Electrical Stimulation Flashcards
Ampere
-rate of current flow
Current
-net mmt of electrons
-high to low
-can be increased by increasing pulse duration and frequency
Voltage
-force of current flow
Good Conductors
-nerve
-muscle
-blood**
Resistance/Impedance
-opposition to electron flow
-skin and fat are highest
-increases as electrode disease increases
-decreases as frequency increases
Ohm’s Law
I= V/R
-more resistance=less current
Good Insulators
-skin
-fat
-bone
-nerve sheath
-tendon
Current Flow: Skin
-insulator
-need more voltage to penetrate skin and layers
Current Flow: Fat
-insulator
-most resistance
Current Flow: Nerve
-conductor
-6x better than muscle, but surrunded by fat and sheath (insulator)
Current Flow: Blood
-best electrical conductor
Current Flow: Tendon
-poor conductor
-most resistance
Current Flow: Muscle
-good conductor
Current Flow: Bone
-Poorest conductor
-most resistance
Frequency vs Impedence
-increased frequencies decreases impedence
Biphasic/Alternating
-goes positive and negative
-pain relieving
-continous flow, changing directions
-no chemical reactions
ex: TENS, IFC
Monophasic/Direct Current
-uninterupted flow of electrons toward positive pole
-can be reversed
-chemical changes: electrolysis
-muscle contraction when meeting threshold
Ex: ionto
Pulsatile
-2+ pulses grouped together
-discontinuous
-most nerve/muscle stimulation
ex: Russian and High Volt
Accommodation Phenomenon
-a fiber subjected to constant depolarization will become unexcitable at the same intensity
Frequency
-cycles per second Hz
-can determine the type of muscle contraction elicited
-Tetany: 50Hz
Intensity
-amplitude/volatge/intensity
-increasing the stimulation or amplitude to reach deeper tissues, more nerves, stronger contraction
-knob on top
Pulse Duration
-pulse width
-targets specific structures
Capacitance
-ability of a tissue to store electricity
-higher capacitance= more time before a response
-capacitance can be reduced by increasing frequency
-larger diameter= smaller capacitance
Muscle: most
Nerve: least
Pulses
-individual waveforms
-monophasic current
Symmetric, asymmetric, balanced, unbalanced
Cycle: biphasic
Pulse Rise
-how quickly the pulse reaches max
-can be adjucted by ramp-up time
Slow: more comfortable, wont decrease impedance, more voltge needed
High: lowers skin impedence, less voltage needed
Duty Cycle
-on off ratio
-stimulation: break for (ms or s)
-1:7= no fatigue
-1:5= less fatigue
-1:1= repid fatigue
Cathode
-negative
-site of depolarization
-most electrons
-usually black
-where muscle contraction happens
IONTO
-alkaline effects
-repels neg/attrac pos
Anode
-positive
-least electrons
-usually red
IONTO:
-repel pos/ attract neg
-acidic effects
Electrodes
Spaced together: superficial
Spaced far: deeper
Larger: decreased current, dispersive
Smaller: higher current, motor point
Placement:
-1.5 away from each other
-parallel to fibers
Monopolar: different sizes
Bipolar: same size electrodes
Quadripolar: 2 sets of bipolarr
Alpha Beta Nerve
-sensory nerves
-100usec chronaxie
-tingling sensation
-TENS, IFC
-largest diameter
Motor Nerve
-contraction and tingling
-200-250usec chronaxie
-TENS, Russian, NMES
Alpha Delta Nerve
-sharp pain
-300-700usec chronaxie
-noxious paresthesias, strong muscle contraction
-TENS
C FIbers
-dull pain
-noxious paresthesias, strong muscle contraction
-1.0msec
Denervated Muscle
-thinnest
-minimizes atrophy and edema
-10msec
Electrical Current Effects: Cellular Level
-excitation
-change in permeability
-protein syn.
