A child
with mutism after bilateral thalamic
infarction.
Pluchon C, Jaafari N, Loiseau-Corvez MN,
Parizel A, Vandermarcq P, Hankard R, Gil
Service de Neurologie,
Unité de Neuropsychologie et
Rééducation du Langage, Centre
Hospitalier Universitaire (CHU) de Poitiers,
France.
The occurence of mutism after thalamic
lesions has rarely been observed before
adulthood. We report a 6.5-year-old girl who
presented with sudden mutism with a decreased
level of alertness. Her MRI revealed a T2-fluid
attenuated inversion recovery hyperintensity in
both thalami, which suggested bithalamic
infarction in the territory of the
thalamo-perforating arteries and, more
specifically, the para-median territories.
Mutism was followed by a deficit of speech
initiation with slow and slurred speech. Her
speech returned to normal at 3 months after the
onset of symptoms. Thus mutism could be the
equivalent of akinetic mutism limited to the
speech sphere.
1. Introduction
Thalamic lesions, including paramedian
thalamic infarction, may cause akinetic mutism
(AM),' -3 a neurological disorder in which the
patient in unable to speak (mutism) and move
(akinesia). AM was described in 1941 by Cairns
et al. in a patient with an epidermoid cyst in
the third ventricle - the patient became more
alert and responsive after several evacuations
of the cyst, but he could not speak.4 Following
this landmark case, the term "akinetic mutism"
has been used to describe a syndrome
characterized by marked reduction of nearly all
motor functions, including facial expression,
gestures, and speech output, but with some
degree of alertness. The critical areas involved
are the frontal lobe (cingulate gyrus,
supplementary motor area, and the dorso-lateral
border zones), basal ganglia (caudate and
putamen), and the mesencephalus and thalamus.
Moreover, thalamic lesions may cause aphasia,
particularly after infarction of the
tubero-thalamic artery and/or the territory of
the paramedian thalamo-perforating artery.''6
These aphasias may cause a reduction in speech,
wordfinding deficits, paraphasias, hypophonia,
and dysarthria, but never mutism only. In
children, thalamic lesions may cause aphasia"'
or AM.9 A strictly isolated mutism has rarely
been documented. We have found only one patient,
17 years of age, who presented with complete
mutism with acute confusion after bithalamic
infarction following a deep cerebral vein
thrombosis.'() Here we report mutism after
paramedian bilateral thalamic infarctions in a
young child, and discuss the significance of
this mutism.
2. Case report
A 6.5-year-old girl without any significant
medical history presented at Centre Hospitalier
Universitaire (CHU), Poitiers, France, after
acute onset of paramedian bilateral thalamic
infarction. Her family, birth history, and
developmental milestones were unremarkable. Six
hours before her admission, she was restless and
had elementary auditory hallucinations before
falling asleep, and once asleep, she could not
be woken by her mother.
On admission she was afebrile, in a
sleep-like state, with a regular heart rate of
84 beats per minute, and blood pressure of 108/
58 mm Hg. Neurologic evaluation showed that she
woke only with painful stimuli. She was
completely mute and did not answer any
questions. When she was awake she could comply
with simple instructions (for example, sitting
on her bed and raising an arm). She had normal
symmetric mobility in her limbs with brisk deep
tendon reflexes, normal pupillary reactions and
normal fundoscopy. Her eye movements were
normal. She had urinary incontinence. When she
was awake, she swallowed slowly without choking.
Her ear, nose and throat evaluation was
normal.
Her cerebrospinal fluid and routine
hematological and biochemical tests were normal,
and were negative for blood alcohol and urine
toxicology. Her coagulation tests, which
included fibrinogen, prothrombin, antithrombin
III, protein C, protein S, factors V, VIII, and
IX were normal. Test activated protein-C
resistance was normal. Tests for the human
immunodeficiency virus, hepatitis B, and the
Epstein-Barr virus were negative. She tested
negative for a collagen-related disease or a
vasculitis syndrome (that is, lupus
anticoagulant, rheumatoid factor,
anticardiolipin antibodies, antineutrophilic
cytoplasmic antibodies, lupus erythematosus
[LE] cell and antinuclear factors). Two
days later, periods of sleep-mess were
alternated with alertness, and although she
could comply with commands, she remained
completely mute.
A brain MRI on admission showed an area of
hyperintensity on T2-weighted and fast
fluid-attenuated inversion recovery images
consistent with infarction and/or edema in the
thalami. Two days after admission, magnetic
resonance angiography showed no vessel
abnormality. Arteriography performed 3 days
after admission showed that Percherons" artery
was normal, and vascularised both thalami
well.
An echocardiogram, using colour Doppler
flow, revealed a small patent foramen ovale with
a left to right shunt. Thus, a paradoxical
embolism from a subclinical venous thrombosis
was presumed to have occurred, causing a
cerebral infarction. A non-surgical
transcatheter closure of the patent foramen
ovale was planned. After a few days of sodium
enoxaparin, she was started on low dose acetyl
salicylate.
Fifteen days later, an electroencephalogram
demonstrated major polymorphic delta waves and
sharp waves predominantly in the bilateral
frontal derivations. Neurologic evaluation
showed a moderate right hemiparesis with right
central facial paresis. We observed fluctuations
in vigilance, and yawning, with
intermittent chewing movements. However, when
the vigilance was normal, the patient was
completely mute - no sound was emitted
spontaneously. She could understand and comply
with instructions (for example, correctly
pointing to her forehead, nose, and her mother's
mouth). She was able to identify simple words
correctly written with doctor's oral commands.
Her mutism progressively receded towards
defective speech initiation with a reduction of
spontaneous speech. One month later, she
obtained a score of 50/100 (normal, average
score of 51 for the same-age population) on a
battery of vocabulary tests for children
(picture denomination) by Chevrie-Muller et al.
12 Three months later, she showed significant
recovery: her speech was fluent and her verbal
expression was normal.
3. Discussion
Stroke affecting the thalamus may cause
aphasia, 5,6 or AM like stroke also affecting
the cingulate gyrus, the basal ganglia
and mesencephalon.3 To our knowledge, this
is the first report of a young child presenting
with mutism only (without other symptoms).
Kothare et al.1° have reported mutism in a
17year-old girl after a hemorrhagic thalamic
infarction secondary to deep cerebral vein
thrombosis. After the mutism had resolved, there
was a deficit of sustained attention and
changing capabilities. Garg and De Myer reported
three children with infarction of the
thalamo-perforating artery, who all presented,
as in our patient, with lethargy, which receded
in 3 or 4 days, but none suffered from
mutism.
Although our patient was not confused, as
were Kothare et al's patients,1° she did
experience disturbances in vigilance. These
changes in vigilance led us to confirm that she
became mute immediately after the stroke. The
mutism subsequently gave way to a speech
initiation deficit, with slow and slurred
speech. Her speech then became normal. What was
the significance of the mutism? It was not
initially a transcortical motor aphasia since
repetition was impossible. When she recovered
from mutism, there was only a slowing of speech.
Thus, it could not be considered aphasia. We
concluded that her mutism could be considered
equivalent to AM limited to speech. This
observation, as also demonstrated by Garg and
DeMyer,7 correlates with the relatively good
prognosis of thalamic infarction in children.
