BRAIN AND LANGUAGE 59, 473–493 (1997)
ARTICLE NO. BL971790

Mutism in an Adult Following Hypertensive Cerebellar
Hemorrhage: Nosological Discussion
and Illustrative Case
William M. Coplin,* D. K. Kim,† Michel Kliot,† and Thomas D. Bird*
*Division of Neurology, Department of Medicine and †Department of Neurological
Surgery, University of Washington School of Medicine
Mutism after cerebellar injury has been associated with tumors, hemorrhage, and
surgery of midline cerebellar structures. Literature review identified 54 cases, primarily in children after surgical splitting of the inferior vermis. We present a 47year-old who developed transient mutism after cerebellar hemorrhage. This represents the first report of transient mutism in an adult with neither tumor nor brainstem
infarction and documents the importance of cerebellar structures for initiation and
production of speech in adulthood. This case further differs from those previous
because of the long mute period and the subsequent return of continued ataxic and
dysarthric speech.  1997 Academic Press

INTRODUCTION

The syndrome of cerebellar mutism following tumor, surgery, or hemorrhage consists of a brief interval of normal speech, followed by weeks or
months of mutism. The returning speech may be normal or very dysarthric
(Rekate, 1985; Yonemasu, 1985; van Dongen, 1994). Patients are all alert
with severe cerebellar ataxia, but have no long tract signs, cranial nerve palsies, nystagmus, or other signs of brainstem involvement. The inferior vermis, and/or the dentate nuclei and their related pathways are putative sites
of this speech deficit. Magnetic resonance imaging does not reveal brainstem
involvement (e.g., infarction, hemorrhage, demyelination, cysts, etc.). The
syndrome is important to recognize because of both its severity and transient
nature. The pathogenesis remains unclear. Our review of the literature identified 54 cases of cerebellar mutism, occurring primarily in children after surgical splitting of the inferior vermis.
We present a case of transient mutism in an adult who suffered a cerebellar
Address correspondence and reprint requests to William M. Coplin, M.D., Departments of
Neurology and Neurological Surgery, Wayne State University, 6E-UHC, 4201 St. Antoine,
Detroit, MI 48201. Fax: (313) 745-2745.
473
0093-934X/97 $25.00
Copyright  1997 by Academic Press
All rights of reproduction in any form reserved.

474

COPLIN ET AL.

hemorrhage. To our knowledge, this case represents the first report in an
adult without a cerebellar tumor or brainstem abnormalities who had the
onset of his mutism following a period of speech competence after his ictus.
This case further differs from those previous because of the long mute period
and the subsequent return of continued ataxic and dysarthric speech.
REPORT OF A CASE

While gardening, a 47-year-old right-handed man experienced abrupt onset of severe left occipital headache accompanied by garbled speech, diaphoresis, and left-sided weakness. Paramedics found him alert, following commands, and conversant; systolic blood pressure was 190 mm Hg. He
developed hyperemesis and had endotracheal intubation. In the emergency
room, his blood pressure was 200/118. On examination his pupils were
equal, round, and symmetrically reactive to light; he visually fixed and
tracked; extraocular movements were intact without nystagmus; corneal reflexes and face were symmetric; a weak gag reflex was present; extremities
were of normal tone, bulk, and strength; sensory examination and deep tendon reflexes were normal and symmetric; plantar responses were flexor bilaterally. He had gait ataxia and dysarthria.
Admission computed tomography (CT) of the head showed a large superior vermian hemorrhage, extending symmetrically and anteriorly to the brachium pontis (Figs. 1A and 1B). The effaced fourth ventricle contained a
small volume of fresh blood; there was no subarachnoid blood. Mild enlargement of the lateral and third ventricles was present. Mild ponto-mesencephalic mass effect was present, but the prepontine, interpeduncular, and ambient cistems were visible. Neither intravenous contrast infusion CT scan
nor cerebral angiography demonstrated an aneurysm or arteriovenous malformation.
In the operating room, a right frontal ventriculostomy released xanthochromic cerebrospinal fluid under high pressure. Immediately postoperatively, he became unresponsive with pinpoint pupils and decorticate posturing. Repeat CT scan showed increased midline posterior fossa blood,
extending bilaterally into the region of the brachium pontis and superior
vermian cistern. The brainstem appeared under compression. He returned to
the operating room, where a suboccipital craniectomy permitted evacuation
of a large clot. Midsagittal splitting of the vermis exposed the fourth ventricle. Pathological examination of the surgical specimen showed only clot and
normal cerebellum.
Postoperative CT scan confirmed removal of a majority of the superior
vermian clot, demonstrating only mild dilation of the lateral ventricles, without evidence of infarction or new hemorrhage (Fig. 1C).
Postoperatively, the patient was intermittently awake, occasionally following commands and remained intubated. After removal of the ventriculostomy

