ESTIM part 1 Flashcards
What are electromagnetic agents?
They apply energy in the form of electromagnetic radiation or an electrical current
What are different examples of electromagnetic agents?
-UV radiation, infrared radiation, laser, diathermy, and electrical current
What is a laser?
Output monochromatic, coherent, directional, electromagnetic radiation that is generally in the frequency range of visible light or IR radiation
What is shockwave diathermy?
Produces heat in both superficial and deep tissues
What is electrical stimulation (ESTIM)?
Is the use of electrical current to induce muscle contraction, changes in sensation, reduce edema, or accelerate tissue healing
What is the clinical application to ESTIM in rehab?
- Pain modulation
- Muscle re-education for strengthening
- Edema prevention/reduction
- Decreasing Inflammation
- Tissue/Wound healing
- Muscle spasm reduction (Spasticity management)
- Drug delivery (iontophoresis)
- Reinverting denervated muscle (EMS)
- EMG Biofeedback
What does TENS stand for?
Transcutaneous (non-invasive) electrical nerve stimulation
What does NMES stand for?
Neuromuscular electrical stimulation
What does EMS stand for?
Electrical muscle stimulation
What does TES stand for?
Therapeutic electrical stimulation
What does FES stand for?
Functional electrical stimulation
Can also be FNS - functional neuromuscular stimulation
What does TENS stimulate?
Sensory stimulation
What does NMES stimulate?
Motor stimulation
What is an action potential?
Messaging unit of the nervous system
How do you stimulate an action potential in a nerve cell?
The electrical current must have sufficient amplitude and duration to cause depolarization
What is depolarization?
Change of flow of the ions across the cell membrane = AP “All or none” event
What is repolarization?
Return to resting membrane potential, which is generally more negatively charged due to electron imbalance inside vs. outside the cell
What is adaptation/accommodation?
A decrease in the frequency of action potentials (APs) and a decrease in the subjective sensation of stimulation when electrical stimulation is applied without variation in the applied stimulus
What is propagation? And what way does propagation travel?
Once an AP is generated it triggers an AP in the adjacent area of the nerve membrane
This occurs in one direction from the stimulus along the nerves axon until it reaches its terminating point
What is the terminating point for a motor nerve?
Motor nerve = muscle - creates a muscle contraction
What is the terminating point for a sensory nerve?
Sensory nerve = spinal cord - creates tingling sensation
What is myelin?
Fatty sheath that wraps around certain nerve axons (increasing the diameter) that increase the speed in which nerves propagate
What are nodes of Ranvier?
Small gaps between the myelin sheath from which AP jump from one node to the next, a process called saltatory conduction, which accelerates AP propagation
For the parameters of waveforms, what are the time-dependent characteristics?
- Phase
- Phase duration (width, cycle)
- Pulse
- Pulse duration
- Interpulse interval
- Frequency (rate)
What are the amplitude-dependent characteristics of the waveform parameters?
- Amplitude (intensity)
- Peak amplitude
- Peak to peak amplitude
- Phase change
- Pulse change
What are the device parameters (NMES) of the waveform parameters?
-On/off time
-Ramp up/down time
What is the phase?
Period when electrical current flows in one direction
What is the pulse?
Period when electrical current flows in any direction
May be made up of one or more phases
What is pulse duration (width, cycle)?
How long a pulse lasts, beginning of the first phase of the pulse to the end of the last phase in microseconds (µs)
What is phase duration?
How long a phase last in microseconds (µs)
What is an interpulse interval?
The amount of time between pulses
What pulse duration parameters are used for NMES for small and large muscles?
- Small muscles: 125 - 200 µs
- Large muscles: 200 - 350 µs
What pulse duration and frequency parameters are used for TENS at a high rate?
Pulse duration: 50 - 80 µs
Frequency: 100 - 150 Hz
What pulse duration and frequency parameters are used for TENS at a low rate?
Pulse duration: 200 - 300 µs
Frequency: 1 - 10 Hz
What is the psychological mechanism of pain control for high rate TENS?
Pain gating effects
What is the psychological mechanism of pain control for low rate TENS?
Endogenous opioid effects
When the pulse duration shortens, the amplitude needs to ____________?
Increase
What is frequency?
- Number of cycles (pulses) per second
- Also called rate
- Inversion of cycle duration
(Hz or PPS)
What does a low frequency do when NMES? And what is the low frequency needed?
