2. Father of EMG Biofeedback : John Basmajian
The term is short for biological feedback.
Definition:
It is the technique of using equipment (usually electronic) to reveal to
human beings some of their internal physiological events, normal and
abnormal, in the form of visual and auditory signals in order to teach
them to manipulate these otherwise involuntary or unfelt events by
manipulating the displayed signals.
• Hence, it is a therapeutic approach whereby we are using non-
physiological events or non-physiological feedback to control
physiological response of the body.
• Traditionally the biofeedback signal has been auditory or visual;
tactile feedback devices (e.g.. vibration) has been recently developed.
3. Middaugh’s Conceptual Framework for Biofeedback
Therapy
3 basic components in the biofeedback process –
• the therapist: evaluates, sets instrumentation parameters, develops
intervention strategies & instructs the patient.
• the patient: attempts to manipulate the biofeedback signal, thereby
altering the physiological mechanism being measured.
• the biofeedback machine:
records the patient generated physiological
events, processes them, and displays the information .
4. BF IN REHABILITATION
When using BF the patient must →
Understand the relationship of electronic signal to the desired
functional task.
Practice controlling the BF signal.
Perform the functional task until it is mastered and the patient no
longer needs the BF.
5. BF can assist in Rehab. process by →
• Providing a clear T/t goal for the patient to accomplish.
• Permitting the therapist & patient to experiment with various
strategies that generate motor patterns so as to achieve the desired
goal.
• Reinforcing appropriate motor behavior.
• Providing a process-oriented, timely & accurate KP or KR of the
pat’s effort
6. TYPES
GENERAL
• Motivational
• Qualitative & not
proportionate
• Alertness of therapist
• Gross external events
• Latency of response
ELECTRONIC
• Informative &
Motivational
• Quantitative,
proportionate, more
objective & consistent
• not reqd.
• minute events
• during performance.
7. Types of Electronic BF
• EMG BF: the myoelectric signals from the muscle are translated
into simple auditory and visual signals that are very easy to
understand (eg. Lights and buzzing sounds) or graphic computer
displays.
• Temperature & Peripheral Blood Flow BF
• B.P BF
• Sphincter control Training
• Respiratory BF
• Position BF: it is indicated when goal of T/t is the regulation of
movement, provided the patient is able to voluntarily recruit and
relax the appropriate muscle groups.
It is used to train the appropriate timing and coordination
needed to control a movement.
8. Application in neurorehab:
training for head control.
coordination and control of hand movements in ataxia and after
hand surgery.
training for joint position in children with cerebral palsy, adults with
hemiplegia and prosthesis wearers.
In stroke rehab when the muscle that must be monitored is
inaccessible or difficult to isolate ( e.g. Pronation & supination)
9. INDICATIONS
Relaxation in Spasmodic Torticollis
Tension & vascular headache (Migraine)
Improvement of functional deficits in paraplegia & quadriplegia
Improvement of postural instability, proprioception, and reduction
in falls
Cerebral Palsy – msl. re-education & relaxation
CVA – foot drop & gait problems
Posture & msl. Tone improvement
Improved voluntary control of involved msls.
Msl. Relaxation in associated rxns.
Speech problems
Muscular training after nerve, msl, ligament, or tendon injury,
repair, or transfers
10. Bell’s Palsy
Measurement of endurance with sustained activity
Functional training and reduction of myoclonus follg. Brain injury
Control of urinary incontinence & other pelvic floor d/o
Respiratory control in asthma, emphysema, and COPD
H. T.
Autogenic training of temperature control in diabetes, vascular
disease
cardiac arrythmias
Stress management
Dysphagia
Pain management and reduction in chemotherapy related
symptoms in cancer patients
Early joint mobilization after surgery
12. CNS signals its intentionto move
↓
signal travels down the spinal cord
↓
AHC discharges
↓
Motor nerve depolarizes
↓
Action potential hits the neuromuscularjunction
↓
Acetyl cholinediffuses across the synaptic cleft
↓
Second actionpotential occurs at the sarcolemma
(conducts more slowlythan the nerveA.P)
↓
EMG registers this sarcolemmaldepolarization
↓
Electricalexcitationtravels through the muscle
↓
Acetylcholinecauses releaseof calciumions
↓
Muscle contraction
13. EMG FB can be used to help the patient ↑se or ↓se the msl.activity :-
• For weak msls. : The goal is usually to increase the EMG signal
(up train)
• For overactive msls. : The goal is to decrease the EMG signal
(down train)
14. Therapeutic interventions in EMG FB
typically require the therapist to:
1) select the msl to be monitored.