CEREBELLAR MUTISM

475

on the tenth postoperative day, a contrast-enhanced CT did not demonstrate
hydrocephalus, abscess, or infarction.
A waxing and waning level of consciousness, which slowly improved,
marked his post-operative course. Two weeks post-operatively, magnetic resonance imaging demonstrated a 3 3 5 3 15 mm area of old hemorrhage
occupying most of the vermis and displacing the fourth ventricle anteriorly
(Figs. 2A and 2B). Edema was evident in the mesial cerebellar hemispheres
and middle cerebellar peduncles. There were no new infarcts.
After 3 weeks, he had slight left arm weakness and dyscoordination. He
spontaneously opened his eyes and tracked, followed commands, and responded appropriately to ‘‘yes/no’’ questions with hand and head motions.
He did not vocalize. Swallowing evaluation showed swift laryngeal elevation
with reflexive swallowing after throat clearing. He continued to require nasoduodenal feeding.
Neurological examination showed minimally decreased lateral excursion
in both eyes. Upgaze and pupillary examinations were normal. He had
marked symmetric orofacial dyscoordination, affecting the purposeful use
of his tongue and his ability to mouth words. He had a weak symmetric gag
reflex. His tongue protruded in the midline. He was able to stand and take
a couple of steps but only with two-person assistance. He had marked ataxia
of all his limbs, with past-pointing, dysmetria, dysdiadochokinesia, dyscoordination and prominent dyssynergia. Check reflexes were poor in all limbs.
Romberg’s sign was present, and he had postural instability with poor maintenance of station. Fine finger movements were poor. Obvious paresis was
absent. Deep tendon reflexes were symmetric and Babinski’s sign was absent
bilaterally.
Head CT scan that day did not reveal any evidence of hydrocephalus,
midline shift, or mass effect. The midline vermis and cerebellar hemispheres,
left more than right, demonstrated hypodense areas. The brainstem appeared
normal.
He exhibited intermittent agitation. He responded appropriately to verbal
questions, was able to perform multistep commands, and could communicate
using his head and upper extremities. Except for occasional grunting, he was
mute. He could sort and categorize objects. Severe ataxia limited his writing.
The patient’s reading comprehension appeared normal, responding by way
of a communication board or head nodding. He accurately used a needs
board, with a light pointer, and an eye gaze board for creating novel messages. He needed supervision to organize his directional eye gaze and exercise control over his ataxia and frustration to use these devices. He could
stabilize a movement or posture when given time. He could use the eye gaze
board to communicate 11 single word and phrase length messages over 15
min. He was able to follow commands. He was able to spell correctly three
words in structured tables. He could perform convergent single-word language tasks. He correctly performed a name-the-capitol/state exercise with

476

COPLIN ET AL.

FIG. 1. (A) Axial, unenhanced CT scan demonstrates a superior vermian hematoma extending to fill the vallecular cistern. (B) The hematoma extends superiorly to the quadrigeminal
cistern. The prominent temporal horns suggest incipient hydrocephalus. (C) Post-operative
axial CT scan demonstrates the evacuation of the hematoma.

CEREBELLAR MUTISM

FIG. 1—Continued

477

478

COPLIN ET AL.

FIG. 1—Continued

CEREBELLAR MUTISM

479

the eye gaze board. He could sort and categorize objects. He did not receive
forced-choice recognition memory testing. He remained completely nonspeaking (mute).
Three months after his ictus, blood pressure was 138/100. The following
were normal on examination: extraocular movements, hearing, tone, motor
strength, tendon reflexes, primary modality sensation, and tongue strength.
He remained mute. He could chew well, but his oropharyngeal coordination
was too poor for swallowing, and he had no gag reflex. He received feedings
by percutaneous gastrostomy. Ataxia precluded self-feeding. He had rare
vocalizations, but no articulation of words. No mouthing of words was apparent. The patient communicated with head nods. Writing attempts were ataxic.
He was able to calculate and identify objects. He was alert and oriented and
not demented. Extensive psychological testing demonstrated no appreciable
cognitive losses. He manifested prominent bouts of emotional lability. Incoordination of the tongue, face, and mouth was greater than that of trunk or
extremities. He could not dress himself, apparently because of ataxia rather
than dyspraxia. The patient could independently position himself in the bed,
but, because of truncal ataxia, he would fall over if he swung his legs over
the edge. He could stand for a shower but could only take a couple of steps
with two-person assistance.
Barium cinematography revealed uncoordinated epiglottic inversion when
swallowing liquids.
Follow-up of his risks for recurrent stroke revealed normal extracranial
Doppler exam of his neck. Because of claustrophobia, the patient refused
follow-up MRI.
Four and one-half months after his ictus, his mutism cleared as he uttered
a comprehensible word. Four days prior, he began to mouth words without
phonation. Over the ensuing 4 days, he was able to speak three names and
two three-word phrases (‘‘I love you;’’ ‘‘I can speak’’). Over the following
4 days, he could speak 46 words with a prolonged ‘‘ah’’ sound for 5–7 sec.
His ability to initiate speech and maintain phonation remained inconsistent.
Effortful, forced exhalation with facial grimacing accompanied all speech
attempts. All phonation was high in pitch and, at times, not coordinated with
articulation. Articulatory errors appeared related to the manner of production
with more errors occurring with sounds that were more complex in motoric
production (e.g., sh, l, r, s). A phonatory/articulatory ataxia, graded as a
moderate/severe ataxic dysarthria, characterized his speech. He exhibited
uncoordinated/inefficient breath support for speech. He continued to have
marked bucco-lingual dyscoordination with dysarthria. He could reliably
spell words vocally.
Ongoing cognitive assessment showed his ability to perform word associations, proverb interpretations, and nonverbal spatial reasoning. He could repeat complex sentences and recall facts from a story in a logical sequence.
After another month, he had barely comprehensible but very ataxic speech

480

COPLIN ET AL.

FIG. 2. (A) Sagittal midline T1-weighted MRI study reveals the hyperintense signal of the
residual hematoma involving the superior and midline vermis. Minimal mass effect is evident.
Note the radiographically normal brainstem. (B) Axial T1-weighted MRI study demonstrates
the residual hyperintense signal of the vermian hematoma. The fourth ventricle is not displaced.

CEREBELLAR MUTISM

481

FIG. 2—Continued

and was able to swallow solids. One year after his ictus, he could propel a
manual wheelchair with his feet. He participated in conversation as a responder, rather than initiator, and kept his verbal responses (sometimes supplemented by gestures) brief. He would become emotional and tearful during
speaking. His speech was characterized by great effort, ataxic dysarthria,
and strained voice, with pitch often higher than normal. Intelligibility was
approximately 75% with known content. He used spelling to remedy commu-

482

COPLIN ET AL.

