Neuromuscular Electrical Stimulation Definition .
Neuromuscular electrical stimulation is becoming one of the popular treatment approaches due to the ease of application and modern look of these machines. Use of electricity to stimulate the nerves that correspond to a targeted muscle or muscle group and cause it to contract has been traditionally termed as neuromuscular electrical stimulation (NMES). Neuromuscular electrical stimulation requires an intact peripheral nerve and healthy muscle tissue. The waveform selection can be bi-directional, symmetrical or asymmetrical.
Symmetrical waveforms are preferred for large muscles and asymmetrical waveforms are preferred for small muscles. Intensity or magnitude of intensity determines the amount of muscular response. Higher amplitudes generate a greater muscular response due to an increase in the number of motor units activated. In symmetrical waveform, both electrodes are active and one should use negative electrode preferably over motor point, while in asymmetrical waveform, negative electrode is more active and place the negative electrode over the motor point.
Distance between electrodes will determine depth of current, it is found that greater the distance, deeper is the flow of current. Frequency or rate of repetition of impulse determines the quality of a muscle contraction and fatigue. Usually 25 to 50 pulses per second rate of repetition that causes tetanic contraction is used. Higher rates like 80 pulses per second elicit muscle fatigue. Using the minimum rate produces a good, tetanized contraction that will help to control onset of fatigue. However, using higher rate produces fatigue and it can be used for the relief of muscle spasm. Medium Frequency Currents
Ramp or surge up/down time can be adjusted since, it helps to offer comfort of treatment and can be used to mimic normal recruitment or physiological contraction. Typical ramp up, is up to three seconds but higher ramp time may be beneficial in minimizing stretch reflex when spasticity is a factor. Clinical uses of NMES are to retard or prevent disuse atrophy, muscle re-education, increase local blood circulation, maintain or increase joint mobility, relax muscle spasm, prevent venous thrombosis in calf muscles and immediately after surgery.
Methods of Application .
Interrupted direct current is used in the treatment of denervated muscles and for electrodiagnostic tests such as strength-duration curves, faradic interrupted direct current test, pulse ratio, etc. Interrupted direct current can also be used for healing purpose. For this purpose, sub-sensory thresholds have been used and this is termed as low intensity direct current therapy (LIDC). Methods of application commonly used in the treatment with interrupted direct current are motor point, stabile and labile. Low frequency Currents
Location of Motor Points in the Body .
You can use these guidelines to find out the motor points during therapeutic stimulation purpose. These guidelines may work in few individuals. I suggest you to try with these guidelines just three times and if you do not get the motor points, then you can search at any other location by trial and error method.
Face motor point .
1. Frontalis: About halfway between hairline and center of eyebrow.
2. Corrugator: Above the outer third of the superciliary arch.
3. Orbicularis oculi: Just below and lateral to the outer angle of eye.
4. Procerus: On side of nose, just below inner angle of eye.
5. Nasalis: Just above ala of nose.
6. Orbicularis oris: Upper point can be located at about halfway between angle of mouth and tip of nose and the lower point approximately in the same position below mouth.
7. Risorius: About one finger breadth lateral to the angle of mouth.
8. Buccinator: About two fingers width, lateral to the angle of mouth.
9. Mentalis: Midline near prominence of chin.
Forearm and Hand motor point .
1. Abductor pollicis brevis: Over the thenar eminence about an inch from the wrist approximately at the center of the thenar prominence.
2. Flexor pollicis brevis: Upper border of thenar eminence.
3. Opponens pollicis: Thenar eminence near wrist, press the electrode in the thenar eminence since it is a deeply situated muscle.
4. Adductor pollicis: In the web, between thumb and index finger equally accessible on dorsal or palmar aspects.
5. Abductor digiti minimi: About a finger breadth distal to wrist on ulnar border.
6. Flexor digiti minimi: To the radial side of point for opponens digiti minimi.
7. Opponens digiti quinti: About halfway between web of the little finger and the wrist, press the electrode since, it is a deeply situated muscle.
