3 Keime-Guibert F, Graus F, Fleury A, Rene R, Honnorat J, Broet P,
Delattre JY: Treatment of paraneoplastic neurological syndromes with
antineuronal antibodies (anti-Hu, anti-Yo) with a combination of immunoglobulins, cyclophosphamide, and methylprednisolone. J Neurol Neurosurg Psychiatry 2000;68:479–482.
4 Blaes F, Strittmatter M, Merkelbach S, Jost V, Klotz M, Schimrigk K,
Hamann GF: Intravenous immunoglobulins in the therapy of paraneoplastic neurological disorders. J Neurol 1999;246;299–303.
5 Graus F, Elkon KB, Lloberes P, Ribalta T, Torres A, Ussetti P, Valls J,
Obach J, Agusti-Vidal A: Neuronal antinuclear antibody (anti-Hu) in paraneoplastic encephalomyelitis simulating acute polyneuritis. Acta Neurol
Scand 1987;75:249–252.
6 Byrne T, Mason WP, Posner JB, Dalmau J: Spontaneous neurological
improvement in anti-Hu-associated encephalomyelitis. J Neurol Neurosurg Psychiatry 1997;62:276–278.
7 Darnell RB, DeAngelis LM: Regression of small-cell lung carcinoma in
patients with paraneoplastic neuronal antibodies. Lancet 1993;341:21–22.
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hypercapnic respiratory failure: Lower motor neuronopathy associated
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Escaramis G, Delattre JY: Anti-Hu-associated paraneoplastic encephalomyelitis: Analysis of 200 patients. Brain 2001;124:1138–1148.
James F. Meschia, MD, Department of Neurology, Mayo Clinic
4500 San Pablo Road, Jacksonville, FL 32224 (USA)
E-Mail meschia.james@mayo.edu

Eur Neurol 2003;50:114–117
DOI: 10.1159/000072512

Focal Hand Myoclonus Caused by a
Small Hematoma underneath the Cerebral
Motor Cortex
P.C. Tsai a, F.C. Chang b, C.H. Tsai b, F.R. Jang a, A.N. Shen a,
Y.T. Huang a, S.C. Lai a, T.H. Yeh a, M.K. Lu b, C.S. Lu a

motor area (fig. 1A). A focal stimulus-sensitive and arrhythmic jerk
of the right hand was developed 5 weeks after the onset of the righthand paresis. It ameliorated gradually and remained in trivial ring
finger flickering 2 months later on follow-up. A series of electrophysiological investigations were conducted to illustrate the nature of the
jerks and the findings of electromyography (EMG) and jerk-locked
back average are shown in figures 1B and 2A. The average EMG
burst duration was 175.09 ms (SD = 44.07). The somatosensoryevoked potential (SEP) study of the upper limb revealed no evidence
of giant SEP and no C-response (data not shown). Since the hematoma was located below the left motor cortex, it is intriguing to know
how the lesion will affect the Bereitschaftspotential (BP). The recording was secured on the 15th day after the onset of myoclonus and the
results are shown in figure 2B.
Discussion
The relationship between the right-hand focal myoclonus and the
tiny hematoma was clearly illustrated by neuroimaging study in the
current case. There was no newly developed hemorrhage or infarction attributing to the appearance of the right-hand jerks (fig. 1A).
Actually the perifocal edema around the hematoma was even diminished in the post-myoclonic films (fig. 1A). The long jerk with EMG
burst duration of 175 ms discriminated the myoclonus from that of
cortical origin [4]. Since the tiny hematoma was localized just below
the primary motor cortex, it is necessary to elucidate the possible
contribution of the cortical components to the generation of the myoclonus. The negative findings of jerk-locked back average and SEPs,
however, made the possibility of ‘cortical’ origin unlikely, suggesting
that the myoclonus could be subcortical in nature. The sparing of the
motor cortex could also be strengthened by the findings of the preservation of the late components of BP. In subcortical lesion, as in the
current case, the neural pathways rather than neurons were most likely to be severed. It would be then that networks connecting the subcortical-motor cortical domains were perturbed to cause the jerks as
proposed by Lance and Adams [5]. In addition to the physical injury
caused by the hematoma, the corruptive effect of hemosiderin, a
decomposition product of hematoma, on the neural structure [6]
should also be considered, which may share a role in the myoclonic
generation in this case.

a Movement Disorders Unit, Department of Neurology, Chang
Gung Memorial Hospital, Taipei, and b Neuroscience
Laboratory, Department of Neurology, China Medical College
Hospital, Taichung, Taiwan

Fig. 1. A Images before and after the onset of myoclonus. B The

Introduction
Myoclonus is defined as sudden, brief, jerky, shock-like, involuntary movements arising from the central nervous system and involving extremities, face and trunk [1]. The causes of myoclonus are various [1]. Rarely, it was reported to be causal linked to a focal central
nervous system lesion [2, 3]. Here we report a case of right-hand myoclonus caused by a small hematoma at the contralateral region underneath the motor cortex.
Case Report
The 59-year-old female patient developed an abrupt onset of
right-hand weakness in association with severe headache and recurrent nocturnal fever about 23 days prior to admission. She was finally
confirmed to have subacute bacteria endocarditis caused by Streptococcus sangui. Neuroimaging studies revealed a small hematoma
causally linked to mycotic aneurysm rupture over the left subcortical

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surface EMG recording over the right flexor carpi radialis (FCR) and
extensor digitorium communis (EDC). A1 CAT scan shows a small
hematoma located over the left submotor cortex. A2 Lateral view of
digitized subtraction angiograms reveal a tiny aneurysm over the
compatible area of A1. A3 Axial (T2-weighted) and A4 sagittal (T1weighted) views of magnetic resonance images verify a tiny hematoma over the left submotor cortex with perifocal edema. A5 Axial
(T2-weighted) and A6 sagittal (T1-weighted) views of magnetic resonance images after the onset of myoclonus reveal the persistent presence of a small old hemorrhagic lesion located over the same area.
The perifocal edema is less distinct (A5) as compared with their corresponding images in A3 and A4. B Simultaneous EMG bursts are
observed over the antagonist muscle pairs. The jerks may run in single or in hypersynchronous duplex EMG discharges (as indicated by
arrows over the EDC). The amplified signal from the EDC reveals
the long-duration nature of the EMG burst.

