| Monitor* | Manufacturer¶ | Parameters | Monitoring range | Notes |
| Unprocessed electroencephalogram (EEG) | Non-proprietary | Alpha, beta, gamma, delta, theta waves, sleep spindles; K complexes, spectral edge frequency, burst suppression; isoelectricity. | No specific index Permutation entropy can be derived | Advantages: Rapid response time, cheap, non-proprietary. Disadvantages: No index or value, requires attention, requires training. |
| High frequency, low amplitude (gamma and beta dominance) | Wakefulness common. | |||
| Alpha oscillations | Drowsiness/sedation common. | |||
| Spindles, K complexes, some delta waves | Explicit recall rare. | |||
| Slow delta waves, spectral edge <12 | Surgical anesthesia common. | |||
| Burst suppression and isoelectricity | Deep anesthesia common. | |||
| Bispectral index (BIS) | Covidien Medical | Bispectral index (proprietary algorithm) based upon beta power, bispectral coherence (synchfastslow), and burst suppression ratio. | 0 to 100 | Raw EEG and parameters such as spectral edge frequency can and should be displayed. Advantages: Index value can be used to guide anesthesia. May improve outcomes. Disadvantages: Slow response time, costly, proprietary. |
| 80 to 100 | Wakefulness common. | |||
| 60 to 80 | Drowsiness/sedation common. | |||
| 50 to 60 | Explicit recall rare. | |||
| 30 to 50 | Surgical anesthesia common. | |||
| 0 to 30 | Deep anesthesia common. | |||
| Entropy | GE Healthcare | State entropy (SE) and response entropy (RE) indices; burst suppression ratio; entropy of EEG signal decreases with sleep and anesthesia. | SE: (0 to 100) RE: (0 to 91) | SE of EEG signal calculated up to 32 Hz. RE includes additional frequencies up to 47 Hz. SE is always ≤RE. Raw EEG can and should be displayed. |
| 80 to 100 | Wakefulness common. | |||
| Sudden drop in entropy | May be associated with loss of responsiveness. | |||
| 40 to 60 | Explicit recall rare. Surgical anesthesia common. | |||
| Sudden rise in RE | May indicate pain or muscle activity. | |||
| Lower entropy numbers and burst suppression | Deep anesthesia common. | |||
| A-line AEP Monitor/2 (Adds EEG parameters) | Danmeter a/s | Middle latency auditory evoked potentials (MLAEPs); ARX Auditory Index (AAI); middle latency (20 to 80 msec); Composite AAI Index (Proprietary - combines EEG and MLAEP information). | 0 to 100 | Full range. |
| 60 to 100 | Wakefulness common. | |||
| 40 to 60 | Drowsiness/sedation common. | |||
| 25 to 40 | Light anesthesia common. | |||
| 15 to 25 | Surgical anesthesia common. | |||
| 0 to 15 | Deep anesthesia common. | |||
| Cerebral State Hand-held device Wireless connection to anesthesia monitor | Danmeter a/s | Cerebral State Index (CSI) (Proprietary); burst suppression electromyography and signal quality are indicated; index derived mainly from alpha and beta EEG ratios, burst suppression. | 0 to 100 | Full range. |
| 90 to 100 | Wakefulness common. | |||
| 80 to 90 | Drowsiness common. | |||
| 60 to 80 | Light anesthesia common. | |||
| 40 to 60 | Surgical anesthesia common. | |||
| 10 to 40 | Deep anesthesia common. | |||
| 0 to 10 | Burst suppression or isoelectric EEG. | |||
| Narcotrend | MT MonitorTechnik GmbH & Co. KG | Cerebrogram (Proprietary); Raw EEG waveform displayed; median and spectral edge frequencies; power in EEG frequency bands is shown. | A to F | Full range. |
| A | Wakefulness common. | |||
| B | Drowsiness common. | |||
| C | Light anesthesia common. | |||
| D | Surgical anesthesia common. | |||
| E | Deep anesthesia common. | |||
| F | Burst suppression or isoelectric EEG. | |||
| NeuroSense monitor | NeuroWave systems Inc. | The index is calculated via analysis of the EEG signals in the gamma frequency band; uses bilateral frontal EEG channels for derivation of index. | 1 to 100 | Conceptualized for use in closed-loop anesthesia. Promoted as having a rapid response time. |
| qCON 2000 monitor | Quantum Medical | The qCON index (proprietary) is a measure of hypnosis that is derived from spectral analysis and burst suppression rate. The qNOX reference scale (proprietary) is derived through EEG signals in patients moving in response to nailbed pressure, and is the component designed for noxiousness. The proprietary algorithm of this device, based on "Adaptive Neuro Fuzzy Inference System" (proprietary), assumes that the EEG signal contains dissociable information on hypnosis and nociception. | 0 to 99 | Theoretically provides information on both hypnosis and nociception. Promoted as having a rapid response time. |
| SEDline | Hospira | Patient state index (PSI) (proprietary); raw EEG waveform displayed; density spectral array (DSA) shown; converts EEG acquired from four active, ground and reference electrodes into a proprietary index; anteriorization of EEG power; loss of coherence. | 0 to 100 | Full range. |
| 90 to 100 | Wakefulness common. | |||
| 50 to 90 | Drowsiness/sedation common. | |||
| 25 to 50 | Surgical anesthesia common. | |||
| 10 to 25 | Deep anesthesia common. | |||
| 0 to 10 | Burst suppression or isoelectric EEG. | |||
| SNAP II | Stryker | SNAP index (Proprietary); spectral analysis of low (0 to 18 Hz) and high (>80 Hz) frequency EEG components; PDA portable device; raw EEG waveform displayed. | 0 to 100 | Full range. |
| 90 to 100 | Wakefulness common. | |||
| 65 to 90 | Drowsiness/sedation common. | |||
| 50 to 65 | Surgical anesthesia common. | |||
| 0 to 50 | Deep anesthesia common. |