2) prepare the skin at the surface electrode site with alcohol or
other skin abrasive.
3) prepare the electrodes and apply to the skin.
4) determine the maximum & minimum EMG readings without
patient feedback, to determine baseline readings. (make sure
signal reaching the patient is artifact free)
5) together with the patient set goals for the session and ensure
patient understanding. Treatment can be progressed after
roughly 2-3 or more successful BF trials.
15. 6) Teach the patient to manipulate the controls of machinery so
as to have maximal patient participation in the intervention
7) Use facilitation or other neuromuscular re-education techs. (to
enhance pat’s motor performance)
8) Remove and clean the device & the patient’s skin after the
session ends.
17. KINEMATIC (JOINT MOTION) FB
• Joint motion is commonly measured by using goniometer.
• An electrogoniometer is an electronic version of the manual
goniometer that employs a potentiometer (variable resistor /
rheostat) attached to the movable & stationary arms.
• Rotating the rheostat changes its resistance, which in turn ↑es or ↓es
the current from the FB device’s signal.
E.g. If a volume control knob or room light dimmer were connected to
an el-gon on a knee, each step would cause the audio signals or lights
to fluctuate.
It is important that FB is linearly related to joint motion.
18. Clinical application:
• Children with orthopedic d/o can be easy to treat by making the
volume of TV or radio contingent on movement in the proper
direction.
• Hemiplegics have successfully learned to reduce knee stance phase
hyperextension and to increase swing phase flexion.
19. STANDING BALANCE FB
• Also k/a Posturography FB.
• It has become ↑ingly popular in treating elderly patients & others
at risk of falling and those with neurological d/o like parkinson’s
disease and hemiplegia.
• It consists of force measuring scales on which the subject is
requested to stand as still as possible. (typically marketed to
measure COG or COM sway)
Balance platforms like balance master only measures COP under
the feet.
20.
21. KINETIC (DYNAMIC FORCE) FB
• It renders information regarding the amount or rate of loading
through the limbs, an audio or visual FB signal is used.
• Goal is to inform the patient whether weight bearing is ‘correct’,
‘insufficient’ or ‘excessive’.
• Limb load monitor
generally have a strain gauge which is built into an insole or the sole
of a sandal. It works by ↓ing the electrical resistance as the force on
the foot ↑es. This permits more electricity to reach the audio speaker
which beeps faster or at a higher pitch as greater loads are applied.
For training symmetrical standing or gait, the Krusen limb load
monitor may be used with hemiplegic adults and children to monitor
the force transmitted through an extremity.
22. The use of a FB cane can help train hemiplegic patients to monitor
the amount of force being borne on an assistive device.
• Foot switches: a buzzer and a battery connected to a footswitch can
warn the patient not to bear weight on a fractured limb, or help
encourage heel-strike gait in hemiplegics or C.P. patient.
Two switches can be used B/L to provide stance time symmetry BF.
24. STROKE
Stroke rehab is a major application of EMG BF. Patients have
shown greater functional improvement with lower-limb training
than with upper-limb training. Age, gender, hemiparetic side,
duration of stroke, previous rehab and number of training
sessions did not have a significant effect.
However optimal time to introduce BF appears to be fairly early
Some significant factors shd be considered:
1) Potential for voluntary control must exist before FB training
begins.
2) Motivation and cooperation are essential.
3) Inability to follow commands and receptive aphasia make BF
training practically impossible.
4) Severe proprioceptive loss, marked spasticity, and the inability to
voluntarily initiate exploratory movements of an extremity all
appear to correlate to diminished functional improvements.
25. Lower limb: the primary functional goals are improved ambulation
and development of the relatively limited number of stereotyped
patterns used during ambulation.
Hip and knee extension is an imp component of the stance phase
of gait.
EMG BF can be used to train the gluteus maximus individually.
It can also be used to encourage recruitment of the quads or
relaxation of the hams, or both. Dual-channel monitoring may be
used to facilitate contraction of the quads and relaxation of hams.
Finally it can be used to train combd hip and knee extension.
Ankle dorsiflexion: foot drop was one of the first areas to be
treated caused by paralysis of the ankle dorsiflexors and spasticity of
the plantarflexors.
Training may begin with either relaxation of Gastrocnemius or
recruitment of the dorsiflexors.
26. Recruitment of the dorsiflexors during relaxation of the
gastrocnemius also may need to be trained.
