Electrotherapeutic Concepts Flashcards
Describe direct current
continuous or uninterrupted unidirectional flow of charged particles; direction determined by polarity chosen; no reversal of current
Iontophoresis is an example of _______ current.
direct
Describe alternating current
continuous or uninterruted bi-directional flow of charged particles; alternating polarity of electrodes; no net chemical run; expressed in HZ or cycles/second
Interferential, premodulated, and Russian protocol stimulation are examples of ________ current.
alternating
Describe pulsed current
can be DC or biphasic - bi-directional movement of charged particles that periodically ceases or is interrupted for a period of time
What is the most common current used in electrotherapy?
pulsed current
Unidirectional pulsed current is also known as
interrupted DC
Bi-directional pulsed current is also known as
interrupted biphasic
What is pulse cycle duration?
time of one pulse current
High Volt is a form of what kind of current?
monophasic pulsed current (appears as spike)
What are some clinical uses of NMES (neuromuscular electrical stimulation)?
increasing muscle contractility/strength, reducing muscle spasticity
What are some clinical uses of TENS (transcutaneous electrical nerve stimulation)?
pain suppression
NMES is used on _____ peripheral nerves.
intact
EMS, electrical muscle stimulation, is used on _____ peripheral nerves.
de-innervated
ESTR, electrical stimulation for tissue repair, is often used for
tissue repair
What type of e-stim applications are useful for tissue repair?
ESTR, HVPC, NMES
E-stim absolute contraindications (10)
- Implanted electrical pacing devices (cardiac demand pacemaker, bladder stimulator)
- over pregnant uterus
- over superficial metal implants
- when active motion is contraindicated - if stimulating for a muscle contraction (acute fracture)
- active bleeding in area being stimulated
- directly over malignancies
- phlebitis / circulation
- severely impaired sensation
- over transthoracic or anterior cervical area
- placement of electrodes over carotid sinus
E-stim precautions (5)
- open wounds or broken skin in treatment area
- extreme edema
- unreliable patients
- cardiac disease
- Malignant tumors
E-stim adverse effects (3)
- skin irritation or thermal; burns under electrodes
- allergy to gel, adhesive backing on electrodes, tape
- allergic reactions to medications used for iontophoresis
pain
_____ allows for more comfortable contraction, slowly rising up/down current intensity.
Ramp
Describe the use of ratios in the parameters of electrotherapy.
1: 1 - fatigues quickly (e.g. 6 sec on /6 sec off)
1: 3 - common (e.g. 6 sec on/18 sec off)
1: 5 - early phase rehab often (e.g.6 sec on / 30 sec off)
Synchronous stimulation of 2 channels:
both channels on and off at same time
Reciprocal stimulation of 2 channels:
alternate stimulation between channels
current density =
ratio of maximum current amplitude to electrode stimulation surface
(expressed in mA/cm2)
________: small active electrode over motor point, a larger dispersive electrode
Monopolar technique
common in DC current application such as iontophoresis and in HVPC stimulation
________: two electrodes of same size
Bipolar technique
common in biphasic PC applications but can use monopolar technique for small muscles or muscle groups
________: 4 electrodes that can be parallel or crisscrossed
qaudripolar technique
Electrode placement consideration:
- over motor points for stimulation of muscles for contraction
- over areas of pain, along dermatomes , referral patterns for electroanalgesia, transarthrally (across a joint)
distance between electrodes affects depth of penetration such that closer =
more superficial penetration
What is the minimum distance between electrodes
2 inches (5 cm)
Orientation of the electrodes?
usually want parallel to muscle being stimulated
muscular (motor) stimulation: may be __-__ minutes dependent on fatigue level and goals of treatment (strength vs. endurance)
5-20 minutes
Amplitude (intensity) is the amount of current applied and is dependent on
dependent on goals; often limited by patient tolerance
For motor stimulation, one electrode is placed on ______ and the other is placed elsewhere on the muscle so that the current flows _____ to the muscle fibers.
motor point (generally middle of muscle belly) current flows parallel
Indications for electroanalgesia?
- acute/chronic pain syndromes (musculoskel, neurological pain)
- post-operative pain
- labor and delivery pain
- prior to painful procedures
motor-level TENS mechanism of action?
release of endogenous opiates (endorphins and enkephalins)
stimulates small un-myelinated A delta and C fibers plus motor efferents to stimulate muscles rhythmically
Electroanalgesia contraindications (8):
- pacemakers/stimulating devices
- eyes
- carotid sinus
- over chest in presence of cardiac dysfxn
- with seizure disorders, avoid head/neck
- cognitive impairment
- over open wounds or compromised skin
- over areas where mvmnt is contraindicated if using a mode that requires visible contractions
Sensory-level mode TENS synonyms:
high rate
conventional
Motor-level mode TENS synonyms:
low rate
acupuncture-like
Sensory-level mode TENS goal:
stimulates large A sensory (myelinated) afferents to “block” pain input
Sensory-level mode parameters:
50-200 pps (usually 150-200)
20-100 microsec
Sensory-level mode most appropriate for:
acute superficial musculoskeletal conditions (can be used for chronic conditions bc it is so well tolerated)
Sensory-level mode effect:
analgesia only while unit is on (not long carry over)
Quadipolar technique is uniquely used for:
biphasic NMES and IFC
Interferential current is unique for:
beat frequency and vector scanning
Motor-level mode is appropriate for:
deep, aching pain, chronic pain
Motor-level modes goal:
- produce visible muscle contraction with 2-10pps frequency (do NOT want tetanic contraction)
should not be uncomfortable - high pulse duration (100-200 microsec)
___________ create bursts of pulses at low repetitions (2 bursts per second)
burst modulated PC
describe IFC (interferential current):
medium frequency current; specialized units which use sinusoidal polyphasic AC waveforms
Describe quadripolar electrode technique:
4 crossed electrodes that create an interference in current
describe Bipolar technique:
2 electrodes on one channel - the interference type current is generated in the machine (known as pre-modulated Interferential current)
describe quadripolar with vector scan:
amplitude of current is varied which increases the field – can only be done with the quadripolar technique; current is felt to move among and between the electrodes
What are the 2 types of beat frequency?
variable (sweep) and constant
describe variable (sweep) beat frequency:
varies within a range (e.g. 1-15 bps, 80-150 bps)
describe constant beat frequency:
set at one unchanging beat frequency
What size area is pre-modulated indicated for?
smaller areas
