Biofeedback machines commonly used in the physiotherapy practice are described along with available evidences for clinical use. Most of the feedback modalities are described along with its use and the mechanism behind it. 22- Force platform- is the device used to measure the ground reaction forces in steady and/or in moving phase. Sensors in the force platform give visual feedback on the screen attached to therapist as well as patient about the weight distribution and other parameters of gait can also be measured. 33- Mirror -used as visual feedback to treat the pain as well as disability in different conditions. It healps to activate the mirror neuron in the brain. Mirrior therapy proposed by Ramchandran et al has been found most beneficial treatment in the phantom limb pain treatment

1. BIOFEEDBACK IN
PHYSIOTHERAPY PRACTICE
MANASI KULKARNI
MPT-
NEUROPHYSIOTHERAPY
GUIDE: DR. SUVARNA
D.V.V.P.F’s College of Physiotherapy, Ahmednagar

2. CONTENT
• Biofeedback- introduction
• Types- 1) Physiological
2) Mechanical
• EMG
• RTUS
• HRV
• Respiratory feedback
• Force plat form
• Limb load monitor
• Inertial sensors
• Electro-goniometry
• TDU
• Pressure biofeedback

3. INTRODUCTION
• Feedback includes all the sensory information that is available as the
result of a movement that a person has produced. This is typically
called response- produced feedback. This feedback is usually further
divided into two subclasses, that of intrinsic feedback and extrinsic
feedback.
• Biofeedback is the technique of making unconscious or involuntary
body processes perceptible to the senses to manipulate them by
conscious mental control.

4. Extrinsic
feedback
Knowledge of
Results
Knowledge of
performance
Relating to
movement
pattern
used to
achieve
goal
Outcome
of the
movement
in terms of
movement’
s goal

5. Intrinsic
feedback
Audio Visual proprioceptive

6. AUGMENTED FEEDBACK
1 Concurrent feedback Feedback presented during the movement
2 Terminal feedback Feedback is given after the movement
3 Immediate Feedback Feedback presented immediately after movement
4 Delayed feedback Feedback given after a brief time delay which allows
time for introspection
5 Faded Feedback Feedback given first after every trial
6 Bandwidth-KR feedback Feedback given only when performance deivates from
correct boundaries
7 Blocked Feedback One source of feedback is provided
8 Variable(random)
Feedback
Multiple source of feedback are provided

7. ADVANTAGES
1. Patient makes changes in performance that are noted and
rewarded
2. Teaches patient to not rely on the trainer. Increases
confidence
3. Improves patient’s perception of what he/she is doing
4. Can be used to detect the errors.
5. Specificity, objectivity, accuracy and quantitative nature of
feedback
6. Can be recorded for comparison or to calculate improvement

8. TYPES
Type Principle
1. Electromyographic
(EMG)
Measures the electrical activity in skeletal
muscles
2. Mechano-myographic Measures the transverse displacement of
the skin over the target muscle based on
the sound produced and /or skin tension.
Quantifies oscillations in the skin caused by
changes in muscle fiber.
3. Peripheral temperature Measures temperature in distal extremities(
ex. Fingers) Increased temperature
indicates relaxed state and decreased
temperature indicate stress, fear or anxiety.

9. 4.
Photoplethysmography
Measures the amount of light reflected by
subcutaneous tissues based on the amount
of blood flow.
5. Galvanic skin
response
Measures the amount of perspiration on the
skin by passing a small current through the
fingers and/or palm. Sweaty skin contains
salt and is a better conductor than dry skin.

11. Neuromuscular
Feedback
Cardiovascular
Feedback
Respiratory
Feedback
EMG
RTUS
HR
HRV
Measuri
ng
breathin
g
Mechanical
Feedback
Inertial sensors
Force plates
Electro-goniometer
Pressure
biofeedback
Camera based
systems

12. EMG
• EMG biofeedback is a
method of retraining
muscle by creating new
feedback systems as a
result of the conversion
of myoelectrical signals
in the muscle into
visual and auditory
signals.

13. • Bradley et al conducted a study to examine the effects of
electromyographic (EMG) biofeedback training on the recovery
of gait in the acute phase post stroke
• Sample size -21 stroke patients
• Outcome measures- Physical examination (MAS, 10 mt walk
test, sensation and proprioception), Psychological (MSQ, IQ)
• Conclusion: this study used EMG biofeedback as an adjunct to
physiotherapy and represented relevant clinical practice, the
results provide little evidence to support the clinical
significance of using EMG biofeedback to improve gait after
stroke.

14. 1) EMG biofeedback can be used to either increase activity in weak or
paretic muscle or it can be used to facilitate a reduction in tone is a
spastic one.
2) Draper and Ballard suggested that EMG biofeedback is more
effective in facilitating the recovery of quadriceps femoris muscle
peak torque than electrical stimulation treatment in participants
post ACL reconstruction.
3) NG and colleagues found that EMG biofeedback was an effective
adjunct to therapeutic exercise for patients with patellofemoral
pain syndrome.
4) Armagan and colleagues demonstrated the potential benefits of
EMG biofeedback in conjunction with exercise in maximizing hand
function in hemiplegic patients.

15. RTUS
• RTUS send short pulses of
ultrasound into the body and
using reflections received from
tissue interfaces, images of
internal structures are
produced thus RTUS is capable
of giving immediate real-time
visual feedback of muscle
activity by allowing the user to
directly see the muscle
changing shape/length on a
display.