Auditory FB is used as the patient is encouraged to watch the foot to
avoid marked inversion.
If the patient has appreciable dorsiflexion, the therapist may combine
Position FB with EMG FB from plantarflexors with a relatively
simple elctrogoniometer.
Shoulder subluxation: by gaining control and strength in the upper
trapezius and anterior deltoid, the patient not only tends to reduce
subluxation but also improves the AROM
The upper trapezius is a good msl to start training. With electrodes
over the msl belly, the patient may be first asked to shrug either the
involved or both shoulders, with FB provided from the involved msl.
a mirror is also used to provide visual FB of the movement done.
With ↑ing control of the shoulder elevators, restoration of normal
scapular posture should result in the reduction of subluxation.
27. HEAD INJURY
EMG BF applications for these patients can be similar to those used
with stroke, given similar motor presentations. It is imp to consider
residual cognitive deficits in deterning the appropriateness of EMG
BF.
Spasticity can be treated assuming that there are some intact
neuronal pathways available to suppress spasticity. (plasticity)
Some investigators invoke the possibility of dendritic sprouting
occurring in the relearning stages to account for the reacquisition of
skills.
BIOFEEBACK TREATMENT OF U.E. DYSFUNCTION IN
‘GBS’(APMR Vol.67, January 1985)
EMG BF in GBS patients demonstrated improvements in msl
strength in U.E. and L.E.
Although inconsistent improvement in functional use of the U.E was
noted.
28. CEREBRAL PALSY
In these patients head-position monitors and foot placement &
pressure switches are undergoing testing.
The former device usually employs a helmet in which a level-
detecting system emits a threshold or varying sound that prompts the
wearer to assume the desired head posture.
Advancements in technology allow for the use of EMF BF in the
computer-assisted feedback (CAF) system which can be used to
provide FB abt msl activity during ambulation. Using it as an adjunct
to physical therapy may prove beneficial.
SPASMODIC TORTICOLLIS
Many brief case studies have been reported. The most thorough
studies of many patients successfully treated with EMG BF combd
with other behavioral techs. Were reported by Brudny and colleagues
& by Cleeland.
Writer’s cramp and Blephrospasm have also been treated with BF.
29. BELL’S PALSY: MUSCLE RE-EDUCATION BY EMG BF.
(APMR Vol.59, May 1978)
The results suggested that EMG BF may be useful in restoring
muscular control and normal facial characteristics to persons
diagnosed with Bell’s palsy and who do not respond to standard
forms of medical intervention.
Post-treatment levels closely approximated the non-affected side,
and resulted in more normal facial characteristics w.r.t. jaw position
and symmetry of smiling. Bidirectional control of the zygomaticus
was also demonstrated
SPINAL CORD INJURIES
A major application reported is the dramatic result with
quadriplegic patients who suffer from orthostatic hypotension.
Provided with direct B.P. monitoring, such patients have learned to
raise and maintain their B.P. by an ‘act of will’, sufficiently to
overcome fainting.
30. Learned Activation of Thoracic Insp.Msls. In Tetraplegics
(AM J PMR-Oct 93;72:312-317)
In the study 10 tetraplegics with lesion level C3-C7 were trained to
↑se the upper rib cage expansion during 9-20 mins session.
The subjects were instructed to ↑se EMG during inspiration & to ↓se
it during expiration. It was shown that the subjects progressively
learned to ↑se insp.EMG
The primary goal in SCI pats. is to reduce hyperactive behavior of
spastic msls that may occur during spontaneous episodes of clonus.
Later efforts are directed towards recruitment of weak msls.
In paraplegics, attempts are made to reduce activity of the
adductors and gastrosoleus.
In partial lumbar SCI pats, FB training enabled many to increase
the speed at which they ambulate and to reduce the number of
required assistive devices.
For quadriparetic patients with voluntary movement, BF combd
with an exercise progm facilitated AROM and improved U.E
function.
31. Head control: volitional aspects of rehabilitation
training in patients with multiple sclerosis compared
with healthy subjects. { APMR 2005 Jul;86(7):1381-8 }
OBJECTIVE: To investigate the role of voluntary mechanisms and
motor learning in head stability and the impact of longitudinal
biofeedback training in head control.
INTERVENTION: The experimental condition in which subjects
walked on the treadmill was compared with that in which the head
was voluntarily stabilized. In another experimental condition,
augmented feedback of head displacement was provided by means of
a laser mounted on the head that projected a laser beam on a screen.
