Week 8 Electrotherapy for Muscle Weakness - NMES Flashcards
(Functional/Neuromuscular) electrical stimulation – muscle strengthening
(Functional/Neuromuscular) electrical stimulation – muscle strengthening, control of movement, orthotic substitution
(Functional/Electrical) muscle stimulation – muscle nutrition/metabolic function for denervated muscle
Neuromuscular; Functional; Electrical
Electrotherapy for Muscle Weakness Parameters
Small muscles - low pulse duration will typically work
Large muscles - (smaller/greater) pulse duration is needed
greater
Use of nmes
Indication:
Muscular strength deficits
Less than _% (symmetry to the other side) MVIC
At PT’s discretion if MVIC unable to be tested
Activation failure:
Identified with burst testing
Most common use of NMES is for the quad, specifically after ACL reconstruction
Burst testing – muscle testing with an NMES contraction superimposed on top of it.
Decreased activation of motor units is commonly seen after injury which leads to less activation of the muscle.
80
NMES
Contraction is achieved by:
Stimulation of the intact (muscle/peripheral nerve)
Stimulation of the muscle membrane
Setting up electrodes over superficial (muscle/peripheral nerves)
peripheral nerve; peripheral nerves
Russian (AC) NMES
Frequency- 50-80pps
Amplitude- At least _% MVIC for true hypertrophy / (minimum/maximum) tolerated above tetany
Pulse Duration - _-_Hz
Treatment time - min, on/off: / with _ sec ramp up
50-80; 50; maximum; 1500- 2500; 10-15; 10/50; 2
Pulsed Current NMES
Frequency - - pps
Amplitude- At least _% MVIC for true hypertrophy / (minimum/maximum) tolerated above tetany
Pulse Duration - - usec ((lower/higher) for larger muscles)
Treatment time: - min, on/off: / with _ sec ramp up
50-80; 50; maximum; 200-600; higher; 10-15; 10/50; 2
Maximizing force: pulse duration
How to recruit more motor units electrically?
Increase recruitment via (increasing/decreasing) phase charge
Phase charge – how much electricity is coming out of the box with any given pulse
Phase charge is a function of our pulse _____ and our (frequency/amplitude).
You recruit more motor units by having a (shorter/longer) pulse duration.
The longer the pulse duration, the (less/more) amplitude is needed to reach the motor neuron.
Picture – shows difference between amplitude and pulse duration. The area under the curve for each of these is larger whether you increase the amplitude or whether you increase the pulse duration and this is good because you want more motor unit recruitment.
increasing; duration and our amplitude; longer; less;
Maximizing force:Frequency
Increasing frequency > increased rate coding = (Twitch/Tetanic) contraction
Force production reaches a plateau maximum between - pulses per second
Once we get to _ pps we get a nice smooth tetanic contraction (that is our first goal).
Tetanic; 50-80; 50
Maximizing force: Frequency
Rate coding: Increased frequency = (decreased/increased) fatigue
Consistent pulse duration and amplitude – force output increases if we increase the frequency.
If we have the same pulse duration we are recruiting the same number of motor units, but now we are telling them to fire more often. So the more often they fire the stronger contraction you are going to get.
Electrically induced fatigue – even though a higher frequency (110pps) gets you a higher output of force , the muscle isn’t able to sustain it for as long which means the net strength gains are going to be less.
Increased frequency has a trade off for increased fatigue.
Fatigue will look like – over the course of the 10 second contraction it will start off as strong tetany but by the end of those 10 seconds it will look like fasciculations and twitching
increased;
NMES Quality of Contraction
Goal = strong (twitch/tetanic) contraction
Stimulation frequency 50-80 bps/pps
Beyond 80 bps/pps, strength gains (are as/are not as) good
tetanic; are not as
