OBSERVATION

Convulsive-like Movements in Brainstem Stroke
Gustavo Saposnik, MD; Louis R. Caplan, MD

Background: Involuntary convulsive-like movements
sometimes occur in patients with brainstem strokes. These
movements vary in nature, frequency, and trigger, including fasciculation-like, shivering, jerky, tonicclonic, and intermittent shaking movements. Some are
interpreted as decerebrate postures or seizures. It is important to recognize this type of motor phenomenon since
it may be a diagnostic clue for early diagnosis and treatment of brainstem strokes.
Design: Case report and review of the literature
Observation: A 72-year-old-man presented with
impaired consciousness and jerks of the upper limbs
mimicking seizures. These episodes consisted of brief
clonic contractions of the proximal and distal upper
extremities. They were observed in paroxysms lasting
for 3 to 5 seconds. Magnetic resonance imaging showed

large midpontine infarction. Magnetic resonance angiography revealed the absence of basilar artery blood
flow. No seizure discharges were observed in the electroencephalogram. Anticoagulation with intravenous
heparin was started. Two days after admission, the
patient had a cardiac arrest and died. We review the frequency and nature of convulsive-like movements in
brainstem stroke in the literature.
Conclusions: Movements associated with brainstem lesions are not easily differentiated from convulsions. Unexpected onset and inexperience of the observers limit
the characterization of this phenomenon. Convulsivelike movements in brainstem stroke may occur more frequently than reported. Early detection of this motor phenomenon may have practical implications.

Arch Neurol. 2001;58:654-657

S

INCE 1868, spontaneous
movements have been described in patients with brainstem lesions.1-4 Tonic postures and jerks or twitching
of the limbs in stroke patients are variously reported as seizures or abnormal
movements.2,3 They were originally described in association with decerebration. The movements often are of sudden
onset and may persist for a variable time.
We describe a patient with brainstem ischemia and convulsive-like movements and review the literature.

REPORT OF A CASE
From the Stroke Unit,
Department of Neurology,
Ramos Mejı́a Hospital, Buenos
Aires University, Buenos Aires,
Argentina (Dr Saposnik); and
the Stroke Unit, Department
of Neurology, Beth Israel
Deaconess Medical Center,
Harvard Medical School,
Boston, Mass (Dr Caplan).

A 72-year-old man presented with impaired consciousness and “seizures.” He
was eating when he suddenly developed
weakness on his left side and fell down.
His wife observed tonic postures in the 4
limbs while the patient was on the floor.
Two days before admission, he reported
dizziness and the persistence of visual images even when his eyes were closed. He

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654

had a history of arterial hypertension and
hypercholesterolemia. He had no history
of migraine, seizures, or stroke.
In the emergency department, he was
immediately connected to a respirator. On
neurological examination, he was quadriparetic and unresponsive. Pupils were 3 mm
and reactive to light. He had rightward gaze
conjugate palsy. Lower brainstem reflexes
were present. He had spontaneous jerking
of the upper limbs lasting for 3 to 5 seconds. These episodes consisted of sudden,
stereotypical, brief clonic contractions of the
proximal and distal upper extremities.
These movements repeated in paroxysms
at irregular intervals regardless of the position of his arms. They were different from
the classic decerebrate posture or myoclonus. During the movements, there was no
change in the level of consciousness. No
movements were detected in the face or
lower limbs.
Results of laboratory studies, including complete blood cell count, electrolyte levels, glucose level, partial thromboplastin time, and prothrombin time, were

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Table 1. Convulsive-like Movements
in Patients With Pontine Hemorrhage

Source, y
Dana,2 1903
Silverstein,14
1967

Figure 1. Magnetic resonance image at presentation showing T2-weighted
hyperintense signal affecting the right pons in the base and tegmentum.

