NMES

Question 1

what are NMES parameters?

Answer 1

waveform: symmetric or asymmetric biphasic PC or burst modulated AC (Russian)

pulse freq= 20-100 pps
pulse duration= 200-600 microseconds (around 30 pps for muscle twitch, 35-50 pps for smooth tetanic contraction, 50-100 pps for max contraction)

amp= adjusted according to the strength of the contraction desired (healthy patients 50% or greater MVC; injured bay have to decrease strength to 10% MVC)

ramp up time: 1-5 seconds
ramp down time: 1-2 seconds

duty cycle = 1:5 to start and can lower

treatment time= at least 10 contractions (usually 10-20 contractions). be careful of DOMS

Question 2

What are motor-level stimulation parameters?

Answer 2

amp= contraction strength increases as amp increases
phase duration= 300-500 microseconds targets motor nerves (shorter phase duration requires larger amp, longer duration with depolarize pain nerves, pain often limits quality and quantity of the contraction)

pulse freq= determines the type of contraction

Question 3

frequency determines the time for ______ ______.

What are low, medium, and high frequencies? and what do they result in?

Answer 3

low =  twitch (individual contractions)[interpulse interval long enough to allow muscle fibers to return to original position]
medium= 15-40 pps --> summation (contractions blend)[interpulse interval allows some elongation, but not to starting point]
high = >40 pps --> tonic (constant contractions)[interpulse interval is not sufficient to allow fibers to elongate]

Question 4

NMES electrode placement?

Answer 4

one over the motor point
one over the muscle (the electrodes should be parallel to fiber direction)
placed at least 2 inches apart

Question 5

NMES contraindications

Answer 5

across or through chest
in region of a cardiac pacemaker
near implanted stimulators such as for the phrenic nerve or bladder
over carotid sinus in the neck
in patients with uncontrolled hypertension or hypotension
in patients with PVD
in patients with thrombophlebitis
over low back, pelvis, abdomen of pregnant women
over pharyngeal gland
in areas of decreased/absent sensation
in patients with history of seizures
in immature or confused patients
over tumor or malignancy.

Question 6

What are adverse effects of electrodes?

Answer 6

BURNS

• only use electrodes that adhere well to the skin
• be sure to have enough conduction medium on the skin
• once the coating on the electrode starts to dry out, the current delivery becomes less uniform, causing even current density (areas with higher currents can be susceptible to a burn)
• inspect electrodes each time
• current density is inversely proportional to the size of the electrode so larger electrodes are more comfortable than smaller ones
• electrodes must sit smoothly on the skin without wrinkles or gaps, maintain good electrode to skin contact
• document placement with diagrams