8. Lumbricals: About three fingers breadth, proximal to each interdigital web. There is one point for each one of the four muscles.
9. Palmar interossei: About one finger breadth proximal to interdigital webs on palmar aspect. There is one point for each of these muscles. A very small electrode should be used.
10. Dorsal interossei: About one or two fingers breadth proximal to finger webs on dorsal aspect. There is one point for each muscle. Press the electrode.
11. Pronator teres: About an inch below elbow and an inch from midline on ulnar side.
12. Flexor carpi radialis: About one-third down from the elbow to the ulnar side of the midline.
13. Flexor digitorum superficialis: Middle and lower third of forearm on ulnar side. Four points can be located on a diagonal line from medial condyle of elbow to the middle of wrist.
14. Palmaris longus: Just inside to the point of flexor carpi ulnaris.
15. Flexor carpi ulnaris: About three fingers breadth below elbow on extreme ulnar border.
16. Flexor pollicis longus: About two inches above wrist near radial border.
17. Flexor digitorum profundus: About three fingers breadth below elbow crease just to ulnar side of midline. Less accessible than superficialis.
18. Pronator quadratus: At about three fingers width proximal to wrist crease press the electrode about medial to midline.
19. Brachioradialis: At about three fingers width from elbow crease with forearm in midprone position.
20. Extensor carpi radialis longus: Below and to the radial side of olecranon.
21. Extensor carpi radialis brevis: A few inches below point for longus.
22. Extensor digitorum: On a line from a radial side of the elbow to the middle of the wrist; three points in the middle third.
23. Extensor digiti minimi: Mid forearm at ulnar side.
24. Extensor carpi ulnaris: About three inches below olecranon and on ulnar side of midline.
25. Anconeus: About two inches above olecranon process.
26. Supinator: Difficult to find but can be tried on the dorsum of the hand at two fingers distal to elbow crease at midline.
27. Abductor pollicis longus: Near radial border about halfway between the elbow & wrist.
28. Extensor pollicis longus: About three-fourths of the way down from the elbow on ulnar side. Sometimes difficult to find.
29. Extensor pollicis brevis: In middle at about two-thirds down from elbow.
30. Extensor indicis: About halfway between elbow and wrist, just ulnar to midline.
Leg and Foot Muscles motor point .
1. Tibialis anterior: About a hand breadth below lower angle of patella and one finger lateral to tibial crest.
2. Extensor digitorum longus: About one finger below prominence of fibular head and slightly towards midline.
3. Extensor digitorum brevis: On the dorsum of foot about two fingers below angle formed by leg and foot. There are two motor points for this muscle.
4. Extensor hallucis longus: About three fingers above ankle at about midline.
5. Gastrocnemius: Medial point at about eight fingers below popliteal crease near medial border of calf. Lateral point at about five inches below popliteal crease near lateral border of calf.
6. Soleus: About two-thirds the way down from knee on point about three fingers each side of midline.
7. Flexor hallucis longus: About three fingers behind and above lateral malleolus.
8. Flexor digitorum longus: In fossa behind medial malleolus, about three fingers above and medial to Achilles tendon.
9. Tibialis posterior: About two-thirds down from the knee medial to soleus against the tibia.
10. Peroneus longus: Just below head of fibula.
11. Peroneus brevis: About a hand breadth above and lateral to external malleolus.
12. Abductor hallucis: Medial border of foot arch about two fingers below medial malleolus.
13. Flexor digitorum brevis: Just forward to center of sole.
14. Flexor hallucis brevis: About three fingers from middle of base of great toe in sole.
15. Abductor digiti minimi: In front of heel near lateral border.
Physiotherapy for Peripheral Nerve Injuries .
