A "flat" EEG, that is, one without waves, could indicate what condition?

A flat EEG, characterized by the absence of electrical activity in the brain, is a significant indicator often associated with a state of death. When there are no detectable brain waves, it typically means that the brain has ceased functioning. This finding can be used in certain clinical contexts to support a diagnosis of brain death.

In contrast, coma, deep sleep, and meditative states can still exhibit brain wave activity. For instance, individuals in a coma may show some residual electrical activity, while during deep sleep, specific patterns of brain waves are present. Similarly, a meditative state can reveal brain waves that differ from the flat pattern observed with a lack of brain activity. The absence of any waveforms on an EEG points strongly to the conclusion of a non-functioning brain, leading to the implication of death as the most accurate condition associated with a flat EEG.