Figure 2. Diffusion-weighted image sequence demonstrating marked signal
changes in the basis pontis and tegmentum.

normal. An electroencephalogram (EEG) showed no cortical discharges. A diffusion-weighted magnetic resonance image (MRI) on admission showed a pontine infarction involving the right basis and the tegmentum
(Figure 1 and Figure 2). A magnetic resonance angiogram showed absence of basilar artery blood flow.
Anticoagulation with intravenous heparin was
started. The next day, the patient was in a coma with no
motor response. His pupils were fixed and nonreactive
to light. At that time, a new diffusion-weighted MRI
showed a large midpontine hyperdense lesion involving
the bilateral base and tegmentum. No cerebral lesions were
detected. The vertebral arteries in the neck were normal, suggesting a proximal basilar artery occlusion. He
had a cardiac arrest and died 48 hours later.
COMMENT

We report brief clonic jerking movements that resemble
those occurring in convulsions in a patient with pontine infarction due to basilar artery occlusion. The MRI
and the EEG showed no cerebral abnormalities or discharges. Curiously, our patient exhibited bilateral arm
movements at the time of the first MRI (when the stroke
was asymmetric). We hypothesize that corticospinal tracts
were ischemic bilaterally, although only the right side of
the pons was infarcted. However, it is difficult to understand why the movements were initially observed in the
arms and not in the lower limbs.
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655

No. With
No. of Convulsive-like
Patients Movements
Method
46
50

3
11

Lesions in
Patients With
Convulsive-like
Movements

Autopsy Tegmentum (pons)
Autopsy 3 Basis pontis
and tegmentum,
7 massive,
1 basis pontis

Involuntary movements of the limbs are occasionally seen in patients with acute strokes.5 These movements vary in nature, amplitude, frequency, and triggers. They include fasciculation-like, shivering, jerky,
tonic-clonic, and intermittent shaking movements. Some
movements are not easily differentiated from convulsions. Witnesses present during the episodes often report them as “seizures.” The spared consciousness and
variability may be evidence against an epileptogenic
mechanism. The upper and lower extremities have been
equally involved, and the movements can be unilateral
or multifocal. The rapid and unexpected onset, low
incidence, and inexperience of the observers limit the
characterization of this phenomenon.
In 1868, Nothnagel4 described the presence of a “convulsive pontine center.” Later, Jasper and Droogleever6 and
Penfield7 postulated a “centrencephalic system” to characterize a group of neurons located in the midbrain reticular formation that functioned as a pacemaker for seizures. The role of the brainstem in the generation of tonic
convulsions was studied more than 4 decades ago; however, the subject is still controversial.8 Experimental evidence in rat and cat models showed that stimulation of
the reticular formation of the midbrain, pons, or medulla
results in tonic seizures with absence of discharges in the
cortex or at the site of the stimulus.9,10 Kreindler et al,9 Bergman et al,11 and others12,13 showed that brainstem stimulation induced tonic or clonic movements depending on
the magnitude of the stimulating current.
Recently, Kohsaka et al12 studied sequential changes
of brainstem function before and during 3-Hz spike and
wave complex discharges in patients with typical absence seizures using simultaneous auditory evoked potentials and EEG. They found changes in the wave III component of the auditory evoked potentials preceding the
onset of cortical paroxysmal discharges. This evidence
reintroduced the classic concept of a centrencephalic system as a seizure-generating mechanism. Similar findings have been obtained in animals and humans with
decreased basilar artery blood flow.13
Table 1 and Table 2 show previous reports of abnormal involuntary movements in patients with hemorrhagic and ischemic pontine strokes. In 1903, Charles
Dana2 studied 46 patients with pontobulbar hemorrhages. Three of them had “twitching of the face, or of
the limbs or both.” He also noted forced laughter-crying
episodes associated with this motor phenomenon when
the contralateral thalamus was involved. Dana and other
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Table 2. Convulsive-like Movements in Patients With Pontine Infarction*

Diagnosis

No. of Patients

No. of Patients With
Convulsive-like Movements

122

32

Autopsy

Fang and Palmer,15 1956

Secondary (acute) vascular
brainstem lesions
Basilar artery occlusions

7

5

Autopsy

Halsey and Downie,16 1966

Vertebrobasilar occlusions

3

1

Fisher,17 1970
Kubik and Adams,18 1946

Vertebrobasilar occlusions
Basilar artery occlusions

5
18

1
1

2 Angiography,
1 autopsy
Angiography
Autopsy

Silversides,19 1954
Siekert and Millikan,20 1955
Silverstein,21 1972

Basilar artery occlusions
Basilar artery occlusions
Pontine infarction
(11 basilar occlusions)

