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BASIC EEG TECHNOLOGY EXAM
WITH CORRECT ANSWERS 2025
Laplacian montage correct answers >> Averaged reference from surrounding electrodes used Least invasive electrode correct answers >> Subdermal Signal measuring 8mm has voltage of 72 uV, What is the sensitivity? correct answers >> 9 In a chain of 3 sequential channels, "the end of chain" occurs when the maximum amplitude of given activity is: A. At the electrode of input 2 of the first channel B. At or outside the electrode of input 1 of the first channel C. At or outside the electrode of input 2 of the last channel D. B and C correct answers >> B and C B. At or outside the electrode of input 1 of the first channel
C. At or outside the electrode of input 2 of the last channel When using a referential (ear) montage, all of the following problems may be encounter except: -Ear contamination -false localization -Phase shift -Amplitude attenuation correct answers >> Phase shift When a 50uV calibration height is 1 cm, what is the amplitude of activity that measures 4mm? -10 uV -20 uV -40 uV -100uV correct answers >> 20uV What type of montage combines activity from many electrodes to form a reference? correct answers >> Average reference If the HFF is set at 70 Hz, about how much attenuation will there be for a 35 Hz wave? correct answers >> 0%
-In a chain of electrodes, Input 2 of one channel is the same electrode as Input 1 of the next -In the USA, the Left sided electrodes appear first, followed by the right sided electrodes With a time scale of 3 cm per second, what is the duration in mm for a 10 Hz wave? correct answers >> 3 mm? What is the amplitude (uV) of activity that measured 12 mm in height, if a 50 uV calibration signal measured 6 mm? correct answers >> 100 uV Electrode "pop" is induced by? correct answers >> Poorly chloride electrodes The LFF can be used for: a. Accentuating lower frequencies b. Reducing lower frequencies c. Reducing sweat artifact d. All of the above correct answers >> All of the above
If both Input 1 and 2 are -20uV, then the result will be? correct answers >> 0 uV What type of amplifier amplifies the difference in voltage between 2 inputs? correct answers >> Differential amplifier When an EEG signal is recorded at sensitivity of 2, what is the voltage of activity measuring 4 mm correct answers >> 8 uV The time constant is determined by: correct answers >> resistance X capacitance If the LFF is set at 5 Hz, how will a 20 Hz wave be affected? correct answers >> There will be no effect which of the following frequencies is most affected by a low filter setting of 5 Hz -0.1 Hz -0.5 Hz -5 Hz
What is useful about the use of long interelectrode distance derivation correct answers >> It is useful in detecting an abnormality of small amplitude Nasopharyngeal electrodes are used for detecting from: correct answers >> The mesial temporal lobe What is the duration of a wave measuring 5 mm, when the 20 mm calibration signal is equal to 200 msec correct answers
50 msec Which type of montage closely gives the true amplitude of EEG activity at a given electrode? correct answers >> Non- Cephalic reference Poorly chloride electrodes The LFF can be used for: a. Accentuating lower frequencies b. Reducing lower frequencies c. Reducing sweat artifact d. All of the above correct answers >> All of the above If both Input 1 and 2 are -20uV, then the result will be? correct answers >> 0 uV What type of amplifier amplifies the difference in voltage between 2 inputs? correct answers >> Differential amplifier When an EEG signal is recorded at sensitivity of 2, what is the voltage of activity measuring 4 mm correct answers >> 8 uV The time constant is determined by: correct answers >> resistance X capacitance If the LFF is set at 5 Hz, how will a 20 Hz wave be affected? correct answers >> There will be no effect which of the following frequencies is most affected by a low filter setting of 5 Hz -0.1 Hz -0.5 Hz -5 Hz What is useful about the use of long interelectrode distance derivation correct answers >> It is useful in detecting an abnormality of small amplitude Nasopharyngeal electrodes are used for detecting from: correct answers >> The mesial temporal lobe What is the duration of a wave measuring 5 mm, when the 20 mm calibration signal is equal to 200 msec correct answers >> 50 msec Which type of montage closely gives the true amplitude of EEG activity at a given electrode? correct answers >> Non- Cephalic reference In 3 Hz spike and wave complex the amplitude of both the spike and the wave were 100 uV when recorded with filter settings of 1 to 70 Hz and sensitivity of 7 uV. If the LFF is changed to 5 Hz, the amplitude of the spike and the wave would be? correct answers >> 100 uV The electrode impedance correct answers >> Is higher with a smaller area of contact
Which of the following frequencies is most affected by low pass filter of 15 Hz -5 Hz -10 Hz -15 Hz -30 Hz correct answers >> 30 Hz Which is the least sensitive setting -2 uV/mm -5 uV/mm -7 uV/mm -20 uV/mm correct answers >> 20 uV/mm Nasopharyngeal electrodes are good for detection activity in the? correct answers >> Inferior-medial temporal cortex Which of the following is most affected by a time constant of 0.3 seconds -10 Hz -5 Hz
-Bipolar -Referential -Average -Laplacian correct answers >> Bipolar The high pass filter is? correct answers >> LFF Sensitivity is conventionally defined by correct answers >> Ration of voltage to height The International 10-20 system of electrode placement was developed primarily because correct answers >> It is a uniform placement among all laboratories nationally and internationally Impedance correct answers >> The opposition to the flow of A/C With sensitivity of 7, what should be the height for the activity of 35 uV? correct answers >> 5 mm
A faster sweep speed (60 mm/sec) allows: correct answers
