Hours of EEG at a glance : meet the DSA !

What is a DSA? 

An EEG records the brain’s electrical activity, sometimes for hours or even days. For physicians, reviewing a long recording means going through thousands of pages of EEG. The DSA summarizes the spectral activity of the EEG, that is, how the signal’s power is distributed across frequencies, and shows how this distribution changes over the hours. 

In Playback, the DSA displays two stacked spectrograms (color maps of this activity), one per hemisphere: the right hemisphere on top, the left hemisphere below. The vertical axis shows frequencies, from the slowest to the fastest (0 to 30 Hz); color shows the intensity of the activity, from dark blue (low) to red (high). 

How the DSA changes EEG review? 

The DSA is designed primarily for long-term EEG, where review takes the most time. It helps physicians: 

• spot changes in activity over the course of the recording; 
• see an asymmetry between the hemispheres, thanks to the two spectrograms stacked one above the other; 
• go straight to the relevant section: one click on the DSA displays the raw EEG at the selected moment. 

The DSA does not make a diagnosis and does not replace reading the raw EEG. It shows where to look; interpretation is always performed on the EEG itself, by the physician. 

Up and running in one click 

Nothing complicated: the DSA opens in one click, updates every 10 minutes, and condenses up to 4 hours of EEG into a single image.