16. • RTUS has also been successfully used to provide visual
feedback of pelvic floor muscle activation. Dietz et al. showed
that 32 of 56 women learned correct activation of their pelvic
floor muscles with less than 5 minutes of RTUS biofeedback
training.

17. HEART RATE MONITOR
• HR can be measured using a heart rate
monitor or an electrocardiogram to
deliver feedback to patients. HR
biofeedback is a therapeutic approach
which allows patients to control their HR
by means of direct representation of the
numerical value of HR on a wearable
device such as a watch or a handheld
display

18. • Houser MM et el conducted a pilot study
• Purpose: Use of HRMs for biofeedback during guided
mindfulness, diaphragmatic breathing, and progressive muscle
relaxation techniques could facilitate anxiety reduction as
compared to these techniques alone.
• Sample size-53 patients.
• Intervention- 20 min session for both groups for 4 weeks
• Results: HRM group had significantly greater improvement in
state anxiety.
So It may be a useful clinical intervention for anxiety and can be
easily incorporated by both behaviorists and non-behaviorist
primary care clinicians into individual or group biofeedback
treatment for patients with anxiety

19. • Another study was conducted by Hallman on the stress
management in patients with chronic neck pain.

20. RESPIRATORY BIOFEEDBACK
• Respiratory biofeedback is delivered by measuring breathing
using electrodes or sensors attached to the abdomen and by
converting breathing to auditory and visual signals for the user.
• Teaching diaphragmatic breathing in patients with respiratory
disease is the most common means of providing respiratory
biofeedback

21. • Kapitza et al. compared the effect of breathing exercises
guided by placebo respiratory biofeedback to real respiratory
biofeedback in a group of participants with chronic LBP.
• The intervention group received ordinary, synchronized
feedback of their own breathing excursions, whereas the
control group received no feedback, but a constant proxy
signal corresponding to a breathing rate of approximately eight
breaths per minute. While higher reductions in pain levels were
noted at rest and during activity in the treatment group there
was no significant differences between the groups at follow up

22. FORCE PLATFORM

23. • Nicholas DS. Conducted s study in Stroke patients
• Measures : steadiness, symmetry , dynamic stability training
• Results : These systems are designed to provide visual or
auditory biofeedback to patients regarding the locus of their
center of force (COF) or center of pressure (COP), as well as
training protocols to enhance stance symmetry, steadiness, and
dynamic stability.
• Mechanism : platform system provides a COF measure or a COP
measure is dependent on the strain-gauge setup within the
force plates. Center of force is calculated only from the vertical
forces projecting on the force plates. Center of pressure is
calculated from both the vertical forces and the horizontal
forces projecting on the force plates, thus accounting for

24. LIMB LOAD MONITOR
• Incorporates a strain gauge attached to the sole or heel of the
shoe.
• When a force or pressure is applied, the strain gauge is
deformed and an auditory signal provides feedback to the
wearer. As pressure increases, the signal becomes louder or
more rapid.
• provides information about the amount of weight-bearing on a
limb.

25. • A study was done by Isacov et al. to see effect of weight
bearing on the affected limb.
• Procedure – pre caliberation procedure was done , then pts
asked to wt bear till the sound was heard .
• Device used- smart step
• Results- device proved to be reliable in improving body wt
loading during gait rehabilitation

26. INERTIAL SENSORS
• Inertial sensing uses accelerometers and gyroscopes to
estimate three-dimensional (3-D) kinematic information of a
body segment, such as orientation, velocity and gravitational
force.

27. • Davis and colleagues used gyroscopic measurements to provide
biofeedback and found significant changes in trunk angular
displacement in both young and older participants during a
number of balance tasks compared to control treatment.
• Verhoeff et al. also examined the effects of a gyroscopic
biofeedback system on trunk sway during dual tasking
(performing a cognitive and a motor task) while walking.

28. ELECTRO-GONIOMETRY
• It is an electro-goniometer to identify the position of the limb
segments to regulate the movement, or train timing and
coordination for a movement. It gives a feedback to the patient
when the joint has reached a predefined joint angle

29. TONGUE DISPLAY UNIT
Study conducted by Vuillerme et al
• Sample size : 12
• Clinical Use :
Enhancing/preserving/ restoring
balance
• Results: Centre of foot pressure
(CoP) displacements were recorded
using a force platform. Results
showed reduced CoP displacements
in the biofeedback relative to the
no-biofeedback condition.
Mechanism: its dense mechanoreceptive innervations and large
somatosensory cortical representation, the tongue can convey higher-
resolution information than the skin can

30. PRESSURE BIOFEEDBACK
• A pressure biofeedback unit (PBU) is a tool developed to aid the
retraining of muscle activity and can provide useful visual
biofeedback during treatment.

31. • Subjects :18 healthy subjects
• Procedure : subjects performed hip abduction with lumbar
stabilization . Pressure biofeedback was used for lumbar
stabilization . EMG activity was recorded from muscles .
• Results : hip abduction with lumbar stabilization is useful in
excluding substitution by quadratus lumborum

32. MIRROR

33. SUMMARY
Type of biofeedback Use
1. EMG activation of specific muscle, relaxation,
pain reduction, Muscle reeducation,
treating bladder dysfunction.
2. RTUS activation of muscle, reeducating muscle
3.HRV Relaxation, control manic attacks
4. Respiratory feedback Relaxation
5. Force platform Measure cop
6. Limb load monitor Weight bearing
7.

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