English to Russian Medical Medical: Instruments Four Channel EEG

Fleming and Smith (21) designed an alternative to the CSA display to eliminate the loss of trended information. The technique called density-modulated spectral array (DSA) uses a two-dimensional monochrome dot matrix plot of time as a function of frequency (Figure 1.13). The density of dots indicates the amplitude at a particular time- frequency intersection (e.g., an intense large spot indicates high amplitude). Clinically significant shifts in frequency can be detected by the DSA earlier and more easily than with CSA (21). However, the resolution of amplitude changes is very poor. Therefore, some DSA analyzers use color-modulated amplitude displays and also provide a separate indication for mean or total power.