Lecture 2-Electrotherapy Flashcards
electrical current creates a mm. contraction through…
-creates mm. contraction through nerve or mm. stimulation
electrical current stimulation uses sensory nerves to…
sensory nerves to help with pain
electrical current creates an electrical field in biol. tissues to
stimulation or alter healing
Applications of e-stim
- MM. strengthening
- mm. re-education
- mm. spasm reduction
- edema reduction
- pain modulation
- wound healing
- iontophoresis
Indications for Estim
- pain modulation
- denervated mm. reducation
- retarding atrophy
- mm. strengthening
- increasing ROM
- dec. edema
- decreasing spasm
- stimulating healing process
- wound/fx/tissue healing
- stimulating nn. regeneration/peripheral n. function
E-stim contraindications
-pacemakers
-over carotid sinus
-venous of arterial thrombosis or thrombophlebitis is present
-pregnancy
(POPV)
Estim precautions
- cardiac disease
- impaired mentation
- infection/open wounds
- malignancies
- MSK conditions where mm. contraction would worsen condition
- adipose tissue (wont work well)
Waveforms of estim
- monophasic current- direct current (DC) (galvanic)
- alternating current (AC)-biphasic current
- pulsatile current- interferential, russian, also biphasic
monophasic current- direct current (DC) galvanic
unidirectional flow of electrons
polarity and direction of flow can be reversed?
alternating current (AC)
biphasic current
- bidirectional- changes direction OR reversing polarity
- w/ symmetrical waveform, polarity shifts with each pulse
pulsatile current-
interferential, russian (also biphasic)
-groups of pulses, interrupted, repeat at regular intervals
Characteristics of electrical current
- amplitude (intensity, strength, voltage)
- frequency (Hz, pps, bps)
- phase duration/ pulse width
- ramp up/down time
- rise and decay time
- duty cycle
amplitude is a measure of..
how much we turn it up
pulse duration =
combined phase durations
use interferential for…
pain modulation
premod for…
pain modulation
russian for…
mm. training
biphasic for…
pain modulation, mm. training, and edema
VMS
mm. training, edema
HVPC
pain modulation, edema, wound healing
microcurrent
wound healing
direct current
iontophoresis, denervated mm.
types of physiological reactions that happen from electrical current
- physio.
- thermal
- chemical
current flow through biological tissue
- blood
- mm.
- skin
blood: composed of water and ions (best conductor)
- peripheral nerve; conductivity 6x>mm.
mm: ~75% water, contraction dependent on ion movement
skin: primary resistance
- higher impedance—> higher intensities
- skin preparation is important (no soap or alcohol!)
fat-
contains 14% water- poor conductor
bone-
- extremely dense
- 5% water
- poorest biol conductor
Accomodation
adaptation by the sensory receptors to various stimuli over an extended period of time
-fiber becomes unexcitable after exposure to constant level of depolarization
to avoid accomodation we…
modulation:
- any alteration in amp, frequency, or duration
- usually built into a machine
- decreases accomodation
shortest durations access…
sensory n., then motor, then pain
Law of Dubois Reymond
- the effectiveness of a current to target specific excitable tissues is dependent on three major factors:
1. adequate INTENSITY to reach threshold
2. CURRENT ONSET FAST ENOUGH to reduce accommodation
3. DURATION long enough to exceed the capacitance of the tissue
motor points
- most comfortable place to get a contraction is the motor point (easiest place with least intensity)
- usualy found within mm. belly where motor nerve fibers synapse w/ mm.
all mm. contain 2 types of fibers:
T1 (slow twitch)
-high endurance, slow to fatigue, low strength, static, postural
T2 (fast twitch)-need more power
-fast contraction, low endurance, fast to fatigue, high strength, dynamic, explosive
T2 are normally ___x the size of T1
2x the size of T1
during mm. contraciton, size principle…
small type 1 fibers recruited first
large t2 fibers recruited later when effort increases!
metal backed electrodes reuqire…
an interface
3 types of electrodes:
metal backed
carbon film
dure-stick plus (specific to pt.) 10 times ues
to minimize electrode resistance:
- use large electrodes
- maintain even, firm contact
- use clean electrodes
- keep sponge interface well moistened?
- remove excess hair and oils
whenever possible use largest electrode possible to reduce…
reduces local increases in current density…when small pads are required use the lowest stimulation intensity necessary to achieve the desired clinical results
electrodes should be placed with ___ inch or more
1 inch or more.. 2 if you can! (lots of trial and error to find best placement)
further apart= deeper current
electrodes can be placed..
- on or around the painful area
- over specific dermatomes, myotomes, or sclerotomes that correspond to painful area
- close to spinal cord segment that innervates an area that is painful
- over sites where peripheral nerves that innervate the painful area becomes superficial and can be easily stimulated
- over superficial vascular structures
- over trigger point locations
- over acupuncture points
- in a crisscrossed pattern around the point to be stimulated so the area to be treated is central to the location of the electrods
- bipolar application resulting in similar physiologic effects beneath each electrode
MOst commonly used gate level TENS set up is…
Bracketed! (criss-crossed pattern)
dermatome=
-surface area supplied by a nerve root
peripheral nerves are made up of…
- several spinal nerve roots
- ex: ulnar n. is made up of C7, 8, T1 nn. roots
- they are most relevant with peripheral injuries and stresses!!
Estim frequencies
low, med, high
low frequency estim
- 1,000 Hz (cycles per second) and below
- BioMed 2000 XL
medium freq. estim
- 1,000 to 100,000 HZ
- Mettler all medium freq.
- vectra genysis
high freq. estim
> 100,000 HZ
- vectra genysis
Mettler sonicator Plus 930
- all medium freq
- interferential- 4000 Hz and 4100 Hz
- premod- 4,000 Hz
- medium freq. (russian) - 25000 Hz, burst!
continous=
no amplitude modulation
surge=
can set the on/off times (NMES)
reciprocation=
stimulation changes from one channel to the other
Vectra genysis=
preprogrammed
Intelect NMES (blacK)
- asymmetric biphasic square pulse
- ONE mode
- pulse amplitude
- pulse freq.
- pulse width
- adjustable on/off time (duty cycle)
Intelect NMES (white)
- asymetric biphasic square wave (3 modes)
- constant- adjustable rate and PW (no on/off time capability)
- alternate (ch. 1 and ch. 2)
- synchronous- channel 1 and 2 run the same
BioMed 2000XL (TENS)
3 modes
- continous
- burst
- modulated
