Flashcards in Electrical Stimulation Deck (65)
When the patient reports tingling but no muscle twitch, what fibers have been exceeded and which fibers have not been reached?
A-beta fibers exceeded
A-alpha motor neurons not reached
What happens when A-alpha motor neurons are reached?
When the patient reports a burning, needling sensation, the capacitance of which fibers have been exceeded?
Does electrical stimulation target nerves or the actual muscle?
Nerves (targeting the actual muscle would be painful)
What is the order in which fibers are reached via electrical stimulation to initiate certain responses?
1 A-beta (tingling)
2 A-alpha (muscle contraction/twitch)
3 A-delta (discomfort)
4 C (PAIN)
What is rheobase?
Minimum amplitude needed to depolarize a nerve fiber when phase duration is infinite
What happens if the peak amplitude fails to exceed rheobase?
the nerve will not depolarize regardless of phase duration
What is chronaxie?
The time (or phase duration) required to depolarize a nerve fiber when the peak current is twice rheobase
When will the patients reach the greatest amount of comfort in terms of phase duration and amplitude?
When amplitude is twice rheobase and phase duration is slightly greater than chronaxie
What is the term for the number of pulses or cycles generated per second?
What affects the number of action potentials elected during the stimulation?
Does a higher or lower frequency lead to summation?
What is the rate limiting factor of the number of impulses that can be generated by a nerve?
Absolute refractory period
What occurs with stimulation at high frequency near the refractory period of the sensory nerve (official name)?
What are the most common treatment frequencies?
1-10 Hz or 60-100 Hz
What are the values for low, medium, and high frequency generators?
Low = up to 1,000 Hz
Medium = 1,000-100,000 Hz
High = greater than 100,000 Hz
What is the frequency for interferential current generators?
What is the main purpose for using high frequency generators?
Thermal purposes (ex. = diathermy)
What is the normal frequency level for Russian stimulation?
What structure attaches the electrodes to the current generator?
How many leads must there be to complete a circuit?
If the electrodes are unequal sizes, to where will the current concentrate?
In the smaller electrode (perception of increased intensity)
What happens to the larger electrode when the sizes vary greatly?
Unable to perceive current - becomes dispersal electrode
What is the main target when two pads are placed close together?
Most concentration in superficial tissues
How does the target change when the pads are further apart?
Current has potential to take deeper path through the nerve and blood vessels that have less resistance
What is the general rule for selecting the size of the electrodes?
Largest possible but small enough to selectively target tissue
What is the size of the electrodes during monopolar electrode configuration?
Two or more unequal sizes (one active, one dispersal)
Monopolar electrode configuration can be used with what types of current?
Biphasic (AC) or monophasic (DC)
Which is found at the target site, and which is found away from the target site: active or dispersal electrode?
At target site = active
Away from target site = dispersal