal. A display, sound or another form of feedback changes with the measurement. The person can observe how the body responds to a task, thought, movement or exercise during the session.
Direct feedback connects an internal response with a visible curve or audible signal. Different strategies can be tried, and their effect on the measured signal can be seen immediately.
In practice
What happens during a biofeedback session
The choice of measurement depends on the person’s concern, clinical history and goal.
1. Clarify the concern
The practitioner reviews symptoms, relevant situations and existing findings. This helps identify which signals may be useful to observe.
2. Record a baseline
Sensors record the selected signals at rest and, where relevant, during a task. The measurement shows how those signals change in that particular situation.
3. Practise with feedback
During breathing, relaxation or activation exercises, the feedback changes with the signal. The person can see which approach fits the situation and goal.
4. Review progress
Measurements from several sessions can be compared and the exercises adjusted. Useful strategies are gradually applied in daily life without the equipment.
Measurement channels
Which signals can be recorded?
Breathing
Breathing rate and pattern change during activation, effort and recovery. Breathing is therefore often considered alongside other signals.
Heart activity and HRV
Heart rate and the intervals between beats change with breathing, effort and recovery. Variation in those intervals is called heart-rate variability, or HRV.
Skin conductance
Sweat-gland activity changes the electrical conductance of the skin. This signal responds quickly to physical and emotional activation.
Peripheral temperature
Temperature at the hands or fingers changes with blood flow in the skin. Considered with other measurements, it can provide information about activation and recovery.
Muscle activity, EMG
Electromyography records the electrical activity of a muscle. Common sites include the shoulders, forehead and jaw.
Context
Biofeedback, neurofeedback and professional guidance
Neurofeedback applies the feedback principle to selected signals of brain activity. Biofeedback works with body signals such as breathing, heart activity, skin conductance, temperature or muscle tension. Depending on the question, the two approaches may be used separately or together.
A measurement becomes useful when the right signal is selected and interpreted in the person’s context. The practitioner considers the history, symptoms and situation, guides the exercises, adjusts the level of difficulty and reviews progress.
Biofeedback provides a direct experience of physiological responses. The person observes a change during the session and can deliberately repeat the strategies that suit them.