TABLE 1
Scores of Patient on the Reading Comprehension
Battery for Aphasia (LaPointe, 1979)a
Score
(percentage correct)

Test
Functional reading
Paragraph-picture
Factual-inferential

90
100
100

a
At 1 year post-ictus. Patient was no longer mute
at the time.

nication breakdowns. He independently used an alphabet board to indicate
the first letter of misunderstood words.
The patient followed complex spoken and written commands. He underwent formal language testing (Table 1). He self-corrected his speech errors,
named without difficulty, and described object accurately. He demonstrated
moderately decreased word fluency on a task requiring generation of members of a category. The patient’s printing was marginally legible at the simple
sentence level secondary to ataxia. He profited from the use of a typewriter to
stabilize his arms, yet ataxia resulted in misstrikes of adjacent keys. Spelling,
grammar, and punctuation were all intact. He did not require cues to operate
the typewriter.
On immediate auditory memory tasks, the patient repeated five sentences
of increasing complexity accurately and recalled in detail the events of two
narrative paragraphs. He could complete two- and three-dimensional block
designs. Visual attention span was consistent at five units, which is normal.
On ideational tasks, he mentally shifted on a forward/backwards spelling
task and completed six of six simple calculations correctly. He performed
pictorial associations of increasing abstraction.
Over the 39 months since his initial ictus, he has made slow, steady improvement, but he still has marked ataxia of his trunk, extremities, and
speech.
DISCUSSION

Our patient presents a picture of prolonged mutism without cranial nerve
findings, and severe ataxia related to a cerebellar hemorrhage. Mutism followed a latent period after surgery that included vermian splitting. His speech
has not returned to its premorbid normal pattern, remaining ataxic over longterm follow-up. He has also had persistent incoordination of his tongue and
deglutition. The exact trigger is unclear. This case did not involve a tumor
as have most of the other cases of cerebellar mutism.
Disorders associated with mutism. Psychiatric disorders account for the
vast majority of mutism cases without brainstem signs (Benson, 1979). Organic causes usually have long tract signs and/or alterations of conscious-

CEREBELLAR MUTISM

483

ness. Seizures, which are extra-cerebellar in origin, may also cause speech
arrest. Six sites or syndromes render mutism: Broca’s aphasia (usually transient), the dominant hemisphere’s supplementary motor area, the mesencephalic reticular formation (associated with akinetic mutism), pseudobulbar
palsy (secondary to diffuse bilateral cerebral hemispheric dysfunction), bilateral thalamotomy in Parkinsonism [Benson, 1979], and bilateral laryngeal
paralysis.
The dominant hemisphere supplementary motor area syndrome includes
buccomotor dyspraxia among the constellation of findings (Rostomily,
1991). Bilateral above the pons lesions can cause so-called pseudobulbar
palsy, sometimes associated with mutism. This usually presents with upper
motor neuron abnormalities and a flat, but labile, affect.
There are described speech abnormalities after posterior fossa injuries.
Review of 40 patients with missile injuries to the cerebellum demonstrated
that unilateral hemispheric lesions caused ‘‘slow, drawing, and monotonous’’ speech that was ‘‘staccato and scanning.’’ Vermian involvement further distributed articulation and phonation. Bilateral hemispheric injury created speech that was nearly unintelligible (Holmes, 1917). The more recent
reports on cerebellar mutism have described a brief interval of normal speech
after cerebellar tumor surgery in children. The mute period has lasted 3 or
more months followed by a severe derangement more characteristic of ‘‘cerebellar speech.’’ Reversion to normal patterns ensued. The patients all were
alert with ‘‘severe cerebellar ataxia,’’ but ‘‘no remarkable brainstem signs.’’
They had preserved phonation, intact comprehension, and could communicate through gestures (Yonemasu, 1985).
In past attempts to control spasticity and dyskinesias in cerebral palsy
patients, bilateral stereotactic dentate nuclei ablation, sparing the lateral
hemispheres, caused transient mutism (Fraioli, 1975; Guidetti, 1977). Speech
returned over 1 to 3 months.
Central pontine myelinolysis may also involve extrapontine structures,
such as the basal ganglia and the cerebellum. Mutism occurs in this syndrome, which may also include pseudobulbar palsy and restless agitation,
besides the typical quadriplegia (Adams, 1959; Kepes, 1965). Disturbances
of the cranial nerves originating in the pons help identify this form of mutism.
In the first description of akinetic mutism (caused by an epidermoid cyst
of the third ventricle) the only utterances were monosyllabic whisperings
(Cairns, 1941). Other cases of akinetic mutism occurred following surgery
for tumors of the thalamus or hypothalamus, basal ganglia, midbrain, anterior
cingulate gyrus, or third or fourth ventricles. These cases usually involved
splitting the vermis at the level of the pyramis (Daly, 1958; Lavy, 1959;
Skultety, 1968), leading to a warning to avoid the dentate nuclei when splitting the vermis (Dandy, 1966). Experimentally, involvement of the caudal
ventromedial mesencephalic tegmentum, inferior quadrigeminal brachia and
periaqueductal gray matter appears to cause this clinical picture (Skultety,

484

COPLIN ET AL.

1968). Occlusion of the mesencephalic artery can also lead to akinetic mutism (Segarra, 1970).
The literature contains several cases of mutism of cerebellar origin, with
the first reports appearing in the mid-1980s (Wisoff, 1984; Rekate, 1985;
Yonemasu, 1985). Cerebellar mutism has been associated with tumors, hemorrhagic lesions, and surgery involving midline cerebellar structures primarily in children (mean age 12.3 years, median age 8 years; Table 2). The mute
patient must be alert and show normal cognitive function. He must be able
to comprehend, write, and read. Mutism is more than simply oral apraxia.
This clinical syndrome is unusual with cerebellar disease. To implicate the
cerebellum as the cause of this problem requires the absence of cranial nerve
abnormalities, brainstem signs, dementia, or aphasia.
Review of 162 patients with nondegenerative cerebellar disease (e.g.,
hemorrhage, infection, tumor) provides evidence implicating the left anterior
paravermian region in those with dysarthria (22 of 31 patients with left-sided
cerebellar injury). Twenty-six of the 162 had primary vermian involvement,
but only 3 of these patients had speech dysfunction, a finding similar to that
of Gilman (1981). An autopsy series showed 70% prevalence of dysarthria
in patients with left cerebellar hemispheric infarction (Sypert, 1975).
In 1985, a report appeared of six children with mutism and new cerebellar
lesions, involving the vermis, hemispheres and deep nuclei (Rekate, 1985).
There are a few earlier suggestions of this syndrome after childhood medulloblastoma surgery (Hirsch, 1979; Wisoff, 1984; Yonemasu, 1985). Subsequently, other authors reported similar cases (Table 2). These patients predominantly have midline pathology. Although, not all case reports describe
the surgical procedure, it appears that in roughly a third of cases there was
surgical incision of the inferior vermis. Patients reportedly all spoke during
the immediate postoperative period, before becoming mute 18–72 hr after
operation. None had phonatory organ disturbance (Ferrante, 1990), but
nearly 30% were unable to eat, even without lower cranial nerve palsies.
Our literature search located 54 reported cases of mutism associated with
cerebellar lesions, almost all in children. Recent reviews found mutism complicating 6 of 105 (5.7%) (Cochrane, 1994) and 9 of 110 (8.2%) (Dailey,
1995) of aggressive pediatric posterior fossa tumor surgeries. The only adults
previously described with mutism had juvenile tumors (two 20-year-olds and
one 45-year-old with medulloblastomas and a 22-year-old with a pinealoblastoma) requiring midline approaches (Salvati, 1991; D’Avanzo, 1993),
or brainstem ischemia (a 48-year-old) (D’Avanzo, 1993).
Cognition and cerebellar mutism. Several authors describe cerebellar hypoplasia in various states of cognitive impairment, such as neocerebellar
posterior vermian hypoplasia in autistic people (Courchesne, 1988), and similarly in Fragile X patients (Reiss, 1988) and learning-disabled children
(Valk, 1988). Children with midline cerebellar hypoplasia have limited vocabularies and significant speech delays (Sarnat, 1980). These situations raise

