Table 3.
EEG findings of patients with Bickerstaff’s brainstem encephalitis.
| Recording datea | The level of consciousness | Main findings | Reactivity | PDR |
Sleep stage |
Vertex sharp transient | Sleep spindle | K complex | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Lack of α attenuationb | Anterior distribution | N1 | N2 | ||||||||
| Case 1 | Day 3 | Stuporous | N2 sleep pattern (spindle coma)c,d | + | NA | NA | + | + | + | + | + |
| Day 8 | Stuporous | N1 and N2 sleep patternsc,e | + | NA | NA | + | + | + | + | – | |
| Day 14 | Awake but disoriented | Poorly organized PDR (8–9 Hz) intermixed with generalized θ waves | + | + | – | + | – | – | – | – | |
| Day 25 | Awake and oriented | Well organized PDR (10–11 Hz) | + | – | – | + | + | + | + | – | |
| Case 2 | Day 11 | Somnolent | N1 sleep patternc,f | Not assessed | NA | NA | + | + | + | + (once) | – |
| Case 3 | Day 6 | Awake but disoriented | Poorly organized PDR (8–9 Hz) | – | + | + | + | – | – | – | – |
| Day 16 | Awake and oriented | Well organized PDR (9–10 Hz) | + | – | – | – | – | – | – | – | |
| Case 4 | Day 1 | Awake and oriented | Well organized PDR (9–10 Hz) | + | – | – | – | – | – | – | – |
| Day 4 | Stuporous | N1 and N2 sleep patternsc,d | + | NA | NA | + | + | + | + | – | |
| Day 10 | Comatose | Generalized θ waves intermixed with occasional δ waves | Not assessed | NA | NA | – | – | – | – | – | |
| Day 14 | Awake but disoriented | Poorly organized PDR (8–9 Hz) intermixed with generalized θ and δ waves | Not assessed | Not assessed | + | + | – | – | – | – | |
| Day 18 | Awake but disoriented | Poorly organized PDR (8–9 Hz) | + | + | + | + | + | + | + | – | |
| Case 5 | Day 12 | Somnolent | Poorly organized PDR (8–9 Hz) intermixed with generalized θ waves | + | + | + | + | + | + | + | – |
| Day 21 | Awake and oriented | Poorly organized PDR (8–9 Hz) | + | + | – | + | + | + | + | + | |
| Day 32 | Awake and oriented | Well organized PDR (10–11 Hz) | + | – | – | + | – | – | – | – | |
NA, not applicable; PDR, posterior dominant rhythm.
a
The date of onset of neurological symptoms is defined as Day 1.
b
Lack of attenuation of PDR by eye opening.
c
“unarousable sleep-like” EEG.
d
PDR appears only for short periods of time after auditory stimuli.
e
PDR does not appear after auditory stimuli.
f
Although no stimuli were executed during the recording, the patient was somnolent at the time of recording.