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115

Fig. 2. A Jerk-locked back average recording with EMG burst from
the right extensor digitorium communis as the trigger. Seven cup
electrodes were taped on the scalp according to the international 10–
20 system (F3, C3, P3, Cz, F4, C4, P4). The figure is the average of
120 individual traces. No preceding electroencephalographic event
could be observed. B BP recording with the EMG signal from the
right and left extensor digitorium communis as the trigger. Fifteen
cup electrodes were taped on the scalp according to a modified inter-

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national 10–20 system (F3, F1, Fz, F2, F4, C3, C1, Cz, C2, C4, P3,
P1, Pz, P2, P4). The figure in each panel is the average of 120 individual traces. Only the amplitudes of BP from the 0.5 s before to the
onset of the voluntary EMG activity were measured. On moving the
right EDC, the amplitudes of BP were 2.17, 2.72 and 2.84 ÌV for C1,
Cz and C2, respectively. The BP elicited by left EDC movement was
also clearly observed over the C1, Cz and C2 with amplitudes of 4.50,
3.67 and 3.39 ÌV, respectively.

Short Reports

Acknowledgements
The authors thank Prof. P.D. Thompson at the Royal Adelaide
Hospital, Australia, for his valuable suggestions in the discussion of
the manuscript. The study was supported by grants from NMRP
047H, CMRP 710 and DMR 92011.
References

Brain MRI (fig. 1) revealed well-defined focal non-gadoliniumenhancing hyperintense (T2) lesions in the posterior part of the internal capsules and globus pallidi bilaterally. These were felt to be compatible with either a demyelinating or ischaemic process. Extensive
investigations including thyroid function, calcium metabolism, fasting serum glucose, cholesterol and triglyceride levels, ESR, ANA,
anti-Ds-DNA antibody, lupus anticoagulant and protein S, protein C

1 Fahn S, Marsden CD, Van Woert MH: Definition and classification of
myoclonus. Adv Neurol 1986;43:1–5.
2 Kao YF, Shih PY, Chen WH: An unusual concomitant tremor and myoclonus after a contralateral infarct at thalamus and subthalamic nucleus.
Kaohsiung J Med Sci 1999;15:562–566.
3 Wang HC, Hsu WC, Brown P: Cortical tremor secondary to a frontal cortical lesion. Mov Disord 1999;14:370–374.
4 Obeso JA, Rothwell JC, Marsden CD: The spectrum of cortical myoclonus.
Brain 1985;108:193–224.
5 Lance JW, Adams RD: The syndrome of intention or action myoclonus as
a sequel to hypoxic encephalopathy. Brain 1963;86:111–136.
6 Pelak VS, Galetta SL, Grossman RI, Townsend JJ, Volpe NJ: Evidence for
preganglionic pupillary involvement in superficial siderosis. Neurology
1999;53:1130–1132.
Dr. Chon-Haw Tsai, Department of Neurology
China Medical College Hospital, 2, Yuh Der Road, Taichung 404 (Taiwan)
Tel. +886 4 220 52121/ext 3685, Fax +886 4 220 33474
E-Mail d8079@www.cmch.org.tw

Eur Neurol 2003;50:117–118
DOI: 10.1159/000072513

Transient Paroxysmal Dyskinesia Associated
with Focal Basal Ganglia Lesions

Fig. 1. Axial FLAIR (TR 9,000 ms/TE 100

ms/IR 2,500 ms/2 excitations) image demonstrating subcentimetre hyperintense lesions in the posterior limb of internal capsules and globi pallidi bilaterally.

Siew-Ju See a, Ling-Ling Chan b, Eng-King Tan a
Departments of a Neurology and b Diagnostic Radiology,
Singapore General Hospital, Singapore

Introduction
Paroxysmal kinesigenic dyskinesia (PKD) is a rare neurological
condition that can be idiopathic or associated with ischaemic, inflammatory or metabolic derangements. Its pathophysiology remains
a topic of intense debate with many investigators believing that it is
related to dysfunction of basal ganglia structures. We report an
unusual case of transient and reversible PKC associated with focal
lesions on brain magnetic resonance imaging (MRI) and discuss the
pathophysiologic mechanism.
Case Report
A 30-year-old woman presented with paroxysmal dystonic posturing of the right upper and lower extremities consisting of shoulder
abduction, elbow and wrist flexion, flexion and extension at the
metacarpophalangeal and interphalangeal joints respectively and
flexion at the hip and knee. These episodes were precipitated by sudden movements such as getting up from a sitting position, and were
preceded by an aura of sensation of ‘tightness’ in the affected limbs.
There were 10–15 attacks per day, each lasting between 5 and 20 s.
Between attacks, neurological examination was normal.

Short Reports

Fig. 2. Corresponding axial FLAIR (identi-

cal parameters) image showing near total
resolution of lesions 15 months later.

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Copyright: S. Karger AG, Basel 2003. Reproduced with the permission of S. Karger AG, Basel. Further
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