European Journal of Neurology 2007, 14: e6–e7

doi:10.1111/j.1468-1331.2007.01719.x

LETTER TO THE EDITOR
Oculopalatal and cerebellar limb
tremor due to hypertrophic olivary
degeneration
K. B. Alstadhaug
Department of Neurology,
Nordlandssykehuset, Bodø, Norway

Correspondence: Karl Bjørnar Alstadhaug, MD, Department of Neurology,
Nordlandssykehuset, 8092 Bodø, Norway
(tel.: +47 755 344 28; fax: +47 755 34737;
e-mail: alstadhaug@operamail.com)
Keywords: cerebellar tremor,
Guillain-Mollaret triangle, hypertrophic
olivary degeneration, ocular tremor,
palatal tremor, pontine haemorrhage
Received 5 October 2006
Accepted 14 December 2006
Oliva dysfunction is associated with
oculopalatal and cerebellar tremor. A
54-year-old man with a previous history of

relatively low frequent amplitude (around
2–3 Hz) form of postural and action tremor
in the upper right extremity.
Several magnetic resonance imagings
(MRIs) had been obtained (Fig. 1). The
initial images showed a relatively large
tegmental pontine haemorrhage (a), but
no medullary affection (b). Neither was
this seen 10 days after the bleeding (c).
Sixty-one days later, however, there was
high signal intensity of the left anterior
medulla (d). Additional asymmetric
enlargement of the same area was
observed on a MRI taken 2 years after the
initial bleeding (e). On the last MRI
obtained 14 September 2006 these changes
were barely present (f).

hypertension suffered from a bilateral, but
dominantly left-sided tegmental pontine
haemorrhage 15 September 2002. He had
sequela in the form of left-sided lower
motor neuron facial weakness, a complex
impaired conjugate horizontal gaze, and a
moderate right-sided hemiparesis. As time
went by (a detailed time course was not
possible to obtain), he was tormented by
oscillopsia and a movement disorder of his
right upper extremity. After a lacunar
infarction in the right posterior internal
capsule 2 years later, which bound him to
the wheelchair due to a left-sided hemiparesis, his right upper extremity movement disorder became disabling.
On examination 19 September 2006, the
patient had a left one-and-a-half syndrome
and symmetric oculopalatal tremor. By
clinical evaluation the oscillations seemed
to have a frequency around 3 Hz and were
synchronous. The vertical pendular
eye-movements also had a small torsional
component. The patient had no tremor at
rest, but a severe wide and violent but

Discussion
The patient obviously had symptoms that
were caused by the pontine damage, like
the one-and-a-half syndrome associated
with involvement of the medial longitudinal fasciculus and the paramedian
reticular formation. Oculopalatal and

(a)

180902

(b)

180902

(c)

(d)

251102

(e)

170904

(f)

250902

140906

Figure 1 Serial transverse T2-weighted magnetic resonance imagings (MRIs) obtained from 3 days after the pontine haemorrhage until
4 years later show the development of hypertophic olivary degeneration (HOD). (a) Hypointensity in the tegmental mid-pons due to
haemorrhage. (b) Normal appearing medulla. (c) Normal appearing medulla. (d) Hyperintensity of the left anterior medulla corresponding
to oliva inferior. (e) Asymmetric enlargement and hyperintensity of the left anterior medulla. (f) Less pronounced asymmetric enlargement
and hyperintensity of the left medulla compared with image (e).

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Ó 2007 EFNS

Letter to the Editor

e7

All symptoms/findings are rarely seen in
the same patient [6]. The present patient
had hypertension, suffered from a pontine
haemorrhage, developed HOD and presented the full triad. One cannot exclude
that his pontine haemorrhage was due to a
cavernous haemangioma bleeding [1].
References

Figure 2 The cartoon illustrates how a focal lesion in the central tegmental tract, in this
case a pontine tegmental haemorrhage, may cause trans-synaptic degeneration in the
ipsilateral inferior olivary nucleus affecting contralateral output from for instant the
contralateral cerebellar tremor are usually
not seen after pontine damage.
However, lesions of different aetiology,
among others pontine haemorrhages [1],
in the central tegmental tract, superior
cerebellar peduncle or dentate nucleus
may cause hypertophic olivary degeneration (HOD) which is regarded a unique
morphologic type of trans-synaptic
degeneration (Fig. 2, 1–6). Instead of
classical atrophy this type of degeneration
is characterized by neuronal hypertrophy
and vacuolation with marked astrocytosis.

Histopathological studies have revealed
that hypertrophic changes begin barely a
month after the causative lesion, and
reach a maximum size after about half a
year [2, 3]. The temporal progression of
hypertrophic olivary degeneration on
MRI corresponds well with pathologic
descriptions of HOD. Hyperintensity and
hypertrophy corresponding to oliva may
appear within a month after the causative
lesion and may last for several years [4].
Oliva dysfunction is a well known cause of
ocular, palatal and extremity tremor [5].

Ó 2007 EFNS European Journal of Neurology 14, e6–e7

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Hypertrophic olivary degeneration following pontine haemorrhage: hypertensive crisis
or cavernous haemangioma bleeding?.
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M. Generation of symptomatic palatal tremor is not correlated with inferior olivary
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