20 - 30 Hz
Will produce a separate muscle twitch contraction
What does the optimal frequency do when NMES? And what is the optimal frequency needed?
35 - 50 Hz
The twitches occur closer together, eventually summating into a smooth contraction
What does the high frequency do when NMES? And what is the high frequency needed?
50 - 80 Hz
May produce stronger contractions, but it also causes more rapid fatigue
What does frequency modulation (burst) for the TENS do?
It is a present frequency combining both high rate and low rates in intermittent burst
This helps limit adaptation/accommodation
What is amplitude based on for NMES?
Current amplitude is adjusted to produce a contraction of the desired strength depending on the goal of the interventions
What is the desired amplitude based on TENS (general)?
To control pain with electrical stimulation, the treatment should be comfortable
What is the desired amplitude of high-rate TENS?
Recommended that the amplitude be set to produce a strong tingling sensation
What is the desired amplitude of low-rate and burst TENS?
Amplitude should be sufficient to produce a muscle contraction that can be seen or palpated by the clinician
What is the ratio for the on/off time?
10 seconds on 50 seconds off
10:50 - 1:5
What is on/off time used for with NMES?
This is used to stimulate voluntary contract and relax phases of physiological exercise
-Helps to prevent muscle fatigue
What is the ramp up vs ramp-down time for NMES?
To minimize the discomfort that can occur when the electrical current turns on and off
What is ramp up time?
Number of seconds it takes for the current to increase from zero to maximum amplitude during (On time)
What is ramp down time?
Number of seconds it takes for the current to decrease from its max to zero during “Off time”
What is the different types of waveforms?
- Direct current
- Alternating current
- Pulsed current
What is direct current?
Continuous flow of electrons/ions in one direction. Can flow negative to positive or positive to negative
What is a form of Direct (DC) current?
Iontophoresis
What does the on time need to be for DC?
≥ 1 sec to be counted as a DC
What is Pulse (PC) current?
Interrupted current flow of electrons where the current flows in a series of pulses separated by periods when no current flows
What is monophasic?
May only flow in one direction only
What is biphasic?
Flow back and forth between polarities during each pulse
What does biphasic help with?
- Control pain
- Promate muscle contraction
What does monophasic help with?
-Used clinically to promote tissue healing
-Manage acute edema
What is alternating (AC) current?
-Always Biphasic
-Alternating between polarity
-Measured in Hz
What are different types of ESTIM use AC?
-IFC
-Premodulated current
-Russian Protocol
What is a quadripolar electrode placement?
Uses 2 pairs of 1 independent circuit, carries slightly different frequencies, which cause interference at their intersecting point
What is beat modulation (IFC current)?
2 different frequencies intersect
The interference pattern produces a beat frequency equal to the difference in frequency between the two alternating current frequenciesq
What is a premodulated current?
-Medium frequency AC
-Single circuit
-2 electrodes (1 Channel)
-Produces same resulting waveform as IFC, which uses 2 circuits and 4 electrodes but only uses a single circuit and 2 electrodes
What is russian protocol and who was it intended for?
-NMES protocol
-Originally intended for LE quad muscle strengthening, for russian olympic athletes
What are the parameters for russian (NMES)?
-Pulse duration: 50 bursts per second
-Burst duration: 10 ms long burst
-Burst Modulation: 10 ms interburst interval
-Frequency: 2500 Hz
What are the different types of modulations?
-Continuous modulation
-Burst modulation: Burst-modulated pulsed current, burst modulated alternating current
-Beat modulation: IFC
When is high rate TENS recommended?
When sensation, but not muscle contraction would be tolerated
-Post-injury
-Inflammation present
-Tissue may be damaged by repeated muscle contraction
When is low rate TENS recommended?
When a longer duration of pain control is desired and a muscle contraction is going to be tired
What does high rate TENS stimulate?
A-beta nerves
When is burst mode TENS recommended?
It is recommended for some individuals to apply more intensity in shorter burst for those with higher tolerance
What are the contraindications for ESTIM?
-Implantable cardiac electronic devices (pacemakers/defibrillators)
-Transcerebral electrode placement
-Unstable arrhythmias
-DVT
-Pregnancy
What are the precautions of ESTIM?
-Cardiac disease
-Epilepsy
-Hemorrhages
-Over neck or mouth
-Impaired sensation/mentation
-Malignant tumors
-Areas of skin irritations or open wounds
