What aspect of EEG readings do Trace alternans represent?

Trace alternans represent normal variations in amplitude observed in EEG readings, particularly during states of non-rapid eye movement (NREM) sleep. These variations indicate a rhythmic fluctuation in the amplitude of the EEG signal, often experienced as an alternating pattern of high and low voltage activity. This phenomenon is typically seen during relaxed or drowsy states and is considered a normal finding rather than indicative of any neurological disorder.

In contrast, seizure activity reflects abnormal, excessive electrical discharges in the brain, while pathological conditions might indicate underlying issues like tumors or encephalopathy. Hemodynamic changes refer to alterations in blood flow, which do not directly correlate with the specific amplitude variations represented by trace alternans. Thus, the characterization of trace alternans as normal variations in amplitude allows clinicians to differentiate between typical brain activity and potential pathological states.