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51 Cards in this Set
- Front
- Back
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What is rheobase?
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The minimum current amplitude with a long pulse duration required to produce an action potential.
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What is chronaxie?
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The minimum time it takes to stimulate the tissue at twice the rheobase
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What limits movement of charged particles?
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Insulator
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What are substances that readily allow the movement of charged particles?
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Conductor
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What is the time period when current is flowing in any direction?
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Pulse
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What is a positive or negative charge of an electrode?
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Polarity
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What is propagation?
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Adjacent nerve membrane is also depolarized, and conducts along the nerve
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What is the purpose of interferential and premodulated current?
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Interfere and produce higher amplitude
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Which type of ES is specifically used for pain modulation?
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TENS
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In AC, as frequency increases, phase duration ______.
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Decreases
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What is direct current used for?
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Iontophoresis
Denervated muscle Some wound healing |
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What is a current that produces a higher amplitude pulse of beats and causes an interference?
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IFC
Premod |
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Does premod use 2 or 4 electrodes?
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2
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What type of current is used for healing or acute edema?
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Monophasic
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When is asymmetrical biphasic current more comfortable? Symmetrical
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Asymmetrical biphasic more comfortable when used to contract small muscle groups.
Symmetrical biphasic more comfortable with larger muscle groups |
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What is the purpose of using amplitude, frequency, and duration modulation?
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To not allow the body to adapt to the current
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What is the purpose of ES?
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Electrical Stimulation causes the nerve membranes to depolarize and propagate an action potential along the nerve.
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Is the inside or outside of the cell more negative?
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Inside
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According to the strength duration curve, what is the order in which nerves are depolarized?
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Alpha-beta sensory
Motor Alpha-delta sharp pain C Dull pain Denervated muscle |
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What type of stimulation is used to depolarize sensory nerves?
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Lower amplitude
Shorter pulse duration |
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What type of stimulation is used to depolarize motor nerves?
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Higher amplitude
Longer pulse duration |
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Denervated muscles using takes __ ms pulse.
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>10
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What are characteristics of NMES?
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Denervated muscle
>10 ms Muscle membrane has to be stimulated, not nerve Denervated muscle membrane does not accommodate Accommodation vs. adaptation Transient increase in nerve excitation threshold vs. Decrease in frequency of AP’s—from no change in parameters |
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What is the ionic effects of ES?
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If a net charge is left in tissues
+ to – attraction, and – to + Repel ionized drugs |
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What are the 2 mechanisms by which muscle strengthening can occur?
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Specificity
Overload |
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What are characteristics of specificity?
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Type II muscle recruited first, then type I = greater muscle force contraction.
ES: stimulates larger diameter axons first, then smaller later = recruitment of type II muscle. Type II fibers atrophy rapidly with disuse, so ES may be beneficial with disuse atrophy. Type II muscle is quickly fatiguing, so more rest between contractions is necessary. |
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What are characteristics of the overload principle?
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Must get strong contraction
Increase in total amount of current gives greater contraction Limited by patient tolerance and fatigue Minimum of 50% MVC—more is better |
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What are physiological versus electrical generation of action potentials?
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1. Order of muscle fiber recruitment:
type II muscle recruited first, then type I = greater muscle force contraction. 2. Smoothness of muscle contraction onset Physiological: gradual recruitment of motor units and asynchronous recruitment ES: rapid and jerky recruitment = all motor units of a given size fire simultaneously 3. Less obvious movement of ions in the tissues with ES |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for muscle strengthening?
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Frequency: 35-80 pps
Duration: 150-200 microsec (small muscles), 200-350 (large muscles) Amplitude: To >10% MVIC in injured, >50% MVIC in uninjured |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for pain control in order to have gating at the spinal cord?
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Frequency: 100-150
Duration: 50-80 microsec Amplitude: To produce tingling |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for pain control in order to have endorphin release?
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Frequency: 2-10 pps
Duration: 200-300 microsec Amplitude: To visible contraction |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for tissue healing during inflammatory phase?
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Waveform: HVPC
Polarity: Negative Frequency: 60-125 pps Amplitude: To produce comfortable tingling |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for tissue healing during proliferation?
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Waveform: HVPC
Polarity: Positive Frequency: 60-125 pps Amplitude: To produce comfortable tingling |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for edema control associated with inflammation?
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Waveform: HVPC
Polarity: Negative Frequency: 100-120 pps Amplitude: To produce comfortable tingling |
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What are the parameters you should use (frequency/rate, duration/width, amplitude) for edema control associated with lack of ROM?
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Waveform: HVPC
Polarity: NA Frequency: 30-50 pps Amplitude: To visible contraction |
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For muscle strengthening, which ES may produce greater and faster strength gains?
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Russian
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_______ pulse durations are more comfortable when stimulating smaller muscles with _______ pulse duration are more comfortable when stimulating large muscles
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Shorter
Longer |
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Why do we go up to 30-80 pps during ES?
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So we can get a tetanic contraction
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What affects gate control the most?
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High rate
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What process attracts neutrophils, macrophages, lymphocytes, fibroblasts (can also enhance fibroblast replication)?
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Galvanotaxis
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During tissue healing, which electrode is used during inflammation? Proliferation?
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Inflammation: negative
Proliferation: positive |
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During tissue healing, where are the electrodes placed?
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In or around wound
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What is the relationship between the negative polarity and edema?
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Negative polarity retards edema formation, but does not rid it of edema once formed (non-motor
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What are main points to edema control?
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Motor level ES to move fluids
Apply to muscles around the main draining veins Elevate legs for best response |
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What is the main theory behind iontophoresis?
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Initially thought to repel ionized medications in to the tissue, now thought to decrease dermal resistance at stratum corneum
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What is the recommended current for iontophoresis treatment?
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40 mA-min
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When setting up iontophoresis, what is important to consider?
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Set the amplitude to patient comfort, then adjust time to accomplish 40 or 80 mA-min
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What is the use of reverse iontophoresis?
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Used to measure blood sugar levels
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What are contraindications for electrical currents?
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Demand cardiac pacemaker or unstable arrhythmias
Placement of electrodes over carotid sinus Areas where venous or arterial thrombosis or thromboflebitis is present Pregnancy-- over or around the abdomen or low back |
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What are precautions for the use of electrical currents?
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Cardiac disease
Patients with impaired mentation or in areas with impaired sensation Malignant tumors Areas of skin irritation or open wounds Iontophoresis after other physical agents |
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What are adverse affects of electrical currents?
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Burns
Allergy to electrode Painful stimulation Fear of electricity |
