Video 1
Example Examination of a Post-anoxic Myoclonus Patient. The (abridged) systematic examination of post-anoxic myoclonus (PAM) Case 2 (Table 2) and the video protocol of this study (Supplement A). Case 2 displays slight myoclonus in rest, but it seems to increase in frequency and severity after the application of stimuli. This patient is the only PAM case of this cohort that survived and recovered with only mild cognitive deficits after 6 months.
Table 1
Clinical Characteristics
| Age, years, mean (SD) | 59 | (16) |
| Male, n | 7 | |
| Initial rhythm, n | ||
| Shockable (VF/VT) | 3 | |
| Non-shockable (bradycardia/asystole/PEA) | 7 | |
| Primary cause of CPR, n (%) | ||
| Cardiac | 3 | |
| Hypoxic | 6 | |
| Unknown | 1 | |
| Location of arrest, n | ||
| OHCA | 8 | |
| IHCA | 2 | |
| Time to ROSC (minutes), median (IQR) | 18 | (10–23) |
| Time to occurrence of PAM (hours), median (IQR) | 14 | (10–36) |
| Initial treatment of PAM, n | ||
| Propofol | 8 | |
| Clonazepam | 3 | |
| Sodium valproate | 3 | |
| Levetiracetam | 2 | |
| Other benzodiazepine | 2 | |
| >1 drug | 4 | |
| SEP N20, n | ||
| Present | 5 | |
| Bilaterally absent | 5 | |
| EEG result, n | ||
| Normal/mild encephalopathic | 0 | |
| Diffuse slowing | 1 | |
| Status epilepticus | 4 | |
| Burst suppression | 4 | |
| Low voltage/isoelectric | 0 | |
| No EEG | 1 | |
| Outcome, n | ||
| Recovery with mild cerebral disability | 1 | |
| Death | 9 | |
| Treatment withdrawal, n | 9 | |
| Time to treatment withdrawal (hours), median (IQR) | 48 | (38–130) |
| Reason for treatment withdrawal, n | ||
| Neurological examination | 4 | |
| SEP | 5 | |
| EEG | 5 | |
| Combination | 3 |
[i] Abbreviations: CPR, Cardiopulmonary Resuscitation; EEG, Electroencephalography; ICU, Intensive Care Unit; IHCA, In Hospital Cardiac Arrest; IQR, Interquartile Range; OHCA, Out of Hospital Cardiac Arrest; PAM, Post-anoxic Myoclonus; PEA, Pulseless Electrical Activity; ROSC, Return of Spontaneous Circulation; SD, Standard Deviation; SEP, Somatosensory Evoked Potential; VF, Ventricular Fibrillation; VT, Ventricular Tachycardia.
Table 2
Video Assessment Scores of Post-anoxic Myoclonus
| PAM Phenotype | Stimulus Sensitivity | Localization | CGI–S | UMRS | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Case | R1 | R2 | R3 | R1 | R2 | R3 | R1 | R2 | R3 | R1 | R2 | R3 | R1 | R2 | R3 |
| 1 | gz | mf | mf | − | − | − | p+d | p+d | p+d | 6 | 5 | 4 | 29 | 35 | 18 |
| 2 | mf | gz | mf | + | − | + | p | p | p | 4 | 4 | 2 | 4 | 8 | 2 |
| 3 | gz | gz | gz | + | − | − | p+d | p+d | p+d | 7 | 7 | 5 | 87 | 52 | 74 |
| 4 | gz | mf | mf | − | − | − | p+d | p+d | d | 4 | 4 | 3 | 22 | 8 | 32 |
| 5 | mf | mf | mf | + | − | − | d | d | d | 2 | 3 | 2 | 1 | 4 | 2 |
| 6 | mf | mf | mf | + | − | − | p | p+d | p | 2 | 2 | 2 | 4 | 6 | 5 |
| 7 | gz | mf | mf | + | − | + | p+d | p+d | p+d | 5 | 4 | 2 | 14 | 19 | 18 |
| 8 | gz | mf | mf | + | − | + | p+d | p+d | p+d | 6 | 6 | 4 | 64 | 41 | 76 |
| 9 | gz | mf | mf | − | − | − | d | p+d | p+d | 6 | 4 | 4 | 33 | 23 | 27 |
| 10 | gz | mf | mf | + | − | − | p | p+d | d | 5 | 5 | 4 | 34 | 22 | 59 |
