Questions and Answers
What is the term used to describe a wide range of treatments and interventions in physical therapy?
Therapeutic modalities
Which of the following represents the use of physical energies such as thermal, mechanical, electromagnetic, or light?
Direct current (DC) is an interrupted and bidirectional flow of charged particles.
False
What is the unit of electric current?
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The pole or electrode with net negativity is termed the ______.
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Which current is defined as the uninterrupted bidirectional flow of ions or electrons?
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What is the driving force that moves electrons in electrical systems?
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Ohm's law states that current is inversely proportional to voltage.
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Which of the following is NOT a type of electrical current?
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What term describes the amount of electrical energy delivered to the tissue with each phase of each pulse?
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The rate at which alternating current switches direction is termed ______.
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What is the difference between monopolar and bipolar electrode techniques?
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What is the purpose of a dispersive electrode in monopolar application?
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In bipolar techniques, both electrodes should be placed over motor points within the same muscle group.
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What are the physiological effects of electrical stimulation?
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Which of the following is NOT a precaution for using electrical stimulation?
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Match the electrode types with their descriptions:
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The _____ response to electrical current improves cell function.
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What should be done if the skin is observed to be damaged before applying electrodes?
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It is safe to apply electrical stimulation over the carotid sinus.
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Study Notes
Introduction to Electrophysical Agents
- Electrophysical agents, or biophysical agents, encompass a variety of therapeutic modalities in physical therapy.
- Physical agents leverage energies like thermal, mechanical, and electromagnetic for therapeutic benefits.
- Critical to effective treatment are optimal doses and procedures, akin to pharmacological prescriptions.
- In 2014, APTA introduced "biophysical agents" as a collective term for physical modalities.
Basic Principles of Electrical Stimulation
- Electric current (I) is measured in Amperes and represents the movement of charged particles.
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Types of Electricity:
- Static Electricity: Charges do not flow.
- Current Electricity: Flow occurs when there’s a potential difference and a conductive path.
- Two poles in electricity:
- Cathode: Negative pole with high electron concentration.
- Anode: Positive pole with low electron concentration.
Types of Electric Currents
- Direct Current (DC): Unidirectional flow of charged particles for at least 1 second; used in Iontophoresis.
- Alternating Current (AC): Bidirectional flow, changing direction at least once per second; used in Interferential current.
- Pulsed Current: Can be unidirectional or bidirectional, with intermittent flow; used in Russian current, interrupted DC, TENS.
Key Electrical Concepts
- Charge: Basic property of electromagnetic force; can be positive or negative and is measured in coulombs (C).
- Voltage: Represents the driving force moving electrons and is measured in volts (V).
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Conductors vs. Insulators:
- Conductors: Materials allowing free movement of charges (e.g., muscle, water).
- Insulators: Restrict movement of charged particles (e.g., rubber, plastic).
Ohm’s Law and Resistance
- Ohm’s Law: I = V/R, where current is proportional to voltage and inversely proportional to resistance (R).
- Factors affecting resistance include:
- Material composition and water content.
- Length and cross-sectional area of the conductive path.
- Temperature, which inversely affects skin resistance.
- Injury and disease increase impedance.
Waveform Characteristics
- Waveform shape represents the pulse's amplitude and duration.
- Symmetrical biphasic waveforms are often most comfortable; asymmetrical may benefit small muscles.
- Amplitude: Determines stimulation strength; higher amplitudes penetrate deeper tissue.
- Phase/Pulse Duration: Refers to the length of the electrical stimulus.
Strength-Duration Curve (SDC)
- Rheobase: Minimum current amplitude for excitation with an infinite stimulus duration.
- Chronaxie: Pulse duration required at double the rheobase for excitation.
- Levels of response:
- Subsensory: No activation.
- Sensory: Tingling sensations.
- Motor: Muscle contractions; activation of A-alpha fibers.
- Noxious: Uncomfortable sensations; activation of A-delta and C fibers.
