EMG biofeedback involves using equipment to accurately measure and provide visual or auditory feedback of electromyography (EMG) signals to help patients learn voluntary control of muscle activity. It has various clinical applications such as neuromuscular rehabilitation, chronic pain management, and treatment of conditions like stroke, cerebral palsy, and incontinence. EMG biofeedback works based on motor learning principles and involves setting thresholds and targets for patients to achieve. Several studies have found EMG biofeedback to be effective in improving muscle strength, relaxation, gait, and balance in patients with injuries or neurological conditions.

1. EMG Biofeedback
Presenter : Ashik Dhakal
Moderator : Mr. Sydney Roshan Rebello

2. Introduction of EMG
Introduction to biofeedback
EMG biofeedback
Clinical application
References

3. Electromyography is a clinical technique that involves recording of the
electrical activity generated in a muscle for diagnostic purposes.

4. Equipments
EMG machine
EMG needle and ground electrode,
needle cable,
and gloves.

6. Types of electrodes
It is a device that converts minute ionic potential into electric potentials
Types :
Stimulating electrodes - surface , needle
Recording electrodes
Ground electrodes

7. Electrodes

8. Patient Preparation and Typical Needle Electromyography Examination
1. Explain the electromyography procedure to the patient to prevent any patient fears.
2. Select first muscle for study.
3. Locate muscle by using anatomic landmarks.
4. Show patient how to activate muscle.
5. Palpate muscle during contraction.
6. Ask patient to relax muscle.
7. Insert needle into relaxed muscle.

9. 8. Ask patient to contract muscle slightly to ensure proper placement.
9. Ask patient to relax muscle fully.
10. Assess insertional and spontaneous activity
11. Assess MUAPs
• Ask patient to contract muscle slightly and gently move needle until MUAPs become
“sharp.”
• Assess several locations for MUAP duration, amplitude, phases, recruitment, and
activation.
• Use isometric contraction, if possible.
12. Proceed to next muscle.

10. The choice of muscle must be based on the following factors:
The differential diagnosis, determined by the clinical findings and nerve conduction
data.
The ease with which the muscle can be located and activated [e.g., although both the
tibialis anterior and medial gastrocnemius are distal leg muscles, the TA is much
easier to activate than the MG.
The degree of pain associated with sampling the particular muscle [e.g., both the first
dorsal interosseous (FDI) and abductor pollicis brevis (APB) are distal C8–T1
innervated muscles, but the APB is much more painful to sample than the FDI for
most patients).

11. Two competing influences make the needle EMG study especially demanding.
First, many of the abnormalities found on the needle study are subtle,
however, the range of normal findings is quite large and varies with age and
with the muscle being studied.
The basics of the needle EMG study, such as needle placement and
recognition of certain types of abnormal spontaneous activity, usually can be
learned in a short time

13. Important Technical Factors Influencing Electromyography
1. Physiologic Factors
• Temperature
• Age
• Proximal versus distal nerve segments
2. Non-physiologic Factors
• Stimulus artifact
• Electrode position
• Co-stimulation of adjacent nerves

14. • Electrode placement for motor studies
• Distance between recording electrodes and nerve
• Distance between active and reference recording electrodes Limb position and
distance measurements

15. Biofeedback

16. Father of biofeedback : John Basmaijan
Biofeedback can be defined as the technique of using equipment (usually
electronic) to reveal to human beings some of their internal physiological
events, normal and abnormal, in a form fo visual and auditory signals in
order to teach them to manipulate these otherwise involuntary or unfelt
events by manipulating the displayed signals.
By observing and monitoring shifts in bodily functions or striate muscle
activity, patients learn to adapt and modify their mental and emotional
responses to alleviate symptoms and help regulate specific health conditions.

17. Principle
Biofeedback is based on the principle of motor learning.
Schimdt defined motor learning as “a set processes associated with practice
or experience leading to relatively permanent changes in capability for
producing skilled action.”

