TEMPO (Topographic EEG Mapping PrOgram)

TEMPO (Topographic EEG Mapping Program) is programming system for visualization of brain electrical activity written for Windows NT/Window 95 operating systems. This program was the first one to allow a real-time 3D topographic mapping of brain electrical activity on personal computers. TEMPO takes standard EEG recordings from .eeg files and makes a sequence of topographic maps. This sequence shows in a window as a animation controlled with standard multimedia controls. Individual maps are generated with improved version of scan-line hidden surfaces removal algorithm. EEG activity is color-coded into scalp region and other regions of head are Gouraud shaded.

TEMPO supports mapping of following EEG scores:

1. raw potentials
2. spectral amplitudes
3. spectral phases
4. spectral power density
5. absolute powers

Main TEMPO window

The primary power of TEMPO environment lies in ability to examine the same map from different viewpoints (see pictures below). User can navigate through virtual space of animation using mouse, and adjust the light position as well. Maps can be saved in .bmp format for future examination.

Mapping parameters, such as EEG epoch length or EEG step length are accessible in any moment. User can also change animation speed - TEMPO is capable to display all spectral scores in real time. A cache-enabled short sequence is refreshed with rates up to 10 frames/sec.

Following variations of nearest neighbor interpolation algorithm are available:

• 3NN with inverse-to-distance interpolation coefficients
• 3NN with inverse-to-squared-distance interpolation coefficients
• 4NN with inverse-to-distance interpolation coefficients
• 4NN with inverse-to-squared-distance interpolation coefficients