Electrical Currents

Front 1

what are the uses of electrical currents in rehabilitation

Back 1

-muscle strengthening
-muscle reeducation
-pain control
-wound healing
-edema reduction
-transdermal delivery of medication

Front 2

electrotherapy

Back 2

-body becomes part of electrical circuit
-simulator generates voltage
-current travels from one electrode to the other

Front 3

electrophysiological effects

Back 3

-thermal
-physiochemical
-physiological

Front 4

thermal electrophysiological effects

Back 4

-movement of electricity
-other applications require high frequencies

Front 5

physiochemical electrophysiological effects

Back 5

-creates ionizing effects
-must have current flowing in one direction long enough

Front 6

physiological electrophysiological effects

Back 6

-causes an action potential to create nerve or muscle stimulation
-stimulus must be of sufficient intensity
-all or none principle

Front 7

Rheobase

Back 7

-minimum intensity (amplitude) needed to depolarize a nerve fiber when phase duration is infinite

Front 8

chronaxie

Back 8

-time (pulse duration) required to depolarize a nerve fiber when the peak current is 2x the amplitude at Rheobase

Front 9

what will result in the greatest comfort for electrical stimulation

Back 9

-amplitude 2x rheobase
-pulse duration slightly longer than chronaxie

Front 10

pulse duration

Back 10

-must be long enough to overcome the capacitance of the target nerve or muscle to overcome an action potential

Front 11

strength duration curve

Back 11

-association b/t intensity and phase duration of a current to achieve a single response

Front 12

percutaneous muscle stimulation

Back 12

-reversal of the size priniciple and a resultant preferential recruitment of fast fibers during electrically induced contractions

Front 13

amplitude

Back 13

-as amplitude increases, more nerve fibers are recruited therefore, more muscle fibers are stimulated causing a stronger contraction

Front 14

Law of Dubois Reymond

Back 14

-effectiveness of current to target specific excitable tissue is dependent on 3 factors
--adequate intensity to reach threshold
--current onset fast enough to reduce accommodation
--duration long enough to exceed capacitance of the tissue

Front 15

electrode considerations

Back 15

-requires positive and negative pole
-there will always be resistance
-conductive, durable, flexible electrodes

Front 16

electrode variations

Back 16

-must have 2 leads to complete circuit
-can bifurcate any lead

Front 17

electrode materials

Back 17

-silicone-carbon impregnated
-tin (overlying sponge or gauze)
-self-adhesive (rubber carbon film)
-interface (conductive gel, adhesive gel, water)

Front 18

electrode size

Back 18

-size used should be based on treatment goal and size of target tissue
-electrode size affects current density

Front 19

current density

Back 19

-amount of current per unit area
-smaller electrodes will have more current density than larger electrodes when the amplitude is the same
-current density decreases when leads bifurcate

Front 20

active and dispersive leads

Back 20

-relevant for monophasic currents
-typically able to toggle b/t the polarity for the active and dispersive lead

Front 21

monopolar electrode configuration

Back 21

-at least 2 unequal sized electrodes
-wave is usually monophasic

Front 22

monopolar rationale

Back 22

-electrodes are farther apart so there is deeper penetration
-allows one polarity to be at the treatment site when using monophasic current

Front 23

physiochemical effects of the anode

Back 23

-acid reaction
-hardens tissues
-decreases nerve irritability

Front 24

physiochemical effects of cathode

Back 24

-alkaline (base) reaction
-softens tissues
-increases nerve irritability

Front 25

bipolar electrode configuration

Back 25

-2 equal sized electrodes
-both considered to be "active"
-usually biphasic (does not really matter)

Front 26

electrical stimulation contraindications

Back 26

-pacemaker or any implanted electronic device
-placement of electrodes over carotid sinus
-areas of venous or arterial thrombosis or thrombophlebitis
-pregnancy
-directly of eyes

Front 27

electrical stimulation precautions

Back 27

-cardiac disease
-impaired mentation or sensation
-malignant tumor
-areas of skin irritation or open wounds
-where muscle contraction may disturb healing process

Front 28

documentation

Back 28

-area of body
-patient position
-stimulation parameters
-electrode placement
-treatment duration
-response to treatment