E-Stim Basics

Question 1

goals and indications for E-stim

Answer 1

• pain modulation
• decrease muscle spasm
• improve ROM
• muscle re-ed
• improve muscle strength/reduce atrophy
• wound healing
• edema reduction
• stimulate denervated muscle

Question 2

contraindications (8)

Answer 2

• pacemaker, insulin pump
• over cartoid artery, thrombosis, eyes, phrenic nerve, pelvis and/or low back in pregnant women
• transcerebrally
• active bleeding/infxn
• over superficial metal implants
• over malignant tumors
• over pharyngeal/laryngeal muscles
• motor-level stimulation in conditions that prohibit motion

Question 3

precautions (6)

Answer 3

• cardiac disease
• impaired mentation
• impaired sensation
• in areas of skin irritation or open wounds
• in pt with uncontrolled hypotension or HTN
• bleeding disorders

Question 4

polarity

Answer 4

net charge of object

Question 5

cathode

Answer 5

net negative

Question 6

anode

Answer 6

net positive

Question 7

voltage

Answer 7

driving force that move electrons

Question 8

amerage/current

Answer 8

rate of flow of electrons (mA)

Question 9

ohm’s law

Answer 9

• more resistance, the greater the voltage needed to push the current through
• I = V/R

Question 10

resistance to current flow

Answer 10

• skin
• hair
• fascia
• ligament
• callus
• fat
• bone
• tendon
• scar

Question 11

if resistance increases…

Answer 11

more voltage will be required to overcome the resistance and produce the same current flow

Question 12

if you have a large increase in voltage what could happen

Answer 12

discomfort, could lead to burns

Question 13

how do you reduce skin-electrode resistance

Answer 13

• minimize air-electrode interface
• keep electrodes clean
• use electrodes on clean skin, minimize hair, oils, abrasions if possible

Question 14

what size electrode do you typically use

Answer 14

• largest that you can to reduce discomfort

Question 15

monophasic current

Answer 15

• unidirectional flow of charged particles

- electrical stim moving from one pad to the other

Question 16

biphasic

Answer 16

• bidrectional flow of charged particles

- electrical stim bouncing back and forth btw 2 pads

Question 17

direct current

Answer 17

• uninterrupted unidirectional flow
• one pad to the other
• type of monophasic

Question 18

alternating current

Answer 18

• uninterrupted bidirectional flow
• bouncing back and forth btw the two pads
• biphasic

Question 19

pulsed current

Answer 19

can either be unidirectional (monophasic) or bidirectional (biphasic) current that periodically ceases for very short period of time
- has additional parameters

Question 20

frequency

Answer 20

pf pulses per second or beats per second

Question 21

pulse duration

Answer 21

• width
• reported in microseconds
• how long each individual pulse lasts

Question 22

amplitude

Answer 22

• mA

- voltage of each individual pulse

Question 23

how does e-stim lead to an action potential

Answer 23

• influx of Na+ which causes a reduction of resting membrane potential leading to depolarization which leads to action potential

Question 24

what must be great enough to cause an action potential

Answer 24

amplitude/intensity

Question 25

what must be long enough to produce depolarization of the cell

Answer 25

duration of the stimulus

Question 26

how is heat created with e-stim

Answer 26

- friction and vibration of particles moving through the material - heat produced depends on intensity of current

Question 27

is it normal to have some redness under the electrodes?

Answer 27

- yes bc some heat is produced - should go away after few hours - should not blister or break skin

Question 28

if intensity is too high....

Answer 28

- may be at risk for burns | - important to remove resistance

Question 29

large electrode pad =

Answer 29

current dispersed over large area = small current density = more tolerated by pt

Question 30

small electrode pad =

Answer 30

current dispersed over small area = greater current density = less tolerated by pt

Question 31

how do you increase the current density

Answer 31

- increase current of estim - decrease size of electrode - can cause skin burns

Question 32

how to avoid burns

Answer 32

- remove resistance - listen to pt's perception - use large electrodes when possible - always maintain good contact of estim pads - use appropriate coupling agent if appropriate

Question 33

monopolar

Answer 33

- one small electrode over target area - one large electrode over remote area - polarity matters

Question 34

bipolar

Answer 34

- both electrodes are of similar size and placed over target area - current bounce btw 2 pads - polarity doesn't matter

Question 35

quadripolar

Answer 35

- 2 electrodes from 2 seperate stimulating circuits are positioned so that the individual currents intersect with each other

Question 36

monopolar configuration

Answer 36

- method when polarity is a concern - wound healing (attract to area) - edema control - iontophoresis (drive into body)

Question 37

with monopolar configuration, where are the electrodes placed

Answer 37

- 1 small electrode is placed directly over target area (active/treatment electrode) - 2 larger electrode is placed away from target area (dispersive) - pads do not need to be on same muscle

Question 38

preferred use for bipolar configuration

Answer 38

- disuse atrophy - neuromuscular facilitation - ROM - spasms - circulatory disorders

Question 39

where are electrodes for bipolar configuration

Answer 39

- connected in same area with target treatment site btw two pads - same size - any wave form except direct current

Question 40

what influences the depth and course of the current

Answer 40

the distance btw the electrodes

Question 41

if the pads are farther apart....

Answer 41

deeper they go

Question 42

do you want the pads touching?

Answer 42

no, creates an arc

Question 43

if youre going for sensory stimulation, put the pads where?

Answer 43

over that sensory pathway

Question 44

if you're going for motor point stimulation, put the pads where?

Answer 44

- where the motor nerve is easily excited | - muscle belly or proximal 1/3 of the muscle

Question 45

common mistakes with muscle stimulation

Answer 45

- placing 1 electrode over a muscle belly and the other over a distal area without much muscle - electrodes too close together when trying to stimulate a deep muscle