Estim (wk 2) Flashcards
What are goals/indications for estim?
a. Pain modulation
b. Decrease muscle spasm
c. Improve ROM
d. Muscle re-education
e. Improve muscle strength/reduce atrophy
f. Wound healing
g. Edema reduction
h. Stimulate denervated muscle
Contraindication or precaution of estim:
Cardiac disease
precaution
Contraindication or precaution of estim:
over superficial metal implants
Contraindications
Contraindication or precaution of estim:
Motor-level stimulation in conditions that prohibit motion
Contraindications
Contraindication or precaution of estim:
Impaired mentation
precaution
Contraindication or precaution of estim:
Anywhere in the body for someone with a pacemaker or other electronic medical device (insulin pump)
Contraindications
Contraindication or precaution of estim:
impaired sensation
precaution
Contraindication or precaution of estim:
Transcerebrally
Contraindications
Contraindication or precaution of estim:
over malignant tumors
Contraindications
Contraindication or precaution of estim:
areas of skin irritation or open wounds
precaution
Contraindication or precaution of estim:
over pharyngeal/laryngeal muscles
Contraindications
Contraindication or precaution of estim:
over carotid artery, thrombosis, eyes, phrenic nerve, pelvis and/or low back in pregnant women
Contraindications
Contraindication or precaution of estim:
patient with uncontrolled hypotension or hypertension
precaution
Contraindication or precaution of estim:
In presence of active bleeding or infection
Contraindications
Contraindication or precaution of estim:
bleeding disorder
precaution
What is polarity of cathode?
net negative
What is polarity of anode?
net positive
What is the amplitude/force of attraction or repulsion?
Voltage
What is rate of flow of electrons?
Amperage/current
Ohms law =
Current (I) = Voltage (V)/resistance (R)
Current is directly proportional to what?
Voltage
Current is indirectly proportional to what?
Resistance
What can act as resistance to flow on skin?
- skin
- hair
- fascia
- ligament
- fat
- bone
- tendon
- scar
What is a unidirectional flow of charged particles? (one pad to another)
monophasic
What is a bidirectional flow of charged particles?
biphasic
What is a uninterrupted unidirectional flow?
direct current
What is a uninterrupted bidirectional flow?
alternating current
What is a current that can either be unidirectional (monophasic) or bidirectional (biphasic) that periodically ceases for short time period?
Pulsed current
A pulsed current will have what 3 chracteristics?
- frequency
- pulse duration (width)
- amplitude
RMP for neuronal cells?
-70
RMP for skeletal muscle cells?
-90
How does electrical stimulation change Na and effect the membrane?
influx of Na+, causing reduction of RMP leading to DEPOLARIZATION of the membrane
Amplitude/intensity needs to be _____ enough and duration must be ____ enough to produce depolarization
Great enough
Long enough
T/F Duration of < 1ms is sufficient to stimulate nerve and muscle cells.
False, < 1 ms is sufficient to stimulate a nerve cell, but is too short to stimulate a muscle cell
Strength duration curve:
- Ab sensory
- motor
- Ad sharp pain
- C dull pain
- denervated muscle
Why does normal redness occur during estim?
Heat is created by friction and vibration of particles moving through the material
- Normal redness dissipate after just a few hours
- Should not blister or result in broken skin
T/F Patients may be at risk for burns if intensity of estim is too high
True
A larger electrode means what size current density? More/less tolerant?
large electrode = current dispersed over a large area = small current density = more tolerated by patient
A small electrode means what size current density? More/less tolerant?
small electrode = current dispersed over a small area = greater current density = less tolerated by patient
increasing current density can cause skin burn. To avoid this:
i. Remove resistance: clean the skin
ii. Listen to patient’s perception
iii. Use larger electrodes when possible
iv. Always maintain good contact
v. Use an appropriate coupling agent if appropriate
Describe electrode configuration of monopolar estim:
one small electrode over target area, and a large electrode placed over remote area (to complete the current).
When would you use monopolar estim?
method choice when polarity is a concern (wound healing - attract to area, edema control, iontophoresis - drive into body).
Describe bipolar electrode configuration:
both electrodes are of similar size and are placed over the target area. Current bounces between two pads.
Preferred uses of bipolar:
- Disuse atrophy
- Neuromuscular facilitation
- ROM
- Spasms
- Circulatory disorders
Describe quadripolar electrode configuration:
2 electrodes from two separate stimulating circuits are positioned so that the individual currents intersect with each other (IFC).
What happens to depth of current when electrodes are placed further a part?
Increase depth of current
recommended that the distance between electrodes be what?
at least one half the diameter of each electrode
If motor stimulation is the goal, where place the electrodes?
