A 63-year-old man presented with aphasia and
right arm paralysis (Medical Research Council
[MRC] grade 0), sparing the leg. With
yawning, his right arm consistently rose to his
chest. Paralysis resumed after yawning. MRI
confirmed an acute ischemic stroke in the left
middle cerebral artery distribution. This
movement ceased after 2 weeks following partial
recovery of arm strength (MRC grade 4).
This phenomenon, first described in the
1844, was recently coined parakinesia brachialis
oscitans. It is speculated to be a release event
in which damaged cortical pathways no longer
inhibit phylogenetically older brainstem
pathways stimulated by yawning.1,2
Figure MRI Diffusion-weighted imaging (A)
and apparent diffusion coefficient (B) sequences
confirm acute ischemic infarct. These images
show involvement of cortical and subcortical
structures in the distribution of the left
middle cerebral artery vascular territory.