-stimulation of fibroblasts and osteoblasts
-microcirculation
Electrical Current Effects: Tissue Level
-contraction
-regeneration
Electrical Current Effects: Segmental Level
-joint mobility
-circulation/lymphatics
-microvasculation circulattioon
Electrical Current Effects: Systemic Effects
-analgestic effects as endogenous pain suppressors
-analgestic effects as stimulation of neurotransmitters
Neuro Muscular Electrical Stimulation (functional electric stimulator)
-NMES/FES
Russian Currents
-muscle strengthening*
-muscle re-education*
-increasing ROM
-Slow atrophy
-Edema control (via muscle)
-2,000-10,00z frequency
-burst mode
-fast oscillating AC current, burst
Interferential Currents
-IFC
-pain control*
-muscle stimulation
-2 bipolar configurations (relief where they cross)
-4000-4100Hz frequencies
-120usec pulse width
Sweep Mode: frequencies modulated to avoid accommodation
Scan Mode: amplitude can be modulated
-for poorly localized pain
Target Mode: move with finger
High-Volt Pulsed Current
-HVPC
-reducing edema
-muscle pump 1:1
-wound healing
-twin peaked monophasic
-unequal electrodes, small over treatment
Transcutaneous Electrical Nerve Stimulation: Conventional
-TENS
-acute pain relief; surgical, labor*
-gate control theory; A-Beta*
-asymmetric biphasic
-tingle with no contraction*
Settings:
-75-150msec Duration/Width
-80-125pps Frequency
-continuous*
- Starting: 100p/100f*
-30mins, til pain is gone*
Iontophoresis
-low volt, continuous direct current
-drive ions into body
-medicine
-less than 30min on big machines
-longer with home devices
Doses:
-40mA-min= 4.0 current x 10min
-40mA-min= 2.0 current x 20min
Meds:
-Acetate, -, calcium depositis
-Dexamethasone, -, tendonitis/bursitis
-Lidocaine, +, trigeminal neuralgia
Voluntary vs. Electrical Motor Stimulation
Voluntary:
-Type 1 fibers
-asynchronous
-GTO protection
-slow fatigue
Electric:
-type 2 fibers
-synchronous
-no GTO protection
-fast fatigue
Motor Point
-part in muscle where lowest threshold is
-best for contraction
-mid muscle belly
-where nerve meets muscle
Wound Care
HVPC:
-promotes faster healing
-Negative Polarity: inflammatory phase of healing
-Positive Polarity:
proliferattion phase of healing (bacterial)
Transcutaneous Electrical Nerve Stimulation: Low-Frequency/Acupuncture/Motor-Level
-TENS
-chronic pain relief*
-Descending Pain control theory: modulation; enkephalin*
-asymmetric biphasic
-tingle AND contraction*
Settings:
-100-600msec Duration/Width
-<20pps Frequency
-Duty cycle: 30-60s*
- Starting: 180p/18f*
-15-60min*
-over motor point
Gate Control Theory
-increase A-Beta afferents triggers release of enkephalin to inhibit 2nd order neuron to block pain
Descending Pain Control: Modulation
-activate opiate receptors in PNS of nociceptive afferent fibers
Transcutaneous Electrical Nerve Stimulation: Noxious- Level
-TENS
-hyperstimulation analgesia
-chronic pain relief*
-Endogenous opiate pain control theory*
-asymmetric biphasic
-high intensity to noxious level; muscle contraction acceptable*
Settings:
-100-1000msec Duration/Width
-1-5pps Frequency
-Duty cycle: 30-45s
- Starting: 250p/2f*
-15-60min*
-over trigger point, until pain is no longer percieved
Endogenous Opiate Pain Control Theory
-peripheral blockage and extrasegmental analgesia
-stimulation of small afferents to release endorphins
Transcutaneous Electrical Nerve Stimulation: Brief Intense
-TENS
-fast pain relief during procedure*
-Descending: peripheral and central anagelsia theory*
-asymmetric biphasic
-muscle fasciculation to sustain contraction*
Settings:
-100-600msec Duration/Width
-100 pps Frequency
-Duty cycle: 30-45s
- Starting: 250p/100f*
-15min*
-around wound
Descending Pain Control: Peripheral and Central Analgesia
-serotonergic efferents from thalamus to activate enkephalin interneurons
Premodulated (Bipolar)
-2 currents switch within the device
-only 2 electrodes
-pain control
-muscle stimulation/reeducation
-slow atrophy
-2 bipolar configurations (relief where they cross)
-duty 10:10, ramp 1-2s, 10-20min
-200-400usec pulse width
E-stim Indications
-pain
-contraction
-muscle reeducation
-slow atrophy
-strengthening
-increasing ROM
-decrease edema
-decrease spasms
-healing
-regenerate tissues
-stimulate PNS
-protein synthesis
E-Stim Contraindications
-pacemaker/defib
-internal stimulators
-chest or heart area
-carotid
-thrombosis/vascular or arterial disease
-confusion
-seizure
-infection
-open wounds (unless treatin)
-cancer
-pregnancy
-high level SCI
Muscle Re-education
-Russian, NMES
-following surgery
-CNS inhibition of muscle
-improve motor control
-200-600 usec/ 35-55 pulse
-15min
-Duty 1:1
Muscle Pump Contractions
-HVPC, Russian, NMES
-increase circulation
-mimic normal contractions
-200-600usec/ 35-55 pulse
-comfortable muscle contraction
-20-30min
-duty 1:1
-elevatte the body part (can use AROM)
Edema Control
-HVPC
-elevate extremity*
-space electrodes far apart*
-negative polarity distal to swelling*
-driving forve to move plasma away
-30min
-best results immediately after injury
-80-120Hz/ low frequency*
-intensity as needed >60*
Muscle Strengthening
-Russian, NMES
-200-600usec/ 50-85pps
-gradual ramp
-duty 1:5
-to muscle fatigue 60% MVIC
-pt working with estim
Increasing ROM
-Russian, NMES
-200-600usec/ 35-55pps
-strong contraction
-interrupted current with gradual ramp
-antagonist muscles to joint contracture
-90min
-duty 1:1
-pt passive
Denervated Muscle
-lost peripheral nerve supply
-if reinnervation doesnt occur in 2 years connective tive replaces contractile elements so recovery not possible
-1st week <1ms duration
-2 weeks >10ms duration
-NMES
Slow Muscle Atrophy
-Russian, MNES, HVPC
-200-600usec/ 50-86pps
-15-20mins
-duty 1:5
-to muscle fatigue
-pt working with estim
IONTO Indications
-analgesia
-bone spurs
-ulcers
-edema reduction
-fungal infections
-sweating
-muscle spasms
-tendonitis
IONTO Contraindications
-estim rules
-impaired skin sensation
-allergy
-recent scar
-broken skin
-metal
