Intro to EEG Technology Flashcards
What are the basic components of an EEG machine? 11
- Electrodes
- Impedance Checker
- Pre-amplifiers
- Differential Amplifiers
- Anti-aliasing Filters
- 12 bit A-D Converter
- Notch Filter
- Monitor
- Printer
- Storage
- D-A Converter
What materials are the most commonly used electrodes made of?
Pure silver coated with a layer of silver chloride
What is the purpose of the Impedance Checker in an EEG machine?
To check how well the electrode is connected to the head
What is the maximum acceptable impedance for optimal artifact-free recording?
Less than 5KΩ
What is the function of pre-amplifiers in an EEG machine?
To amplify the very small signals emitted from the cortex before transmitting them to the main amplifier
Define a differential amplifier.
An amplifier that amplifies the difference in voltage between two active inputs
What is the common mode rejection ratio (CMRR)?
The ratio of the amplification of the differential signal to the amplification of the common mode signals
True or False: The black lead in EEG is also known as lead 1.
True
What does ‘Black Upwards Negative’ mean in EEG convention?
When the black lead is negative with respect to the white lead, an upward deflection is recorded
What is the routine setting for the high-frequency filter in EEG?
70Hz
What is aliasing in the context of EEG?
The misidentification of a signal frequency, introducing distortion or error
Fill in the blank: The low frequency or high pass filter in EEG is routinely set at ______.
0.5Hz
What is the purpose of a notch filter in EEG?
To cut out all waveforms that have a frequency of 50Hz, which is produced by mains electricity
What is the Nyquist frequency?
The minimum sampling frequency that must be at least twice the maximum frequency required in the recording
What are the display parameters in EEG monitoring?
- Sensitivity
- Filters
- Paper Speed
- Montages
- Colours
