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112 terms

Electrical Stimulation

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Frequency
The number of waves or pulses per second.. usually measured in Hz..turned up to pt. tolerance or until you get desired response(sensory or motor)
Alternating Current
Continuous and bidirectional flow of charged particles (+ and -)..no net charge
Interpulse Interval
Time between pulses in a pulsed current
Cathode
The negatively charged electrode
Amplitude
The magnitude of the current or voltage, the distance from the zero line to the peak or trough
Frequency Modulation
Usually referred to a sweep
Anode
The positively charged electrode
Pulse Duration
The time from the beginning of the first phase to the end of the last phase of one pulse, the width of the pulse
Pulsed Current
Electrical current delivered discontinuously with on times and off times
Impedance
Opposition to the current flow, tissue that resist flow; adipose, bone, tendons, fascia
Direct Current
Used for inotophoresis, stimulating denervated muscles to contract, wound care
Interferential Current
what is a waveform produced by the interference of two medium frequency sinusoidal AC's
Duty Cycle
Ratio of on time to total cycle time; On 10 sec, off 50 sec = 10/60 x 100= 16% or 1:6 duty cycle. The higher the duty cycle the more fatiguing
Ramp up or rise time
Time it takes current to go from zero to maximum amplitude
Amplitude Modulation
what is usually referred to as scan
Ohm's Law
what is the relationship between voltage (V), electrical current (I) and resistance (R)
Electrical Current
Measured in Amperes (A) and has an abreviation of (I)
Electrical Current
Flow or movement of charged particles through a conductor following an applied electrical field
Voltage
what is electrical force driving charged particles through a conductor between two regions or points
Resistance
what is the property of the conductor that resists the flow of charged particles
Resistance
what is measured in Ohms and is abreviated (R)
Impedance
what is a more accurate descriptor of the relationship between voltage and current than resistance
Ohm's Law
what is (V= I x R)
Direct Current
what does DC stand for
Direct Current
what is continuous and unidirectional flow of charged particles (either + or -)
Alternating Current
what does AC stand for
Frequency
what is another name for pulse rate
Pulse Duration/Phase Duration
what is another name for Width
Comfort of stimulation
small pulse width
Intrapulse or Interphase interval
what is the time between phases of a single pulse
Decay Time or ramp down
Time it takes from peak amplitude to decrease to zero during a phase
Ramp up/Ramp down
what allows the patient to acclimate to the stimulation
Symmetrical biphasic pulsed
what type of estim is most comfortable for patients and provides the most torque for muscle strengthening
HVPC
what type of estim is used for tissue healing or acute edem
Burst Mode
what is a series of pulses delivered in an "envelope" as singe pulse also called a pulse train
Resting potential
The homeostasis that exists between eithor side of the cell membrane. Inside of the cell is -, outside is +, -70mV
Depolarize
when the inside of the cell membrane becomes less negative than the outside
Repolarize
when the inside of the cell membrane returns to more negative state & resting potential is restored
opening of Na channels pulls Na in to the cell by the negative charge inside and because of the larger concentration of Na outside the cell
what happens during the Depolarization of an action potential
Channels close and K channels open; K is pushed out of the cell because of the large concentration of K inside of the cell and the positive charge inside the cell
what happens during the Repolarization of an action potential
Absolute refractory period
when the membrane is depolarized, and it is not possible to create another Action potential
Nerve diameter and myelination
what does propagation speed depend on
Strength-Duration Curve
what is the minimum amount of electrical current required to depolarize the nerve and produce and Action potential in a specific type of nerve
Sensory nerves
Nerve with a large diameter that takes a lower current amplitude and shorter pulse width to depolarize
Motor nerves
Nerves with a medium diameter that takes a medium current amplitude and medium pulse width to depolarize
Pain-transmitting C fibers
Nerves with a small diameter that takes a high current amplitude and large pulse width to depolarize
Accommodation
decreased response to same amplitude of nerve stimulation over time
Muscle cell membrane
denervated muscles contract via depolarization of what