The motor learning was investigated with biofeedback training
sessions. Positional feedback was represented by the laser beam,
with subjects having to stabilize the beam while walking on the
treadmill.
32. RESULTS: Voluntary mechanisms play a role in head stabilization
during gait. Augmented biofeedback of head displacement may be
effective in reducing head oscillations.
INTEGRATING NMES & EMG BF
An alternative application is the use of EMG-triggered NMES,
where NMES is initiated once the client achieves a predetermined
level of EMG activity in the targeted msl.
The threshold of EMG for the onset of NMES can be manipulated
by the therapist to engage increasing levels of client active control.
The success of this application is emphasized in hemiplegics in
↑ing levels of EMG activity and subsequent improvement in ROM in
the involved arm & leg.
A variation of this application is NMES triggered by ‘Positional
FB’ such that NMES is initiated once the patient actively moves
through a portion of the available ROM at a joint. This has proven to
be effective in improving wrist motion in patients follg stroke.
33. RELAXATION THERAPY
BF has provided an instrumental method to constantly monitor the
level of relaxation achieved by the patient. An improved style of
daily living combd with this shd be practiced at home & work.
(Tension headache, anxiety, stroke-emotional stress)
NERVE TRANSPLANT
BF can be used to help the patient learn the new msl action. It
informs the patient when he/she is making the correct response.
34. BRAIN WAVE FB / NEURO FB
In the late 1960's and 1970's it was learned that it was possible to
recondition and retrain brainwave patterns. Some of this work began
with the training of alpha brainwave activity for relaxation. This
training is called EEG biofeedback or neurofeedback
Neurofeedback training offers additional opportunities for
rehabilitation through directly retraining the brain.
ADD/ADHD, a learning disability, a stroke, head injury, deficits
following neurosurgery, uncontrolled epilepsy, cognitive dysfunction
associated with aging, depression, anxiety, obsessive-compulsive
disorder, or other brain-related conditions.
Even though the problem is biological in nature, it acts as an
alternative treatment. . Neurofeedback is also being used increasingly
to facilitate peak performance in "normal" individuals and athletes.
35. During typical training, a couple of electrodes are placed on the
scalp and one or two are usually put on the ear lobe. Then, high-tech
electronic equipment provides you with real-time, instantaneous audio
and visual feedback about your brainwave activity.
Brainwave patterns are relayed to the computer and recorded.
Ordinarily, we cannot influence our brainwave patterns because we
lack awareness of them. However, when we can see our brainwaves
on computer screen a few thousandths of a second after they occur, it
gives us the ability to influence and change them.
The mechanism of action is operant conditioning. We are literally
reconditioning and retraining the brain. At first, the changes are short-
lived, but the changes gradually become more enduring. With
continuing feedback, coaching, and practice, we can usually retrain
healthier brainwave patterns in most people
36. Recent developments in biofeedback for neuromotor
rehabilitation J Neuroengineering Rehabil. 2006; 3: 11.
• The original use of biofeedback to train single muscle activity in
static positions or movement unrelated to function did not correlate
well to motor function improvements in patients with central nervous
system injuries.
• The concept of task-oriented repetitive training suggests that
biofeedback therapy should be delivered during functionally related
dynamic movement to optimize motor function improvement.
Current, advanced technologies facilitate the design of novel
biofeedback systems that possess diverse parameters, advanced cue
display, and sophisticated control systems for use in task-oriented
biofeedback.
37. • Patients in older biofeedback studies learned to regulate a specific
parameter through a quantified cue while in a static position, or they
performed a simple movement unrelated to the activities of daily
living (ADL). We define this as "static biofeedback"; EMG is a classic
form. Static EMG biofeedback therapy may thus produce only
specific and limited effects on motor function recovery.
• Task-oriented biofeedback therapy and robot or other assistive
device aided repetitive task practice should be more effective because
this integrated sensorimotor therapy would provide patients with
motor deficits an opportunity to actively and repetitively practice a
task.
• VR based displays could also increase the motivation and attention
of patients in the task training, improve sensorimotor integration
through multimodal augmented feedback, and, consequently, improve
training efficiency.
38. REFERENCES
• Physical Medicine Rehabilitation ( Principles & Practice),Vol –
II,Joel A. Delisa, 4th edition.
• Physical Rehabilitation-assessment & treatment, Sullivan,4th
edition
• Umphred.
• Biofeedback in Rehabilitation: A Review of Principles and
Practice. ( APMR Vol.62:469-475,1981)
• Physical Medicine Rehabilitation – Braddom
