Unit 5 Electrical Stimulation for Pain Flashcards
What are the Charateristics of Acute Pain?
- Tissue damage, trauma, or infection
- Last less than 12 weeks (3 months)
- Sharp and easy to locate
- Acute deep-tissue pain from muscles, joints, or viscera can be diffuse and difficult to locate
What are the characteristics of Chronic Pain?
- 3 to 6 months or pain that persist beyond the normal time expected to heal injured tissues
- Central Sensitization, or the amplification of neural signaling with the CNS
- Dull, burning sensation
- Associated with physical, emotional, social and financial disability
Nociceptive Afferents
What are the Characteristics of A-delta Fibers?
- High threshold
- Myelinated
- Fast conducting (5-30 m/sec)
- Responds to high intensity heat, cold, and mechanical stimuli
- Generates fast/first pain with withdraw refelxes and sensations
- Associated with the precise location of noxious stimuli on the body
Nociceptor Afferents
What are the Characteristics of C-Fiber?
- High Threshold
- Unmyelinated
- Slow Conducting (0.5-2 m/sec)
- Responds to high intensity heat, cold, mechanical and chemical stimuli (polymodal)
- Generates slow/seconds pain sensations
- Assocaited with the prevention of further tissue damage
What is the Frequency for Transcutaneous Electrical Nerve Stimulation (TENS)?
- Low Frequeny: 1 to 120 Hz
What is the frequency of Interferential Current (IFC)?
- Median Frequency: 4000 Hz - 4100 Hz is the most common
With TENS, what are the different Modulation Parameters?
- C - Continuous: This set of therapy current remains constant for the duration of the therapy session
- B - Burst Mode: Short electrical pulses are generated, with intervals
- M - Modulation Mode: This set duration of the pulse width is slowly decreased and increased from the set
What are the 2 most common waveforms for TENS?
- Biphasic Symmetrical Pulse Current
- Asymmetrical Bophasic Balanced Pulsed Current
Modes of TENS
What are the Characteristics of Conventional TENS?
- Low Intensity = Comfortable tingling sensation
- High Frequency = 80 to 110 Hz
- Short Pulse Duration = 50 to 100 usec
Modes of TENS
What are the Characteristics for Acupuncture-Like TENS?
- High Intensity = Muslce Contraction
- Low Frequency = Less than 10 Hz
- Long Pulse Duration = 200 usec
Modes of TENS
What are the Characteristics of Burst Train TENS?
This is a combination of Conventional and Acupuncture-Like TENS
- Intensity = Produces muscle contraction
- High Frequency trains of pulse = 100 Hz
- Low-burst Frequency = Less than 10 Hz
Modes of TENS
What are the Characteristics of Brief Intense TENS?
- Intensity = High but tolerable
- High Frequency = 100 to150 Hz
- Long Pulse Duration = 150 to 250 Hz usec
What are the Common Parameters used for Pain Control with Conventional TENS?
- Frequency = 10 - 250 Hz
- Pulse Duration = ≤ 100 usec
- Amplitude/Intensity = Sensory Level
What are the Common Parameters used for Pain Control with Acupuncture-Like TENS?
- Frequency = < 10 Hz (1-4 Hz)
- Pulse Duration = 150 - 200 usec
- Amplitude/Intensity = Motor Level
What are the Common Parameters used for Pain Control with Burst Train TENS?
- Frequency = 100 Hz, delivered at 2 Hz
- Pulse Duration = 150 - 200 usec
- Amplitude/Intensity = Motor Level
What are the Common Parameters used for Pain Control with Brief, Intense TENS?
- Frequency = 100 -150 Hz
- Pulse Duration = 150 - 200 usec
- Amplitude/Intensity = Noxious Level
What are Commonly used Parameters with Conventional TENS with Acute Conditions?
- Waveform = Mono- or Biphasic pulsed current
- Pulse Frequency = 100-150 Hz
- Pulse Duration = 50 -80 usec
- Amplitude = mA to Maximum comfortable perception (or paresthesia). No or barely visible motor activity
- Duration = 20 - 30 min (Longer if Used During Activity)
What are Commonly used Parameters with Amplitude-Like TENS with Chronic Conditions?
- Waveform = Mono- or Biphasic pulsed current
- Pulse Frequency = 2 - 10 Hz
- Pulse Duration = 150 - 300 usec
- Amplitude = mA to visible muscle twitches
- Duration = 20 - 45 min
What is the Gate Control Theory?
Selective stimulation of the Large-diameter afferent fibers (A-beta) can result in a gating, or blocking, or noxious afferent input from small-diameter unmyelinated nopciceptive C-fibers and small myelinated A-delta fibers at the level of the Spinal Cord
Differentiation of Mixed Peripheral Nerve
What is the Function of A-Beta fibers? What is the diameter?
