Journal of the Neurological Sciences 356 (2015) 217–218

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Journal of the Neurological Sciences
journal homepage: www.elsevier.com/locate/jns

Letter to the Editor
Multifocal dystonia as a manifestation of
acute midbrain infarction
Keywords:
Dystonia
Midbrain
Stroke

Dear Sir,
The basal ganglia-motor loop is considered a neural substrate related
to dystonia [1]. More recently, the cerebellar-motor loop has been implicated as a key anatomical region associated with dystonia [2]. Case studies
have shown secondary dystonia in patients with lesions in the cerebellum
or the cerebellar-motor connections [3,4]. It is unclear whether the cerebellum is the origin of dystonia or connects the cerebellar and basal ganglia loops [5]. This study describes a patient with multifocal dystonia
combined with ataxia in an acute midbrain infarction.
A 66-year-old man visited the Neurology Department due to gait
disturbance and difficulty of writing for 3 weeks. He also had dysphagia
and dysarthria. He had a 30 year history of hypertension. He had no
family history of neurological disorders, including tremor or dystonia.
Twelve years earlier, he experienced an ischemic stroke in the left
basal ganglia, for which he underwent carotid angioplasty in the left
proximal ICA. Since then, he has been taking an antiplatelet agent, a
statin, and an antihypertensive medication regularly. He did not have
any neurological deficits after the first stroke, including motor weakness
and dystonia. Neurological examination showed dystonia in both hands
and feet (Video-Still 1). Dystonia of the right hand was aggravated
when writing, accompanied by mirror dystonia of the left hand
(Video-Still 2). The tongue exhibited involuntary contractions while
the patient was resting. His speech was dysarthric. The score on the
Burke–Fahn–Marsden dystonia movement scale was 35 (range, 0–
120). Cerebellar function tests showed ataxia of both arms and legs
(Video-Still 3). The patient exhibited gait disturbance with wide base,
and he swayed in both directions on tandem walking. Diffusionweighted MRI of the brain revealed an acute infarction in the right midbrain (Fig. 1A). T2-weighted MRI three weeks after symptom onset
showed high signal intensity in the same area (Fig. 1B). The lesion was
located in the paramedian caudal midbrain, which contains the superior
cerebellar peduncle, the decussated superior cerebellar peduncle, and
the caudal portion of the ventral tegmental area including the
rubrospinal fiber. Old ischemic lesions were observed in the left putamen (Fig. 1C), which were thought to be related to the first clinical
stroke, and the right globus pallidus (Fig. 1D). Treatment with clonazepam and trihexyphenidyl did not improve the dystonia of the limbs and
tongue.
The patient described here showed multifocal dystonia, involving
his arms, legs and tongue, without involvement of the trunk. The patient

http://dx.doi.org/10.1016/j.jns.2015.06.068
0022-510X/© 2015 Elsevier B.V. All rights reserved.

also presented with limb ataxia and cerebellar gait disturbance. The lesion observed on brain MRI suggested that the neurological manifestations in this patient were caused by the acute midbrain infarction.
Therefore, according to the consensus classification system, dystonia
in this patient could be classified as late adult onset, multifocal acquired
dystonia of vascular origin [6]. Brain MRI also showed evidence of an old
ischemic stroke in the basal ganglia. The basal ganglia lesions can cause
dystonia and other movement disorders. However, the temporal relationship between dystonia and MRI findings suggested that dystonia
in this patient was caused by the acute midbrain infarction, not by old
lesions in the basal ganglia.
Decussated fibers of the superior cerebellar peduncle constitute the
bilateral output pathway from the cerebellum to the thalamus. Therefore, caudal paramedian midbrain infarctions usually cause bilateral cerebellar dysfunctions, including dysarthria, bilateral limb ataxia, and gait
and truncal ataxia [7]. Although showing typical neurological deficits,
this patient also presented with dystonia of both limbs, which is considered highly unusual. Acquired dystonia after midbrain infarction has
rarely been reported [3,4]. Moreover, multifocal dystonia involving
both arms and legs has not been reported as a manifestation of midbrain
infarctions. Most patients with acquired dystonia after midbrain lesion
showed hemidystonia contralateral to the lesion side or cervical dystonia [3,4]. Lesions in patients with hemi-dystonia due to midbrain lesions
were found to involve dopaminergic dysfunction, as shown by dopamine transporter (DAT) image [8]. The midbrain lesion in our patient
did not directly extend to the anatomical region related to the
nigrostriatal dopaminergic system. Although the lesion extended into
the ventral tegmental area, this likely did not directly cause acute dystonia because this area has been associated functionally with emotion,
cognition and reward systems [9].
The patho-mechanism of multifocal limb dystonia in this patient is
unclear. One possibility is that the basal ganglia lesions caused by the
previous ischemic stroke may have led to the development of dystonia
following the midbrain infarction. The basal-ganglia and cerebellarmotor loops have long been considered distinct control circuits and to
be entirely separated anatomically and functionally [10]. More recently,
however, the cerebellum and basal ganglia have been regarded as communicating with each other and as linked within a functional network
[2]. Therefore, they can compensate for each other in patients with
structural and functional disorders. In this patient, the cerebellarmotor loop might have compensated for the dysfunction in the basal
ganglia motor circuit after the previous basal ganglia infarction. Subsequently, acute destruction of the compensatory mechanism for the
basal ganglia motor loop from the cerebellar circuit may have caused
acute dystonia after midbrain infarction.
Post-stroke movement disorders usually develop several months to
years after the acute stage of stroke [11]. Reorganization of basal-ganglia
motor circuits or generation of hyper-excitable areas after the acute
stage of insult may cause delayed hyperkinetic movement disorders
[11]. However, our patient showed multifocal dystonia as a manifestation of acute stroke, suggesting that dystonia in this patient was not

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Letter to the Editor

Fig. 1. Initial diffusion-weighted MRI (A) and follow-up T2-weighted MRI (B) showing cerebral infarction in the caudal paramedian midbrain. T1 weighted MRI showed an old ischemic
lesion in the left putamen, related to the first clinical stroke (C), and in the right globus pallidus (D).

caused by neuronal reorganization mechanisms. Rather, acute dystonia
may have been caused by acute insult to the cerebello-thalamo-cortical
tract itself, supporting a close relationship between the cerebellar and
basal ganglia motor loops. Therefore, dystonia should be considered
not only as a disorder of the basal ganglia, but also as a circuit disorder
involving the cortico-ponto-cerebello-thalamo-cortical and corticobasal ganglia-thalamo-cortical pathways. These linkages were shown
directly in animals and indirectly by clinical neuroimaging and neurophysiology [5]. Acute multifocal dystonia as a neurological manifestation of cerebral infarction involving the cerebellar output circuit in this
patient may be an important evidence of a functional cerebellar–basal
ganglia connection.
Supplementary data to this article can be found online at http://dx.
doi.org/10.1016/j.jns.2015.06.068.
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Hye-Yeon Choi
Yu Jin Jung
Department of Neurology, Kyung Hee University College of Medicine, Kyung
Hee University Hospital at Kangdong, Seoul, Republic of Korea
Hae-Won Shin
Department of Neurology, Chung-Ang University College of Medicine, Seoul,
Republic of Korea
Corresponding author at: Department of Neurology, Chung-Ang University College of Medicine, 102 Heukseok-ro, Donjak-gu, Seoul 156755, Republic of Korea.
E-mail address: haether@gmail.com.
16 April 2015