| A | B |
|---|
| Ectopic beats | A heart beat that does not originate at the sino-atrial node. |
| EEG | The electroencephalogram or electrical recording of the brain. |
| EMG | The electromyogram or electrical recording of the muscles. |
| End-tidal CO2 | Measurement of the amount of carbon dioxide in the air expired from the lungs at the end of a breath. |
| EOG | The electrooculogram or electrical recording of movement of the eyes. |
| Epoch | A set period of time. |
| Esophageal manometer | A device used to measure the pressure in the esophagus. |
| Excessive fragmentary myoclonus (EFM) | A sleep study leg EMG finding consisting of frequent rapid bursts of activity scored during N sleep. |
| Eye blinks | Blinking of the eyes occurs during W and produces a distinctive EOG pattern. |
| Fibrillation | Rapid, irregular contraction of muscles, especially the muscles of the heart. |
| Frequency | The number of cycles of a signal in a fixed period of time (usually 1 second). |
| High frequency filter | A filter to reduce the amount of fast frequency noise in order to see slower frequency activity more clearly. |
| Hypnagogic foot tremor (HFT) | Bursts of leg muscle activity with a frequency of 0.3 to 4 Hz. |
| Hypnagogic | An EEG pattern associated with NI sleep in children. |
| Hypopnea | A decrease of the amplitude of the nasal pressure signal associated with oxygen desaturation. |
| Hypoventilation | Inadequate ventilation resulting in an increase of carbon dioxide. |
