BIOFEEDBACK

What is Biofeedback?A clinical technique that involves recording electrical activity generated in a muscle for diagnostic purposes

Utilizes an instrument that measures, processes & provides feedback reinforcing information via visual or auditory signals • Does not monitor actual response (strength of contraction)

but rather the conditions associated with the response

Not used as a modality like heat or cold, but can be used for rehabilitation & research purposes

Can be used to help regain function of a muscle that may have been lost

Biofeedback Units4 types of Units: • Peripheral temperature,

• Finger Phototransmission,

• Electrical resistance units/ Skin Conductance Activity

• Electromyography (EMG),

EMG - most typically used form of biofeedback

Scale on unit can be both visual and audio

Measured in microvolts, 0-10 scale, or some form of pitch

EMG & Other Units

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Biofeedback UnitsPeripheral temperature units• Indirect measure of the diameter of peripheral

blood vessels• Easily seen in toes & fingers

• Variations in body reactions change temperature temperature indicates relaxed state temperature indicates stress, fear, anxiety

• Measured in degrees Fahrenheit

Biofeedback UnitsFinger Phototransmission• Measured indirectly using a Photoplethysmograph

• Monitors amount of light reflected by subcutaneous tissues based on amount of blood flow

• As blood volume increases the amount of light detected decreases

• Monitor finger pulse

Biofeedback UnitsElectrical resistance units/ Skin Conductance Activity• Measures amount of perspiration on the skin

• Sweat contains salt which increases electrical conductivity

• Passes a small current through the fingers (volar surface) and/or palm

• Measures impedance of electrical current

• Lie detector testing

Lie Detectors

Biofeedback UnitsElectromyographic (EMG)• Measures electrical activity in skeletal muscle• May be very simple to very complex• Take-home models

Electrodes – you will mostly see surface electrodes• Active electrodes:

• Detects electrical activity from muscle contraction & converts into visual or auditory signals

• Reference electrode (ground electrode): • Filters “noise” or unwanted electrical activity in the environment

(other electromagnetic energy); • Point of reference to compare the electrical activity recorded by

the active electrodes

EMG Units

Indications for EMG UseFacilitation for muscle reeducation

Restoration of neuromuscular function

Increase muscular strength

Promotion of relaxation of spasm

Reduction of muscle guarding

Assistance with pain control

Neurological Conditions (following stroke, spinal cord injury, cerebral palsy, incontinence)

Advantages for using EMGProvides feedback with a chance to make appropriate small changes in performance that are immediately noted & rewarded

Patient learns early in rehab to do something for him/herself instead of relying on the athletic trainer

Proven to reduce myofascial pain, migraine & tension headache pain and stress reduction

With neuromuscular effects, biofeedback helps with input that is lost from receptor

Contraindications

If movement of a joint or isometric contractions are contraindicated

Conditions in which muscle contractions might exacerbate the condition• Unhealed tendon grafts, avulsed tendons, 3rd

degree tears of muscle fibers

Unstable fractures, injury to joint structure, ligaments, capsule or articulating surfaces

Patient Set-up & ApplicationShave area if applicable

Clean skin to remove all dirt, oil, lotion, etc.

Area may have to be mildly abraded if unit is sensitive

Secure electrodes OVER the muscle belly. The active electrodes MUST be on target area. Reference electrode may be secured anywhere on the body, but is usually in between the two active electrodes

Distance between active electrodes is usually close

Patient Set-up & Application

Plug electrode lead(s) into unit

Turn unit on

Adjust output to desired mode

THE PATIENT SHOULD NOT BE DISTRACTED BY OUTSIDE NOISES DURING SESSION.

Various protocols