Evoked Potentials 1 Flashcards
Electrode Impedance
Opposition to Alternating Current Flow
Desired value for electrode impedance
Must be less than 5000 Ohms
Corkscrew Electrode
Spiral - allows for greater SA - very dangerous if pulled out, can cause a gash and plastic head can leave bruising
Hook Wire Electrode
Used for facial/cranial nerve EMG monitoring - can get deeper into the muscle
Spinal Epidural Electrode “Tripolar”
Placed between the lamina and the dura, used to record evoked potentials from the spinal cord, or to stimulate the spinal cord (always placed by surgeon)
Subdural (Cortical) Grid
Made of platinum or stainless steel contacts embedded in silicone. Placed directly on the cortex for electrocorticography or cortical mapping; allows for multiple simultaneous sites. Seen in epilepsy, brain tumor surgery
Tympanic Membrane (T M) ECochGtrodes
Used for T M recordings during auditory evoked potential monitoring, placed right near ear drum, ear canal
Primary stimulus site for the median nerve
Between the tendons for the Flexor Carpi Radialis and the tendon for the Palmaris Longus
Secondary stimulus site for the median nerve
Through the medial third of the antecubital fossa (medial to the biceps)
Primary stimulus site for the ulnar nerve
Right under pisform depression
Secondary stimulus site for the ulnar nerve
Between the ulna and the medial epicondyle of the humerus
Primary stimulus site for the posterior tibial nerve
Just behind the medial malleolus of the tibia
Secondary stimulus site for the posterior tibial nerve
The knee - the popliteal fossa
Primary stimulus site for the peroneal nerve
The fibular head below the lateral knee
Monopolar probe
Single cathode tip; more sensitive; less specific