Voltage
What is directly related to current flow
Voltage
What is measured in volts and abreviated (V)
Voltage
What is indirectly related to current resistance
Controlling acute and chronic pain
Indication for estim
Edema reduction
Indication for estim
Muscle spasm reduction
Indication for estim
Reduction of joint contractures
Indication for estim
Minimize atrophy
Indication for estim
Facilitate tissue healing
Indication for estim
Strengthen muscle
Indication for estim
Facilitate fracture healing
Indication for estim
pacemaker
contraindication for estim
Cancer
contraindication for estim
Acute infection
contraindication for estim
Exposed metal
contraindication for estim
Carotid sinus
contraindication for estim
Pregnancy/1st trimester/over abdomen
contraindication for estim
DVT
contraindication for estim
Active TB
contraindication for estim
active bleeding
contraindication for estim
recent fracture or surgical site
precaution for estim
decreased sensation
precaution for estim
impaired cognition
precaution for estim
pregnancy/during labor
precaution for estim
heart conditions
precaution for estim
obesity
precaution for estim
eczema, psoriasis, acne dermatitis
precaution for estim
epilepsy or other neruoloical deficit/ in cervical area
precaution for estim
EMS
Electrical muscle stimulation; stimulation of denervated muscle to maintain viability via HVPC
ESTR
Electrical stimulation for tissue repair;edema reduction, increase in circulation, wound and fracture healing via HVPC
NMES
Neuromuscular estim for stimulation of innervated muscles
TENS
Transcutaneous Electrical Nerve Stimulation for pain control
IF
Interferential; pain control delivered at a deeper level than TENS
FES
Functional electrical stimulation delivered for a specific functional purpose
Positive electrode/Red
Causes proteins to coagulate and hardens tissue due to an increase in acidity below the electrode
Negative electrodes/Black
Causes proteins to liquify and softens tissues due to an increase in alkalinity below the electrode
All or non principle
single neurons or single motor units respond completely or not at all to an electrical stimulus
Capacitance
allows current flow to pass through easily; nerves, muscle, blood
Tetany
a physical state in a muscle when action potentials from nerves arrive at the skeletal muscle motor end plate rapidly enough to cause a steady contraction
Motor point
area on the surface of the skin that is hypersensitive to flow. A place above where blood vessels and nerve bundles enter the muscle
CNS contraction
small muscle fibers fire first
Estim contraction
large muscle fibers fire first
CNS contraction
Asynchronous firing of motor units
CNS contraction
Action potential moves away from the cell body
Estim contraction
Is more fatiguing than a CNS contraction
Estim contraction
Synchronous firing of motor units
Estim contraction
Action potential moves in all directions from the site of depolorization
Estim contraction
Is less comfortable than CNS contraction
balanced asymmetrical
shape of the positive phase and the negative phase of a single biphasic pulse are different but the amount of current delivered by each is the same, no net effect
unbalanced asymmetrical
shape of the positive phase and the negative phase of a single biphasic pulse are different and the amount of current delivered by each is not the same, there can be a net effect
Law of DuBois Reymond
The amplitude, rise time, and pulse width of a stimulus must be adequate to depolarize a membrane and cause a contraction
Can increase total current
increase in amplitude
Can increase total current
Increase in frequency
Can increase total current
increase in pulse width
The larger the electrode
the smaller the current density per square inch
edge effect
when two electrodes are touching amplitude along the borders can spike
decrease conductivity/impedance
warm tissues, long pathway, small electrodes, oil, hair, dry skin, adipose, bone, ligaments, tendons
increase conductivity/capacitance
cold tissues, short pathway, large electrodes, clean skin, moist skin, motor points
Large electrodes
density is shallow, less selectivity, stronger contraction, more comfortable, greater current spread
small electrodes
density is deeper, less current spread, better selectivity, weaker contraction , less comfort
monopolar
1 channel, one small electrode is at the treatment site, with a larger dispersive pad placed proximally; ionto, woundcare
bipolar
1 channel, 2 electrodes are placed at the treatment site; NMES
quadripolar
2 channels, 4 electrodes at treatment site that are criss crossed; IF, TENS
dual bi-polar
2 channels, 4 electrodes; usually put on agonist/antagonist for NMES