THE MEDICAL JOURNAL OF AUSTRALIA

462

MARCH 26. 1977

CORRESPONDENCE
Letters should not exceed 300 words in length. Otherwise it may not be possible to find space for them.
CAT FINDINGS IN A CEREBELLAR STROKE RESULTING
IN PALATAL MYOCLONUS
SIR: "Palatal myoclonus" means synchronous continuous pseudorhythmical contractions of the soft palate and pharynx muscles (in
some cases spreading to other craniocervical and even skeletal muscles)
at a frequency of 100 to 200/min and sleep resistant. It is conceived
as a liberation phenomenon due to lesions along the central tegmental
tract fibres. which are supposed to come from the contralateral
dentate nucleus, homolateral red nucleus and periaqueductal grey,
and projecting on to the inferior olive, but possibly also distributed
along the so-called "Guillain and Mollaret triangle" (that is, inferior
olive, red nucleus, dentate nucleus and connecting pathways).' 2 3
Cerebellar stroke, which accounts for about 10% of all intracranial
intraparenchymal bleedings," 5 is mainly haemorrhagic in nature.

A 65-year-old woman was admitted to hospital for unsteadiness of
gait and tremulous voice, both dating from a stroke suffered one year
before. The patient had long-standing hypertension and oft-recurring
dull, but severe, non-throbbing occipital headache, sometimes coupled
with dizziness or drowsiness. She was admitted to a neurosurgery
unit a year before for sudden loss of consciousness with vomiting:
she gradually regained consciousness in two days, and presented with
mild right hemiparesis, but no speech, sensory or visual field defects.
A few days later right conjugate deviation appeared. Routine blood
and urine tests gave negative results, as did electroencephalography
and left carotidography. The cerebrospinal fluid pressure, taken a
few days after the stroke, was normal and the fluid was clear with only
very slight xanthochromic discolouration.
Neurological Status One Year After Stroke.-On admission to the
Milan University Neurology Department, the patient had only slight
bilateral dysmetria and moderate hypotonia of all four limbs, but no
loss of strength. Typical palatal and pharyngeal myoclonus was
constantly present as well as modified phonation resulting in fine
tremulousness of the voice. The electroencephalogram, technetium
brain scan, chest, skull and atlanto-occipital roentgenograms (with
tomography) gave negative results. CAT findings (Dr Ugo Salvolini,
Radiology Department of the Ancona General Hospital, Ancona,
Italy) showed reduced density due to circumscribed softening of the
left dentate nucleus region (Figure I). Asymmetrical dilatation of the
fourth ventricle was present too. The patient was discharged from
hospital with her disturbances unchanged.
Commenr.-Our retrospective diagnosis was that the patient had
had an acute haemorrhagic infarction of the left dentate region" 10
a year before, which had left her with constant palatal myoclonus due
to the dentate interruption of the dentato-olivary projection. Brainstem compression and ventricular obstruction due to a rapid asymmetrical cerebellar blowing-up might explain both the sudden
haemorrhage-like clinical onset, and the subsequent transient unilateral
brain-stem signs.
As far as we know, this is the first reported case of a clear-cut
clinical-anatomical correlation between palatal myoclonus and cerebellar infarction to be established in vita. Further, although the
dentate nucleus is not always correlated with palatal myoclonus, II
this case is in line with (i) the high frequency of dentate and/or dentatoolivary lesions in palatal myoclonus- and (ii) a unilateral lesion
coupled with a symmetrical bilateral palatal myoclonus.">
Department of Neurology,
MADDALENA GASPARINI,
University of Milan,
HANS SPINNLER.
via Fr. Sforza. 35-Milano, Italy.
ROBERTO STERZl.
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I

2

FIGURE

l.

The dentate nucleus artery, claimed to branch from the superior
cerebellar artery," 7 is the most often involved vessel" Computerized
axial tomography (CA T) enabled us to ascertain the clinical-anatomical
correlation between a small softening of a dentate nucleus and
permanent palatal myoclonus.

HORMONAL EPIDEMIOLOGY OF PROSTATIC CANCER
SIR: A hormonal epidemiology of prostatic cancer related to
fertility. as considered in the Comments section of the Journal, I is
most interesting. However, of equal interest are studies which