List and definition of the clinical and paraclinical features
| Features | Definition |
| Sex | – |
| Age* | – |
| Memory impairment | Clinical description, confirmed by cognitive tests |
| Dysexecutive syndrome | Clinical description, confirmed by cognitive tests |
| Temporal lobe epilepsy | At least two clinical seizures, with clinical and/or EEG evidence suggesting a mesial temporal lobe origin |
| Behavioural disturbances | Clinical description, including confusional state |
| Cerebellar ataxia—permanent | Clinical description |
| Cerebellar ataxia—paroxysmal | Clinical description |
| Altered general state | Asthenia and/or weight loss and/or anorexia |
| Weight loss | At least 5 kg, or qualified as ‘major’ or ‘important’ |
| Hyperkinetic movement disorders | Myoclonus, dyskinesia, chorea-like movements |
| Insomnia—non-characterised | Patient reports difficulty to sleep, no further specifications |
| Major insomnia | Patient reports complete or near-complete loss of sleep |
| Nocturnal hallucinations | Clinical description |
| Agrypnia excitata* | Polysomnography |
| Sleep apnoea* | Polysomnography |
| Peripheral nerve hyperexcitability (PNH) | Fasciculations, myokimia, cramps with or without ENMG correlate |
| Functional impairment due to PNH motor symptoms | Involuntary muscular contractions with moving of segments of limb impairing walk or basic activities |
| Generalised PNH motor symptoms | Involving four limbs±trunk |
| Severe signs of PNH on ENMG | Multiplets, and/or after discharges, and/or complex repetitive discharges, and/or myokimic discharges, and/or neuromyotonic discharges |
| Dysautonomia | Clinical description |
| Severe dysautonomia | Profuse hypersudation (several changes per day), or orthostatism-independant blood pressure fluctuations, or postural syncopes, or intestinal pseudo-obstruction |
| Neuropathic pain | Clinical description |
| Malignant thymoma* | Histology |
| Myasthenia gravis | ENMG |
| Dyspnoea | Clinical description |
| Abnormal MRI* | Medial temporal lobe hypersignal |
| Abnormal EEG* | Abnormal rhythms, periodic patterns and epileptiform abnormalities |
| Inflammatory CSF* | Pleocytosis >5 cells and/or increased proteinorachia and/or presence of OCB |
*Variables not included in the classification analysis.
CSF, cerebrospinal fluid; EEG, electroencephalography; ENMG, electroneuromyography; OCB, oligoclonal bands.