NDXT 131 Final
The minimum allowable level of common mode rejection (according to ACNS) in a digital EEG system is:
80 dB
If the symptom is that the data has electrical artifact present the cause could be:
- Causes include high electrode impedances - a bad patient ground lead - a bad system reference lead - a bad chassis or outlet ground
Factors in electrical injury include:
- Current pathway - Duration of exposure - Current intensity
Acute reaction from electrical injury include:
- Respiratory Arrest, Paralysis, or anoxia - Renal failure (kidney failure) - Spinal cord transection, and central nervous system shut down - Asystole and dysrhythmias
Up until the point that you actually activate the program in which you wish to collect or analyze neurodiagnostic data, you are mainly dealing with:
- its operating system (Windows, NT, or DOS) - the hardware peripherals associated with it (keyboard, mouse, monitor, network, external drives) - the basic computer and startup routine (BIOS or CMOS)
Critical Systems in the body that are potentially harmed by electrical injury are:
- Brain and spinal cord - Renal system - Respiratory - Cardiovascular
The advantages to Digital Filters includes the following:
- they can be constructed and modified easily - they need not introduce any time delay (phase shift) - they have a relatively sharp frequency cutoff if desired
Bipolar Montages:
usually contain less EKG and muscle artifact and are good for localizing focal abnormalities with phase reversals
The ACNS Guidelines call for Biological Calibration. This is best done on a digital instrument by _____.
viewing all the electrodes' input in a montage that pairs each of the electrodes to the system reference.
Increasing the inter-electrode distances
will increase the differential amplifier's ability to record low voltage activity.
The program will engage but will not allow the collection of data a possible cause is:
you may be accessing a reader only version of the program.
Name an artifact seen on analog EEG instruments but never on digital EEG instruments.
Defective pen mount
___________can be used to map the sensory and motor strips on the brain's surface using a strip of sterile electrodes placed directly on the surface of the brain to guide surgical resection.
ECog
Examples of biological or physiological artifacts are ____.
EMG, EKG, EOG
An algorhithm that transforms EEG data into a graphic representation of various voltages and frequencies present in the signal is called ____.
FFT
True or false: Data collection during surgery has not yet expanded to multiple modality monitoring.
False
True or false: Digital EEG Instruments differentially amplify all inputs in relation to ipsilateral references and then the software programs form montages by effectively subtracting input 1 from input 2 for each derivation.
False
True or false: Digital EEG is recorded in a bipolar montage and is then remontaged referentially.
False
True or false: If your digital instrument performs square wave calibration, it should be done at the start and end of the recording using a montage that includes every electrode on the patient's head, but if your instrument does not perform square wave calibration, calibration of the instrument should be performed according to the manufacturer's specifications.
False
True or false: Research does not support EEG as an important tool for diagnosing clinical and subclinical status epilepticus to help insure earlier intervention and better patient outcomes.
False
True or false: The ground electrode or common electrode placed on the patient is the same thing as the ground electrode in the electrical plug on the instrument.
False
True or false: There is no difference between the calibration function in an analog and a digital EEG instrument.
False
True or false: Using Fp1-O2 for a BioCal on a digital equipment would only show the frequency response in those two electrodes in all individual amplifiers.
False
Artifacts originating from the patient are ___.
no different with digital machines than they are with analog machines
Anything extra or added on for your computer, such as a modem, a mouse, or a fax adapter, can be added on externally or installed inside the machine.
peripherals
A term used in cardiology to denote a low level of electric current applied directly to myocardial tissue as little as 0.1 mA causes ventricular fibrilation
Microshock
The sample rate of an A-D converter must be at least twice that of the fastest frequency to be recorded. This frequency is known as the ____________ frequency.
Nyquist
True or false: A stress loop in an electrode lead wire is a bad idea because it acts as an antenna and picks up electrical current in the air. It is best to tape down a zig-zag rather than a loop.
True
True or false: Aliasing is what happens to a waveform when it is sampled at too low a sampling rate.
True
True or false: Authentication is the process of establishing who you are.
True
True or false: Birds on electrical lines do not get shocked because they are not grounded.