22
28
83

3
4
8

Autopsy
Autopsy
Autopsy

Ropper,22 1988

Basilar occlusions

8

8

4 Autopsy,
3 CT, 1 MRI

Source, y
Cannon,3 1951

Method

Lesions in Patients With
Convulsive-like Movements
NA
Tegmentum
and inferior olives
NA
NA
Basis pontis
and tegmentum
NA
NA
3 Paramedian, 2 tegmentum,
3 basis pontis and
tegmentum
Tegmentum

*NA indicates data not available; CT, computed tomography; and MRI, magnetic resonance imaging.

authors believed that the abnormal movements observed in pontine lesions were not convulsive in nature.
In 1967, Silverstein14 reported on 50 patients with pontine hemorrhages. Eleven patients (22%) had “convulsive seizures,” 3 of them unilateral. These motor movements were the initial symptom in 7 patients (63%). Two
of 11 patients with unilateral pontine hemorrhages mainly
involving the basis pontis and tegmentum had convulsive seizures, while 7 of 28 patients with bilateral basis
pontis lesions and 2 of 11 patients with tegmental hemorrhages had convulsive seizures. These are the 2 largest series reporting convulsive-like movements in pontine hemorrhages.
In 1951, Cannon3 reported convulsion-like episodes in 32 (26%) of 122 patients with acute brainstem
lesions, most of them secondary to tumors. Convulsive
movements ranged from isolated twitching of the extremities to generalized seizures. However, only 17 patients (14%) in that series had basilar artery occlusions,
and the frequency of convulsions was not reported.
Other authors observed similar movements in patients with basilar artery occlusive disease (Table 2).
Kubik and Adams,18 in their pathological study of basilar
artery occlusions, found 1 patient (case 3) (6%) with convulsive seizures among 18 individuals studied. Fang and
Palmer15 reported clonic movements in 5 of 7 patients, and
Siekert and Millikan20 described “twitching of the extremities” in 3 patients (11%) and generalized convulsions in
1 (4%) of 28 patients with basilar artery occlusions.
Halsey and Downie16 described 3 patients with “decerebration rigidity” with spared consciousness. One of
these patients was a 34-year-old woman who presented
with occipital headache and vertigo. Her family observed 3 “severe shaking episodes” with urinary incontinence. Angiography showed proximal basilar artery stenosis. Silverstein21 analyzed 83 autopsies of patients with
pontine infarcts. Eleven (13%) had basilar artery occlusions. He found 8 individuals who had “convulsiveseizures” (2 focal, 6 generalized), all of whom had “tremors and clonic jerks of the muscles of the extremities.”
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656

The infarct was located in the paramedian area in 3 patients, in the central tegmentum in 2, and in the tegmentum and basis pontis in the remaining 3. Miller Fisher17
analyzed transient symptoms in patients with vertebral
artery occlusion. In 1 patient, jerkings of the left arm with
spared consciousness were observed.
In 1988, Ropper22 reported convulsive-like movements in 8 patients with basilar occlusions. Autopsy results were available for 4 patients and showed that the
tegmentum was the most commonly affected area. Magnetic resonance imaging or computed tomographic scans
of the head were performed for the remaining patients.
Thalamic, occipital, and pontine lesions were found in
these individuals (Table 2).
Considering all reports that analyzed convulsivelike movements, 66 (23%) of 287 patients with pontine
strokes had abnormal movements. The presence of convulsions was more frequent in patients with pontine infarction (23/91 [25%]) than in those with pontine hemorrhage (14/96 [15%]). However, we cannot exclude a
selection bias, since we only considered those studies reporting movements in brainstem strokes. Therefore, caution must be taken when interpreting the real frequency
of convulsive-like movements in this condition.
In summary, we believe that the movements in our
patient may be related to ischemia of the corticospinal tracts
rather than to true convulsions with a brainstem nuclear
origin. Convulsive-like movements may be seen in patients with either hemorrhagic or ischemic pontine lesions. Recognition of these movements may allow earlier
diagnosis of pontine stroke. The pathophysiological mechanisms remain uncertain. Further functional studies are necessary to clarify the nature of this phenomenon.
Accepted for publication July 5, 2000.
We thank Jose A. Bueri, MD, for his kind collaboration.
Corresponding author and reprints: Gustavo Saposnik, MD, Charcas 44314 “10,” Buenos Aires C1425BMN,
Argentina (e-mail: gsaposnik@intramed.net.ar).
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