Electrotherapy and Pain Modulation Flashcards
What are the levels of physiologic response (4)
- Cellular
- Tissue
- Segmental
- Systemic
What are the cellular level responses to electrotherapy (5)
- Excitation of excitable cell membranes
- Changes in cell membrane permeability
- Protein synthesis
- Stimulation of fibroblasts and osteoblasts
- Modification of microcirculation
What cell membranes are excited by electrotherapy (2)
- Nerve
2. Muscle
What are the tissue level responses to electrotherapy (3)
- Skeletal muscle contraction
- Smooth muscle contraction
- Tissue regeneration
True or False:
Tissue level responses to electrotherapy require multiple cellular events
True
What are the segmental level responses to electrotherapy (5)
- Modification of joint mobility
- Modification of muscle contractility
- Muscle pumping action to change circulation and lymphatic drainage
- An alteration of microvasculature not associated with muscle pumping
- Increased movement of charged proteins into lymphatics resulting in fluid moving centrally
What are the systemic response to electrotherapy (3)
- Analgesic effects as endogenous pain suppressors are released
- Analgesic effects from the stimulation of certain neurotransmitters
- Stimulate spinal gate
What are the effects of electrical stimulation (3)
- Nerve depolarization
- Muscle depolarization
- Ionic effects
What has a slightly higher resting membrane potential nerves or muscles
Muscles
True or False:
The membrane of cells has differential permeability to different electrically charged ions
True
Is K+ easily or slightly permeable to the membrane
Easily permeable
Is Na+ easily or slightly permeable to the membrane
Slightly permeable
True or False:
The membrane is impermeable to large negatively charged protein and phosphates (anions)
True
True or False:
There are a large number of anions trapped inside the cell
True
True or False:
Depolarizing something in the middle will cause depolarization on both directions
True
Which way does the Na+/K+ pump move Na+ and K+ in relation to the cell
Na+ out
K+ in
Where is Na+ in higher concentration
Fluid surrounding the cell
Where is K+ and anions in higher concentration
Inside the cells
What is the resting membrane potential for muscle
-90 mV
What is the resting membrane potential for peripheral nerves
-70 mV
What maintains the negative resting membrane potential
The Na+/K+ pump moving 3 Na+ out and 2 K+ in resulting in a negative charge
True or False:
Larger diameter nerve fibers conduct the action potential faster
True
How fast do A alpha motor nerves carry APs
60-120 m/sec
How fast do A gamma and A delta nerves carry APs
12-30 m/sec
True or False:
Myelin makes the AP conduct faster
True
What is the AP jumping from node to node called
Saltatory conduction
True or False:
Most nerves in humans are mixed nerves leading to different nerve fibers firing at different rates
True
Where is the cell body and axon located in motor nerves
Cell body: Ventral horn or brainstem motor nuclei
Axon: Terminate on muscle
Where is the cell body and axon located in sensory nerves
Cell body: Dorsal root ganglion or cranial nerves sensory nuclei
Axon: 50% end as free nerve endings and 50% are specialized sensory receptors
What are the A alpha nerve diameter, conduction velocity, and type of nerve fiber (3)
- 12-20, 72-120, Muscle spindle primary afferent
- 12-20, 72-120, Golgi tendon organ afferent
- 12-20, 72-120, Skeletal muscle efferent
What are the A beta nerve diameter, conduction velocity, and type of nerve fiber (2)
- 6-12, 36-72, Touch pressure receptor afferent
2. 5-12, 20-72, Muscle spindle secondary afferent
What are the A gamma nerve diameter, conduction velocity, and type of nerve fiber (1)
- 2-8, 12-48, Muscle spindle efferent
What are the A delta nerve diameter, conduction velocity, and type of nerve fiber (1)
- 1-5, 6-30, Pain temperature afferent
What are the B nerve diameter, conduction velocity, and type of nerve fiber (1)
- Less than 3, 2-18, Preganglionic autonomic efferent
What are the C nerve diameter, conduction velocity, and type of nerve fiber (2)
- Less than 1, Less than 2, Pain temperature afferent
2. Less than 1, Less than 2, Postganglionic efferent
What are Ia nerve diameter, conduction velocity, and type of nerve fiber (1)
- 12-20, 72-120, Muscle spindle primary afferent
What are Ib nerve diameter, conduction velocity, and type of nerve fiber (2)
- 12-20, 72-120, Golgi tendon organ afferent
2. 12-20, 72-120, Skeletal muscle efferent
What are II nerve diameter, conduction velocity, and type of nerve fiber (3)
- 6-12, 36-72, Touch pressure receptor afferent
- 5-12, 20-72, Muscle spindle secondary afferent
- 2-8, 12-48, Muscle spindle efferent
What are III nerve diameter, conduction velocity, and type of nerve fiber (2)
- 1-5, 6-30, Pain temperature afferent
2. Less than 3, 2-18, Preganglionic autonomic efferent
What are IV nerve diameter, conduction velocity, and type of nerve fiber (2)
- Less than 1, Less than 2, Pain temperature afferent
2. Less than 1, Less than 2, Postganglionic efferent
What does the Gasser scheme name
Peripheral nerve fibers
What does Lloyd scheme name
Sensory fibers only
What is the strength duration curve
Graphic representation of minimum combination of current strength and pulse duration needed to depolarize that nerve
What do lower current amplitudes and shorter pulse durations depolarize
Sensory nerves (A beta and A delta)
What do higher current amplitudes and longer pulse durations depolarize
Motor nerves (A alpah and A gamma)
What do higher yet current amplitudes and longer pulse durations depolarize
Pain transmitting C fibers
True or False:
You feel the electrical current before you see movement
True
What is sub-threshold
Amplitude duration below curve for particular nerve
What is threshold stimulation