True
True or false: Can Digital EEG systems monitor patients in the ICU using multiple formats including compressed spectral arrays, and integrating data on body temperature, heart rate and intracranial pressure.
True
True or false: Current modern Neurodiagnostic instruments are usually optically isolated protecting the patient from injury when the patient is connected to the instrument.
True
True or false: Digital EEG Instruments differentially amplify all inputs in relation to a common reference and then the software programs form montages by effectively subtracting input 2 from input 1 for each derivation.
True
That portion of a computer through which a peripheral device may communicate. Often identified with the various plug-in jacks on the back of your computer. On a network hub, it is the connector that receives the wire link from a node.
port
Changes in sensitivity on a digital EEG instrument ____.
adjust only the visual representation of the stored data on the display screen.
To copy programs and data onto an auxiliary storage medium (disk, tape,etc.) for long-term retention, such as when disk space has become full.
archive
Technologist notations (comments) on the digital EEG machine _____.
are very important for later interpretation
After recording, filter settings on digital EEG machines can ____.
be adjusted in the displayed data during review, to aid in interpretation.
During the digital recording, it is necessary for the technologist to change display montages on the computer screen in order to ______.
define artifacts, localize activity, stage sleep, see alpha reactivity, etc.
The requirement for verifying that the electrodes and electrode board (head-box) are connected to the instrument
demonstrates to the interpreting physician that the electrodes are placed on the patient's head and the cabling is connected to the equipment.
The difference between display montage and recording montage is that the_____.
display montage is what you see on the computer monitor, recording montage is what is stored to disk.(raw data)
A computer component that you can see and touch:
hardware
60 Hz artifact can be reduced or eliminated by ____.
making sure that the electrode impedances are low 1-5K ohms and balanced.
A reviewer can recognize end of chain situations by looking for focal deflections that are
maximal at the last electrode in the chain.
A flat line in all channels could be ____.
a bad ground electrode or system reference.
The minimum vertical screen display resolution for viewing EEG should be:
4 pixels per vertical mm or better, which most currently are
Match the level of current with the probable effect: 1. Tingling sensation: almost not perceptible 2. "Let go" current for an average child 3. "Let go" current for an average woman 4. "Let go" current for an average man 5. Maximum current for a person to grasp and then let go 6. Tetany of skeletal muscles 7. Paralysis of respiratory muscles: respiratory arrest 8. Threshold for ventricular fibrillation 9. Asystole (Heart stops beating) 10. Common household circuit breakers 11. Maximal intensity of household current (US)
1. 1mA 2. 3-5mA 3. 6-8mA 4. 7-9mA 5. 16mA 6. 16-20mA 7. 20-50mA 8. 50-100mA 9. > 2 Amps 10. 15-30 Amps 11. 240 Amps
Match the amount of voltage buildup with the amount of impedance: 1. Least voltage buildup 2. Medium amount of voltage buildup 3. Most voltage buildup
1. Small amount of impedance 2. Medium amount of impedance 3. Large amount of impedance
Match the amount of average amplitude with the Neurodiagnostic modality: 1. Sensory Evoked Potentials 2. Electroencephalogram "EEG" 3. ECG or EKG 4. Motor Evoked Potentials 5. Electromyogram "EMG"
1. ~10vV 2. ~20uV 3. ~1.5mV 4. ~2.5mV 5. ~3mV
The minimum screen resolution to properly display a 10 second page of digital EEG would be:
1024 x 768 pixels or more
The vertical resolution of an A-D converter should be at least _____ bits per ACNS guidelines?
11 bits
The ACNS recommendations for recording clinical EEG on digital media state that the sampling rate should be ____ and the resolution of the A to D converter should be ____.
200 or higher, 12
Typical sample rates for EEG A-D converters are:
256 Hz - 512 Hz
30 mins of Digital EEG with video requires approximately ___ of disk space.
300 MB
What component is responsible for assigning numeric values to the Analog EEG signal?
A-D converter
The ability to record a patient's EEG over an extended period of time in almost any environment is called ____.
