Awake, eyes open
30%
EMG
0%
SR
0%
ARTF
27.8
SEFL Hz
27.8
SEFR Hz
- Waveform:
- Low-amplitude, fast, irregular activity.
- DSA:
- Diffuse low-power band above 13 Hz; no organised peak.
- Meaning:
- Conscious. Frontal alpha is small with eyes open.
EEG & spectrogram
Raw frontal EEG and density spectral array (DSA) examples. Synthetic teaching waveforms built from textbook spectra — not patient recordings.
Paradoxical excitation (beta)
0%
EMG
0%
SR
0%
ARTF
22
SEFL Hz
22
SEFR Hz
- Waveform:
- Fast 13–25 Hz waves of moderate amplitude.
- DSA:
- Bright band at 13–25 Hz.
- Meaning:
- Light sedation on induction or emergence; patient may move or respond.
Alpha–delta (surgical)
0%
EMG
0%
SR
0%
ARTF
12.5
SEFL Hz
12.5
SEFR Hz
- Waveform:
- Large slow waves with superimposed 8–12 Hz spindles.
- DSA:
- Two bands: alpha at ~10 Hz and slow-delta below 4 Hz.
- Meaning:
- Typical propofol surgical anaesthesia; unconscious.
Real-world style example
Slow-delta dominant
0%
EMG
0%
SR
0%
ARTF
15.3
SEFL Hz
15.3
SEFR Hz
- Waveform:
- Large slow waves with little alpha.
- DSA:
- Power concentrated below 4 Hz; alpha band faint.
- Meaning:
- Deep anaesthesia, or an older brain with reduced alpha.
Burst suppression
0%
EMG
50%
SR
0%
ARTF
12.8
SEFL Hz
12.8
SEFR Hz
- Waveform:
- Bursts of activity separated by flat periods.
- DSA:
- Vertical dark stripes interrupting the spectrum.
- Meaning:
- Excessive depth for most surgery; associated with postoperative delirium in older patients.
Isoelectric
0%
EMG
100%
SR
0%
ARTF
0
SEFL Hz
0
SEFR Hz
- Waveform:
- Flat line (< 2 µV).
- DSA:
- Almost uniform dark field.
- Meaning:
- Profound overdose, hypothermia or cerebral hypoperfusion. Act now.
Emergence
30%
EMG
0%
SR
0%
ARTF
25.5
SEFL Hz
25.5
SEFR Hz
- Waveform:
- Alpha fades; faster activity returns with movement artefact.
- DSA:
- Alpha band disappears and power drifts up into beta.
- Meaning:
- Propofol washing out; return of consciousness approaching.
Real-world style example