CEREBELLAR MUTISM

485

the question of the role that the posterior vermis might play in acquiring
speech skills.
In olivopontocerebellar atrophy (OPCA), positron emission tomographic
(PET) studies demonstrate a correlation between the ataxia of speech and
hypometabolism in the cerebellar vermis and hemispheres, and the brainstem, but not in other brain structures, such as the parietal cortex. The association between this and the degree of anatomical cerebellar change is weaker
(Gilman, 1993). Neuropsychiatric evaluation of OPCA patients suggested
some occult intellectual deficits, including verbal memory and intelligence as
well (Kish, 1988). Motor learning seems likewise impaired in these patients
(Sanes, 1990).
Motor and cognitive functions seem to have distinct somatotopic representations in the cerebellar cortex. Other PET studies have defined bilateral posterior vermian and inferolateral hemispheric activation with single word generation and the cognitive imagery before speech initiation (Petersen, 1988).
In normal adults, during word association, blood flow increases in the
superior anterior lobule of the cerebellar cortex just lateral to areas where
similar changes occur with eye or finger movements. The lateral inferior
right cerebellar cortex remains similarly active when subtracting motor activity (tested separately) from these blood flow studies. This suggests a pure
cognitive function to this area (Petersen, 1988). Thus the cerebellum appears
involved in the functions of speech coordination, initiation, planning, and
timing.
Anatomy and postulated mechanisms. The areas believed responsible for
the speech disturbances of autistic patients and those with other nondegenerative cerebellar diseases are Larsell’s lobules H VI and VII (Gilman, 1981;
Courchesne, 1988). Auditory and visual stimulation also make these posterior vermian areas active (Snider, 1944; Altman, 1976). Spinocerebellar
tracts pass by way of these areas (the pyramis, tuber, and uvula) which also
receive sensory input from the head. Spindle afferents from the tongue and
the other muscles of speech production also project there, by way of the
mesencephalic nucleus of the trigeminal nerve. These areas also receive input
from cerebral sensorimotor areas (Allen, 1974) (Figs. 3A and 3B). The adjacent simplex lobule contributes to laryngeal motor outflow (Larson, 1978).
Left cerebellar hemispheric lesions may thus not be clearly responsible for
mutism but may be so for dysarthria (since they coordinate the sensory input
for the outflow of monitored speech patterns).
Cerebral dysfunction along the above-mentioned cerebellar sensory input
pathways thus could explain mutism; however, our patient had no suggestion
of such abnormality either on examination or imaging studies. Pontine nuclei, the ventrolateral thalamus, and cerebral cortex (supplementary motor
and other areas) connect with the dentate (Carpenter, 1991). The intracerebellar connections between the dentate nuclei and the vermian and paravermian
regions parallel the pathways between the cortex and the nuclei interpositi

Wisoff, 1984

Wisoff, 1984
Wisoff, 1984
Wisoff, 1984
Rekate, 1985
Rekate, 1985

Rekate, 1985
Rekate, 1985
Rekate, 1985
Rekate, 1985
Yonemasu, 1985
Yonemasu, 1985
Yonemasu, 1985
Yonemasu, 1985
Volcan, 1986
Humphreys, 1989

Humphreys, 1989
Humphreys, 1989
Humphreys, 1989

Humphreys, 1989
Ammirati, 1989

Ferrante, 1990

Ferrante, 1990

Ferrante, 1990

2*
3*
4*
5
6

7
8
9
10
11
12
13
14
15
16

17
18
19*

20*
21

22

23

24

1st author/year

1*

Case
No.

6M

5.5 F

9F

10 F
14 F

3M
7M
4.5 M

22
10 M
92
112
—
—
—
—
8F
7M

12 M
3.5 M
17 M
8F
6M

6M

Age
(yr), sex
Midline, IV vent
Malignant astrocytoma
Vermis, L IV medulloblastoma
Vermis, IV medulloblastoma
Vermis, L IV vent astrocytoma
Vermian medulloblastoma
Vermis, L hemisphere
Cystic astrocytoma
2, Ependymoma
2, Medulloblastoma
2, Medulloblastoma
2, Medulloblastoma
Bilateral ependymoma
Bilateral ependymoma
Bilateral medulloblastoma
Bilateral medulloblastoma
IV vent medulloblastoma
Vermis, R hemisphere
Medulloblastoma
IV vent medulloblastoma
IV vent medulloblastoma
Vermis, IV vent
Fibrillary astrocytoma
Vermis, IV vent ependymoma
Vermis, IV vent
Pilocytic astrocytoma
Vermis, MCH, IV vent
Pilocytic astrocytoma
Vermis, MCH, IV vent
Pilocytic astrocytoma
Vermis, IV vent, R hemisphere
Pilocytic astrocytoma

