Electrode Placement and Montages Flashcards
6 cards from real EEG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Electrode Placement and Montages flashcards as text
What is the modified combinatorial nomenclature (MCN) designation for the traditional T3 electrode position?
Answer: T7
In the modified combinatorial nomenclature system, the traditional T3 position is redesignated as T7, following the logic that odd numbers indicate left hemisphere and the '7' indicates the temporal row position.
In a bipolar transverse montage, the electrode chains run in which direction?
Answer: Left to right across the head (coronal)
Bipolar transverse montages chain electrodes from left to right across the head in coronal rows, complementing the longitudinal (anterior-posterior) montage and helping lateralize epileptiform discharges.
Sphenoidal electrodes are used to improve detection of epileptiform discharges from which brain region?
Answer: Mesial temporal lobe structures
Sphenoidal electrodes are inserted near the foramen ovale to record from the inferomedial temporal region, improving detection of mesial temporal epileptiform activity that may not reach standard scalp electrodes.
The Laplacian (source derivation) montage differs from standard montages by:
Answer: Subtracting the weighted average of surrounding electrodes from each electrode, enhancing focal activity and suppressing diffuse activity
The Laplacian montage estimates the second spatial derivative of the surface potential by subtracting the weighted average of surrounding electrodes from each electrode, effectively acting as a spatial high-pass filter that enhances focal sources and suppresses widespread activity.
When measuring for electrode placement, the preauricular point is identified as:
Answer: The depression anterior to the tragus of the ear at the root of the zygoma
The preauricular point is the small depression just in front of the tragus at the root of the zygomatic arch, serving as a key landmark for measuring transverse electrode distances in the 10-20 system.
A double banana montage is another name for which standard montage?
Answer: Bipolar longitudinal (anterior-posterior) montage with temporal and parasagittal chains
The 'double banana' is the colloquial name for the standard bipolar longitudinal montage featuring two parasagittal chains and two temporal chains running anterior to posterior, resembling two banana shapes on the page.