Electrical Stimulation Part 2 Flashcards
Monophasic (direct or galvanic current):
a unidirectional flow of charged particles. A current flow in one direction for a finite period of time is a phase (upward or downward deflection from and return to baseline). It has either a positive or negative charge.
Biphasic wave (alternating current):
Bidirectional flow of charged particles. This type of wave form is illustrated as one half of the cycle above the baseline and the second phase below the baseline. One complete cycle (two phases) equals a single pulse. It has a zero net charge if symmetrical.
Polyphasic wave:
Biphasic current modified to produce three or more phases in a single pulse. This waveform in medium frequency may be Russian or interferential current.
Continuous mode:
uninterrupted flow of current
Interrupted mode:
intermittent cessation of current flow for ~1 second
Surge mode:
a gradual increase and decrease in the current intensity over a finite period of time
Ramped mode:
a timed period with a gradual rise of the current intensity which is maintained at a selected level for a given period of time, followed by a gradual or abrupt decline in intensity.
Goals of electro stimulation
pain modulation, decrease m. spasm, impaired ROM (increase ROM), muscle reeducation, soft tissue repair, edema reduction, spasticity control, denervated m.
Pain modulation is achieved with electro stimulation by activation of _____ mechanisms
gate; Gate theory
Initiation of __________ inhibition mechanisms (_________ opiate production) helps with pain modulation.
descending, endogenous
Explain the descending endogenous opiate system.
Supraspinal pain modulation that produces a descending inhibition of pain chemically at the dorsal horn of the spinal cord. The pariaquaductal gray matter secretes endogenous opiates in the blood plasma and cerebral spinal fluid. The spinal gate is closed from influence from above.
Chronic pain patients have been found to have _____ normal levels of ______ in their cerebral spinal fluid
below, endorphins
Endorphins have been shown to increase the cerebral spinal fluid with ______ level electrical stimulation
twitch
Goal of electrotherapy is to boost the levels of ______ in patients
endorphins
muscle fatigue:
tetanic contraction sustained for several minutes by means of continuous modulation
muscle pump:
interrupted or surge modulation producing rhythmic contraction and relaxation of the muscle to increase circulation.
muscle pump and heat:
combination of ES and US to increase tissue time and produce muscle pumping at the same time.
What are the 3 ways to decrease muscle spasm?
- create muscle fatigue
- provide muscle pumping to increase circulation
- use muscle pump & heat with US
When is indicated for impaired ROM?
Mechanical stretching of CT & m. is used when M. STRENGTH is deficient or NEUROMUSCULAR DYSFUNCTION (e.g., spasticity) prevents adequate joint movement. Encourage joint motion to DECREASE PAIN. Decrease EDEMA if significant impediment to motion is present.
What 3 ways is muscle reeducation helps?
- provides proprioceptive feedback
- assist in coordinated m. movement
- act as active assistive exercise
What types of currents are effective in wound healing for soft tissue repair? How does it improve wound healing?
pulsed currents (monophasic, biphasic, polyphasic) with interrupted modulations. The improved circulation via the m. pump improves tissue nutrition and hasten metabolic waste disposal.
Monophasic currents consist of low-volt ____ modulations and high-volt ____currents
continuous, pulsed
What is the electrical potential theory?
restoration of electrical charges in wound area
What is the bactericidal effect?
disruption of DNA, RNA synthesis or cell transport system of microorganizms
What does biochemical effects result in?
increased ATP concentration, amino acid uptake, increased protein and DNA synthesis
What is the galvanotaxic effect?
it is the attraction of tissue repair cells via electrode polarity.
What is present in the inflammation phase?
macrophages (positive); mast cells (negative); neutrophils (positive or negative)
What is present in the proliferation phase?
fibroblasts (positive)
What is present in the epithelialization phase?
epithelial cells (positive)
What types of intensities can be applied to help with wound healing?
low intensity continuous nonpulsed for:
- low volt direct current &
- high volt pulsed current
What is the amplitude and treatment time indicated for wound healing?
low amplitude current for 30-60 minutes
How does electrical stimulation decrease edema? What is this phenomenon called?
The muscle pump increases lymph and venous flow. This is known as the electrical field phenomenon where the electrical charge on interstitial proteins increases lymph and venous flow.