Lesion location and histology

TABLE 2
Reported Cases of Cerebellar Mutism

36

48

48

24
48

—
—
72

—
—
—
—
18–72
18–72
18–72
18–72
24
24

72
48
48
48
72

48

Latency
(hr)

8 days

8 days

4 days

10 wk
6 wk

7 wk
10 wk
7 wk

2 months
2 months
3 months
3 wk
4–12 wk
3 wk
4–12 wk
4–12 wk
2 wk
16 wk

2.5 wk
10 days
‘‘several weeks’’
3 months
3 months

2 wk

Mutism
duration

486
COPLIN ET AL.

Dietze, 1990
Salvati, 1991
Nagatani, 1991
Herb, 1992
Catsman-Berrevoets, 1992
Catsman-Berrevoets, 1992
Catsman-Berrevoets, 1992
D’Avanzo, 1993
D’Avanzo, 1993

D’Avanzo, 1993
D’Avanzo, 1993
Cakir, 1994
van Dongen, 1994

van Dongen, 1994

van Dongen, 1994
van Dongen, 1994
van Dongen, 1994
van Dongen, 1994
van Dongen, 1994
Silveri, 1994
Dailey, 1995
Dailey, 1995
Dailey, 1995
Dailey, 1995
Dailey, 1995
Dailey, 1995
Dailey, 1995
Dailey, 1995
Dailey, 1995
Coplin, 1997. Present case

26
27
28
29
30
31*
32*
33
34

35
36*
37
38*

39*

40*
41*
42*
43*
44*
45
46*
47
48*
49
50*
51
52*
53
54
55

6M
8F
8M
5M
4M
67 M
4M
12 F
9F
6.75 F
3M
6F
2.5 M
20 F
10 F
47 M

4F

22 M
48 M
61 M
10 M

15 F
20 M
4F
9M
6M
8F
8M
20 F
45 M

7M

Vermis, MCH, IV vent
Medulloblastoma
Vermian AVM
Vermis, IV medulloblastoma
Vermian medulloblastoma
Vermis, IV medulloblastoma
Vermis, IV medulloblastoma
Vermian medulloblastoma
Vermis, IV medulloblastoma
IV vent medulloblastoma
Vermis, R hemisphere, IV vent
Medulloblastoma
R mesencephalon pinealoblastoma
R ponto-mesencephalic ischemia
R hemisphere metastasis
R hemisphere, peduncle, IV vent
Ependymoma
Ventral posterior fossa
Meningioma
IV vent medulloblastoma
Vermian medulloblastoma
Vermis, IV vent medulloblastoma
Vermian medulloblastoma
IV vent, R medulla ependymoma
R hemisphere infarction
2, Ependymoma
2, Medulloblastoma
2, Medulloblastoma
2, Medulloblastoma
2, Medulloblastoma
2, Astrocytoma
2, Medulloblastoma
2, Astrocytoma
2, Medulloblastoma
Vermian hemorrhage
Average
24
48
24
,24
24
with ictus
24
immediate
12
12
24
24
48
12
60
2 (see text)
35.6–41.2 hr

—

72
72
—
—

—
46
24
12
24
48
24
48–72
68

—

5 wk
5 wk
2 wk
8 wk
3 wk
‘‘few hours’’
2 wk
1 wk
4 wk
12 wk
1.5 wk
6 wk
3 wk
8 wk
3 wk
4.5 months
46.6–51.6 days

—

4–6 months
16 wk
4 days
2 days

3 months
4 wk
78 days
10 wk
6 wk
6 wk
8 wk
5 months
3 months

6–12 wk

Note. IV vent, fourth ventricle; MCH, medial cerebellar hemispheres; —, data not available. *Mutism not in the absence of brainstem findings;
L, left; R, Right.

Dietze, 1990

25

CEREBELLAR MUTISM

487

488

COPLIN ET AL.

FIG. 3. Schematic representations of cerebellar bidirectional connections with the frontal
cerebral cortex (A) and other brain areas (B) purported to be involved in speech production.

and fastigial nuclei (Tolbert, 1978). The pars intermedia receives from the
spino- and cuneo-cerebellar tracts as well as the cerebrum, seemingly calibrating motor output (Allen, 1974; Ghez, 1991).
The role of the cerebellum in coordinating sensory input and executable
motor outflow, thus planning the execution of motor speech, may be at play
in causing cerebellar mutism. Surgical splitting of the cerebellum breaches
the corpus medullarae of the inferior deep cerebellar white matter. The corpus medullarae is part of a more-complex system connecting not only the
adjacent ipsilateral lobules but also the contralateral infero-lateral areas of
the two hemispheres (Eager, 1963; Carpenter, 1991; Ghez, 1991). Feline
studies further suggest such collateral cerebellar communication (Rosina,
1984) to the neocerebellum and the postero-central vermis (which includes
the pars intermedia and Larsell’s, lobules V and VI) by way of pontine nuclei.
The supplementary motor and premotor areas also give to these pontine nuclei. This would explain intra- and trans-cerebellar communication in coordination with cortical motor planning and outflow. Additionally, that some
zones are phylogenetically more recent could help explain their involvement
in not only motor aspects of speech but also the cognitive aspects of language
(Leiner, 1993). Such ‘‘commissural’’ disruption may interrupt the bilateral
loop involved in the anatomy of the buccofacial dyspraxia seen after bilateral

