4) Electric, Mechanical, and Light Therapy Flashcards
_____ can produce specific physiological events and target specific tissues
- Type of current
- Current’s parameters (intensity, phase duration, and pulse frequency)
- Electrode size and arrangement
Electrical stimulation has little, if any, direct effect on
- Cellular level inflammation response
Direct current
- Uninterrupted, one-directional flow of electrons
Continuous current flow on only one side of the baseline as the electrons travel from (direct current)
- Cathode (negative pole) to the anode (positive pole)
Example of direct current used therapeutically
- Iontophoresis
Alternating current [AC]
- Cyclically changes from positive to negative
Pulsed current
- Flow of electrons are interrupted by discrete periods of noncurrent flow
Excitable tissues
- Nerves, muscle fibers, and cell membranes
- Influenced directly by the electrical current
Electrical current prefers to follow
- The path of least resistance
- Those formed by muscle, nerves, effusion, and blood
Electrodes introduce the current to the body from the stimulator via
- The electrode leads, forming a closed circuit
As the size of the electrode increases
- Current density decreases
Electrodes are close together
- Current flows superficially, forming a relatively small number of parallel paths
Increasing the distance between electrodes
- Current can reach deeper into the tissues
Subsensory level
- Point at which the output intensity rises from zero to the point where the patient first receives a discrete electrical sensation
- This type of stimulation does not appear to cause therapeutic benefits
Sensory level
- Only depolarizes sensory nerves; this level is found by increasing the output to the point at which a slight muscle twitch is seen or felt, and then decreasing the output intensity by approximately 10%
Motor level
- An intensity that produces a visible muscle contraction without causing pain
Noxious level
- Current applied at an intensity that stimulates pain fibers
Muscle fiber level
- Stimulation is applied with a long phase duration and output intensity that directly causes muscle fibers to depolarize
Accommodation
- Nerve’s rate of depolarization decreases while the depolarization stimulus (an electrical current) remains unchanged
- Require increasingly intense stimulus throughout the treatment to reach the depolarization threshold
Habituation
- CNS process of filtering out a continuous, nonmeaningful stimulus
- Tolerance to the stimulus developed across multiple treatments
Neuromuscular re-education
- “Teaching” a muscle how to contract again
- Low-duty cycle = muscle relax and recover between contractions
- Pulse frequency must produce tetanic contraction (60 pps)
Neuromuscular re-education protocols should not be administered when
- Tendinous attachment is not secure
- Muscle cannot tolerate the tension
- Joint motion is contraindicated
When the goal is to increase the muscle’s strength
- Electrically induced muscle contractions can supplement but should not substitute for voluntary contractions
The functional load placed on the muscle must be equal to at least
- 30% to 60% of maximum voluntary isometric contraction [MVIC]