Electrical Stimulation for muscle contraction - Lecture #6 (modalitites) Flashcards
Estem for pain modulation is
Transcutaneous Electrical Neural Stimulation (TENS)
Estem for the purpose of activation of peripheral motor nerve (for muscular contraction)
Neuromuscular electrical stimulation (NMES)
* If were not getting any muscle contraction were not achieving our goal - there has to be a visible or palpable muscular contraction for this to be considered working
This can be used to faciliate strengthening (make muscle fire when it otherwise wouldnt) and prevent atrophy
What nerve does NMES stimulate?
Peripheral motor nerve
* the nerve must be in good working order to the motor units in order for NMES to work
Which kind of electrical stimuation would we use for deinnervated muscle tissue?
Electrical muscle stimulation (EMS)
* This essetially stimulates the sarcolima not the peripheral nerve
What works by stimulating the peripheral motor nerve and not just the individual muscle fibers (sarcolima)
Neuromuscular electrical stimulation not electrical muscle stimulation
Which has poor evidence to support the use: NMES TENS or EMS
EMS
Because muscles not attached to neurons (deinnervated) don’t have much left to live for so don’t do well with electrical stimulation
With a stroke patient would we use NMES and EMS?
NMES
The problem w/ stroke pts is getting the impulse from the brain to the spinal cord. Theres nothing wrong w/ the peripheral nerves so we can activate them all day so they can recruit those motor units and cause muscle contraction
Would we use EMS or NMES in an incomplete spinal cord injury?
Incomplete because some of those peripheral nerves are still intact
What is functional electrical stimulation?
NMES or EMS for the purpose of facilitation of functional activity
EX: Knee extension w/ sit to stand, wrist extension to faciliate grip
Theres an anterior tib one that is used when walking. Essentailly they walk and when they hit terminal stance (beginning of going into DF) it triggers electrical stimulation to allow them to DF the foot while they go through swing phase
We just don’t want it to shock the muscles into concentrically contracting when they should be lengthening
KNOW: The primary goal for NMES is muscle force (getting that actual muscle contraction)
* Our goal is to improve the voluntary contraction that occurs
Secondary goal: ROM / gait speed / prevention of contracture (because we now have more muscle force we should be able to work into this)
What population should use NMES?
People w/ weak yet innervated muscles
* In early rehab stages, especially with poor voluntary contraction
* Its great in early phases of rehab its great because you don’t have to move a pts joint to get muscle contractoin
* works great early on because it allows us to recruit more motor units - however - it doesnt increase muscle size, so lateral on in rehab its not great because we stop getting stronger because we’ve recruited all the motor units but the muscles havent actually gotten bigger (therefore fore can no longer increase)
* Also, for NMES to work we have to get a similatr contraction of the m as they would in EX. However, this amount of current is really uncomfertable so strength training in a healthy population is better (because they can just train on their own) - EX is more comfertable on m tissue than NMES
* NMES combined w/ EX > EX alone
However, in the healthy, non-weak population there was no difference between estem and EX in strengthen gaints
* No added benefit to combining ES and EX
KNOW: if were thinking about using NMES for strengthening we need to think about progressive overload (just like normal strengthening)
* We need to increase it over time to promote strength gains
* However, if we just want to stop atrophy from happening we can use the same amount everytime
Which order are motor units recruited in skeletal muscle w/ strength training?
What about w/ NMES?
Smaller –> Larger motor units recruited
NMES = Random patterns of recruitment
KNOW: Neural adaptations = increased motor units
* They increase the # of motor units recruited
* Increase the frequency that motor units are recruited
* Recruit more motor units at the same time
For NMES to induce strength gains, intensity must match traditional strengthening program
Does NMES cause hypertrophy?
No cear evidence
It can only prevent atrophy - we cannot build up muscle mass w/ this
With strength training or NMEs do a,, motor units have the same firing rate?
NMES
This can lead to a faster rate of fatigue
* with normal EX you can vary the frequency of contractions and which ones you recruit (big to small)
* With this you’re just sticking the electrodes on and they all fire at the same rate and big and small are stimulated (because everything under the pad is going to fire)
NMES also leads to improved muscle extensibility (the ability to extend or be stretched)
* this is by activiating the muscle to go through its full ROM and then allowing it to relax
* Through this you can improve an agonist / antagonist tissue
NMES can be used to reduce spasticity
* flexors are spasticitic so i put the pads on them to contract them a bunch to fagitue them out so they can relax
* Or you can put the muscles on the anatognist and cause the flexors to be stretched over and over
Conditions indicated for NMES:
Post surgical: The idea so to get muscle contraction w/o moving the joint
* ACL repair
* Meniscus repair
* TKA
* etc
Critically Ill or Frial (so to keep that atrophy from happening)
Generally inactive (to prevent atrophy)
* Secondary to pain (w/ pain)
Neurological:
* Stroke (Cerebral vascular accident [CVA])
* Spinal cord injury
* Cerebral palsy
* Multiple sclerosis
Precautions: for both
Pain of unknown origin
Active/open epiphysis
Titanium and most orthopedic implants are nonconductive to electricity and it is OK to place electrodes in this area
Adhesive allergy (for the actual pads)
* Consider changing to a gelled carbon electrode
Contraindications:
Local application of e stim in area of:
* Pacemkaer (chgest gion L>R) -Cervical, lumbar, LE and distal UE have been shown to be OK, still clear w/ a cardioologist though
Pregnancy (lumbosacral, abdominal regions)
Carotid sinus (anterior neck)
Damaged skin
Lack of sensation
Malignant tumors
Eyes, internally, or reproductive organs
Poor cognition, inability to communicate - with tens this is a contraindication (because you need to know the strong comfortable senastion)
* However, not a contraindication w/ NMES / EMS because you can see when you get your desired affects (actual m contraction)
* howver it is a precuations for these because you need to do consistent skin checks to make sure you’re not burning them
Thrombosis/thrombophlebitits
Hemorrhage
KNOW: You could def do Estem for a total knee pt joint because their implant is non electrically conductive (as long as it was made in the USA/europe)
If nerve is severed than theres no point in NMES - could do EMS for the deinnervated muscle
Could pair this w/ ROM deficits and pair that w/ a functional activity
Dont forget skin inspection for thermal affects
* Only do this if they have lack of sensation (but I would air on the side of caution for this and do it anyways)
KNOW: if they have a patellar tendinopathy you wouldnt want to put estem on their quads and have them go through a long arc quad - that might irritate them
* so be careful that the activation of the muscles you turn on itsnt actually moving / negatively affecting the joint you’re trying to avoid
If they have activity partipation issues we can put the estem on and turn on when they really need to muscle to contract (think turning on for the DF part of ambualation then turning back off)
With electrical stimulation (Tens or NMES / EMS doesnt matter which one) when we put the electrodes on does it recruit larger or smaller diameter nerves?
* what kind of nerves are motor nerves
Larger
Remember - this is talking about peripheral nerves not motor units (motor units are recruited randomly)
* NOTE: the biggest nerves are motor nerves
Even though the biggest nerves (recruited first) are motor nerves we get a sensory response before a motor response - this is also based on the location / placement of the electrodes. if they arent placed near those big motor nerves we can actually turn on those peripheral sensory nerves (even though their smaller) first.