CEREBELLAR MUTISM

489

injury of the cerebral frontal association cortices (Groswassa, 1988; Mao,
1989).
Work elucidating the role of the cerebellum in speech continues. It appears
to serve to adjust the tempo and force of the finely coordinated muscular
movements involved in speech production (Brown, 1949). Dysarthria, monotony, scanning, hesitancy and explosive speech most commonly mark cerebellar speech disorders (Flourens, 1823; Charcot, 1877; Holmes, 1917;
Holmes, 1922; Zentay, 1937).
Some evidence points to the superior vermis and/or cerebellar hemispheres as the site(s) of these prevailing cerebellar speech deficits (Mills,
1914; Holmes, 1917; Holmes, 1922; Lechtenberg, 1993). Vermian or paravermian lesions alone may not be sufficient to cause mutism. Dysarthria may
occur with lone cerebellar hemispheric lesions, but patients with vermian
involvement seem to have greater speech difficulty (Holmes, 1917; Holmes,
1922). Paravermian and lateral hemispheric cerebellar tumors are most likely
to cause dysarthria, while vermian damage is an uncommon cause of speech
disorders (Amici, 1976). Some authors implicate the superior left hemisphere
more than other areas (Lechtenberg, 1978; Ferrante, 1990). The left superior
paravermian region receives inputs from cranial nerves VIII and X, as determined by electrical stimulation studies. The midportion of the left superior
paravermis appears to coordinate sensorimotor and cortical inputs, particularly auditory and visual ones (Dow, 1939; Lam, 1952; Kent, 1976). One
suggestion is that the posteromedial paleodentate, modulating preprogrammed motor speech commands from the cerebrum, mediated by interconnections with the vermis and paravermis, might provide a memory of the
learned movements for speech. Injury to this circuit might abolish motor
speech (Eccles, 1969; Ito, 1970; Dietze, 1990-1991).
‘‘Cerebellar speech’’ is dysarthric and dysrhythmic, with inappropriate
emphases. Scanning speech is an example of this, in which there is deliberate
correction of the motor speech program. This disturbed coordination disturbs
fluency. Comprehension and language functions are undisturbed. Scanning
speech, as seen in multiple sclerosis, or ethanol intoxication, appears most
related to left-sided paravermian cortex (Lechtenberg, 1978). An apparent
inconsistency is that the left cerebellum interacts with the right thalamus and
right cerebrum, whereas cerebral language functions predominate on the left
(Lechtenberg, 1993).
The dentato-rubro-thalamic tracts are of particular interest in further elucidating the cerebellum’s role in language processing. Dorsomedial dentate
lesions produce the classical outflow tremor and ataxia, unlike disruption of
pathways from the phylogenetically newer ventrolateral neodentate. These
tracts travel by way of the medial ventrolateral thalamus to frontal neocortex
areas 4 (motor), 6 (premotor/supplementary motor), and 8 (intellectual performance, initiative, and frontal eye fields directing contralateral fast saccades). Areas 4, 6, and 8 receive a majority of their dentate input from the

490

COPLIN ET AL.

dorsomedial portion of the nucleus. Fibers from the most medial portion
of the ventrolateral nucleus feed ‘‘Broca’s area,’’ Brodman’s 44 (encoding
articulation), and the more prefrontal area 45 (word finding). Temporal lobe
language areas project to the cerebellum by way of pontine nuclei. Frontal
language areas project either byway of this pathway, by wayof fronto-temporal
fibers, or directly by way of fronto-pontine tracts (Figs. 3A and 3B).
The lateral cerebellum receives input from the frontal cerebrum in two
ways. In one, mossy fibers project there from the pons. In the other, the
inferior olivary nucleus (receiving cortical input by way of the red nucleus)
sends climbing fibers to the cerebellum. This completes the eloquent loop
system between the lateral cerebellum and the frontal cerebrum (Fig. 3B).
The exact cause of mutism in patients with these cerebellar injuries remains elusive. Exactly what the presence of pseudobulbar affect means anatomically and pathologically is unclear both in this syndrome and in our
patient. Brainstem function and comprehension are intact, and this mutism
occurs only after posterior fossa surgery, with prominent cerebellar speech
during the recovery period. Neither meningitis, hydrocephalus (Ferrante,
1990; Salvati, 1991), vasospasm, nor stroke seem likely causative, since
these do not occur uniformly with this syndrome. Likewise, neither postoperative dentate edema nor tracking brainstem edema (Volcan, 1986; Ammirati,
1989; Humphreys, 1989) occur universally with cerebellar mutism, and these
entities would render impossible other functions these patients are able to
perform.
Several authors point to lesions of the left more than right cerebellar hemisphere and vermis, involving the deep nuclei, as the anatomic site of the
syndrome (Lechtenberg, 1978; Rekate, 1985; Humphreys, 1989). Bilateral
stereotactic ablation or ischemia of the dentate nuclei has caused transient
mutism (Fraioli, 1975; Guidetti, 1977; Ackermann, 1992), as has accidental
injury of the nucleus interpositus (Siegfried, 1970). The likelihood of developing mutism my be proportionate to the extent of injury to the cerebellar
midportion (vermis and paravermis) and dentate nuclei (Dietze, 1990;
Dietze, 1991).
CONCLUSION

It appears that either vermian splitting or dentate destruction, discussed
above, could account for the presented patient’s mutism. That he was able
to speak, when first seen by the medics, would suggest that the splitting of
the inferior vermis is the more likely cause of the syndrome of cerebellar
mutism, if we assume that the initial hemorrhage caused only dentate damage
and that it was not until surgery that the vermis was incised. The postoperative MRI study shows dentate and vermian damage without brainstem injury.
Because he remained intubated in the postoperative period, we cannot say
whether or not there was a latent period of speech before the onset of his
mutism (which we first discovered when he was later extubated).