Unlike the previous edition, physiotherapy treatment for peripheral nerve injury is described here for a quick and handy reference. It consists of electrical stimulation, passive movements, splints, counseling and reassurance (you can memorize with CRESP where C stands for counseling, R for reassurance, E for electrical stimulation, S for splint and P for passive movements). Physical Principles of Light
Electrical Stimulation .
Electrical stimulation is given to the paralyzed muscles so as to maintain nutrition of muscles and prevent disuse atrophy, degeneration and fibrosis. Selection of the current can be done on the basis of faradic interrupted direct current test.
Passive Movements .
Passive movements should be given to the affected joints so as to maintain the range of motion and thereby prevention of overstretching of paralyzed muscles, tightness and contracture of intact antagonist muscles.
Splints/Orthoses .
Splints or orthoses should be advised so as to preserve the function and avoid overstretching of affected muscles by antagonist.
Counseling .
Counseling of the patient should be done. It may involve instructions about prevention of injury to desensitized parts.
Reassurance .
Reassure that the loss of function and sensation could be temporary and will return within few weeks to few months.
Classification of Nerve Injuries .
Peripheral nerve injuries mainly occur due to pressure, trauma and exposure to cold (memorize with CPT it is not abbreviation for chest physiotherapy but here C for cold, P for pressure and T for trauma). These peripheral nerve injuries can be classified, so as to get an idea about their nature of injury, severity, prognosis and treatment planning. There are various classifications of peripheral nerve injuries such as, Seddon’s classification, Sunderland’s classification and Schaumburg, Thomas and Spencer’s classification.
Seddon’s Classification of Nerve Injuries .
As per Seddon’s classification, peripheral nerve injuries can be classified as neuropraxia, axonotmesis and neurotmesis.
1. Neuropraxia .
It is a type of peripheral nerve injury characterized by transient physiological conduction block without any significant pathological changes. For example, neuropraxic lesion of the facial nerve in Bell’s palsy. Neuropraxia causes transient ischemia at the point of nerve injury, which leads to degeneration of the myelin sheath and hence physiological conduction block occurs at the site of nerve injury. However, there is no loss of axonal continuity, there is no Wallerian degeneration. Nerve deficit is completely reversible.
2. Axonotmesis .
It is a type of nerve injury characterized by intrathecal rupture of axons or nerve fibers. For example, the radial nerve injury associated with fracture of the shaft of humerus. Pathologically, there is rupture of the nerve fibers, but the myelin sheath remains intact. Axon undergoes the Wallerian degeneration in its distal cut end and up to the first node of Ranvier proximally. There is complete loss of nerve conduction distal to the injury.
3. Neurotmesis .
It is a type of peripheral nerve injury characterized by rupture of both nerve sheath as well as nerve fibre. Neurotmesis may be partial or complete. In partial neurotmesis, only the portion of nerve is cut. In complete neurotmesis nerve is divided across its whole thickness. Example of this nerve injury can be complete ulnar nerve cut as a result of glass cut injury.
Pathological changes in form of Wallerian degeneration occur in distal part of the cut end of the nerve and up to the first node of Ranvier proximally. Disruption of Schwann cells and endoneurimal connective tissue also occurs. There is complete loss of conduction distal to the site of nerve injury.
Sunderland’s Classification of Nerve Injuries .
Peripheral nerve injuries are classified as first degree, second degree, third degree, fourth degree and fifth degree injuries. First and second degree injuries are similar to neuropraxia and axonotmesis respectively. Neurotmesis type of injuries comprise third, fourth and fifth degree injuries.
In third degree injury, there is interruption of nerve fibers. In fourth degree, there is connective tissue damage in addition to interruption of nerve fibers. In fifth degree, there is severance of nerve, in addition to above changes.
Schaumburg, Spencer and Thomas Classification .
Schaumburg, Spencer and Thomas classification classifies the peripheral nerve injuries into class one, class two and class three types of injuries. Class one is same as that of neuropraxia, class two is similar to axonotmesis and class three is like neurotmesis .
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