| as anticonvulsants in the united states | 6 | location |
| during the late 1990s | 2 | temporal |
| originally | 2 | manner |
| agent → be → approved | 18 |
| agent → be approved for → use | 10 |
| negative | neutral | positive |
| 0.178 | 0.562 | 0.260 |
| Raw frequency | 28 |
| Normalized frequency | 0.367 |
| Modifier score | 0.600 |
| Perplexity | 402.007 |