Electrotherapy Basics Quiz

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Questions and Answers

What is the primary objective of electrical stimulation in therapy?

To activate skeletal muscle and improve movement (correct)

To increase metabolic rate significantly

To eliminate all body pain

To replace medications for chronic pain

Which type of current is commonly used in electrotherapeutics?

Pulsed current (correct)

Continuous current

Alternating current

Direct current

Which unit is most commonly used in therapeutic applications to measure current?

Kilowatts

Milliamperes (correct)

Volts

Microvolts

What is electrical stimulation primarily applied through?

Surface, transcutaneous electrodes Signup and view all the answers

What is the movement of ions or electrons in a conductor called?

Electrical current Signup and view all the answers

Which of the following characteristics of electrical stimulation does NOT affect its therapeutic effects?

Color of the electrodes Signup and view all the answers

What is the primary effect of electrical stimulation on tissue?

Increased cell activity and repair Signup and view all the answers

What should a clinician understand before applying electrotherapy?

Fundamental principles of electricity Signup and view all the answers

What characterizes pulsed current (PC) in relation to the other types of electrical current?

It is a third major class among electrical currents. Signup and view all the answers

Which parameter describes the characteristics of current in the horizontal axis of a waveform?

Time or duration Signup and view all the answers

What is the frequency range for low frequency currents?

1-1000 Hz Signup and view all the answers

In which situation would you typically use direct current (DC)?

Wound care and iontophoresis Signup and view all the answers

What does the term frequency describe in relation to alternating current (AC)?

The rate at which AC switches direction Signup and view all the answers

Which current type is characterized by a frequency of 1 kHz?

Medium Frequency Current Signup and view all the answers

Which of the following best defines interrupted DC?

Flow that ceases before resuming in the same direction Signup and view all the answers

What defines a burst in electrical currents?

Two or more consecutive pulses separated from another series Signup and view all the answers

What is the key difference between reversed DC and interrupted reversed DC?

Interrupted reversed DC involves a combination of flows ceasing and changing direction. Signup and view all the answers

Which of the following is an example of high frequency currents?

Short wave current Signup and view all the answers

How does direct current (DC) differ from alternating current (AC) concerning the direction of flow?

DC is a unidirectional flow, while AC is bidirectional. Signup and view all the answers

What is the relationship between frequency and pulse duration in electrical currents?

Inverse relation Signup and view all the answers

Which current waveform characteristic allows direct current to be referred to as galvanic current?

It is uninterrupted and unidirectional. Signup and view all the answers

What type of current is characterized by its flow stopping periodically before the next electrical event?

Pulsed Current (PC) Signup and view all the answers

What is the term used to describe the period of time when no current flows between pulses in pulsed current?

Interpulse Interval Signup and view all the answers

Which of the following best describes a monophasic pulsed current?

Current that flows in only one direction during a pulse Signup and view all the answers

Which waveform is characterized by a rapid instantaneous rise, prolonged duration, and a sharp drop-off?

Rectangular (Square) Wave Signup and view all the answers

In which pulsed current type does the waveform allow for current to flow back and forth during a pulse?

Biphasic Current Signup and view all the answers

Which shape of the waveform is most likely to provide equal energy levels under both positive and negative phases?

Sine Wave Signup and view all the answers

What is a characteristic feature of twin-spiked forms of waveforms?

They allow for greater penetration due to very short pulse width. Signup and view all the answers

How often must alternating current change direction in a second?

At least one time Signup and view all the answers

What characterizes a monophasic pulsed current?

It deviates from the isoelectric line in only one direction. Signup and view all the answers

Which of the following best defines pulse duration?

The total time from the beginning to the end of a single pulse. Signup and view all the answers

What is the key difference between monophasic and biphasic pulsed current?

Monophasic currents induce chemical changes while biphasic do not. Signup and view all the answers

How is phase charge defined within a pulsed current?

Charge within one phase of a pulse. Signup and view all the answers

What describes the interpulse interval in pulsed current?

Time between consecutive pulses. Signup and view all the answers

What is true about the relationship between phase charge and pulse charge in monophasic current?

They are always identical and interchangeable. Signup and view all the answers

Which of the following statements is accurate concerning chemical effects from monophasic currents?

They only occur when the stimulus is continuous for a certain time. Signup and view all the answers

What is meant by the term 'interphase interval' in pulsed current?

Time between the two phases within a single pulse. Signup and view all the answers

What characterizes symmetrical biphasic waveforms?

The phases have identical current amplitude and duration. Signup and view all the answers

What determines if a biphasic waveform is classified as balanced?

The area under the curve of both phases is equal. Signup and view all the answers

In which scenario would a biphasic waveform be termed unbalanced?

The area under the curve of one phase is greater than the other. Signup and view all the answers

What is the primary measurement unit for amplitude in electrical stimulation (ES) applications?

Milliamps Signup and view all the answers

When does a symmetrical biphasic waveform not require specific lead wire designation for electrode polarity?

When it is balanced. Signup and view all the answers

What does frequency in the context of electrical stimulation refer to?

The number of pulses per second. Signup and view all the answers

What defines peak amplitude in a monophasic pulse?

The highest current or voltage reached in a phase. Signup and view all the answers

Which statement is incorrect regarding the classification of biphasic waveforms?

Symmetrical waveforms require unequal area under the curve. Signup and view all the answers

Study Notes

Electrotherapy II - 1st Lecture

The lecture covers an introduction to electrical stimulation and electrical currents.
The instructor is Dr. Ahmed aboulfotouh.