19. Primary factor that influence motor learning are:
Stage of learner
Type of the task
Practice
Feedback

20. Feedback
Intrinsic : It is the body’s internal feedback mechanisms which uses visual,
auditory, vestibular, and proprioceptive mechanism.
Extrinsic : it is derived from external source. Eg biofeedback signal.

21. Feedback loop

22. Types
Positive feedback
Negative feedback

23. You have to have a accurate feedback

24. Electromyographic biofeedback
It is a therapeutic procedure that uses electronic or electromechanical
instruments to accurately measure, process, and feedback reinforcing
information via auditory or visual signals.
In clinical practice, it is used to help the patient develop greater voluntary
control in terms of either neuromuscular relaxation or muscle re education
following injury.
The MUAP is recorded and displayed graphically
as EMG signals

25. Features of EMG devices
Gain settings : affects the basic sensitivity of the machine
1. High gain setting :
Highly sensitive
Small flicker produces large response
Used for paretic muscles and nerve injury
2. Low gain setting :
Patient requires to make considerable effort
Used in later stages of rehabilitation

26. Sound
Offers audible feedback along with visual information.
Change in sound such as the frequency and pitch of the ‘beeps’ increases
with increased EMG activity.
Visual feedback
Lights (LEDs)
Meter deflection
Video monitors: pattern generated is used as a template for targeted activity.

28. Threshold
Enables the patient to set target.
Buzzer is heard only when patient generates specific level of muscle activity
and threshold is reached.
Once patient exceeds this level, threshold is increased and he is motivated for
further recruitment of muscle activity. This is called ‘shaping of responses’.

29. Peak hold facility
Enables the signal to be fed back on a continous basis (peak hold off) or by
providing the peak signal over a slower time frame (peak hold on eg., 3 sec)
Peak hold on is useful in later stage recovery when sustained activity is more
important than instantaneous EMG spikes.
Peak hold off used for patients who are struggling to achieve significant
EMG activity.

30. Emg activity into meaningful information

31. Working

32. Raw EMG - activity in muscle is an alternating
voltage , direction or polarity is constantly
reversing
Rectification is the summation of electrical
activity, to determine the overall increase and
decrease in electrical activity, deflection
towards the negative pole must be flipped
towards the positive pole
Emg signal is then smoothed to eliminate the
peaks valleys or high frequency fluctuations.
The signal may then be integrated by
measuring the area under the curve for a
specified period of time. Integration forms the
basis for quantification of EMG activity.

34. Indication
Muscle reeducation
Regaining neuromuscular control
Increasing isometric and isotonic strength of a muscle
Relaxation of muscle spasm
Psychological relaxation

35. Contraindications
If the patient is prohibited from moving the joint, the BF should not be used
Unhealed tendon grafts
Tear of muscle fibers
Unstable fracture
Injury to joint structure, ligaments, capsule or articulating surface.

36. Main clinical application of BF

37. 1. Neuromuscular Rehabilitation
The therapeutic goals are those of physical rehabilitation
To increase muscle strength
Enhance muscle relaxation
Improve muscle coordination
Decrease pain
Improve function during daily activities and work

38. Spasticity control
3 stages for training:
Stage 1 :
Spastic muscle at rest
Reduce the stretch stimuli
Maintain relaxation inspite of overflow
Stage 2 :
Learning to inhibit spasticity produced by passive static and dynamic stretching of spastic muscle
Stage 3 :
Training of active use of spastic limb
Activate the antagonist and inhibit co-contraction of spastic target muscle .

39. 2. Chronic pain disorders
Relaxation of body muscles with BF useful in low back pain.
If LBP related to muscle tension.

