Background: Parakinesia Brachialis
Oscitans (PBO) is a rare movement disorder
described in some cases of hemiplegia, when the
onset of yawing is associated with an
involuntary raising of the paralysed arm
(Walusinski et al, 2005).
Objective: To describe two patients
who developed PBO after ischemic stroke in the
brainstem.
Methods/Results:
Case 1- A 39-year-old man with severe
systemic arterial hypertension, developed sudden
dysartria, dysphagia, dysesthesia and
incoordenation in the left lower limb. The
neurological examination showed hyperreflexia in
the left upper and lower limbs, left Babinski
sign, gait ataxia, dysmetria and
dysdiadochokinesia associated to alodynia in the
left upper limb. When the patient had yawning
his left upper and lower limbs had spasm
associated to the involuntary elevation of the
left upper limb. The brain MRI showed an infarct
in the right side the pontine area. The work-up
discovered an elevated level of
homocysteine.
Case 2: A 55-year-old man presented a
sudden vertigo when he turn left his head, when
he was riding a bicycle, followed by weakness
and paresthesias of the left lower limb. The
neurological examination demonstrated left lower
limb paresis, associated to spasticity and
increased of the profound reflexes. There is
also a tactil hyposthesia in the left lower
limb. This patient described that when he had a
yawning his left lower and upper limbs has
dystonic posture and the left upper limb has an
involuntary elevation. Brain MRI showed a small
infarct in the right side of the medulla
oblonga. The extensive work-up demonstrated the
presence of patent foramen ovale, with
microembolization.
Conclusion: The authors describe two
patients with brainstem stroke who developed
Parakinesia Brachialis Oscitans.
Discussion: In 2005, Walusinski et al
coined the term "parakinesia brachialis oscitans
(PBO) to describe four patients who developed
hemiplegia due stroke, most often localized on
the internal capsule. In these cases of
hemiplegia, the onset of yawning was associated
with an involuntary raising of the paralyzed
arm. These authors proposed that the section of
the cortico-neocerebellum tract of the
extra-pyramidal system disinhibits the
spino-archeocerebellum tract, enabling a motor
stimulation of the arm by the lateral reticular
nucleus, which harmonises central respiratory
and locomotor rhythms.
In the last 150 years there are some
descriptions of these phenomenon in the world
literature, and probable Abercrombie and Gendrin
published the first case of PBO in
1835(Abercrombie J, Gendrin A, 1835).
Töpper et al studied three patients
with involuntary stretching during yawning,
after pyramidal lesions. The authors discussed
that yawning might be the somatomotor
manifestation of a particular emotional state
characterized by boredom and fatigue. They
stated that involuntary movements of the plegic
arm in patients with pyramidal tract lesions
support the concept of the existence of an
independent emotional motor system, which has an
input to mononeurones in the brain stem and the
spinal cord. On the other hand Blin et al
published a single report of a hemiplegic arm
stretching related to yawning. The authors
performed further investigation using
apomorphine administration.
4- Töpper
R, Mull M, Nacimiento W. Involuntary
stretching during yawning in patients with
pyramidal tract lesions: further evidence for
the existence of an independent emotional motor
system. European Journal of Neurology 2003;
10:495-499.
mise à jour
du
8 mai
2010
Parkinsonism Relat
Disord
2012;18(2):204-206
Parakinesia
Brachialis Oscitans
Report
of three cases.
Plínio M. G. de Lima, Renato
P. Munhoz, Nilson Becker
Hélio A. G.
Teive
Movement Disorders
Unit, Neurology Service, Internal Medicine
Department, Hospital de Clínicas, Federal
University of
Paraná.
The term parakinesia brachialis oscitans
(PBO) was coined recently by Walusinsk et
al.[1,2] to describe cases of hemiplegia
in which the initiation of yawning caused
involuntary raising of the affected upper limb,
usually followed by its drop during expiration.
The phenomenon is still rarely described and
considered as a curiosity, probably because it
is, in fact, under recognized.
Here we report three additional cases of PBO
discussing the phenomenology and possible
physiopathology of this phenomenon.
