Table 1. Electroencephalographic and Hemodynamic Variables during Three Types of Response to Command

Data are presented as mean ± SD (95% confidence interval for mean). Power refers to the amplitude (μV) of waveforms in the electroencephalogram, which typically fall into one of four frequency bands: delta (0.5–3.5 Hz), theta (4.0–7.75 Hz), alpha (8.0–13.5 Hz), and beta (13.75–30 Hz) frequency. In general, high-frequency waveforms of low amplitude characterize an awake conscious brain.