Current Modulation Techniques
- Modulation reduces accommodation, a phenomenon where nerve cells do not generate action potentials despite stimulation.
- Types of modulation include amplitude, duration, frequency, and surged modulations.
Types of Current Modulation
- Burst Modulation: Involves consecutive pulses, separated to enhance treatment effects.
Application Techniques & Electrode Configurations
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Electrode Types:
- Metal Plate Electrodes.
- Carbon-Impregnated Rubber Electrodes.
- Self-Adhering Electrodes.
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Application Techniques:
- Monopolar: One active and one dispersive electrode; focuses current delivery.
- Bipolar: Two equal-sized electrodes within the treatment area, providing equal stimulation.
- Quadripolar: Two channels with two electrodes each, allows for intersecting currents enhancing effects.### Electrical Stimulation Configurations
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Various quadripolar configurations include parallel placements (e.g., TENS) and agonist-antagonist placements in NMES.
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Current volume in tissues is influenced by the distance between electrodes and their size.
Effects of Electric Current on Tissues
- Direct effects occur along current flow lines, while indirect effects stimulate physiological events remotely.
- Tissues are categorized into excitable (nerves and muscles) and non-excitable.
- Excitable tissues respond directly to current, while non-excitable may be influenced by electrical fields.
Responses of Excitable Tissues
- Stimulation of sensory nerves provides sensation modulation for pain relief.
- Stimulation of motor nerves induces muscle contractions.
- Stimulation of autonomic nerves alters blood flow.
- Direct stimulation of denervated muscle results in contraction.
Responses of Non-Excitable Tissues
- Electric current improves cell function and stimulates extracellular protein synthesis.
- Increased release of cellular secretions is observed.
- Gap junctions allow communication between neighboring cells, coordinating responses to extracellular messages.
Physiological Effects of Electrical Stimulation
- Induces muscle contraction and modulates pain.
- Enhances blood flow and reduces edema.
- Alters ionic distribution and promotes tissue repair.
General Therapeutic Uses of Electricity
- Controls pain (acute and chronic), strengthens muscles, reduces edema and muscle spasms.
- Minimizes joint contractures and disuse atrophy, facilitates healing processes.
Precautions for Electrical Stimulation
- Avoid in patients with unstable fractures, cognitive impairments, documented history of neurological conditions, recent surgeries, and open skin.
Contraindications
- Do not apply over certain areas during pregnancy (abdominal, lumbar, pelvic).
- Avoid regions over the carotid sinus, larynx, pharynx, and in proximity to pacemakers or cancerous lesions.
- Contraindicated in cases of arterial disease, DVT, and infectious conditions.
Clinical Decision-Making for Electrotherapy
- Define clinical goals and assess patient appropriateness for electrotherapeutic agents.
- Identify suitable electrotherapeutic agents aligned with goals.
- Evaluate equipment availability, waveform parameters, electrode configurations, and adjust treatment plans as needed.
Documentation Tips for Electrical Stimulation
- Record selected waveform (e.g., symmetrical biphasic square) and specific parameters (pulse duration, frequency).
- Document electrode type, placement, skin integrity before and after treatment, patient positioning, dosage, and treatment duration.
Safe Application of Electrical Stimulation
- Use electrodes recommended by the manufacturer, ensuring high quality and uniform conductivity.
- Choose appropriately sized electrodes for the target muscle to enhance comfort and efficacy.
- Inspect and prepare skin properly before application to avoid complications.
- Place electrodes at least one inch apart for uniform current distribution.
- Remove electrodes gently and store them properly to maintain integrity.
- Check skin for redness or burns post-treatment for safety monitoring.
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Description
This quiz covers the fundamental concepts of electrophysical agents used in physical therapy, including types of electricity and their therapeutic applications. Learn about the principles of electrical stimulation and the significance of optimizing treatment procedures. Perfect for students and professionals in the field of physical therapy.