-Easier measurement of faster frequencies -Easier identification of 60 Hz artifact -Better identification of degree of synchrony between 2 hemispheres What LFF is equivalent to a time constant of 0.03 seconds? correct answers >> 5 Hz Is higher with a smaller area of contact Which of the following frequencies is most affected by low pass filter of 15 Hz -5 Hz -10 Hz -15 Hz -30 Hz correct answers >> 30 Hz Which is the least sensitive setting -2 uV/mm -5 uV/mm -7 uV/mm -20 uV/mm correct answers >> 20 uV/mm Nasopharyngeal electrodes are good for detection activity in the? correct answers >> Inferior-medial temporal cortex Which of the following is most affected by a time constant of 0.3 seconds -10 Hz -5 Hz -Bipolar -Referential -Average -Laplacian correct answers >> Bipolar The high pass filter is? correct answers >> LFF Sensitivity is conventionally defined by correct answers >> Ration of voltage to height The International 10-20 system of electrode placement was developed primarily because correct answers >> It is a uniform placement among all laboratories nationally and internationally Impedance correct answers >> The opposition to the flow of A/C With sensitivity of 7, what should be the height for the activity of 35 uV? correct answers >> 5 mm A faster sweep speed (60 mm/sec) allows: correct answers >> -Easier measurement of faster frequencies -Easier identification of 60 Hz artifact -Better identification of degree of synchrony between 2 hemispheres What LFF is equivalent to a time constant of 0.03 seconds? correct answers >> 5 Hz With sensitivity of 20, what voltage is needed to yield 10 mm deflection in calibtation? correct answers >> 200 uV What is the frequency of a wave having a duration of 800 msec? correct answers >> 1.25 Hz What statement is true concerning biological calibration and square wave calibration? -The input signal for a biological calibration is from DC rather that from AC -There is no need to do a square wave calibration if you do biological calibration -Biological calibration demonstrates the integrity of the system from patient to instrument
Common mode rejection ratio is closely related to correct answers >> Balance amplifier The most commonly used metal for EEG electrodes is? correct answers >> Silver-silver chloride or gold Transverse bipolar montage is more accurate than longitudinal montage in localizing the activity correct answers >> Spreading from temporal to parasagittal region In the expanded 10-20 system, an electrode named C1 would be placed mid-distance between correct answers >> Cz and C Which metal is not commonly used in making EEG electrodes? -Gold -Iron -Silver -Platinum correct answers >> Iron which is the correct formula to calculate voltage -V=SxH
-H=V/H
-S=V/H correct answers >> All -V=SxH -H=V/H -S=V/H Calibration signal (both square and wave and biological) is: -Useful only to detect amplitude scale -Useful only to detect time scale -Not necessary -Useful to detect various recording parameters correct answers >> -Useful to detect various recording parameters If the vertical scale (sensitivity) is 5 uV/mm then a 60 uV wave will measure? correct answers >> 12 mm Longitudinal bipolar montage is more sensitive that transverse in detecting focal activity correct answers >> Spreading from temporal to parasagittal electrodes
Time constant correct answers >> time required for the capacitator to charge to 63% of its full charge Resistance correct answers >> The force opposing D/C flow Ampere correct answers >> Unit of current (I) Ohm correct answers >> unit of resistance (R) Volt correct answers >> unit of electromotive force (E) Ohm's Law correct answers >> V=IR Farad correct answers >> unit of capacitance HFF tend to round the shape of the rapid upswing and down swings in waves (fast transient activity) correct answers >> Less current flows down the output voltage terminal when over the capacitator because it would prefer to flow in and
out of the capacitor since the (R) to current flow across the capacitor decreases markedly with high frequency A/C with high frequency Sensitivity = correct answers >> V/H Voltage = correct answers >> SxH Height = correct answers >> V/S How to calculate frequency correct answers >> 1/ by duration Aliasing is caused by correct answers >> insufficient sampling rate All electrodes used in END testing should have correct answers >> DIN 42-802 standard connectors What level of constant voltage is likely to cause asystole? correct answers >> >2A
-in phase cancellation -common mode rejection causing no deflection Sampling skew is a problem with early digital EEG instruments (no longer a problem with modern instruments) caused by _____. correct answers >> inability of older/first generation instruments to simultaneously sample multiple channels of EEG An EEG insturment's input impedance at the amplifier should be _____. Note: this is not to be confused with the electrode impedance correct answers >> very high In an EEG instrument, what component transforms alternating current into direct current? correct answers >> the power supply A patient can become the pathway for least resistance and therefore electrically susceptible to shock when ____. correct answers >> the patient has an indwelling heart catheter
According the ACNS Guidelines, the minimum sampling rate for EEG data, should be at least _____ times the high frequency filter setting.(In other words, how many times the highest frequency you are wanting to record should your sampling rate be?) correct answers >> three or more Resistance ______ correct answers >> describes the forces opposing direct current flow At an equivalent paper speed (aka: time base, epoch, analysis time, etc) of 30 mm/sec, one page of printed EEG represents 10 seconds. At an equivalent paper speed of 15 mm/sec, one page of printed EEG represents _______. correct answers >> 20 seconds How will changing the time base/epoch/equivalent paper speed from 10 seconds to 20 seconds alter the frequency of a 12 Hz alpha rhythm? correct answers >> It will be compressed (bunched up) but the frequency will be the same A burn with damage to the superficial dermis which is red, painful and often blistering is ________ correct answers >> Second degree