Amplitude and duration on the curve
What is supra-threshold
Amplitude and duration above the curve
True or False:
The peripheral nerve membrane is more excitable than the muscle membrane
True
What is the minimum current amplitude with a very long pulse duration required to produce an action potential called
Rheobase
What is the minimum duration it takes to stimulate that tissue twice the rheobase amplitude called
Chronaxie
What is rheobase dependent on
Current amplitude
What is chronaxie dependent on
Time/duration
What is all or none response
Once threshold is achieved nerve fiber fires
What is accommodation
If stimulus is too slow nerve can adjust threshold level
What are the 2 types of AP propagation
- Orthodromic
2. Antidromic
What is orthodromic propagation
Normal physiological stimulation where the AP propagates one way only
What is antidromic propagation
AP propagated both ways
What controls peripheral nerve axon recruitment
Intensity
What does a current that is applied at an intensity and duration just strong enough to reach threshold stimulate in a mixed nerve
Large superficial fibers
What does an increased current intensity now stimulate in a mixed nerve
Medium sized superficial and deeper large sized fibers
What does further increasing current amplitude now stimulate in a mixed nerve
Small superficial, medium deeper, and large deepest fibers
What is TENS used for
Pain modulation
What can selective stimulation of A beta fibers do
Block pain transmission in the spinal cord via the gate control theory
What are the parameters for E-stim trancutaneously (conventional)
Short pulse duration (50-80), pulse frequencies 100-150, and low current amplitude (cause tingling)
How long will conventional TENS block pain
Only as long as the stimulation is on
True or False:
Conventional TENS can be used 24 hours a day
True
How do you control for adaption (2)
- Modulate rate
2. Modulate width
What are the parameters for low rate or acupuncture like TENS
Frequencies of 2-10, long pulse duration (100-200), and higher current amplitude (visible contraction)
How long will acupuncture like TENS control pain after 20-30 minutes of treatment
4-5 hours
How does acupuncture like TENS control pain for 4-5 hours
By stimulating the endogenous opioid system
What is the half life of endogenous opiates
4.5 hours
What fibers does acupuncture like TENS stimulate (3)
- A delta nociceptive
- A alpha
- A beta
What are the parameters of noxious intensity TENS
Short duration stimulation (less than a minute), can use low (1-5) or high frequencies (80-110), pulse duration up to 1 sec, and amplitude 2 times motor threshold
What is the intent of noxious intensity TENS
Stimulate C-fibers
What is the motor threshold
When you see the muscle twitch
What fibers does noxious intensity TENS stimulate
A delta, C fibers, A alpha, and A beta
True or False:
Noxious intensity TENS uses opioid mediated and nonopioid mediated analgesia
True
What does noxious intensity TENS mediate in the cord
Serotonin and noradrenaline
Where does noxious intensity TENS mediate muscarinic
Supraspinally
What does burst mode TENS work like
Low frequency TENS
How is the stimulation delivered in burst mode TENS
Bursts or packages of 10 pulses
What is the pulse duration of burst mode TENS
100-300 pps
What types of nerves does interferential current depolarize
Sensory and motor nerve
What are the therapeutic effects of IFC (3)
- Increase pain threshold
- Muscle contraction
- Muscle pumping
How does IFC work
Stimulator imparts 2 different currents into the body and the currents interfer giving you a beat current which is the difference between frequencies.
True or False:
The beat frequency can be changed to get pretty much any effect you want
True
What is the pulse frequency of IFC for pain management
50-120 pps
What neurons do you want to stimulate to modulate pain with IFC
Large diameter afferent neurons
What is the pulse frequency of IFC for muscle contraction
20-50 pps
What is the pulse frequency of IFC for acutism pain relief
1 pps
True or False:
30 pps gives a smooth tetanic contraction when using IFC
True
What are the indications for IFC (2)
- Pain of known origin
2. Possibly for muscle exercise to increase blood flow, muscle relaxation, and edema reduction
What are the therapeutic purposes for high voltage pulsed current (3)
- Sensory TENS pain management
- Muscle contraction
- Motor TENS pain relief
What is the pulse frequency for HVPC sensory TENS pain management
80-120 pps
What is the pulse frequency for HVPC muscle contraction
30-60 pps
What is the pulse frequency for HVPC motor TENS pain relief
2-4 pps
What does HVPC sensory TENS pain management stimulate
- Large diameter afferent neurons
2. Activate spinal gate
What does HVPC motor TENS pain relief stimulate
Endorphin descending loop
True or False:
E-stim can activate the spinal gate to decrease pain
True
How does E-stim activate the spinal gate to decrease pain
Stimulate A-beta fibers which closes the spinal gate by competing with A-delta and C-fibers
What is AC current
An alternating sinusoidal curve
What is DC current
Current that stays on the same side of the line
How does AC current cause muscle contraction
Stimulates the alpha motor neuron
How does DC current cause muscle contraction
Stimulates the muscle its self
What type of contraction does AC current produce
Smooth tetanic contraction
What type of contraction does DC current produce
A twitch
Why are A-beta fibers the first fibers stimulated
The are small diameter myelinated fibers
Why is a shorter phase duration more comfortable
The electric current is flowing in one direction for a longer time
How do you stimulate the ascending and descending endorphin loops
By stimulating the A-delta and C-fibers
Does E-stim directly stimulate receptors
No it stimulates the nerve attached to the receptor