Case Reports:
Case 1: A 63-year-old right handed man
was initially admitted to the hospital because
of sudden onset of left disproportionate (upper
limb predominant) hemiparesis and mild
dysarthria. Brain CT scan on admission revealed
a right middle cerebral artery territory
infarct. Brain MRI disclosed a recent right
cortical/subcortical fronto parietal stroke.
Carotid ultrasound revealed a 30&endash;40%
bilateral internal carotid artery stenosis.
Transthoracic echocardiogram showed a mild left
ventricle hypertrophy. His past medical history
was positive for elevated blood pressure
detected 5 years ago and treated regularly with
enalapril 10mg bid. He was discharged after 4
days with partial improvement of lower limb
function but remained with minimal left upper
limb strength (grade 1 distal, 2 proximal).
After six months he was seen at the outpatient
clinic where he was now followed for secondary
prevention of cerebrovascular disease, using
clopidogrel 75mg qd, enalapril 10mg bid and
simvastatin 20mg qd. His lower limb function
showed additional improvement during this period
and he was now able to walk unassisted. His
upper limb remained completely dysfunctional and
was now spastic assuming a position of partial
flexion and pronation of the forearm. At this
time, he spontaneously related that his paretic
arm presented unexpected and involuntary
abduction and lifting during yawning. This
phenomenon was reproduced twice during the
consultation, always triggered exclusively by
yawning, the first time while sitting and
another while standing. He could recall
occasional episodes triggered by yawning while
lying down, just before sleep. The movement
started during inspiration leading to minimal
extension of the forearm, but a relatively wide
abduction and elevation of the whole upper limb,
reaching an angle of about 60 degrees from his
body. The movement lasted for almost 2 seconds
and slowly returned to the resting position by
the end of the yawning act. He first noticed the
phenomenon two months after his cerebrovascular
event. Although curious, he was not bothered by
the involuntary movement, nor did he feel that
it interfered negatively with functionality.
Indeed he viewed it as a sign of potential
functional improvement in the near future.
Case 2: A 39-year-old man with severe
hypertension, presented with sudden dysarthria,
dysphagia, dysesthesia and incoordenation in the
left lower limb (LL). On neurological
examination he also presented increased deep
tendon reflexes in the UL and LL, a left
extensor plantar reflex, gait ataxia, dysmetria
and dysdiadochokinesia with sensory symptoms
(alodynia) in the left UL. When he presented
spontaneous yawning, his left UL presented with
involuntary elevation (abduction and flexion),
associated with short amplitude extension of the
left LL. Brain MRI (Figure 1) showed a right
wedge-shaped lesion in the pontine base
extending from the basal surface to the deep
basis pontis. Brain and cervical MRA showed no
abnormalities. Cardiological evaluation was
negative. Extensive work-up demonstrated normal
results, except for elevated homocysteine
levels. After four months, the patient was
reassessed at the outpatient clinic, with
complete remission of the abnormal involuntary
movements, treated for secondary prevention of
cerebrovascular disease, using folic acid 5 mg
qd, vitamin B complex bid, clopidogrel 75mg qd,
and anlodipine 5 mg / losartane 10 mg qd.
Case 3: A 55-year-old man presented with
sudden onset of vertigo when he turned his head
to the left, while riding his bicycle. That was
followed immediately by weakness and
paresthesias of the left LL. On neurological
examination he had left LL paresis, with
spasticity and increased deep tendon reflexes.
Sensation was also abnormal with tactile
hyposthesia in the left LL. He described that
while yawning, his left LL and UL presented
contractures, the UL elevating with the hand
deviating to the direction of the opposite side
of his chest. Brain MRI showed a infarct in the
right rostral medulla oblongata (Figure 2). An
extensive work-up, including brain and cervical
MRA were normal, and trans-esophageal
echocardiography demonstrated a patent foramen
ovale. Trans-cranial doppler confirmed
microembolization. In the follow-up, after 6
months, neurological examination demonstrated
only pyramidal signs in the left LL.