AEEG or ambEEG
The system reference would be best placed where anatomically?
CPZ behind Vertex (between Cz and Pz)
One of the greatest advantages of the digital EEG recording over analog recordings ____.
Is the ability to change montages and filter settings after the recording has been made.
Symptom: The system will not power up and there are no lights on any component. What is the first troubleshooting question?
Is the machine plugged in?
Digital instrument filter settings allow ranges from ___LF to ___HF which is well in compliance of ACNS recommendations for ECI recording filters settings.
LF .1 Hz - HF 100 Hz
A term used in cardiology to denote a moderate to high level of electric current passing across two areas of intact skin: aprox 100 mA can cause ventricular fibrillation
Macroshock
Time scale, Time Base, Display Time or epoch, are terms used in digital EEG that are similar to the term ______ , used with analog EEG.
Paper speed
True or false: Digital systems incorporate a scaling of the waveforms that relates to the analog to digital conversion, the vertical resolution, the number of bits, etc. An amplitude legend/scaled tool bar is used by digital systems to display the specific amplitude of the waveform selected.
True
True or false: Problems that occur only when accessing the neurodiagnostic programs involve the neurodiagnostic software, hardware itself, or some interaction between the neurodiagnostic program and the computer's hardware.
True
True or false: Sampling skew is an error in the timing of the sampling of waveforms and was a problem in early digital EEG instruments but no longer a problem in modern digital EEG instruments.
True
True or false: Sweat decreases the body's defenses against against electrical injury.
True
True or false: The Laplacian at an electrode X can be approximated as the sum of the potentials at the four nearest neighbors to X minus four times the potential at X.
True
True or false: The ability of the computer to store a large amount of data over an extended period of time has also allowed for the continuous recording of the EEG (cEEG) and continuous video EEG with Video (cVEEG).
True
True or false: Using Fp1-O2 for a BioCal on a digital equipment would only show the frequency response in those two amplifiers, the system reference and ground. It does nothing to test the frequency response of the other amplifiers.
True
What is the best way to measure sensitivity on a digital EEG instrument?
Use the computerized voltage indicator, usually an on screen ruler or legend, or use the cursor function found in the software itself.
A device or system that is capable of carrying out a sequence of operations in a distinctly and explicitly defined manner. The operations are frequently numeric computations or data manipulations, but also include data input and output
computer
Devices that allow you to enter information and communicate with the computer:
input devices
The ability to access a computer from outside a building in which it is housed. It requires communications hardware, software, and actual physical links, although this can be as simple as common carrier (telephone) lines or as complex as TELNET login to another computer across the Internet.
remote access
The recommendations for electrode impedance are that they should be under 10,000 ohms but over 100 ohms. This guideline was written for use with analog equipment. Digital equipment users ____.
should follow the same ACNS guidelines.
Data or information used to run a computer:
software
The __________of data in a computer network is of critical importance, especially when sending data from the operating room that requires immediate interpretation.
speed of the transmission.
Digital systems either require that an additional electrode be placed on the scalp a combination of regularly applied electrodes to serve the same purpose as a:
system reference
The recording montage typically records data to the computer, using a ____.
system reference; referential montage
1,099,551,627,776 bytes, often used to mean one trillion bytes (1,000,000,000,000).
terabyte
During an ECS/ECI recording it is necessary to ____.
test the integrity of the entire recording system
Guidelines for recording digital EEG in the United States were written by:
the American Clinical Neurophysiology Society (ACNS)
A great advantage of digital instruments in performing Polysomnography is ____.
the ability to run sleep scoring programs and produce customized reports.
Perhaps the greatest advance in IONM monitoring has been:
the digital network
The ACNS guidelines for recording electrocerebral silence studies states ____.
the full compliment of 21 electrodes plus ground and system reference (International 10/20 System) are required for ECS/ECI recordings and montages should be used with an inter-electrode distance of at least 10 cm.
The three components directly responsible for the display on the monitor are ____.
the monitor, monitor cable and video card
If the resolution of waveforms improves when data is printed compared to the resolution of data on the screen, the fault may be ______.
the resolution of the video display (pixels)