40. 3. Stroke :
Treatment of foot drop by activation of the dorsiflexors.
Prevent shoulder subluxation and improving shoulder joint ROM,
strengthening of upper trapezius and anterior deltoid muscle fibers with EMG
BF.
Strengthen the weak muscles.
Reduce spasticity

41. 4. Spinal cord Injury
Application is very limited in cases of SCI, no use in cases of complete injury
In incomplete injuries, improvement is achieved in active range of motion
and function of the extremities.
For muscle relaxation or strengthening.

42. 5. Cerebral palsy
Is used for spasticity treatment, balance training and strengthening of
weak muscles.
6. Post- Orthopaedic Surgery
Muscle weakness occuring after orthopeadic surgeries benefit from BF.
Eg quadriceps muscles strength after menisectomy.

43. 7. Incontinence
Pelvic floor muscle training (kegel exercises), alone or with BF is effective in
stress incontinence.
BF enables the patient to improve pelvic muscle strength and coordination
through muscle awareness.

44. Advantages of Biofeedback:
Can be integrated with other therapeutic intervention
Acts as enhancer of the therapy
Reduce patient’s reliance on the therapist
Gain and maintain control without either therapist or machine.

45. Evidences for EMG Biofeedback

46. Date Title Methods Conclusion
2013
Effect of EMG
biofeedback
training of
gluteus maximus
muscle on gait
parameters in
incomplete
spinal cord injury
30 ISCI pt, group 1(EMG
BF+ traditional rehab and
gait training), Group
2(traditional and gait
training), 5d/w for 4w
Outcomes : EMG
amplitude, step
length,walking velocity and
cadance)
The study concluded that
EMG BF when given
specifically over gluteus
maximus resulted in
improvement of EMG
amplitude and various gait
parameters (walking
velocity, cadence).
2017
EMG - Supported
Biofeedback
Training in a
Person with
Multiple Sclerosis
- A Case Study
74yr female with MS for 6w
11 sessions (each 20mins),
outcome : Functional gait
assessment and 10mwt (pre,
3w, 6w)
pwMS may be benefited
from biofeeedback training
regard to improve gait and
postural control. More
research is necessary to
examine BF therapy options
in order to support pwMS in
their current motor
impairments.

47. Title Methods Conclusion
2017
Effects of kinetic chain
exercise using EMG-
biofeedback on balance
and lower extremity
muscle activation in stroke
patients
30 pts, CKC+bf
(15pt),
OKC+BF(15pt),20
mins/day, 5d/wk, for
6wk, Outcome :
balance activity and
EMG activity of
lower extremity
muscle
This study showed that
CKC exercise using EMG-
biofeedback is effective for
improving balance ability
and lower extremity
muscle activation in stroke
patients.
2018
The efficacy of
electromyographic
biofeedback on pain,
function, and maximal
thickness of vastus
medialis oblique muscle
in patients with knee
osteoarthritis: a RCT
Group 1(EMGBF
+isometrics), group
2(isometrics only).
46 pt with OA
Outcome: VAS,
ultrasonography of
vmo, emg activity.
Both groups led to
significant improvements
in pain and function of
patients with knee OA.
Real EMGBF was not
superior to exercise
without biofeedback in any
of the measured variables,
except for VAS score.

48. Date Title Method Conclusion
2015
Evaluation of
Novel EMG
Biofeedback
for Postural
Correction
During
Computer Use
20 participants
Group1(verbal
postural coaching),
group 2(vpc + emg
bf)
Results demonstrate the short-term
effectiveness of a real-time
HDsEMG biofeedback
intervention to achieve postural
correction, and may be more
effective at creating an inferior
shift in trapezius muscle activity in
comparison to verbal postural
coaching alone.
2015
The efficacy of
EMG-
biofeedback
training on
quadriceps
muscle strength
in patients after
arthroscopic
40 patients,
5 series of emg bf
application for 2
weeks postoperative
Outcome : ROM,
Lysholm knee score,
EMG activity
On 3rd day, 14th
results showed that EMG-B was
an effective treatment modality in
improving quadriceps muscle
strength after arthroscopic
meniscectomy surgery

53. Thank you