PHYSMOD_ELECTRICAL STIMULATION

ES for Pain Relief

Electrical stimulators capable of delivering ____ currents, for _____ peripheral nerve fibers (sensory) through the skin using surface electrodes.

• can also influence the motor nerve fibers

Application of ______ electrical current for inducing _____ (APTA, 2001)

Primarily used for pain relief

• pulsed

• depolarizing

• pulsed

• electroanalgesia

Mechanisms of Pain Relief

Gate Control Theory

• Gating mechanism performed by the _______ located at the lamina of spinal cord at which allows passageway of pain if gates are open

  • As pain reaches the _____ and higher centers of

    the brain, the sensation will be perceived as painful.

  • Transmitted by ___ & ___ fibers

• ES stimulates A-beta fibers (highly myelinated, larger diameter) which will allow faster nCV to the higher centers

  • Reaches substantia gelatinosa first to activate the

    inhibitory nature of the area, thus closing the gate to block pain signals

  • Helpful since the majority of the pain signals are

    being blocked at this level.

  • Can’t be perceived by the brain anymore as

    painful; less painful

  • ___% of the pain signals can still be perceived as they don’t pass through the substantia gelatinosa

Short term effect: __________

• substantia gelatinosa

• thalamus

• A delta and C fibers

• 20%

• Pt might experience pain again but not as intense as before

Only takes effect when the A-beta fibers are affected at an instant. Once stimulus (any modality) is removed, pain relief won’t take that much effect already.

_________________ (DPIT)

• aka Endogenous Opiate System / Endorphin Release

• Mediated by the opiate system inside the body

  • Function of the endogenous opiates (“optiopeptines”) which are also referred to as ____ & ____

  • act similarly to morphine

  • Optiopeptines control pain by binding specific opioid receptors in the nervous system

• ES will allow the release of optiopeptines to influence certain areas of the brain such as _______ & _______ (both from the brainstem).

  • Strongly inhibits the transmission of pain signals that is being sent from the spinal cord to higher brain centers, which causes analgesia

• Chemical in nature

  • Stays more in the ____ system and _____ system

  • ______ effect in the body compared to Gate Control Theory

• Descending Pathway Inhibitory Tract

• endorphins and enkephalins

• periaqueductal gray matter and raphe nucleus

• blood & nervous system

• Long Lasting effect

Modes of Application

• aka High-Rate TENS; Most-commonly used mode of TENS

• Uses ____phasic/___phasic ____ current

• Treatment duration: ____ mins

• Uses ____-duration ____-frequency pulses to produce comfortable sensation without muscle contractions to modulate ___ pain (GCT)

• Stimulus is modulated to prevent accommodation

  • ________: process where adaptation happens → decreased frequency of action potentials, decreased subjective sensation of stimulation when ES is applied without variation

• If a parameter is constantly applied, a nerve will adapt at a certain point which causes alteration of effective response to ES

• Conventional TENS

• monophasic/biphasic pulsed current

• 20mins

• short-duration high-frequency pulses → acute pin

• Accommodation

Conventional TENS Parameters

Cameron

• Waveform : _____ → ____

• Pulse Frequency : _____ → ____

• Pulse Duration : _____ → ____

• Intensity : _____ → ____

• Treatment time : _____ → ____

Cameron

• Waveform : ——

• Pulse Frequency : 100-150 pps

• Pulse Duration : 50-80 usec

• Intensity : Confortable, tingling sensation

• Treatment time : 20-30 mins

Modes Of Application: ________

• aka Low-rate TENS

• The more we increase the intensity, the more that we can also activate and influence the motor nerve fibers. Repetitive stimulation of motor nerves to produce brief repetitive ________ ; OR

  Stimulation of ___ nerves to produce ______ pain (DPIT)

• Electrically-induced

• Activation of DPIT; chemical in nature → ____ pain

  relief

• If a patient perceives brief sharp pain at the sensory level prior to muscle twitches at the motor level, there is no need to increase the intensity. (Sufficient enough to activate DPIT)

• Acupuncture Like TENS

• Repetitive muscle contractions/twitches

• Aδ → brief sharp

• longer pain relief

Acupuncture Like TENS Parameters

Cameron

Waveform : _____ → ____

Pulse Frequency : _____ → ____

Pulse Duration : _____ → ____

Intensity : _____ → ____

Treatment time : _____ → ____

Cameron

• Waveform: ——-

• Pulse Freq: 2-10 pps

• Pulse Duration: 200-300 usec

• Intensity: Visible muscle twitches (motor); brief sharp pain (sensory)

• Treatment Time: 20-45 min

Modes Of Application: ________

• Combining _______(high frequency, short pulse duration) & _____ (low frequency, long pulse duration)

