Emg biofeedback in neurological diseases

1. ROLE OF EMG BIOFEEDBACK IN
NEUROLOGICAL DISEASES
DR. SHUBHAM GARG
SR NEUROLOGY
GMC KOTA

2. Feedback
• Feedback is a response to a process or activity.
• According to Weiner, 1948, ‘feedback is a method of
controlling a system by reinserting into it the results of its past
performance.
• Physiological feedback is a self-regulatory biological system in
which the output or response affects the input either
positively or negatively.

3. Feedback

4. • Physiological feedback refers to intrinsic information.
• These include kinesthetic, visual, cutaneous, vestibular, and
auditory signals.
• Feedback from some measuring instrument refers to extrinsic
information.
• Also referred to as biofeedback.

5. In Biofeedback…
• The information is detected, provided in an understandable
way to the patient who can then, at their own initiation, use
the information to achieve a measure of control over the
same process.
• Engaging the patient in a ”closed loop” learning, using
feedback until enough development of his motor skills occurs,
so that an “open loop“ movements can be achieved.

7. 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.”

8. Three detailed conceptualizations:
• Override: visual or audio feedback may activate the
somatosensory cortex by entering at a level higher than the
level of damage;
• Bypass: an appropriate feed forward system can be
established via the brain stem motor nuclei;
• Repetition with existing neural circuitry: central synapses
previously unused in executing motor commands may be
activated by visual and audio feedback.

9. Four primary factors that influence motor learning are :
1. Stage of learner
2. Type of the task
3. Feedback
4. Practice

10. Different types of biofeedback
1. Electromyography (EMG) - measures muscle tension
2. Thermal biofeedback - measures skin temperature
3. Neurofeedback/ electroencephalography (EEG) - measures brain
wave activity
4. Electrodermography (EDG) - measures skin electrical activity
5. Heat Flux - measures the rate at which heat is being dissipated
from body
6. Pneumography - measures abdominal/chest movement when
breathing
7. Capnometry - measures end-tidal carbon dioxide
8. Hemoencephalography - measures the differences in the color of
light reflected back through the scalp based on the relative amount
of oxygenated and unoxygenated blood in the brain
9. Photoplethysmography (PPG) - measures peripheral blood flow,
heart rate, and heart rate variability

11. Neurological rehabilitation
• Neurological rehabilitation - special field of rehabilitation that
requires highly-qualified specialist personnel and use of
complex methods enabling the treatment of physical,
cognitive, behavioural and social deficits diagnosed in patients
with neurological problems.
• It is used in case of injuries or diseases within cerebrum or
spinal cord.

12. Neurological rehabilitation
Three types of biofeedback used
• EMG biofeedback
• Position biofeedback
• Force biofeedback

13. EMG biofeedback:
• Weak and poorly controlled muscles.
• Training relaxation of overactive muscles.
• Determine patients potential.
Position biofeedback:
• Train regulation of movement.
Force feedback:
• Gives information regarding force being transmitted through
specific body segment.

14. JOINT ANGLE BIOFEEDBACK :
• Efficient for improving joint movement control, even more
than EMGBF.
• When the active joint motion is presented but limited in
patients with neuro-motor deficits, joint angle BF might be
promising for effective and expeditious recovery of joint
control.
• Angle BF is indicated when the goal of training is the
regulation of joint movement, such as correction of genu
recurvatum or the control of movement with appropriate
timing and coordination.
• Joint angle BF may be used when the muscle that must be
monitored is inaccessible or difficult to isolate.

15. • Electro-goniometers reliably reproduced the clinical
measurements of joint angle, they have been widely
employed in angle BF devices.
• Other applied sensors include mercury tilt switches and
gyroscopes.
• The quantified joint angle is fed back to the patient during
single joint movement for targeted angle tracking, or during
multi-joint coordinated movement, such as gait.

17. PRESSURE OR FORCE BIOFEEDBACK :
• Indicated when information concerning the amount of force
being transmitted through a body segment or assistive device
is desired.
• Force/pressure sensitive platforms are used.
• Used for retraining of balance.
• The derivative of force or pressure measurements such as
center of force (COF), center of pressure (COP), or center of
gravity (COG) is displayed as a cursor projected on a two-
dimensional (2D) screen in front of patients.
• The goal of the patients is to move the cursor to a desired
location or within a targeted area.

19. EMG BIOFEEDBACK
• EMG is the study of muscle function through analysis of the
electrical signals emanated during muscle contraction.
• The depolarization produced at the motor unit is manifested
as motor unit action potential (MUAP).
• This MUAP is recorded and displayed graphically as EMG.
• In BF retraining :used to down-train hyperactive muscles or
up-train flaccid or weak muscles in patients with various
sensori-motor deficits.

21. Features of EMG device
Gain setting:- affect sensitivity of the machine.
High gain setting:-
• Highly sensitive, small flicker produces feedback. Used for
relaxation.
Low gain setting:
• Patient requires to make considerable effort. Used for muscle
recruitment.
• Used in paretic muscles.

22. EMG Biofeedback
Advantages:
• Can be integrated with other therapeutic interventions.
• An enhancer of the therapy.
• Reduce patient’s reliance on the therapist.
• Gain control without reliance on the therapist, and once
gained, maintain control without either the therapist or the
machine

23. BIOFEEDBACK MODALITIES
VISUAL FEEDBACK :
◦Visual displays available with BF devices include banks of lights,
liquid crystal display (LCD), meters, oscilloscopes, or computer
monitors.
◦ The visual display can be binary (0/1 in value or light on/off),
digital (integral numbers), or continuous (signal waves or
value bar).
◦ The sensitivity scale in the visual display should be determined
by the goals for the BF training.

