Biofeedback

What is Biofeedback?

Receiving real time feedback about physiologic processes in order to gain conscious control over them

Individual uses conscious control and increases awareness of performance

EMG Biofeedback

• The monitoring, detecting, and assessing of skeletal muscle activity for the purpose of influencing future skeletal muscle activity

• Uses an EMG signal

• No current is delivered

Primary Goals of Biofeedback

• Improved function

• Increase or decrease muscle activity

  • Facilitatory or inhibitory

• Decreased pain

• Improved kinesthetic awareness of motion

• Helps neuromuscular re-education

• Can make training engaging and fun

How does it work?

• Surface electrodes (sensors) are placed over target muscles

• An activity/contraction is performed

• A device detects and transduces the electrical activity of muscle

• This is converted to visual and/or auditory feedback

Sensitivity and Gain

Sensitivity = how much input signal is needed to produce an output response on the display

•Lower gain = lower sensitivity

•System is less sensitive to small EMG signals

•Higher gain = higher sensitivity

•Smaller electrical signals amplified more

Electrode placement

• Usually has specialized electrodes

• Detects muscle fibers closest to the electrode

• Parallel to muscle fibers

• Wide electrode placement- detects larger muscle volume

• Narrow electrode placement- detects small muscle volume

With decreased volitional muscle activity such as post surgical, what sensitivity and electrode placement would you use?

• Wide electrode placement

• Large muscle volume

• High gain

• for lower muscle activity

• Low gain

• for higher muscle activity

• Narrow electrode placement

• Small muscle volume

Thresholds and Key Points

• Inhibitory or faciliatory thresholds set

• If threshold is met, an audio/visual cue will occur

• Pt needs to have partial innervation or partial activation of the muscle in order to be successful

• Used to assess or train

Biofeedback Gamification

Combining real time feedback with games to enhance learning and engagement

Key Evidence Review

• Biofeedback improves pelvic floor muscle function, reduced urinary symptoms, and improved QOL (Fitz, 2012)

  • Biofeedback for Pelvic Floor Video

• Helpful in early phase (2 wks) post ACL surgery for inc knee extension

  • No sig differences at 6 weeks on knee function, swelling, and pain (Christanell, 2012)

• Post stroke- mixed evidence

  • OT + FES + biofeedback led to greater gains in UE ROM and function post stroke then those with OT + FES (Lourencao)

• In iSCI, a reduction in Trendelenburg was noted for individuals who used biofeedback training on the glute med (Petrofsky)

Biofeedback improves pelvic floor muscle function, reduced urinary symptoms, and improved QOL (Fitz, 2012)

Biofeedback for Pelvic Floor Video

Helpful in early phase (2 wks) post ACL surgery for inc knee extension

No sig differences at 6 weeks on knee function, swelling, and pain (Christanell, 2012)

Post stroke- mixed evidence

OT + FES + biofeedback led to greater gains in UE ROM and function post stroke then those with OT + FES (Lourencao)

Biofeedback plus FES

• Pt activates a muscle until a target EMG is reached

• Once target is reached, FES completes the remainder of the motion that the pt can’t complete independently

1. Pt activates muscle to best degree possible

2. Target EMG threshold is reached

3. FES assists to finish motion that pt cannot do due to strength/fxn limitations

Complex Biofeedback in Action

HAL senses bio-electrical signals from the muscle or senses pressure changes from weight shifts and then the power unit assists with voluntary movement

Action Steps - biofeedback

1. Determine if biofeedback is appropriate

   1. Do you have muscle activity to increase or decrease?

   2. Is there partial innervation present?

   3. Can your patient cognitively understand the feedback given?

2. Determine muscles to monitor

3. Wipe skin with alcohol wipe

4. Place sensors over muscle belly.

   1. Determine wide vs narrow placement

5. Connect wires from device to sensor

6. Set sensitivity

7. Set inhibitory vs facilitatory

8. Begin training program with your functional task

9. Adjust according to pt progress

   1. inc or dec the sensitivity, alter placement, alter activity challenges