Clinical features of the cases according to likelihood categories and NMDAR-Ab levels
| Likelihood category | Definite (n=25) | Possible (n=18) | Unlikely (n=13) | ||||
|---|---|---|---|---|---|---|---|
| Definite paraneoplastic | Definite non-paraneoplastic | ||||||
| NMDAR-Ab | Positive | Positive | Low Positive | Positive | Low Positive | Positive | Low Positive |
| Total number | N=9 | N=9 | N=7 | N=5 | N=13 | N=2 | N=11 |
| Age range (median) | 17–48 (25) | 16–41 (26) | 18–68 (44) | 22–80 (65) | 22–71 (54) | 72, 77 | 17–67 (49) |
| F:M | 8:1 | 7:2 | 3:4 | 3:2 | 4:9 | 0:2 | 4:7 |
| CSF NMDAR-Ab positive any time | 3/3 | 1/1 | 1/4 | 0/1 | 0/2 | 0/1 | 0/0 |
| Psychiatric | 6/8 | 8 | 3 | 3 | 4/12 | 0 | 3 |
| Encephalopathy | 8/8 | 9 | 6 | 5 | 6 | 0 | 0 |
| Cognitive | 8/8 | 9 | 7 | 5 | 6/12 | 2 | 4/10 |
| Seizures | 7/8 | 7 | 4 | 2 | 5 | 1 | 3 |
| Extrapyramidal | 6/8 | 7 | 5 | 2 | 3/12 | 0 | 2 |
| CSF lymphocytosis or OCBs* | 5/7 | 8 | 4/6 | 4/4 | 4/11 | 1/2 | 1/10 |
| 3 or more core clinical features (including abnormal CSF) | 8/8 | 9 | 7 | 5 | 6 | 0 | 1 |
| Investigations | |||||||
| MRI MTL | 1 | 0 | 1 | 1 | 2 | 0 | 0/10 |
| MRI WM | 0 | 2 | 3 | 0 | 3 | 1 | 1/10 |
| MRI atrophy | 0 | 1 | 1 | 3 | 3 | 0 | 1/10 |
| EEG epileptic | 2 | 3/8 | 1/2 | 1/3 | 2/10 | ND | 2/8 |
| EEG slowing | 8 | 8/8 | 2/2 | 2/3 | 5/10 | ND | 2/8 |
| Outcomes | |||||||
| Treated | 9 | 9 | 7 | 2 | 4 | 2 | 0 |
| Responded | 8 | 8 | 7 | 0 | 1 | 0 | 0 |
*In many cases, OCB were not systematically looked for.
Phenotypes are given from the retrospective clinical data where available. Denominators are given in cases of censored data. Initially normal but subsequently abnormal tests around the time of presentation (MRI, EEG, CSF) were counted as abnormal in this analysis, unless stated in the online supplementary table S1.
CSF, cerebrospinal fluid; F:M, female:male; MTL, medial temporal lobe abnormalities; ND, not done; NMDAR-Ab, N-methyl-d-aspartate receptor autoantibody; OCB, oligoclonal band; WM, white matter abnormalities.