| Similarity | Rank | |
|---|---|---|
| EEG | 0.701 | 33656 |
| Sleep | 0.694 | 10565 |
| wakefulness | 0.692 | 61910 |
| Melatonin | 0.662 | 55486 |
| R.E.M. | 0.656 | 84288 |
| Insomnia | 0.650 | 40461 |
| brainwaves | 0.648 | 82701 |
| Nocturnal | 0.646 | 87067 |
| Apnea | 0.644 | 58715 |
| sleepiness | 0.642 | 39645 |
| sleepwalking | 0.639 | 73293 |
| sleep | 0.635 | 1323 |
| heartbeat | 0.622 | 15814 |
| apnea | 0.621 | 17021 |
| melatonin | 0.620 | 27894 |
| SCN | 0.620 | 96076 |
| drug-induced | 0.620 | 78060 |
| Transient | 0.617 | 73217 |
| entrainment | 0.616 | 62176 |
| Nervous | 0.610 | 41878 |
| Dopamine | 0.610 | 75238 |
| Biofeedback | 0.609 | 85635 |
| brainwave | 0.606 | 54462 |
| RLS | 0.605 | 55557 |
| waking | 0.604 | 9812 |