Objectives

Define electrical stimulation and electric current.
Differentiate between alternating, direct, and pulsed currents.
Categorize various waveforms and pulse characteristics.
Identify the different parameters of electrical stimulation.

Introduction

Electrical stimulation (ES) is the application of electrical currents to elicit or facilitate a therapeutic response.
Common uses of ES include activating skeletal muscles for strengthening or improving movement, decreasing pain, and facilitating tissue healing.
These effects are based on stimulating tissues using applied electric currents.

Electrical Stimulation: How?

Electrical stimulation can be delivered by implanted or external stimulators using electrodes.
In physiotherapy, external stimulators, using external, surface, or transcutaneous electrodes, are commonly used to deliver electrical currents.

Basics of Electricity

Discussing electrotherapy applications without understanding fundamental electricity is like playing a game without knowing the rules.
Functional electrotherapy understanding must begin with the basics.

Electrical Current

Electrical current is the movement of ions or electrons in a conductor in response to a voltage force.
The flow of current is directly proportional to the voltage.
The standard unit for current is the ampere (amp or A); however, milliamperes (mA) and microamperes are often used in therapeutic applications.

Types of Currents and Waveforms

Main types of electrical currents are direct current (DC), alternating current (AC), and pulsed current (PC).
In electrotherapy, pulsed current is the most common type.
This classification considers the flow as: Direct (DC); Alternating (AC); and Pulsed (PC).

The Waveform

A waveform is a visual representation of current characteristics, showing shape, magnitude, and duration.
All currents have parameters in the vertical (y-axis) and horizontal (x-axis) directions.
Horizontal axis parameters describe and quantify duration (milli- or microseconds); vertical axis parameters describe and quantify magnitude/intensity (milli- or microamps or milli- or microvolts).

Waveforms (Examples)

Examples of waveforms include square, rectangular, and triangular waveforms.

1- Direct Current (DC)

DC is a continuous, unidirectional flow of ions or electrons for at least 1 second.
By convention, upward deviations from the isoelectric baseline indicate positive current flow and vice versa.
Common clinical uses of DC include iontophoresis and wound care.
DC is also known as galvanic current.

Forms of DC

Variations of DC exist, but variations must remain unidirectional and uninterrupted for a period of time.
Common forms of DC include interrupted DC, reversed DC, and interrupted reversed DC.

2- Alternating Current (AC)

AC is an uninterrupted, bidirectional flow of ions or electrons that changes direction at least once per second.
The frequency of the direction changes is measured in hertz (Hz), or cycles per second.
AC is the most common electricity type in homes.

3- Pulsed Current (PC)

PC (or pulsatile current) is the unidirectional or bidirectional flow of ions or electrons that periodically ceases for a set period before the next electrical event.
A pulse is an isolated electrical event separated from the next by an interpulse interval.

Shapes of Pulse

Pulses can be square, rectangular, or triangular in shape.

Electrical Current Parameters

Current characteristics are described by: waveform, pulse and phase, pulse duration, amplitude, and frequency.

Wave Forms

Various waveform types exist (sine, rectangular (square), spike, combined, and twin-spiked).

Pulse and Phase

Pulsed current flows in a series of pulses separated by interpulse intervals.
A pulse is an isolated electrical event.
Current flow during a pulse can be monophasic (single direction) or biphasic (back and forth).

Monophasic or Biphasic

Monophasic pulses deviate from the isoelectric line in a single direction.
Biphasic pulses deviate in both directions.

Difference between Monophasic and Biphasic

Monophasic current effects primarily occur with continuous stimulation over a period of time.
Biphasic current does not usually lead to polarity effects.

Pulse Duration & Phase Duration

Pulse duration is the total time for a pulse, including the interphase interval.
Phase duration is the time from the beginning to the end of a single phase.
The interphase interval is between phases within a pulse, while the interpulse interval is between successive pulses.
Duration is commonly measured in milliseconds (msec) or microseconds (µsec).

Phase and Pulse Charge

Phase charge is the charge within a phase of a pulse, while pulse charge is the cumulative charge in a single pulse.
In monophasic pulses, phase charge and pulse charge are the same.
The total charge greatly affects the electrophysiological effects.

Symmetrical & Asymmetrical Waveforms

Symmetrical waveforms have identical characteristics in both phases, while asymmetrical waveforms have different characteristics in each phase.

Balanced & Unbalanced

Balanced biphasic (symmetrical) waveforms have equal charge in each phase. Unequal charge signals unbalanced waveforms.

Amplitude

Amplitude measures the magnitude of current or voltage concerning the isoelectric or baseline, typically reported in milliamperes (mA) or microamperes (µA).
Peak amplitude refers to the highest voltage during any phase of either a monophasic or biphasic waveform.

Frequency

Frequency is the number of pulses per second.
Measured in hertz (Hz), it describes the rate at which an alternating current (AC) switches its direction. Pulses per second also describe frequency in pulsed current.
Inverse relationship exists between frequency and pulse duration.

Frequency (Types)

Low frequency currents stimulate nerves (1-1000 Hz).
Medium frequency currents stimulate nerves after modulation (1 kHz range).
High-frequency currents have no effect on nerves (above 1 MHz).

Burst

A burst is a series of consecutive pulses separated by an interburst interval.
Burst frequency refers to the frequency at which bursts are generated.
The underlying waveform frequency within a burst is the carrier frequency.

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Description

Test your knowledge on the principles of electrotherapy with this quiz. Explore the types of electrical currents used in therapeutic applications and the effects of electrical stimulation on tissue. Ideal for students and practitioners in physical therapy and rehabilitation.