• Intensity up to patient’s _______ (DPIT)

  • Exhaust maximal level

  • Very intense, hence shorter time duration

Brief Intense Stimulation

• sensory TENS & motor TENS

• patient’s maximal tolerance

BRIEF INTENSE STIMULATION

Michovitz

Waveform : _____ → ____

Pulse Frequency : _____ → ____

Pulse Duration : _____ → ____

Intensity : _____ → ____

Treatment time : _____ → ____

Michovitz

• Waveform: Mono/Biphasic PC

• Pulse Freq: High ~ 100 pps

• Pulse Duration: Long : > 150 usec

• Intensity: Visible muscle twitches (motor)

• Treatment Time: <15min

Modes Of Application: ________

• aka Point Stimulation / Electroacupuncture

• Applied using a ______ over acupuncture points

  • Probe → smaller area of coverage → higher current density

  • applied via acupuncture needles inserted into the body through the skin at the appropriate points

• Pain relief via ____

  • ______ density activates DPIT as its form of

    pain relief

  • reduce ___, ____, and ____ associated with knee OA; improve function in patients with frozen shoulder

  • decrease plasma cortisol, suggesting that the reduction in pain also results in a reduction in stress

• decrease chronic neck pain when applied together with exercise

• decrease postoperative pain and analgesic use after spinal surgery

• Mechanisms are likely similar to low-rate TENS; effects of electroacupuncture are reversed by naloxone → suggests that it promotes endorphin release

• It is advisable for first-time users to use____frequency and_____ duration.

  • We need to reach the point of pain.

Hyperstimulation

• probe electrode

• DPIT

• Higher current

• reduce pain, stiffness, and disability associated with knee OA

• low pulse freq & long pulse duration

HYPERSTIMULATION

Michovitz

Waveform : _____ → ____

Pulse Frequency : _____ → ____

Pulse Duration : _____ → ____

Intensity : _____ → ____

Michovitz

• Waveform: Monophasic PC

• Pulse Freq: Low: 1-5 pps , High : 100 pps

• Pulse Duration: Long : > 250 usec up to 1 sec

• Intensity: Highest tolerated painful stimulus (noxious)

• Treatment Time: 30-60 sec on each acupuncture point

HYPERSTIMULATION

Levels of Sensation/Effects:

• _____ - pt doesn’t feel anything

• ______ - pt starts to feel electricity

• _____ - muscle contractions

• _____ - pain (tolerated)

• Subsensory

• Sensory

• Motor

• Noxious

Modes Of Application: ________

• Stimulation is delivered in bursts

• ___: series of pulses delivered in groups or packets

• Pain relief via ____

• same mechanisms as low-rate TENS but may be more

  effective → more ____ is being delivered; better ____ by some individuals

  • Sometimes, machines will ask for the burst per second parameter. Other machines may ask for frequency level.

  • It depends on the machine you’re using.

  • Some other features are already built in

BURST MODE TENS

• Burst

• DPIT

• more current & better tolerated

BURSTMODE TENS

Cameron → Clinical Setting

Waveform : _____ → ____

Pulse Frequency : _____ → ____

Pulse Duration : _____ → ____

Intensity : _____ → ____

Cameron

• Waveform: ——-

• Pulse Freq: 10 bursts

• Pulse Duration: Long : 100-300 usec

• Intensity: Visible muscle contraction (motor)

• Treatment Time: 20-30 min

Modes Of Application: ________

• Application of _______-frequency currents (1,000-10,000 Hz), which are slightly out-of-phase, through the tissues that are amplitude-modulated to low-frequency current for ____ relief, ____ re-education, improving _____ and ______.

• Electrical effects ranges between the ___-frequency and ____-frequency currents

• A pulsed biphasic waveform which is commonly produced by 2 interfering ACs

• Is the waveform most commonly used for pain control

• If skin resistance is too high, pt has a tendency to feel discomfort when low-frequency currents are being applied.

• _____-frequency current by itself has no effect in the body; it doesn’t produce pain relief but can still penetrate the body since it causes lower skin resistance.

  • Conversion has to be made where in the medium frequency

    current can be converted to low frequency (concept of IFC).

  • Should be slightly out of phase from each other

    • 1950s, Vienna, Australia: Dr Nemeck

INTERFERENTIAL CURRENT

• Alternating medium freq currents ( 1,000-10,000 Hz)

• for pain relief, muscle re-education, improving circulation and wound healing

• low - medium freq currents

• Medium

Used for diffused Pain

INTERFERENTIAL CURRENT

• “Amplitude-modulated”: medium → low

  • _____ frequency current which causes low skin resistance is originally used.

  • By the time the medium frequency enters the body, it will be ____ to produce a low frequency current.

  • ____ frequency current will be responsible for the physiologic changes inside the body.

