This course identifies the main areas of Amplifiers, Filters and Output Systems used in EEG recording and can be applied for most Neurophysiological recording apparatus.
The following lesson notes will often refer to the EEG machine, however most of these principles apply to all Neurophysiology recording apparatus and neurophysiological signals such as evoked potentials (EP) , sensory nerve action potentials (SNAP) and compound muscle action potentials (CMAP) to name a few.
The EEG machine is a very sensitive measuring device, the working of which can be altered by various factors including mechanical components, setting choices and environmental influences. The result of these changes can be that faults occur in the recording, faults that are not always easily recognised. Digital EEG apparatus are numerically driven by specific software, so mechanical faults, or faults caused by failing moving parts are no longer a concern. Machine settings and environmental influences are however, still a cause for changes to the recorded data.
It is therefore necessary that the technologist /scientist who is working with the machine know the technical characteristics and check these regularly. In this course we will be discussing the EEG amplifier, the filter systems and the output system of the EEG apparatus.
The areas of research in alignment with ANSA Inc EEG Competency Statements are:-
- Explain the function and purpose of differential amplifiers
- Define common mode rejection ratio and understand its function and purpose
- Identify the recording parameters and how they differ from display parameters including sensitivity and filters
- Amplifiers
- Identify and explain the implication and use of frequency filters on the EEG
- Identify the routine acquisition parameters
- Identify bandwidth and frequency response characteristics
- Identify and explain the implication and use of frequency filters
- Identify artefacts and their source
- instrumental and or environmental artefacts
- Define the machine settings used for EEG
- Explain the importance and the information provided by the calibration signal including display alignment, sensitivity, linearity, centring, damping, high frequency filters, low frequency filters, time constant, display speed, machine noise
NB: Alignment, centring and damping are no longer required areas of research but they may be of interest to you for historical reasons.