Touch and Pressure
- 5-12 um
This Activates Substantia Gelatinosa neurons
Differentiation of Mixed Peripheral Nerve
What is the Function of A-Delta fibers? What is the diameter?
Pain and Temperature
- 2-5 um
This Inhibits Substantia Geltinosa neurons
Differentiation of Mixed Peripheral Nerve
What is the Function of Dorsal Root (Type C) fibers? What is the diameter?
Pain
- 0.4 - 1.2 um
This Inhibits Substantia Geltinosa neurons
What is the Analgesic Mechanisms of Low-Frequency TENS?
Low-Frequency TENS (Less than 10Hz) triggers descending inhibatory pathways that include the ventrolateral periaqueductal gray (PAG) that sends projections to the rostal ventromedial medulla (RVM), which then projects to the spinal cord
What is the Analgesic Mechanisms of High-Frequency TENS?
- Increases the conentration of B-endorphins in the bloodsteam, CSF, and methinine encephalin in the CSF in human subjects
- Reduces glutamate and aspartate concentrations in the spinal cord dorsal horn by activating opioid (delta) receptors
What are Clinical Administrations of TENS?
- Electrodes: The most common type; reusable self-adhesive electrodes are designed for use on a single patient and are not used with conductive gel
- Size of Electrodes: Condider the SIZE of the treated area
- Larger Electodes: Comfortable
- Smaller Electrodes: Cause more Discomfort
When placing electodes on a patient, why would we place them wider?
Wider Placement will result in greater depth of penetration than narrower
With the administration of TENS, what are the electrode configurations?
- Around or over the painful area
- Parallel or crossed
- Over Acupuncture points, Motor Points on the myotomes related to area of pain, and Trigger points
- Nerve Traject
What are the Contraindications of TENS?
- Pacemakers or other implants (local)
- Pregnancy (local)
- Carotid Sinus (local)
- Damaged skin (local)
- Lack of normal skin sensation (local)
- Lack of normal skin sensation (local)
- Impaired cognition
- Thrombosis or thrombophlebitis
- Hemorrhage (local)
- Malignant tumors (local)
- Eyes, internally, and on reproductive organs
What are the Precautions for TENS?
- Active Epiphysis
- Undiagnosed Pain
What is the Main use of Interferential Currents (IFC)?
Pain control
- IFC claims to provide better patient comfort and reach deeper tissues due to its higher frequency than traditional TENS
Can also be used for muscle contractions or edema control but rarely used for these
With IFC, what are the 2 Sinusoidal Alternating Currents?
In and Out phases; the interference amplitude gradually increases and decreases. Then IFC is referred to as Amplitude-Modulated AC or Beat Frequency
- These Currents have a Median Frequncy Current (4 KHz or 4000 H)
With the IFC Parameters, what is the name of the Alternating Currents?
Carrier Frequency
- 2kHz = Induce Muscle Contraction
- 4 kHz = Reduce Pain
With IFC Parameters, what frequncy produces the Therapeutic Effect?
Beat Frequency OR Amplitude-Modulated Alternated Frequency
With IFC, what beat Frequncy is the most common used to Induced Analgesia?
100 Hz
With IFC, why are 4 Electrodes used?
This is necessary to produce that interference in the patient’s body. The interference happens in the Central region of the electrodes
- When 2 electrodes are used, the interference happens inside the machine
With IFC, what is Sweep Frequency?
This is the Modulation of the beat frequency, which automatically and rhythmically increases and decreases with a range that may be specified by the theraist
- This is used to avoid sensory accommodation or habituation
With ICF, what are the 3 Parameters of Sweep Frequency?
- Triangular Sweep: 6/6 frequency oscillates over 6 second period
- Rectangular Sweep: 1/1 Sweep pattern delivers the base and peak AMFs for 1 second
- Trapezoidal Sweek: 1 ^ 5 ^ 1, the base AMF is retained for 5 seconds; then frequency goes over to high frequency in 1 second and is kept for 5 seconds, then the frequency returns in 1 second to the lowest
What are the Parameters for Pain Modulation with IFC?
What is the Analgesic Mechanisms of IFC?
- The most cited analgesic mechanism of IFC is the gate control theory of pain, previously described.
Other mechanisms
- Increased blood flow, activation of descending analgesic pathways, physiological blockade of nerve conductions, and placebo effect
What are the Contraindications for IFC?
- Pacemaker or other active implants
(local) - Pregnancy (local)
- Carotid sinus (local)
- Damaged skin (local)
- Lack of normal skin sensation (local)
- Impaired cognition
- Thrombosis or thrombophlebitis
- Hemorrhage (local)
- Malignant tumors (local)
- Eyes, internally, and on reproductive organs
What are the Precautions for IFC?
- Active Epiphysis
- Undiagnosed Pain