Over the muscle belly
2 common mistakes of estim placement:
- one electrode over muscle belly with the other over not much muscle
- too close together when trying to stimulate deep muscle
What are the goals of NMES?
i. Atrophy treatment/ prevention
ii. Strengthening
iii. Achieve synchronous firing/ recruitment of motor units
WHen using NMES, describe recruitment of motor units and the number recruited:
i. More random recruitment, large and small together (voluntary is small to large motor units)
ii. Cannot alter # of motor units recruited (voluntary can alter # recruited)
NMES: Pulse width= Pulse frequency = ON/OFF time = Ramp= Amplitude=
Pulse width= 200-800 Pulse frequency = 30-100 ON/OFF time = 10s on 50s off 10 min Ramp= 1-5 s Amplitude= max contraction/tolerance
What is burst modulation (russion) NMES?
Variation of alternating current that is interrupted and delivered in short bursts (AKA medium frequency burst alternating current)
T/F Amplitude can stay the same in NMES during treatment and between treatments
False, decrease a chance of adaptation and optimize strengthening with ES current amplitude should be increased as often and as much as tolerated
shorter the off time and the longer the on time of nmes =
greater chance for fatigue
longer the on time of nmes =
a decrease in force output over time
Align the electrodes ____ to the direction of the m fibers
parallel
T/F Despite widespread use of Russian Current in clinical practice NMES pulsed current has been found to produce similar neuromuscular adaptations with less perceived discomfort.
True
NMES shown to improve strength and function in patient ____
post surgery
Functional estim (FES), a type of NMES in which the electrical stimulation is utilized as an alternative or supplement to orthotic devices or braces, is commonly used on what body parts?
shoulder subluxation and foot drop (swing phase foot clearance)
What are the goals of interferential current (quad setup)?
- Most commonly used for pain modulation
2. production of muscle contraction and reduction of edema
Describe interferential current (quad setup) setup:
Characterized by crossing of two sinusoidal waves that interfere with one another to generate an amplitude-modulated beat frequency
What is constructive interference?
when the two waves are in phase, the sum of the superimposed wave is large
What is destructive interference?
sum of the two waves is zero when the waves are 180 degrees out of phase
What is beat frequency ((amplitude-modulated)?
resultant frequency produced by the two frequencies going into and out of phase
interferential current (quad setup) Pulse width= Pulse frequency = ON/OFF time = Amplitude=
Pulse width=200-400
Pulse frequency = 10-150
ON/OFF time = 10-30 min
Amplitude= strong but tolerable sensation
T/F IFC is said to be more comfortable than equal amplitudes delivered by conventional means
True
T/F IFC is effective alone
False, alone not effective, but when combined with other physical therapy treatments leads to above outcomes
What is the goal of High Rate tens? Theory?
Pain modulation through activation of central inhibition of pain transmission (gate control theory)
At what phases can high rate tens be used to decrease pain?
Acute or chronic
High Rate tens Pulse width= Pulse frequency = duration Amplitude=
Pulse width= 50-80
Pulse frequency = 50-100
duration = 10 - several hours
Amplitude= comfortable tingling sensation; no muscle response
High rate tens onset of pain relief and duration of pain relief?
Onset of pain relief: relatively fast
Duration of pain relief: temporary
Low rate TENS goal? Theory?
Pain modulation through descending pathways generating endogenous opiates
Low rate TENS used at what phase for decreasing pain?
chronic
Low rate tens: Pulse width= Pulse frequency = duration = Amplitude=
Pulse width=150-300
Pulse frequency = 1-5
duration = 20-40 min
Amplitude= strong, but comfortable rhythmic muscle twitch
Brief intense TENs is used when?
Used to provide rapid-onset, short term pain relief during painful procedures (wound debridement, passive stretching, joint mobilizations)
Burst mode TENs is what?
Combines characteristics of both high and low rate TENS. Stimulation of endogenous opiates, but current is more tolerable to patient than low rate TENS
What is hyperstimulation (point stimulation) TENS?
noxiously stimulate trigger point or local area of pain such as tendonitis
What is modulation mode TENs?
a method of modulating parameters of any of above TENS to prevent adaptation due to constant ES; alters frequency, intensity, or pulse durations by > 10% (body does not get used to high intensity)
Low intensity DC (micro-current) is used for what?
Wound healing
Describe theory behind Low intensity DC (micro-current)>
b. Does not stimulate sensory/motor nerves
c. Used for tissue repair, wound healing
What is the wound healing concept?
a. Intact skin surface negative with respect to deeper epidermal layers
b. Injury to skin develops positive potentials initially and negative potentials during healing process
What is the goal of iontophoresis?
i. Application of a continuous direct current to transport medicinal agents through the skin or mucous membranes for therapeutic purposes; Need prescription to apply medication
ii. Like charges repel like charges
iii. Unlike charges attract unlike charges
(ex: dexamethasone is negative - place cathode to repel)
How does NMES help with edema reduction?
Muscle pump: interrupted mode produces rhythmic contraction and relaxation of muscle to replicate muscle pump and improve circulation
T/F recent animal study suggest Estim for denervated muscle has positive effect
False, negative effect
