EMG biofeedback is a therapeutic technique that uses electronic instruments to measure and provide visual or auditory feedback on muscle electrical activity. This feedback allows patients to develop voluntary control over muscles. Biofeedback is used to help retrain and relax muscles, reduce pain, and regain neuromuscular control following injuries. It works by measuring a patient's muscle electrical signals, amplifying and processing the data, and providing feedback the patient can use to modify their muscle activity.

1. EMG-bio feed back

2.  An electromyography – is a clinical technique
that involves recording of the electrical
activity generated in a muscle (muscle AP) for
diagnostic purposes
 An electromyogram - is a graphic
representation of those electrical currents
associated with muscle action

4.  It is a method of controlling a system by
reinserting into it the results of its past
performance.
-wiener1948
‘A technique which enables the individual to
readily determine the activity levels of a
particular physiological process, and with
appropriate training, learn to manipulate the
same process by an internalized mechanism.’

5. “Operant
conditioning
learning”

10.  Positive feed back
 Negative feed back

11.  Electromyographic  Photophlethysmography
 Measures electrical activity in  Measures the amount of light
skeletal muscle reflected by subcutaneous tissue
 Peripheral Temperature based on the amount of blood
 Measures temperature flow
changes in distal extremities  Galvanic skin response
 Increased temperature  Measures electrical resistance in
indicates a relaxed state the skin
 Decreased temperature  Moist skin conducts a current
indicates stress, fear, or better than dry skin
anxiety
© 2004

12. ADVANTAGES
 Chance to make appropriate small changes in
performance
 Eventually larger changes or improvements
in performance can be accomplished
 The goal is to train the patient to perceive
these changes without the use of the
measuring instrument so that he or she can
practice independently

13. Biofeedback instruments may use
the following
signals/devices/sources
Eg: Temperature- thermometer-skin

14. Type What's Measured Basic method Used For
Brain waveEEG Electrical activity in the Sensors placed on Alcohol and drug
brain scalp addition, brain
damage, epilepsy,
hyperactivity, insomnia
Breathing Breath rate, rhythm, Sensors around chest Anxiety, asthma,
volume, and location and abdomen or hyperventilation
around mouth and
nose
Electro dermal Sweat gland activity Sensors placed on the Anxiety, overactive
response muscle group in sweat glands
question
Electro-myography May help treat Incontinence, muscle
Muscle spasms and rheumatoid arthritis, pain, physical
tension premenstrual rehabilitation, stress,
syndrome, menstrual teeth grinding (TMJ),
cramps, and tension headaches,
menopausal symptoms torticollis ("wry neck")

16. 1.Providing feed back
 Appropriate
 Proportional
 Sensitivity and specificity of equipment
 Appropriate method
 Time/scheduled feed back

17. 2.User control
 Over the method
3.Proper starting position
4.Shaping behavior
Avoid fatigue
 Initial success
 Set upper and lower threshold
 Change goals

18.  It is a therapeutic procedure that uses
electronic or electromechanical instruments
to accurately measure, process, and feed
back 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 reeducation following injury.

19. Identify Signal
Get the eletromyographic signal from the
body
Amplify Signal
Filter out background noise
Similar to a volume control on a radio,
enhance the strength of the signal to
meaningful levels
Rectify Signal
Make all values “positive”
Integrate Signal
Group the data into meaningful
clusters
© 2004

20.  Muscle reeducation
 Regaining neuromuscular control
 Increasing isometric and isotonic strength of
a muscle
 Relaxation of muscle spasm
 Decreasing muscle guarding
 Pain reduction
 Psychologic relaxation

21.  Measuring muscle activity
 Separation / filteration
 Electrodes
 Displaying the feedback

22.  Biofeedback Measures electrical activity of
muscle, not muscle contraction.
 Gives information about the quality of a
muscle contraction
 Does not measure the strength of that
muscle contraction specifically.

23. “Active” Electrodes
Detect electrical signal
“Reference” Electrode
Filters nonmeaningful information
 Basic units have one channel composed of
three surface electrodes on a self-adhesive
electrode
© 2004

24. electrical energy received through an electrode
separated or filtered from other extraneous electrical
activity on
the skin
amplifies the electrical energy
then converted to information that has meaning to the user

26. • Noise must be eliminated
• Noise – by power lines , motor , lights , appliances.
• Accomplished by using 2 active electrodes and a
single ground/reference electrode
 differential amplifier
 CMRR-common mode rejection ratio
• Filters are also used
• Use :
 Mask true electrical activity
 Decrease the reliability of the information being generated

28.  After filtering, signal indicates true muscle
activity – “raw” activity
 Raw activity – alternating voltage
 Biofeedback measures the overall increase
and decrease in electrical activity
 To obtain this rectification is done
 Rectified signal can smoothed and
integrated

30.  Skin preparation
 Application of electrodes
 Selection of output modes
 Selection of sensitivity settings
 Comfortable positioning of the patient
 Begin with easy task
 Teach the patient how to use the unit
 Brief explanation
 Demonstration

31.  Skin preparation
 Reduce skin impedance
 Positioning of electrodes
 Placed as near to the muscle being monitored to
minimize noise
 Parallel to the muscle fibers
 Spacing between electrodes
 More the distance between the electrodes – will
include signal from nearby muscles
 Types
 Surface electrodes
 Needle electrodes

32.  Made of stainless steel or nickel plated brass
kept in a plastic holder
 Size : 4mm in diameter – small muscle
activity
12.5mm –for large muscle groups
 Increase in size will not increase the
amplitude of the signal
 Conducting gel/paste/cream with high salt
content is used
 Can be disposable and non-disposable

35. MONOPOLAR NEEDLE

36. CONCENTRIC NEEDLE

37. BIPOLAR CONCENTRIC NEEDLE

38.  Visual feedback
 Audio feedback

39. ▪ Line travelling across a monitor
▪ Light/series of light that goes on and
off
▪ Bar graph
▪ Incorporated video games

41. ▪ Tone
▪ Buzzing
▪ Beeping
▪ Clicking

44.  An Increase  increased electrical
activity  used to strengthen muscle
contractions
 Decrease  decreased electrical activity
 used for relaxation

46.  Goal is to reestablish neuromuscular control
 Used to regain normal agonist/antagonist
muscle action
 For postural control retraining
 Useful in patients who perform poorly on
manual muscle tests
 Balance/mobility

47.  Muscle guarding
 Muscle guarding different from muscle
spasticity
 Goal : to induce relaxation or to modulate
pain by reducing electrical activity
 Patient attempts to reduce visual/auditory
feedback to zero
 Positioning is important
 Verbal cues should be given to enhance
relaxation

48.  Purpose : reduce/modulate pain
 Breaking “pain-guarding-pain” cycle
 Reduces pain in headaches and low back pain
 Techniques of imagery and progressive
relaxation is used

49.  Hemiplegia
 Stroke
 Spinal cord injury
 Spasticity
 Cerebral palsy
 Facial paralysis
 Urinary and fecal incontinence

50.  HTN
 Stress
 Reynaud's disease
 Respiratory control

51.  severe psychosis
 depression
 psychopathic personalities
 diabetics and others with endocrine disorders
 Any musculoskeletal condition in which a
muscular contraction might exaggerate that
condition