There have been few described cases of
hemiplegia with involuntary elevation of
paralyzed arms while yawning, symptoms referred
to as parakinesia brachialis oscitans.
Brain imaging shows lesions mainly
associated with internal capsule or pons. We
report a patient with involuntary hemiplegic arm
raising during yawning after acute infarction
involving the right motor cortex and frontal
subcortex. Case : A 59-year-old man presented
with sudden onset of left-sided weakness.
On admission, neurological examinations
revealed alert mental state, a left hemiplegia
(MRC grade 2/5 in the left upper limb, 3/5 in
the left lower limb) and dysarthria. Sensory
exam was unremarkable. Deep tendon reflexes were
asymmetrically brisk on the left. Babinski's
sign presented on the left. Diffusion weighted
magnetic resonance imaging (MRI) demonstrated
increased signal intensities on the right
precentral gyrus and frontal subcortex. One day
after the stroke, the patient's wife reported
that his left hemiplegic arm was spontaneously
elevated every time he yawned (video).
This peculiar phenomenon persisted during a
17 day admission period. At the last contact
with the patient's family five years after the
stroke onset, his left hemiplegia still
continued with the MRC grade of about 3/5,
however, abnormal movement in his hemiplegic arm
during yawning disappeared.
Conclusions or Commentes : The underlying
mechanism of parakinesia brachialis oscitans has
yet to be clarified. However, activated
projections from disinhibited subcortical
structures to the brain stem extrapyramidal
motor control systems or the existence of an
independent emotional motor pathway has been
suggested as the possible pathophysiological
explanation for the association between
involuntary movements of the hemiplegic arm and
yawning.