Discussion
The term synkinesis defines the occurrence of
an involuntary muscle contractions accompanying
voluntary movements, as seen, for example, in
cases of facial synkinesia that occurs in
patients with Bell`s palsy, in which smiling
induces involuntary contraction of the
orbicularis oculi muscle leading to partial eye
closure.[3,4] In the case of a
hemiparesis, synkinesias occur in the affected
hemibody as voluntary movements are produced in
non the side, including an exacerbation of the
spastic posture of the paralyzed limb, movement
of the affected synergistic muscles, and
imitation synkinesis, when the affected limb
attempts to perform a similar movement occurring
in the non affected limb.[5] PBO, on the
other hand, represents a phenomenon triggered by
a reflex movement, not a voluntary one.
Therefore, the term synkinesis does not apply in
this case. Parakinesia, as defined by the
authors who coined the term PBO, is defined as
"an abnormal involuntary movement that acts as a
parasite, caricature or replacement of a normal
movement".[1,2] Oscitans means yawn in
Latin.
We report three cases of PBO, all caused by
vascular ischemic disorders located in the
cerebral hemispheres, the pontine and bulbar
areas. Among the few cases of PBO reported in
the literature,[1,2,5-9] etiologies
varied included cerebrovascular disease, either
ischemic or hemorrhagic, amyotrophic lateral
sclerosis (ALS), and brainstem tuberculoma.
There was no preference for laterality and no
correlation with dominance. Onset occurred after
the acute insult or later during the spastic
phase, in most cases within 6 months from the
causing insult. The movement is typically
evident in the upper limb and include abduction
or adduction, and the movement occurs
exclusively with onset of the yawning act,
returning to the resting posture when the yawn
is over.[1,2,6] Cases in which there is
motor recovery, PBO tends to
disappear.[1] The location of the lesion
includes the territory irrigated by the middle
cerebral artery territory, and a pontine
infarction in cases related to vascular origin;
a pontomedullary lesion with Millard-Gübler
syndrome related to a tuberculoma, and a case of
ALS with prominent bulbar
involvement.[1,2,5-9]
From an anatomic standpoint, the
hypothalamus, the medullary and pontine regions
play important roles in yawning, as well as
their connections to frontal and cervical spinal
areas.[9,10] Also, it seems obvious that
the muscles innervated by cranial nerves V, VII,
IX, X, XI, XII, phrenic nerve and the dorsal
nerves innervating the intercostals, play an
accessory role. Although so far there have been
no convincing hypotheses concerning the
anatomical pathways responsible PBO, one of the
possible physiological explanations for PBO is
that during yawning, the strong contraction of
respiratory muscles forms a proprioceptive
signal that eventually leads to the stimulation
of the anterior spinal horn from C4 to C8.
[1,2,10] This mechanism, however, does
not explain the short concomitant involuntary
movements in the LL described in case 2 and 3
presented here. Additionally, these two cases
may represent variants of classic PBO as they
also broaden the phenomenological spectrum of
PBO as in case 2 there was no hemiparesis at
all, and in case 3 only the LL was paretic.
We agree with the conclusion of previous
reviews, indicating the few cases of PBO
reported in the literature may not mirror its
true frequency.[1,2] The clinical
relevance, complete phenomenology and
physiological implications of PBO are subjects
to be addressed in future case series and
reviews.
[6]. Lanari
A, Delbono O. The yawning and stretching
sign in hemiplegics. Medicina
1983;43;3:355-6
[7]. Louwerse
E. Forced yawning as a pseudobulbar sign in
amyotrophic lateral sclerosis. J Neuroscience
Research 1998;12:s392
[8]. Töpper
R, Mull M, Nacimento W. Involuntary
stretching during yawning in patients with
pyramidal tract lesions: further evidence for
the existence of an independent emotional motor
system. European J Neurology 2003;10:495-9
[9]. Wimalaratna
HS, Capildeo R. Is yawning a brainstem
phenomenon ? a stroke patient who stretched his
hemiplegic arm during yawning. Lancet
1988;1:8580
[10]. Walusinski
O. Can stroke localisation be used to map
out the neural network for yawning behaviour? J
Neurol Neurosurg Psychiatry 2007;78:1166.
