Table 2.
Features that increase suspicion of an autoimmune etiology
| Clinical features | Polysomnographic features | Neurological workup |
|---|---|---|
| Subacute onset, rapid progression symptoms | Status dissociatus | CSF: inflammatory profile |
| History of other autoimmune conditions | Undifferentiated Non-REM sleep | MRI brain: limbic encephalitis, diencephalic encephalitis, rhombencephalitis |
| Recent history of cancer | Poorly structured N2 sleep | PET brain: occipital lobe hypometabolism |
| History of an infectious-like prodrome | Atypical rapid eye movements in Non-REM sleep | EEG: Delta Brush |
| New onset encephalopathy and/or seizuresa | Rapid periodic leg movements | EMG: peripheral nerve hyperexcitability |
| Other involuntary movements: chorea, oral dyskinesia | ||
| Autonomic dysfunction | ||
| Robust objective responsive to immunotherapy | ||
| Late onset narcolepsy | ||
| Agrypnia excitata |
REM = rapid eye movement sleep; N2 = N2 sleep; CSF = cerebrospinal fluid; MRI = magnetic resonance imaging; PET = positron emission tomography; EEG = electroencephalography; EMG = electromyography
aEspecially seizure semiologies such as faciobracial dystonic seizures and pilomotor seizures