eemagine EEG 1.0 tutorial

eemagine EEG 1.0 is a software tool for efficient review and analysis of EEG data. The analysis of EEG based on methods like spike detection and dipole mapping provides useful information about spike activity. Moreover, it gives an indication about the possible location of the generators of such spikes.

Step 1

When starting up the eemagine EEG 1.0 software from the program manager, the the eemagine Study Manager pops up. This dialog allows you to open an existing study (e.g., you may want to save this case study and just open it), or to generate a new study, based on one of the existing Analysis Templates. The templates, which are represented by eemagine icons in the Study Manager, provide solutions to different problems. The most interesting and best suitable template for exploring the powerful concept of eemagine is called "Spike Detection and Localization". Double-click this icon to proceed.

 

Step 2

based on your choice to run the study called "Spike Detection and Localization", a new document is opened. The document always consists of three main elements: the Dialog Interface in the left upper corner, the Project Navigator underneath the dialog interface, and the Visualization Area.

The dialog interface allows you to select files, adjust parameters, and to move to the next step in the workflow. The project navigator shows how far you are with the completion of your study, and lets you navigate to other steps. The visualization area shows all kinds of data using different views. This area can be split into one to four views. Note that with each step in the workflow protocol, you will be prompted with a new user interface and -if so defined in the workflow- with a new layout for the visualization area.

Step 3

You press the Next button to enter into the first actual step in the workflow, which is called "Open EEG Data". The EEG file name can be directly edited or entered using the Browse button next to the edit field. Choose the "rolandic_55sec.eeg" data file in the "Profile" EEG sample data directory.

 

Step 4

After you pressed the Next button in the Open EEG Data step, this command will be executed and the EEG data appear on the screen. You can use the scrollbar controls to move back and forth in the EEG, or you simple use the keyboard for navigation. The arrow keys can be used for paging (left and right key), whereas the sensitivity can be adjusted with the up/down keys. You can press the Next button to go through the "Electrode Set-up" step. With this step, we load standard locations for the electrodes.

 

Step 5

The EEG file is the only input data requested from the user. All other data, such as electrode locations, the head model and MRI, are provided with the eemagine software. The next step in the workflow, "Select channels", lets you remove unwanted channels from the montage. You work in the "Channel List View", which is just one of various list views available.

Step 6

The following steps are "Head model" and "MRI". With the current version, you just press "Next" to proceed. The standard data set is loaded. The visualization meanwhile shows the 3D mapping view and the EEG data view. Note that both views are combined with each other, i.e. the current latency shown in the EEG data view corresponds with the voltage map. The current latency is a marker in the EEG view, which is characterized by a black triangle in the top of the view.

Step 7

We moved now from the "Preparation" to the "Spike Detection" section. The "Adjust Parameters" step lets you select a number of spike parameters, such as the spike duration (total time of ascending and descending slopes of the spike). It is not necessary to change any defaults. You execute the spike detection pressing the Next button. The spike detection takes about 3 seconds for one minute of data. After completion, you can click at a spike event in the "Spike List View" to see the respective EEG interval. Spikes are marked in the EEG data view. The active channel with the spike is highlighted.

Step 8

The spike detection provides the necessary information for the following feature - the dipole fit. Dipoles can be seen as focal representations of spike activity. The "Run Fit" step has just one important parameter. The acceptance level lets you skip all dipoles with a low fit quality. The default is fine.

Once you pressed the Next Button, the dipole fit is performed for each spike event. This takes about 3 seconds per spike event. With about 40 spikes, the total computation time for this step is about 2 minutes. 

 

Step 9

When the dipole fit is completed, a new visualization layout pops up showing the 3D mapping, the dipole list, the standard MRI, and the EEG Data view. This is the most complex and impressive combination of views, and shows the power of the eemagine concept to combine the different aspects of EEG analysis. All views are combined with each other and show different facets of the same data. Click at one of the dipoles in the Dipole List View, and you obtain the respective Voltage map, dipole location in the MRI, and page of EEG containing the respective spike data.

Dipoles can be sorted according to their properties listed in the view. You can sort the dipoles, e.g., according to their goodness of fit (GOF), and select and uncheck all dipoles with a GOF of < 90%. To do this, click at the the column called GOF in the dipole list view.

You can also graphically select dipoles in the MRI view by dragging (with the left mouse button clicked) a rectangle around the dipoles.

 

Step 10

The analysis study is made complete by adding a report. The report automatically puts all relevant information, e.g., patient and recording information, the table of spike events, a picture with the dipoles in the MRI, into a MS^®-Word^® document. Different report document templates can be chosen. Their differ in the amount and type of data that is taken into the document. The default template is OK. The data, such as patient information, list of spike events, MRI images with dipole locations, are transferred to the document. This takes a while, usually ca. 10 seconds. We use MS^®-Word^® as a reporting component. If you are prompted with messages from Word, press continue or OK. When the document is ready, you can work as if you were working in MS^®-Word^®. Try the menu option "View/Online Layout" to see all entries in the document. You can click at such an entry (bookmark) to page to the requested part of the document.

You can skip the "Print Report" and "Save Report" step because they are not mandatory steps (mandatory steps are marked with a red circle).

The final "Save/Close" step saves the complete analysis study in one file. Next time you open eemagine EEG, you will find the document in the Study Manager.

Summary

The eemagine software follows a new concept, providing maximum efficiency in the clinical analysis of EEG. With this guidelines, we want to assist you in learning the most prominent features of our product. 

You have learned how to start working in a new analysis study, to load and navigate through a recording, to find spike events, to generate dipole solutions, and to report everything in a ready-to-print document.

Please note that the tutorial presented here does not nearly describe our product. It is recommended that you further explore the functionality by running studies on different data, trying out other analysis templates etc. In case of any questions, problems or suggestions, please do not hesitate to contact us.

We appreciate your interest in our product.