• STA/R® - interactive clinical software package (rapid epilepsy analysis)
• Boolean Averager - research software package for experimental design and data collection

MAGNES Software Package
In addition to the basic software package of the Magnes 3600 WH system, which includes modules for data acquisition, head shape digitization, data editing, averaging and selective averaging, data manipulation (power spectra, digital filtering, waveform addition/subtraction, baseline correction, etc.), data archiving/dearchiving, event detection, interactive dipole fitting, contour and waveform displays and utilities for system maintenance, there are the STA/R, Spatial Temporal Analysis/Review, clinical software package and the Boolean Averager/Artifact Detection package, which allows the user to process complex cognitive data quickly.

STA/R Clinical Software Package:
The STA/R software package was co-developed with ETIAM, a software firm collaborating with the University of Rennes, France. STA/R provides an interactive interface linking the 4-D MEG signal and MEG source modeling with an anatomical reference, usually a MRI, to allow users to quickly and easily visualize their data. STA/R incorporates standard 4-D software modules, adds features, and provides additional communication pathways between related applications.

The STA/R software package is a Store Service Class Provider for DICOM v3. This means that MRI images that conform to the DICOM standard can be imported from a network directly into the STA/R program for processing. Thus, there is no need for separate MRI conversion software, and no need for additional file transfer steps. If the DICOM standard is not followed at the institution, 4-D’s standard MRI format is also supported, and existing MRI data can be imported into STA/R.

The STA/R package requires only a single MRI series. MRI data imported into the STA/R program go through two pre-processing steps. The first is an isotropic interpolation, creating a MRI volume set from which other views are reconstructed. This allows any view to be reconstructed from a single imported series (typically 124 slices or more). This feature greatly reduces MRI costs, since a shorter scan time can be used. The second step is a 16-bit to 8-bit conversion, which reduces the size of the MRI volume and memory requirements during processing. After these two steps are completed, the MRI is ready for registration.

STA/R provides three separate image/MEG registration methods. The first is a manual method in which the user identifies three fiducial markers on the MRI. These markers are contrast pills placed on the subject’s head prior to the MRI scan (similar to the standard 4-D method). The pills are placed at the locations that were identified and marked during the MEG data scan. The second, is an automatic method in which the subject’s digitized head shape, at the time of the MEG data scan, is matched to the skin surface of the MRI. The use of the automatic registration requires two additional MRI pre-processing steps. Although this adds time to the procedure, the resulting registration is more reproducible and requires less human interaction. The last method of registration relates the MSI data to the Talairach referential system, by identifying the Anterior and Posterior Commissure.

The STA/R software provides critical real-time communication links between the MEG data and the MRI image. With these links, the user is able to interactively view waveform and field contour plots, select latencies and view the dipole source localizations on the subject’s MRI. The user can then add the resulting dipole localizations to an ongoing list. Dipoles that are selected can also be sorted by user-defined criteria e.g. correlation, source strength, etc. and saved to a file. This feature greatly decreases the time required to review and analyze data, such as that obtained during an epilepsy surgery evaluation.

Conversely, if data has already been analyzed and is submitted for review, the reviewer can select any dipole source that has been superimposed on the subject’s MRI, either directly from the MR image or from the loaded list of dipoles, and then review the waveform and contour plots of the selected dipole source instantaneously. This interactive feature allows the reviewer to more efficiently scan for artifacts, thereby helping to ensure that reported sources are true physiological events.

Boolean Averager/Artifact Dectection Package:

The Boolean Averager/Artifact Detection package was developed specifically for use with studies of cognitive activity. The power of the Boolean Averager comes from its ability to analyze many different cognitive conditions at one time. The Boolean Averager can examine multiple complex combinations of stimuli and responses from a single run. It allows the user to test many different hypotheses with a single quick, pass through complex data. The user specifies the order and timing of both stimuli and responses required for each hypothesis, and the application then extracts the appropriate data sets, averages them if desired, and generates statistics about each condition.

The power of the Boolean Averager is greatly enhanced when used in conjunction with the Artifact Detection pre-processor. This routine identifies various artifacts such as eye-blinks and motion artifacts using different detection algorithms including peak-to-peak and thresholding techniques. These same algorithms can be used to identify physical events such as eye movements. Each artifact type or physical event type is identified with a unique code, which can then be used in the Boolean Averager for selection, sorting and timing.

In defining the conditions for each type of cognitive response the user is investigating, the Boolean Averager provides a number of tools to specify the order and timing relationships between stimuli, responses, artifacts and physical events. These include:

- Process all events that share the same stimulus code, response code, or physical event code (Example: average all events with right index finger responses).
- Process all events within a certain code range (Example: average all events with codes right index through right ring finger responses).
- Process all events not having a given response (Example: all responses in which there are no right index finger responses).
- Process events that occur within a given time period of another (Example: all right finger responses, which occur within 250 ms of the red, dot, but not longer than 500 ms).
- Process only those response events that follow stimulus event “X”.
- Process only those response events that follow stimulus event “X” within n seconds and stimulus event “Y” within m seconds.
- Independent definition of debounces times for each stimulus and response code is provided.

The power of the Boolean Averager is controlled by high-level commands placed in an averaging command file (ACF). Each command line of the ACF file represents one cognitive condition and the appropriate processing instructions. Each ACF file can consist of many command lines that are all processed in parallel during one pass through the data file. To form a command line, the above conditions can be combined using Boolean logic rules to construct highly complex conditions of state and timing.

The outputs of the Boolean Averager include raw epoch files, for examination with single-trial analysis techniques, averaged files, and statistics reports including stimulus response times, hits and miss rates, etc.

The STA/R software also provides color and black and white postscript output capability, making possible the generation of high quality printouts and effective case reports.
 

For more information about our totally integrated research software package for advanced modeling and image processing.
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