CEREBELLAR MUTISM

491

Perhaps mutism is the most severe form of dysarthria, the ultimate dyspraxia of voice coordination, rendering eloquence of speech impossible.
Clearly the patient presented demonstrates that prolonged mutism can occur
in adults with a non-neoplastic midline cerebellar lesion.
REFERENCES
Ackermann, H., Vogel, M., & Petersen, D., et al. 1992. Speech deficits in ischaemic cerebellar
lesions. Journal of Neurology, 239, 223–227.
Adams, R. D., Victor, M., & Mancall, E. L. 1959. Central pontine myelinolysis. American
Medical Association Archives of Neurology and Psychiatry, 81, 154–172.
Allen, G. I., & Tsukahara, N. 1974. Cerebrocerebellar communication systems. Physiology
Reviews, 54, 957–998.
Altman, J. A., Bechterev, N. N., Radionova, E. A., et al. 1976. Electrical responses of the
auditory area of the cerebellar cortex to acoustic stimulation. Experimental Brain Research, 26, 285–298.
Amici, R., Avanzini, G., & Pacini, L. 1976. Cerebellar tumors. In Monographs in Neural
Sciences v. 4. Basel: Karger.
Ammirati, M., Mirzai, S., & Samii, M. 1989. Transient mutism following removal of a cerebellar tumor. Child’s Nervous System, 5, 12–14.
Benson, D. F. 1979. Aphasia, alexia, and agraphia. New York: Churchill Livingstone. Pp.
163–164.
Brown, J. R. 1949. Localizing cerebellar syndromes. Journal of the American Medical Association, 141, 518–521.
Cairns, H., Oldfield, R. C., Pennybacker, J. B., et al. 1941. Akinetic mutism with an epidermoid
cyst of the 3rd ventricle. Brain, 64, 273–290.
Cakir, Y., Karakisi, D., & Kocanaogullari, O. 1994. Cerebellar mutism in an adult: Case report.
Surgical Neurology, 41, 342–344.
Carpenter, M. B. 1991. The cerebellum. In Core text of neuroanatomy: 4 ed. Baltimore: Williams and Wilkins. Pp. 224–249.
Catsman-Berrevoets, C. E., van Dongen, H. R., & Zwetsloot, C. P. 1992. Transient loss of
speech followed by dysarthria after removal of posterior fossa tumour. Developmental
Medicine and Child Neurology, 34, 1102–1109.
Charcot, J. M. 1877. Lectures on the diseases of the nervous system v. 72. London: The New
Sydenham Society. Pp. 192–193.
Cochrane, D. D., Gustavsson, B., Poskitt, K. P., et al. 1994. The surgical and natural morbidity
of aggressive resection for posterior fossa tumors in childhood. Pediatric Neurosurgery
20, 19–29.
Courchesne, E., Yeung-Courchesne, R., Press, G. A., et al. 1988. Hypoplasia of cerebellar
vermal lobules VI and VII in autism. New England Journal of Medicine, 318, 1349–
1354.
D’Avanzo, R., Scuotto, A., Natale, M., et al. 1993. Transient ‘‘cerebellar’’ mutism in lesions
of the mesencephalic-cerebellar region. Acta Neurologica Napoli, 15, 289–296.
Daly, D. D., & Love, J. G. 1958. Akinetic mutism. Neurology, 8, 238–242.
Dailey, A. T., MacKhann, G. M., II, & Berger, M. S. 1995. The pathophysiology of oral
pharyngeal apraxia and mutism following posterior fossa tumor resection in children.
Journal of Neurosurgery, 83, 81–89.
Dandy, W. E. 1966. The brain. Hagerstown: Prior Publishing. Pp. 452–458.
Dietze, D. D., Jr., & Mickle, J. P. 1990–1991. Cerebellar mutism after posterior fossa surgery.
Pediatric Neurosurgery, 16, 25–31.
Dow, R. S. 1939. Cerebellar action potentials in response to stimulation of various afferent
connections. Journal of Neurophysiology, 2, 543.

492

COPLIN ET AL.

Eager, R. P. 1963. Cortical association pathways in the cerebellum of the cat. Journal of
Comparative Neurology, 121, 381–393.
Eccles, S. C. 1969. The dynamic loop hypothesis of movement control. In K. N. Lerbovic
(Ed.), Information processing in the nervous system. New York: Springer. Pp. 245–269.
Ferrante, L., Mastronardi L., Acqui M., et al. 1990. Mutism after posterior fossa surgery in
children. Journal of Neurosurgery, 72, 959–963.
Flourens, M. J. P. 1823. Recherches sur les proprietes et les fonctiones du systeme nerveux
dans les animaux vertebres. Archives Generales de Medicin (Paris), pp. 321–370.
Fraioli, B., & Guidetti, B. 1975. Effects of stereotactic lesions of the dentate nucleus of the
cerebellum in man. Applied Neurophysiology, 38, 81–90.
Ghez, C. 1991. The cerebellum. In E. R. Kandel, J. H. Schwartz, T. M. Jessell (Eds.), Principles
of neural science, 3 ed. Norwalk, CT: Appleton & Lange. Pp. 626–646.
Gilman, S., Bloedel, J. R., & Lechtenberg, R. 1981. Disorders of the cerebellum. Philadelphia:
F.A. Davis Co.
Gilman, S. 1993. Positron emission tomographic studies of cerebellar disorders. In R. Lechtenberg (Ed.), Handbook of cerebellar diseases. New York: Dekker. Pp. 131.
Groswassa, Z., & Kom, C. 1988. Mutism associated with buccofacial apraxia and bihemispheric lesions. Brain and Language, 34, 157–168.
Guidetti, B., & Fraioli, B. 1977. Neurosurgical treatment of spasticity and dyskinesias. Acta
Neurochirgica, 24(suppl.), 27–39.
Herb, E., & Thyen, U. 1992. Mutism after cerebellar medulloblastoma surgery. Neuropediatrics, 23, 144–146.
Hirsch, J. F., Renier, D., Czernichow, P., et al. 1979. Medulloblastoma in childhood: Survival
and functional results. Acta Neurochirgica, 48, 1–15.
Holmes, G. 1922. The Croonian lectures on the clinical symptoms of cerebellar disease and
their interpretation. Lancet, 1, 1177–1182; 2, 59–65, 111–115.
Holmes, G. 1917. The symptoms of acute cerebellar injuries due to gunshot injuries. Brain,
40, 461–535.
Humphreys, R. P. 1989. Mutism after posterior fossa tumor surgery. In Concepts in pediatric
neurosurgery v. 9. Basel: Karger. Pp. 57–64.
Ito, M. 1970. Neurophysiological aspects of the cerebellar motor control system. International
Journal of Neurology, 7, 162–176.
Kent, R., & Netsell, R. 1976. A case of an ataxic dysarthria: Cineradiographic and spectrographic observations. Journal of Speech and Hearing Disorders, 41, 115–134.
Kepes, J. J., Reece, C. A., & Oxley, D. K. 1965. Central pontine myelinolysis in a 7-yearold boy. Journal of Neurology, Neurosurgery, and Psychiatry, 28, 39–47.
Kish, S. J., El-Awar, M., Schut, L., et al. 1988. Cognitive deficits in olivopontocerebellar
atrophy: Implications for the cholinergic hypothesis of Alzheimer’s dementia. Annals of
Neurology, 24, 200–206.
Lam, R. L., & Ogura, J. H. 1952. An afferent representation of the larynx in the cerebellum.
Laryngoscope, 62, 486–495.
LaPointe, L. L., Homer, J. 1979. Reading comprehension battery for aphasia. Tigard, Oregon:
C.C. Publications, Inc.
Larson, C. R., Sutton, D., & Linderman, R. C. 1978. Cerebellar regulation of phonation in
the Rhesus monkey. Experimental Brain Research, 33, 1–18.
Lavy, S. 1959. Akinetic mutism in a case of craniopharyngioma. Psychiatry and Neurology
(Basel), 138, 369–374.
Lechtenberg, R. (Ed). 1993. Handbook of cerebellar diseases. New York: Dekker. Pp. 39–40.
Lechtenberg, R., & Gilman, S. 1978. Speech disorders in cerebellar disease. Annals of Neurology, 3, 285–290.
Leiner, H. C., Leiner, A. L., & Dow, R. S. 1993. Cognitive and language functions of the
human cerebellum. Trends in Neuroscience, 16, 444–447.
Mao, C. C., Coull, B. M., Golpher, L. A. C., & Raw, M. T. 1989. Anterior opercular syndrome.
Neurology, 39, 1169–1172.