  • Low frequency will now be more comfortable to the patient.

  • Modulating the frequency

• Medium

  • heterodyned

• Low

INTERFERENTIAL CURRENT EFFECTS

• Low Freq Current ( 1-1000 hz)

  • Minimum frequency required for evoking ______

  • Disadvantage: Causes high_______ (might perceive as uncomfortable)

• Medium Freq Current ( 1,000-10,000 Hz)

  • Causes _______

• High Freq Curremt ( > 10,000 Hz)

  • Thermal Effects

Low Freq

• tetanic muscle contraction

• skin resistance

Medium Freq

• lower skin resistance

High Freq

• Thermal

INTERFERENCE OF WAVES

• ______ Interference

  • If both waveforms fall on the positive side, they add up

    • If both waveforms fall below the isoelectric line, they add up -- producing a lower peak

• _____ Interference

  • If 1 waveform has positive effect and the other has

    negative effect, they negate each other

• Constructive Interference

• Destructive Interference

IFC = 2 waveforms are used simultaneously, which is combined later on.

INTERFERENCE OF WAVES: Phase

• _______: Constantly adding up on the positive and negative side because they have the same waveform/length

• _______

  • If the 2 waveforms have different wavelengths (one is

    longer, one is shorter), there is a point where the

    waveforms add up and a point where they cancel out.

    • There is a point where constructive interference would occur & there is a point where destructive interference

      would occur

• In-phase

• Out of Phase

IFC: AMPLITUDE MODULATED CURRENT

• _______: slight difference between C1 and C2

  • 4,100𝐻𝑧 − 4,000𝐻𝑧 = 100𝐻𝑧

Beat Frequency

__________

• Process wherein lower frequency is produced from 2 medium frequency currents

• Since waves are slightly out-of-phase, a series of_____-______-_____ interference is formed

• Creating groups of impulses known as beat where AMF are summated

• (C2-C1=____ =Beatfrequency)

  • Considered low-frequency therefore it is capable of producing physiological effects in the body

  • ____: physical phenomenon by which the amplitude-modulated frequencies are summated

Heterodyne

• constructive-destructive-constructive

• 100Hz

• Beat

FREQUENCIES

• ___________- lesser frequency of the 2 interfered original AC coming from the 2 medium frequency currents

  • Sensory application: ___

  • Motor application:____

• CARRIER or BASE Frequency

• 4kHz ; 2 kHz

FREQUENCIES

• ______ - difference between the 2 original AC’s; typical between ___ Hz

• Net effect of the heterodyne process

• For pain relief:______ Hz

• For motor application:____ Hz

• _________ / Selective Beat Frequency

  • Constant differences between the 2 circuits

  • E.g. if beat frequency is 100 Hz; beat frequency throughout the treatment is 100 Hz

• __________/ Automatic or Sweep Beat Frequency

  • Frequency between the 2 circuits varies within preselected ranges (modulated type to address nerve accommodation)

  • E.g. constant beat frequency = 100 Hz variable beat frequency = 20 Hz = +/- 10 Hz

  • Frequency plays around __ - _ Hz

• BEAT Frequency → between 1-200 Hz

  • 80-200 Hz

  • ≤ 50 Hz

• Constant Beat Frequency

• Variable Beat Frequency

  • 90 - 110 Hz

TYPES OF IFC

1. ___________

   • 4 pads, 2 pads = 1 circuit , 2 circuits are made

     • Satisfying the need of 2 medium-frequency

       currents in IFC

     • Currents are heterodyne to create beat frequency

2. __________

• Application of two-medium frequency currents via four electrodes so that they intersect in the tissues [quadripolar]

• Need to intersect each other

• 1st circuit should cross the other circuit

• Quadripolar Static Mode / Two-Circuit Static Interference

  Field

• Quadripolar Scanning Mode / Two-Circuit Scanning Interference Field

TYPES OF IFC

1. ____________

• Maximum amplitude modulation effect occurs at 45° to perpendicular lines extending between the 2 circuits

• represented by clover leaf shape below

• Can concentrate electricity on that area

• Used for ____ Pain

2. _____________

• Scanning of amplitude-modulated beats at an arc of ~45° that allows current to conduct through a greater volume of tissue

• clover leaf shape rotates to cover a ____ area

• ______ motion

• Used for ____ pain

• Quadripolar static

  • localized

• Quadripolar Scanning

  • larger area

  • Sweeping

  • diffused

TYPES OF IFC

3. _______________

   • Application of two-medium frequency currents by mixing the two currents in the stimulator prior to application via two electrodes (one-circuit) [bipolar]

   • Modulation happens in the machine before reaching the pt

     • 2 medium frequency currents are heterodyned inside the machine; beat frequency is generated inside the machine and is delivered via 2 electrodes

