1. Teaching NeuroImages Neurology Residents and Fellows Section
A Newborn Male with Rhythmic Extremity Movements
Teaching NeuroImages Neurology Residents and Fellows Section
© 2014 American Academy of Neurology

2. Vignette
A newborn male suffered a profound hypoxic-ischemic insult at birth.
He developed rhythmic myoclonus within one hour which was initially assumed to be seizures, but was unresponsive to escalating antiepileptic therapy.
On careful exam, it was evident that myoclonus could be induced and suppressed.
Walsh et al.
© 2014 American Academy of Neurology

3. Imaging Walsh et al. Figure Legend: Amplitude Integrated EEG
Amplitude integrated EEG monitoring showed transient increases in amplitude concerning for possible seizures (red arrows) in contrast to baseline (black arrows). Concurrent raw EEG trace (dashed lines) showed an intermittent rhythmic pattern time-locked to the paroxysmal limb movements.
Walsh et al.
© 2014 American Academy of Neurology

4. Imaging
Video Legend: Video EEG of Myoclonus and Associated Artifact
Part 1: Spontaneous onset of rhythmic movements of right upper limb, with a synchronized rhythmic EEG pattern over left hemisphere. Note the infant’s head resting on left-sided electrodes. Movements are suppressed on holding the limb, with simultaneous resolution on EEG.
Part 2: Tactile stimulation induces rhythmic movements of left upper limb, with synchronized rhythmic EEG pattern over left hemisphere. Movements are suppressed on holding, with simultaneous resolution on EEG.
Part 3: Infant’s head repositioned, now resting on right-sided electrodes. Tactile stimulation induces rhythmic movements of right upper limb, with synchronized rhythmic pattern with a maximum over right hemisphere. Movements are suppressed on holding.
Walsh et al.
© 2014 American Academy of Neurology

5. Nonepileptic Myoclonus in a Neonate Following Severe Hypoxic-Ischemic Injury
Nonepileptic myoclonus is a brainstem release phenomena [1] that can be difficult to distinguish from seizures without detailed clinical examination combined with EEG [2].
Timely diagnosis can prevent unnecessary treatment and can inform prognosis.
Care in this case was ultimately redirected when neuroimaging confirmed severe injury.
References
1. Huntsman RJ, Lowry NJ, and Sankaran K. Nonepileptic motor phenomena in the neonate. Paediatr Child Health 2008; 13 (8):
2. Mizrahi EM and Kellaway P. Characterization and classification of neonatal seizures. Neurology 1987;37:
Walsh et al.
© 2014 American Academy of Neurology