CEREBELLAR MUTISM

493

Mills, C. K., & Weisenburg, T. H. 1914. Cerebellar symptoms and cerebellar localization.
Journal of the American Medical Association, 63, 1813–1818.
Nagatani, K., Waga, S., & Nakagawa, Y. 1991. Mutism after removal of a vermian medulloblastoma: Cerebellar mutism. Surgical Neurology, 36, 307–309.
Petersen, S. E., Fox, P. T., Posner, M. I., et al. 1988. Positron emission tomographic studies
of the cortical anatomy of single word processing. Nature, 331, 585–589.
Reiss, A. L., Patel, S., Kumar, A. J., & Freund, L. 1988. Preliminary communication: Neuroanatomical variations of the posterior fossa in men with the fragile X (Martin-Bell) syndrome. American Journal of Medical Genetics, 31, 407–414.
Rekate, H. L., Grubb, R. L., Aram, D. M., et al. 1985. Muteness of cerebellar origin. Archives
of Neurology, 42, 697–698.
Rosina, A., & Provini, L. 1984. Pontocerebellar system linking the two cerebellar hemispheres
by intracerebellar branching. Brain Research, 296, 365–369.
Rostomily, R. C., Berger, M. S., Ojemann, G. A., et al. 1991. Postoperative deficits and functional recovery following removal of tumors involving the dominant hemisphere supplementary motor area. Journal of Neurosurgery, 75, 62–68.
Salvati, M., Missori, P., Lunardi, P., et al. 1991. Transient cerebellar mutism after posterior
cranial fossa surgery in an adult. Clinical Neurology and Neurosurgery, 93, 313–316.
Sanes, J. N., Dimitrov, B., & Hallett, M. 1990. Motor learning in patients with cerebellar
dysfunction. Brain, 113, 103–120.
Sarnat, H. B., & Alcala, H. 1980. Human cerebellar hypoplasia. Archives of Neurology, 37,
300–305.
Segarra, J. M. 1970. Cerebral vascular disease and behavior. I: The syndrome of the mesencephalic artery (basilar artery bifurcation). Archives of Neurology, 22, 408–418.
Siegfried, J., Esslen, E., Gretener, U., et al. 1970. Functional anatomy of the dentate nucleus
in the light of stereotaxic operations. Confin Neurology, 32, 1–10.
Silveri, M. C., Leggio, M. G., & Molinari, M. 1994. The cerebellum contributes to linguistic
production: A case of agrammatic speech following a right cerebellar lesion. Neurology,
44, 2047–2050.
Skultety, F. M. 1968. Clinical and experimental aspects of akinetic mutism. Archives of Neurology, 19, 1–14.
Snider, R. S., & Stowell, A. 1944. Receiving areas of the tactile, auditory, and visual systems
in the cerebellum. Journal of Neurophysiology, 7, 331–357.
Sypert, G. W., & Alvord, E. C., Jr. 1975. Cerebellar infarction. A clinicopathological study.
Archives of Neurology, 32, 357–363.
Tolbert, D. L., Bantli, H., & Bloedel, J. R. 1978. Organizational features of the cat and monkey
cerebellar nucleocortical projections. Journal of Comparative Neurology, 182, 39–56.
Valk, P. E., Budinger, T. F., Levin, V. A., et al. 1988. PET of malignant cerebral tumors
after interstitial brachytherapy: Demonstration of metabolic activity and correlation with
clinical outcome. Journal of Neurosurgery, 69, 830–838.
van Dongen, H. R., Catsman-Berrevoets, C. E., & van Mourik, M. 1994. The syndrome of
‘‘cerebellar’’ mutism and subsequent dysarthria. Neurology, 44, 2040–2046.
Volcan, I., Cole, G. P., & Johnston, K. 1986. A case of muteness of cerebellar origin (Letter).
Archives of Neurology, 43, 313–314.
Wisoff, J. H., & Epstein, F. J. 1984. Pseudobulbar palsy after posterior fossa operation in
children. Neurosurgery, 15, 707–709.
Yonemasu, Y. 1985. ‘‘Cerebellar mutism’’ and speech disturbance as a complication of posterior fossa surgery in children. Thirteenth Annual Meeting of the Japanese Society for
Pediatric Neurosurgery, Tsukuba.
Zentay, P. J. 1937. Motor disorders of the nervous system and their significance for speech.
I. Cerebral and cerebellar dysarthrias. Laryngoscope, 47, 147–156.