Premodulated Mode / Exogenous / Bipolar method

TYPES OF IFC

4. _____________

• Created when three-circuit IFC is applied with three pairs of electrodes contained within two Y-shaped applicators that allows the three currents to intersect within the tissues

• Use of 3 circuits where concentration happens in the intersection of the 3 circuits

  • Depicts the 3-dimensional nature of tissues

  • Concentration at the center

Hexipolar mode / Three-Circuit IFC

Physiologic Effects of IFC

Sensory Effect

• Cutaneous stimulation of sensory nerve fibers

• Analgesic effect via____

  • _______ of type C nociceptive fibers

  • Making stimulation more comfortable

  • Addresses _____ type of pain

    (addressed by type C fibers; acute is by A )

• GCT

• Wedensky Inhibition

• non-acute

Physiologic Effects of IFC

Motor Effect

• Synchronous excitation of the large-diameter, lower threshold, and more excitable motor nerve fibers

  • Versus Physiologic Muscle Contraction →

    asynchronous excitation of motor nerve fibers; fatigue occurs earlier

    • Physiologic without electricity

    • With electricity: stimulate all of them together; synchronous → fatigues easily

• _______ Effect = IFC may also mimic pattern of normal physiologic muscle contraction

  (asynch) eventually, but not during initial part

  • Sync at first and then async eventually

• _______n of motor nerve fibers If IFC is applied for long a period of time, it can inhibit muscle response d/t adaptation or loss of excitation of nerves as they are already in the refractory state

  • To prevent inhibition, variability in beat frequency is needed

• Gildemeister Effect

• Wedensky Inhibition

Clinical Applications of Electrical Currents for Pain Control

Acute Pain

• TENS produced a clinically significant reduction in pain severity for patients with moderate-to-severe acute pain and reduced anxiety secondary to pain

• Help with postoperative pain, significantly reducing analgesic medication intake

Chronic Pain

• interferential current helped reduce pain intensity and pain scores

  • reduce chronic pain associated with conditions

    including knee OA and diabetic neuropathy

• TENS has also been found to reduce pain in patients with diabetic neuropathy

• effectiveness of TENS for controlling chronic low back pain remains uncertain

INDICATIONS

BOTH TENS & IFC

• _________

IFC ONLY

• Relief of________

• Promote _________

• _____ reduction

• _____ re-education

• PAIN CONTROL

IFC ONLY

• Relief of muscle spasm

• Promote Tissue Healing

• Edema reduction

• Muscle re-education

CONTRAINDICATIONS (TENS & IFC)

• Over __________

  • Carotid nerves may be activated

    • Vagus nerve may be influenced; affecting heart & lung function

• _______ or _______ cardiac pacemakers or implanted cardioverter-defibrillators (ICD)

  • May be fatal if these internal machines are influenced

• __________ (DVT)

  • May dislodge and cause pulmonary embolism, stroke injuries and/or affectations of the heart

• Over ______, _____ or _____ areas of pregnant woman in 1st trimester

  • TENS & IFC may influence the growth of the embryo

• _____ episodes

  • Electricity may trigger epileptic attacks

• Over _____ area

  • TENS & IFC may aggravate the hemorrhage

• Over _____ area

  • May increase growth of cancer cells

• Within ___m from SWD device

  • Interference may happen between the 2 machines

• anterior cervical area

• Rate-responsive or demand-type cardiac pacemakers

• Deep venous thrombosis

• abdominal, pelvic or lumbar

• Epileptic

• hemorrhagic

• cancerous

• 3m

PRECAUTIONS

• Over ______ area

  • If pt is too skinny, superficial internal organs may be stimulated

• Over ______ area

• Over ______

  • TENS & IFC does not cause too much heat, but we need to be careful and monitor our pts

• Confused or unreliable patients or impaired ______

  • Treatment relies on the pt’s sensation of electricity

  • If pt is confused or unreliable, other mechanisms must be used to monitor the pt’s reaction to electricity

• Over________

  • TENS & IFC may cause further damage and/or

    prolong healing time of damaged tissues

• thoracic cage area

• cranial area

• metal implants

• impaired mentation/sensation

• over damaged skin

ADVERSE EFFECT

• Burns

  • Electrical and thermal

    burn

• Blistering

  • If modalities are not applied properly

• Mild erythema

• Itching underneath the electrodes

Documentation

TENS

<mode of TENS> x <pulse frequency> x <pulse duration> x <treatment duration> using <TENS machine> over <affected area> for pain relief.

IFC

<type/mode> IFC x <base frequency> x <constant beat frequency> x <variable beat frequency, if applicable> x <chronicity> using <name of IFC machine> over <affected area> for <rationale>.

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