Physical Agents Final Review Flashcards
What is the minimum amount of electrodes you need for a closed current?
at least two
What is the positive side of an electrode
Anode
ion deficient
what is the negative side of an electrode
Cathode
ion rich
What type of current has one electrode positive as the other stays negative?
Direct
Which type of current has the electrodes swtiching between positive and negative
Alternating
Which type of current is constantly changing direction of flow?
alternating
Which type of current moves in the same direction at all times?
Direct
How many phases = a pulse in biphasic current
2 phases = 1 pulse
once the current crosses isoelectric line it becomes a new phase therefore the charges are canceled out
What type of current is high volt?
Monophasic
1 phase= 1 pulse
What is monophasic current used to treat?
can decrease edema from the build up of charge
What is the unit for how strong the current is?
amplitude
What tends to be a more comfortable frequency for the patient?
HIGHER
How do you stimulate denervated muscles?
must directly stimulate muscle because there are no nerves
What is the order of recruitment on the strength- duration curve when increasing the pulse duration?
- A beta sensory
- motor
- A delta sharp pain
- C dull pain
- denervated muscle
What is the x- axis on the curve measuring?
pulse duration
What is the y-axis on the curve measuring?
amplitude
What does accommodation do?
Prevents you from having to keep turning up the e stim in order to feel e-stim.
Make sure you stay in the correct therapeutic range.
What is propagation of an impulse along a conduction system in the SAME direction it normally travels.
Orthodromic
What is propagation of an impulse along a conduction system in the OPPOSITE direction it normally travels.
Antidromic
can occur artificially during estim
How to calculate the current density?
Current density: current ÷ size of electrode
What size electrodes does AC current use?
sAme size so they have the sAme current density
What size electrodes does DC current use?
uses Different sizes
Indications for TENS
Pain control/relief
Reduce dependency on pain medication
Increase functional movement and mobility with less discomfort
Give patient active role in pain management
Contraindications for TENS
Pacemaker
Unstable arrhythmia
Over carotid sinus, arterial/venous thrombus
Pregnancy over trunk
Precautions for TENS
Cardiac disease
Impaired sensation/mentation
Malignancy
Skin irritation/open wound
Adverse effects of TENS
Burns
Skin irritation
Pain
TENS conventional parameters
Gate-control Immediate pain relief, little residual effect No muscle contraction Frequency: 100-150 pps Pulse duration: 50-80 usec
TENS acupuncture parameters
endogenous opioids mechanism longer pain relief; 5 hours after twtich muscle contraction frequency: 2-10 pps pulse duration: 200-300 us
IFC paramters
Two medium-frequency currents interfering with each other
Difference between carrier frequencies = beat frequency
Mimic TENS modes
May be more comfortable, cover larger area → controversial evidence
Conventional or acupuncture
Criss-cross 4 electrodes
Sweep accommodation is for what type of modulation
frequency
one carrier frequency flucutaes 150 Hz
Scan accommodation is for what type of frequency
amplitude
can treat a larger tissue area
What to do if pt. is getting an inappropriate response?
- Decrease pulse duration.
- Increase frequency.
- Last resort: use reduced amplitude.
→ Will lose therapeutic effect!
indication for NMES
Produce muscle contraction
Prevent atrophy
Neuromuscular re-ed
Promote movement to decrease edema
contraindications for NMES
Pacemaker
Unstable arrhythmia
Over carotid sinus, arterial/venous thrombus
Pregnancy over trunk
precautions for NMES
Cardiac disease
Impaired sensation/mentation
Malignancy
Skin irritation/open wound
strengthening parameters for NMES
Amplitude to >10% MVC for injured tissue
Frequency: 35-80pps
Pulse duration: 150-200 (small)
200-350 (large)
On:off time: 10sec on/50sec offspasm/edema pump NMES parameters
Spasm / edema pump
Amplitude to visible tetanic contraction
Frequency: 35-50 pps
Pulse duration: 150-200 (small)
200-350 (large)
On:off time: 5sec on/5sec offindications for ionto
Alternate method of drug delivery
Unidirectional flow of ions into a site of tissue injury
contraindications for ionto
Allergy to drug Unstable arrhythmia / pacemaker Over carotid sinus Pregnancy over trunk Metallic implants
precautions for ionto
Cardiac disease
Impaired sensation/mentation
Malignancy
Skin irritation/open wound
current density parameters for ionto
Max current density
Cathode:
how is dose calculated for ionto
intensity X time
40-80 mA min
current amp for ionto
4 mA minimum
Safe amplitude: current density = current amplitude / surface of electrode
**Be able to calculate maximum safe amplitude
electrode placement for ionto
Delivery electrode over target area, dispersive electrode over remote location (generally proximal)
what does a cathode do?
Repels negative ions
Decrease edema
Sclerolytic effect: decreases protein density (repels proteins)
Decreasing protein density decreases edema
what does an anode do?
Repels positive ions
Sclerolytic effect: increases protein density (attracts proteins)
Helps build tissues
what is EMG?
Quantifies muscle tone.
Records electrical activity of muscles using surface or fine wire/needle electrodes.
During muscle contraction, record will show deviations away from straight isoelectric line.
Number and size of deviations show amount of muscle tissue that is electrically active.
Advantages of EMG
Can adjust sensitivity to detect very low levels of activity that are not palpable.
Timing of contraction and relaxation can be recorded.
Can use as biofeedback.
Provides pt’s with a way to learn how to initiate contraction or relaxation.
Small machine that provides auditory feedback.
Can differentiate between neural and biomechanical muscle tone.
what type of muscle tone is relaxed muscle demonstrates resistance to passive stretch but no electrical activity (no EMG reading).
Biomechanical
what type of muscle tone is relaxed muscle demonstrates resistance to passive stretch and electrical activity (EMG reading).
Neural
disadvantages of EMG
Measures only local area of tissue under electrodes (surface or internal).
Requires specialized equipment and training.
Not available in most clinical settings.
May need to rely on palpation skills and clinical reasoning.
What is nerve conduction velocity
Measures speed of electrical impulse through a nerve.
Can determine if there is nerve damage or destruction.
Two electrodes are placed over a nerve.
Electrodes can be surface or internal.
One electrode stimulates nerve → sends mild impulse through nerve → other electrode receives and records this impulse.
how is nerve velocity calculated?
Distance between electrodes ÷ conduction time.
what type of nerve will transmit the fastest?
a larger nerve with greater amount of myelination
what is the normal range of NCV?
50-60 m/s
what will be impeded with nerve damage?
speed and intensity of the nerve signal
conditions indicating NCV testing
Carpal Tunnel Syndrome Cubital Tunnel Syndrome Cervical or lumbar radiculopathy Chronic inflammatory polyneuropathy (d/t diabetes or alcoholism) Peripheral nerve injuries Guillain-Barre Charcot-Marie-Tooth Unexplained pain, weakness, numbness, tingling.
precautions and contraindications for NCV
Decreased skin sensation
Anti-coagulation medications
Skin conditions in area of testing Decreased cognition Pacemaker, cardiac defibrillator Fear of needles Electrodes should not be placed over the eyes (duh)
implications for PT and NCV
NCV testing rarely performed by physical therapists.
Can be board certified.
Physical therapists often not provided with NCV test results unless requested.
NCV test results can support our clinical hypothesis.
Results may or may not change our course of action.
Treat the impairments.