How does ES reduce spasticity (hypertonicity)?
creates fatigue of the agonist which causes reciprocal inhibition (stimulation antagonist & inhibit agonist)
What current, pulse duration, and contraction can stimulate a denervated muscle?
monophasic or biphasic currents with long pulse duration, producing a vermicular contraction
What is the goal to providing ES to a denervated muscle?
the goal is to retard the effects of disuse atrophy and shorten recovery time, however this could interfere with regeneration of neuromuscular junction and subsequent reinnervation. It can also tramatize the hypersensitive denervated muscle.
What are the 6 contraindications of ES?
- healing fractures (unless specifically used for bone stimulation usually MICROCURRENT)
- areas of active bleeding
- malignancies or phlebitis in treatment area
- superficial metal implants
- pharyngeal or laryngeal muscles
- demand-type pacemaker, myocardial disease
What are the 3 precautions of ES and 2 reasons why you wouldn’t use the unit?
- areas of impaired sensation
- during pregnancy
- severe edema
- don’t use if there is evidence of broken or frayed wires
- don’t use if the unit is not connected to a ground fault circuit interrupter
One electrode called the ________electrode is often placed on the _________. The second electrode (sometimes larger) is called the _______ electrode.
active (stimulating), motor point, dispersive electrode
Electrodes are usually the same size except with _______ forms such as ________ & _________ stimulation where dispersive electrodes are used.
monophasic, hi-volt, galvanic
The current density is relative to the ____________.
electrode size
A given current intensity passing through the smaller active electrode produces high current density and thus a ____ stimulus. The same current is perceived as ____ intense under the larger dispersive electrode due to the ____ current density.
strong, less, lesser
What are the 3 basic set-ups for ES?
wound care (2 options), pain control (this may vary widely with TENS), & muscle stimulation
What are the 2 options of ES set-up for wound care?
The active electrode is placed in the wound bed and the dispersive electrode is placed at a remote site. The electrodes are placed on either side of the wound bed.
What is the ES set-up for pain control?
the two or four electrodes (TENS/TNS or interferential) are placed in a pattern that surrounds the area of treatment.
What is the ES set-up for muscle stimulation?
The active electrode is usually placed over the treatment site (motor point), in order to produce a stimulation effect. The dispersive electrode may be placed on the treatment site or a remote site.
What is the electrode placement for unipolar/monopolar?
One single electrode or multiple (bifurcated) active electrodes placed over treatment area. Usually larger-sized dispersive electrode (inactive) placed ipsilaterally away from treatment area.
What is the electrode placement for bipolar?
Equal-sized active and dispersive elctrodes on same muscle group or in same treatment area. Smaller bifurcated treatment electrodes may be used to better conform to small treatment areas.
What is the smallest distance the electrodes can be placed away from each other?
at least the diameter of the active electrode
The greater the space between electrodes the ____ the current density in the intervening superficial tissue and the _____ the stimulation. What is the purpose of this?
lesser, deeper. This minimizes the risk of skin irritation and burns.
What can occur with long-term ES use; especially transcutaneous ES and other ES modalities?
it can irritate the skin and initiate skin breakdown. Be sure to be vigilant with skin inspection.
What are ways one can reduce skin resistance of ES?
apply a hot pack, alcohol rubs, & gentle abrasion
What are the two meaning of amplitude?
the strength of the individual phase & how high you turn up the intensity knob
What are 2 general guidelines on how high to turn up the machine?
PAIN CONTROL: you want a SENSORY RESPONSE, no motor contraction, it should be felt, but feel good (aka patient comfort).
MUSCEL STRENGTHENING: you want a strong muscle contraction (MOTOR RESPONSE) that is just below the pain (aka patient tolerance)
What are 7 reasons for using ES?
- tissue/wound healing
- pain control
- muscle strengthening
- muscle spasm (2 set ups)
- edema control via muscle pump
- ROM
- muscle re-education
What is the basic set-up for muscle strengthening, muscle spasm or edema (m. pump) or ROM?
How many muscle contractions are sufficient to obtain goal?
What is the duty cycle & on/off ratio?
Slowly increase intensity until a muscular response is observed.
10-25 m. contractions may be sufficient to obtain treatment goal.
Interrupted/ramped modulation of current allows the m. to recover between stimulation periods. On/off ratio of 1:3 is used to minimize the fatigue effects of ES.
In order to decrease muscle spasm with fatigue what duty cycle is used?
continuous, this is to exhaust the m. thereby causing it to relax its spasm.
To provide muscle reeducation how long are the treatment sessions?
10-30 min depending on patient’s mental and physical tolerance
