| very | 7 | degree |
| in some patients | 4 | location |
| for about 50% of attacks | 2 | other |
| oxygen → be → effective | 13 |
| oxygen → be → efficient | 6 |
| negative | neutral | positive |
| 0.035 | 0.253 | 0.712 |
| Raw frequency | 19 |
| Normalized frequency | 0.386 |
| Modifier score | 0.500 |
| Perplexity | 138.453 |