Electronotes
Electronotes
Electronotes
Basics
current density inversely proportional to electrode size longitudinal placement (parallel to mm fibers) is 4x more effective than transverse placement (perpendicular to mm fibers) constant voltage is safer, but constant current is more consistent and preferred because current is responsible for physiological changes motor point moves proximally for denervated muscles
Types of Current
Direct Current (DC)
"Galvanic current"
continuous flow in one direction for at least 1 sec iontophoresis, wound healing, stimulation of denervated muscle
Types
"Faradic current"
Continuous flow in alternating directions stimulating inervated muscle, soft and osseous tissue regeneration, pain management
Types
Waveforms
pulse isolated electrical event separated by time o finite time of charge movement periodic interruptions in current flow most common
o
Types
Characteristics of AC/PC
Qualitative o waveform; visual representation on a graph o number of phases current flow in one direction for a finite period o symmetry symmetrical: same shape and charge asymmetrical: different shape balanced: same charge (safer) unbalanced: different change development of net charge
Quantitative
amplitude-dependent peak amplitude peak-to-peak amplitude (highest (+) and lowest (-)) root mean square (RMS) effective current shape-dependent average current shape dependent
time-dependent
phase duration pulse width time from start to end of a phase pulse duration interphase/intrapulse interval interpulse interval rise time (0-peak) decay time (peak-0) on/off time duty cycle (on time:off time) period (time from one refernce point to the next) frequency/pulse rate period and frequency are inversely proportional phase charge pulse charge
Current Modulation
ramp up/down time refers to the entire duration of treatment; rise/decay time is for each individual pulse
Techniques
Monopolar
one active ("treatment" or "stimulating") electrode on target area larger, non-treatment ("return" or "dispersive") electrode in another area dermal ulcers, wound healing, edema, iontophoresis, stimulation of smaller mm (eg. facial mm)
Bipolar
both electrodes on target area mm disuse atrophy, neuromuscular facilitation, ROM limitation, protective mm spasm, most circulatory disorders
Electrodes
Anode (+)
attracts anions, repels cations acidic (HCl formation) proteins solidify; tissues harden hyperpolarization; sedative few, large O2 bubbles red
Cathode (-)
attracts cations, repels anions alkaline (NaOH formation) proteins liquefy; tissues soften depolarization; stimulant many small H bubbles black