Biofeedback: Application for Neuromuscular Control

Question 1

Definition of Biofeedback

Answer 1

• they use of instrumentation to bring physiological events to conscious awareness
• objectively measure the process
• converts what is being measured into feedback that optimizes the desired effect
• ex: keeping BP cuff inflated to certain pressure with muscle activation
• requires A LOT of coaching
• can be goo post surgical tool to coach contraction

Question 2

Effectiveness of Biofeedback

Answer 2

• primarily used as a teaching aide to help train a deficient athlete or correct/smooth a muscle activation pattern
• must be timely: immediate, statistics
• must be precise: simplistic to functional

Question 3

Instrumentation

Answer 3

• varies: electrical units, mirrors, taping, voice cues
• cost varies
• may be objective or subjective
• results may be instantaneous or over time (a few minutes, not days though)

Question 4

EMG Biofeedback

Answer 4

surface electrodes are used to transform signals

• permits awareness of neural recruitment of muscles
• electrical activity of muscle recorded and transformed into visual and auditory signals
  
  • as motor units are recruited into a contraction, the amount of electrical activity within the muscle increases
  • EMG converts this muscle activity into visual cues and noises
• electrical activity associated with contraction is measures, NOT the actual force being produced

Question 5

EMG Biofeedback Instruments

Answer 5

• fine internal wires
• self-adhesive, easy to apply, inexpensive, less training
• small electrical unit or large machine

Question 6

EMG Biofeedback Electrodes

Answer 6

3 electrode positioned over muscle or muscle group

• 1 point of reference electrode: filters out non-meaningful electrical activity
• 2 active electrodes over muscle
• as motor units are recruited, these signals are picked up by the electrodes, amplified and converted into visual and auditory signals

Question 7

Electrical Unit Components

Answer 7

• circuit that receives EMG signal
  
  • electrical signal detected at electrode
  • conducted to electrical circuitry within unit
  • raw EMG signal received through electrode is FILTERED…AMPLIFIED…RECTIFIED…INTEGRATED…TRANSDUCED
• the amount of proportional electrical activity in the muscle that can be seen and/or heard = 1 piece of data generated by all the info compiled by the computer

Question 8

Filtering

Answer 8

removal of “noise” from high and low frequency sources

• electromagnetic energy in the environment is absorbed by the body and detected by the unit
• must be filtered out before relevant activity is determined

muscle activity is 80-250Hz
–> anything above or below is filtered out

Question 9

Amplification

Answer 9

the process of taking a raw signal of muscle in the microvolt range and amplifying it to the MILLIVOLT range

Question 10

Rectification

Answer 10

• all deflections from the isoelectric line are made positive or negative
• allows for either an all positive or all negative reading = easier to read

Question 11

Integration

Answer 11

integrated signal: fitting curve through sample points

• smoothes the signal, allowing area of curve to be quantified
• —> can then power lights or sound to provide immediate feedback

Question 12

Indications

Answer 12

• muscle re-education (more meaningful way of doing russian stim)
• relaxation: decrease number of motor impulses being relayed to the spasming muscle by contracting muscle around it (i.e.. muscle guarding) ** do not use a lot
• ROM: must be able to do activity without amplifying pain through ROM or contraction
• -> ultimate GOAL:
• decrease pain and/or
• increase function

Question 13

Clinical Applications: Restoring Voluntary Control

Answer 13

decreased ability to contract muscles fully due to neural inhibition post op

• poor movement patterns
• increased pain and swelling

Biofeedback used to:

• mimic movement patterns
• help enhance control of volitional contraction
• train recognition and firing patterns of muscles
• must have muscle twitch/be innervated

Question 14

Clinical Applications: Functional

Answer 14

• muscle re-education of patterns: complex motor patterns are executed from motor/movement pattern
• –> “functional progression”
• –> injury, pain, swelling, and instability can inhibit normal execution and coordination
• progress to active exercises beyond simple volitional contraction (Open Chain –> Closed Chain / sport specific activities)

Question 15

Concerns of Biofeedback

Answer 15

• total inability to contract a muscle
• imperfect practice (must have good form) or inappropriate feedback
• lack of adjustment to sensitivity of EMG (too much noise)
• lack of increased challenges (must progress and in sports related activities)
• lack of incorporation complex motor tasks

Question 16

Contraindications

Answer 16

• patient prohibited from moving joint

- if isometric contractions are contraindicated