| AHI (Apnea-Hypopnea Index): | Number of apneas and hypopneas per hour of sleep |
| Apnea | Cessation of breathing during sleep |
| Apnea Index | Number of apneas per hour of sleep |
| Arousals | Brief awakenings that are typically more than 3 seconds and less than 15 seconds in duration. |
| Central Sleep Apnea | cessation of breathing during sleep due to lack of respiratory effort |
| Cheyne-Stokes Respiration (Breating) | A very specific form of central sleep apena, mostly due to cardica problems or brain problems. |
| CSA | Central Sleep Apnea |
| Desaturation | Decrease in oxygen saturation in blood. |
| DI (Desaturation Index) | Number of the times that oxygen saturaiton decreases by 4% and comes back to normal level per hour of sleep. |
| Hypopnea | Shallow breathing during sleep that is significant enough to cause a drop in blood oxygen, or causes arousals of the brain. |
| Hypopnea Index | Number of hypopneas per hour of sleep |
| Hypoventilation | Shallow breathing to a degree that carbon dioxide accumulates in the blood |
| Insomnia, Sleep-Maintenance | Difficulty falling back to sleep after nocturnal awakening |
| Insomnia, Sleep-onset | Difficulty initiating sleep |
| Nocturia | Urination after falling asleep (going to bathroom) |
| Obstructive Sleep Apnea | Cessation of breathing during sleep due to closure of the throat |
| OHS | Obesity Hypoventilaton Syndrome |
| OSA | Obstructive Sleep Apnea |
| Oxygen desaturation | Decrease in blood oxygen saturation |
| PLM | Periodic Legs Movement, leg twiches that occur during sleep, and the person is unaware of them. This is a test finding. |
| PLMD | Periodic Limbs Movements Disorder; leg twiches that occur during sleep, and the person is unaware of them. This is a clinical diagnosis. |
| RDI (Respiratory Disturbance Index) | Apnea Index + Hypopnea Index + RERA Index |
| RERA | Respiratory-Related Arousals; Shallow breathings that do not cause oxygenation problem, but cause brain arousals |
| RLS | Restless Legs Syndrome |
Peninsula Sleep Center, Inc.