Random Questions Flashcards
Adequate number of electrodes are essential to ensure?
To ensure the eeg activity having a small area of representation is recorded & To analyze accurately the distribution of more diffuse activity.
A small number of electrodes (<16) is appropriate for normal EEG recordings. True or False
False
Why? 21 electrodes covers the surface area, 16 channels.
(19 plus ground and reference totals 21 electrodes).
Ground electrodes in EEG in digital EEG devices serve as a safety hazard just as were earth grounds in early analog EEG devices?
False : Ground electrode is earth ground is built in amplifiers works different and not needed.
No electrode should ever be connected to the _________ of the equipment or the ____________.
Chassie , earth ground
Electric hazards
__________ should be checked as a routine pre-recording procedure during EEG recording.
Inter-electrode impedances under 5 ohms
Do not over prep to cause skin breakdown or break skin.
Impedances that are balanced and up-to 10kOkms are acceptable for EEG recordings.
True
Impedances are important for common mode rejection.
True
Common mode rejection: is the amplifier the takes in the same noise, filtered same noise and then the amplifier amplifies the difference of the noise.
Short circuit and shunt is indicated on the EEG by ________ and possibly related to ______ in the scalp.
Impedances below 100 Ohms & Salt bridge
Related to high and unbalanced Ohm -flatline - re-prep location.
Recording electrodes should be free of ______ & _______ and should not significantly attenuate signals between _____ Hz ____ Hz.
Inherent noise, Drift
0.5Hz, 70Hz
Channels are high quality and calibrate
Meaning of IFCN is
Meaning of IFCN is
International Federation of Clinical Neurophysiology.
Meaning ACNS
American Clinical Neurophysiological Society.
Beyond consideration of patient discomfort and risk of injuries to personnel, needle electrodes are disadvantageous because?
They have higher impedances which results in potentially higher levels of noise.
Reference electrodes is one of the 10/10 or 10/20 system electrodes? True or False
False
It is a required electrode, they are not in the placement no specific location on the head.
The use of link ear as a digital recording reference is specifically encouraged.
True or False
False
linked ear montage can not produce accurate reading.
Contra -opposite side
Epsi- same side
_________ calibration is not necessary for digital system but may occasionally help in detecting errors in the montage selection process for analog recordings.
Biologic
System reference replaced the Bical eeg.
_________ is defined as the ratio of input voltage to trace deflection.
Sensitivity
How many minimum channels required for recording the EEG to decrease error as well as for transient activities?
16 Channels additional channels are often needed for monitoring other physiological activities and for highlighting activity recording in specific regions
______ wiring should meet the underwriters Laboratories standards required for hospital ser-vice, as per state and local electrical code.
AC current
According to ACNS guidelines what is the settings preferred for recording EEG (HFF, LFF, Notch Filter Sensitivity).
LFF 1Hz, HFF 70Hz, Notch 60/50 Hz. Turned off always, sensitivity 5-10uV/mm start at 7uV/mm
Is the time constant the same as the Low frequency filter.
They are not. They are very different.
Time constant is a 0.6 or 0.3. Very low
What is Neuron?
Building blocks of nervous system
Human brain has how many neurons?
60 billion neuron
Presynaptic neuron sends signals to the postsynaptic to become more active
EPSP
Presynaptic sends negative to post synaptic signals
IPSP
Cerebral Hemisphere
83% of total brain mass, covers the diem cephalon and the upper brain stem
Bumps (guru) and grooves (Sulci)
Characteristic patterns of sulci fissures over surface.
Korbinian Brodmann 1868-1918
German Neurologist
Died 50 yrs
52 cortical areas the differs histologically