24. Working

25. AUDIO FEEDBACK :
• ◦ Available devices offer auditory feedback in the form of a
tone, buzzer, click, or a combination of these possibilities.
• ◦Similar to visual feedback, the audible feedback could be
binary, discrete, or continuous.
• In devices with binary display, a monotone buzzer is heard
only when the patient achieves a specific feedback value
preset by the therapist.

27. Tactile Feedback :
◦Applied tactile sensation arises from a simple mechanical
vibrating stimulator attached to the skin.
◦By modulating the vibration frequency and amplitude, the
vibrating stimulator feeds back the sensed physiological signal
to the user.
◦Vibrotactile feedback is safe, free the user from having to
maintain visual attention to the feedback cues, and presents
minimum distraction to others.

31. Uses
• Facilitate muscle contractions.
• Promote increased motor recruitment.
• Regain neuromuscular control.
• Decrease muscle spasm.
• Promote relaxation.

32. Indications
1. Stroke
2. Spinal cord injury (SCI)
3. Complex regional pain syndrome
4. Low back pain
5. Arthritis
6. Headaches
7. Gait training
8. Urinary incontinence
9. Bell’s palsy
10. Temporomandibular disorders
11. Dysphagia

33. Contraindications/Precautions
• If the patient is prohibited from moving the joint or isometric
contractions, then BF should NOT be used
• Unhealed tendon grafts
• Avulsed tendons
• Third degree tears of muscle fibers
• Unstable fracture
• Injury to joint structure, ligaments, capsule, or articulating
surface

34. EMG BIOFEEDBACK IN STROKE
• A major application of biofeedback in rehabilitation hospitals
and outpatient clinics lies in the treatment of patients
following stroke.
• Motor dysfunction after stroke may be characterized by
muscle weakness, abnormal muscle tone, abnormal
movement synergies, and lack of coordination during
voluntary movement.
• EMGBF is a useful tool for reeducating neuromuscular control
in stroke rehabilitation.

37. EMG BIOFEEDBACK IN BALANCE
• Major application of BF in stroke rehabilitation is the training
of balance control.
• The training protocols address three components of the
function:
1. Steadiness,
2. Symmetry,
3. Dynamic stability.

38. EMG BIOFEEDBACK IN SPINAL CORD
INJURIES
• The primary goals for interfacing patients with SCI with
EMGBF are much the same for stroke patients.
• First, attempts are made to reduce hyper-motor responses to
induced length changes in spastic muscles.
• Once the patient can reduce such responses in supine, sitting,
and ultimately standing postures, efforts are directed toward
recruitment of weak muscles.

39. • For patients with tetra-paresis and obvious residual voluntary
movement, feedback combined with an exercise program
facilitated active range of motion (ROM) and improve
extremities function.
• Feedback may be beneficial for SCI patients because this
modality may be easily incorporated into exercise programs in
immobilized patients during the acute phase of injury.

40. EMG BIOFEEDBACK IN CEREBRAL
PALSY
• EMGBF use to monitor the spastic muscles in patients with
cerebral palsy (CP).
• EMGBF employed to down-train the sensitivity of tonic stretch
reflex.
• It significantly decreased the stretch reflex, the contracture
are not altered; thus, EMGBF might only be useful for
preventing the progress to muscle contracture.
• Head position control using positional BF, control of drooling
using EMGBF, and trunk sitting posture control by angular or
pressure BF have been used with CP patients.

41. EMG BIOFEEDBACK IN BELLS
PALSY
• Facial palsy causes weakness or paralysis of the facial muscles,
accompanied by other complications.
• Synkinesis is one of the complications and is an abnormal
involuntary associated facial movement during blinking.
• The underlying mechanism of synkinesis is inappropriate
reinnervation of the regenerating facial nerve fiber to the
facial muscle.
• EMGBF is an efficient rehabilitation intervention for patients
with facial palsy.
• Results from various studies have shown that after EMGBF
training, there was substantial improvement in facial
symmetry and voluntary functions.

45. Evidence for EMG biofeedback

46. Evidence for EMG biofeedback

47. Evidence for EMG biofeedback

48. SUMMARY AND CONCLUSION
• Biofeedback remains an important adjunct to the tools of the
rehabilitation therapies;
• It has been subjected to intensive scientific scrutiny with
controlled studies of varying quality pervading its history, and
ineffective procedures are being extricated.
• In addition to traditional, static BF training strategy, further BF
study may shift attention from static to task-oriented
biofeedback training, which may enhance motor functional
recovery.

49. REFERENCES
1. Biofeedback-principles & practice for clinicians.-Basmajian.
2. Physical rehabilitation- Susan o sullivan
3. http://en.wikipedia.org/wiki/Biofeedback
4. http://bme2.aut.ac.ir/~towhidkhah/MotorControl/Resource
s/EMG.pdf 3.
5. http://www.electrotherapy.org/modalities/biofeed.htm
6. Low & Reed, Electrotherapy Explained, principle and
Practice, 6th edition, 2019, Elsevier,
7. Jagmohan Singh, Textbook of Electrotherapy,3rd Edition,
2015, Jaypee Publications.

51. EMG BIOFEEDBACK IN DYSTONIAS AND
DYSKINESIAS