Strength Duration Curves Flashcards
A ____-_____ test is an electrodiagnostic technique used to identify the state of injury or recovery of a motor nerve or muscle
strength duration
SD testing = stimulation of a motor nerve with electrical pulses of varying ______ and detecting the _____ of current necessary to get a minimally palpable contraction.
duration; amplitude
Can SD testing be used for both motor and sensory nerves?
YES
When doing SD testing, you start with the (shortest/longest) pulse and progress to the (shortest/longest)
longest; shortest
An external electric charge musts reach a certain minimum value to ______ a nerve.
depolarize
______ ____ (Q) = current intensity x current duration.
phase charge
______ _____ = area under the curve
phase charge
For constant current stimulation using a _______ square wave pulse, the phase charge = mA.msec
monophasic
What are 3 important concepts for nerve depolarization in terms of estim?
- Intensity of electrical stimulus
- pulse duration of stimulus
- rise time of stimulus
The intensity of a stimulus must be sufficient to depolarize the nerve or muscle cell membrane to threshold, a change of ~ __-__ mV.
10-15
Very ___ current intensity cannot depolarize nerve, no matter how long it is applied
low
There is a _____ current intensity required to depolarize a nerve.
minimum
Pulse duration must be sufficiently long to allow _____ balance to be disturbed.
ionic
The ____ ____ must be short enough to reach critical excitation level before accommodation can occur.
rise time
We use ___ or ______ waveform in practice.
square; rectangular
_______ _____ _____ = the current intensity at a given pulse width at which a just perceptible motor contraction disappears.
minimum effective charge
______ = the minimum current needed to fire a nerve impulse at a long duration.
Rheobase
In practice, the rheobase is the minimum _____ intensity required to get a just perceptible contraction when using a pulse width greater than or equal to ___msec.
100