Lecture 50 - Modalities Flashcards
NMES (Neuromuscular Electrical Stimulation) Function
Uses electrical current to stimulate muscle contraction
T or F: The nerve fibers closest to the electrode is excited first and the density of currents is greatest closest to the electrode and rapidly diminishes as distance from electrode increases
T
What are 5 indications of NMES
- Prevents atrophy (atrophy)
- Targets strength (muscle weakness)
- Spasticity
- Orthotic Substitution
- Functional electrical stimulation
Is NMES more effective than exercise at preventing muscular atrophy
No, while both increase muscle strength and reduce hospitalization length, only exercise increases functionality
T or F: NMES does not increase ROM
F, it does
How is spasticity reduced through NMES
Acts as an antagonist through reciprocal inhibition to relax spastic muscles
What are 3 areas of the body NMES can help with healing in collaboration with a brace
- Orthotic substitution - foot drop (tibialis anterior)
- Scoliosis
- Shoulder subluxation (middle deltoid)
How does NMES aid (3 things) in GAIT (functional electrical stimulation)
- Improves self esteem
- Improves blood flow
- Prevents osteoporosis
6 characteristics of slow twitch fibers
6 characteristics of fast twitch fibers
Describe the strength duration relationship between noxious, motor, sensory and subsensory stimuli
Distinguish between rheobase and chronaxie
Rheobase: Minimum intensity necessary to excite a motor response
Chronaxie: Minimum time (pulse duration) required to excite muscle tissue for stimulus at twice rheobase
Henneman’s Size Principle
In a voluntary contraction, motor units are recruited from smallest to largest as contraction increases
Electrical contraction
As the magnitude of stimulation is increased, larger fibers have lower resistance and more induced current passes into these fibers compared to the smaller fibers (large recruited first)
Compare and contrast voluntary contraction compared to electrical stimulation
What is important about the location of the electrodes to stimulate contraction (2)
- Closest nerve fibers to electrode are stimulated first
- Density of currents is greatest closest to electrodes and diminishes as distance from electrodes increases
Describe the frequency of a tetanized contraction
Frequency becomes so rapid that the contraction merges and becomes consistent
Bipolar vs monopolar electrode placement
Monophasic pulsed current
What is monopolar electrode set up and its 3 characteristics
Biphasic pulsed current
What is the bipolar electrode set up and 3 characteristics
Bipolar method (electrode application)
2 electrodes of equal size are placed around the painful site
Monopolar Method (electrode application)
The active electrode is placed on the site of pain and the dispersive electrode is placed at another point (proximal at a nerve trunk)
To reduce NMES fatigue we need to
- Minimize frequency (critical fusion frequency)
- Optimize intensity (surf for motor point and use bipolar set up)
- Have on/off time ratio at 1:3 (off time should be 60 seconds between each contraction)
Process of using NMES (5)
- Perform assessment and determine if NMES is appropriate
- Clear contraindications (electrical current and muscle activation)
- Decide on muscles to be stimulated and motor points
- Set parameters (duration = 250-300 usec; frequency: As low as possible)
- Decide between monopolar (small muscles) or bipolar placement (large muscles)
