Surg Neurol 1991;36:307-9
307
Mutism After Removal of a Vermian Medulloblastoma: Cerebellar Mutism Kazuhiko
Nagatani, M.D., Shiro Waga, M.D., D.M.Sc., and Yutaka Nakagawa,
M.D.
Department of Neurosurgery, Mie University School of Medicine, Edobashi, Tsu, Japan
Nagatani K, Waga S, Nakagawa Y. Mutism after removal of a vermian medulloblastoma: cerebellar mutism. Surg Neurol 1991;36:307-9.
A case of mutism after removal of a vermian medulloblastoma from a 4-year-old girl is reported. Postoperatively, the patient was mute without disturbance of consciousness, language comprehension, or lower cranial nerve function. Computed tomography scans demonstrated no abnormal findings except for the surgical lesion in the posterior fossa. The mutism lasted for 78 days, followed by a period of dysarthria, but she gradually became fluent. The mechanism of"cerebellar mutism" is briefly discussed. KEY WORDS: Cerebellar mutism; Cerebellar tumors; Dysarthria; Medulloblastoma
Conditions causing complete absence of speech in a conscious patient, ie, mutism or muteness, have been described by Benson [1] as follows: (1) damage to Broca's area, (2) damage to the supplementary motor area of the dominant hemisphere, (3) damage to the reticular formation of the mesencephalon, (4) diffuse bilateral cerebral hemispheric damage causing pseudobulbar palsy, and (5) bilateral thalamotomy for Parkinson's disease. In addition, cerebellar damage has been known to produce mutism [ 3 - 6 , 8 - 1 0 , 1 2 ] . This type of mutism has some unique clinical characteristics: (1) most reported cases involve children; (2) the mutism occurs after extensive removal of posterior fossa tumors; (3) the tumors have a midline location; and (4) during the mutism, comprehension is preserved and lower cranial nerve function is intact. The cerebellar site responsible for mutism is controversial, probably because the previous cases were reported in the computed tomography (CT) era before magnetic resonance imaging (MRI) had become available, and possibly because psychic causes could not be completely ruled out in some cases [3].
Address reprint requests to." Kazuhiko Nagatani, M.D., Department of Neurosurgery, Mie University School of Medicine, 2-174 Edobashi, Tsu 514, Japan. Received January 2, 1991; accepted March 20, 1991.
© 199I by Elsevier Science Publishing Co., Inc.
Case Report A 4-year-old girl was admitted to our hospital on August 28, 1986, with a 2-week history of unstable gait and complaints of occasional vomiting for a period of several months. Neurological examination showed slight truncal ataxia and bilateral papilledema. Computed tomography scans revealed a large midline cerebellar tumor and triventricular dilatation (Figure 1). She underwent a midline suboccipital craniectomy. The inferior vermis was incised and the tumor was totally removed with a Cavitron ultrasonic surgical aspirator, using microsurgical technique. The floor of the fourth ventricle was not invaded by the tumor. Histological examination demonstrated that the tumor was a medulloblastoma. Twentyfour hours after the operation, the patient became completely alert, but did not speak. Although the gag reflex and other lower cranial nerve functions were normal, she refused to eat for about 1 month, and did not speak. The mutism continued for 78 days, followed by a period of dysarthria, which showed a slow monotonous pattern and was not explosive nor scanning. H e r speech returned slowly and gradually without any specific treatment. During the period of mutism, her language comprehension was normal, and CT scans demonstrated no abnormal findings except for the surgical lesion (Figure 2). She became fluent about 4 months after the operation.
Discussion Dysarthria produced by cerebellar dysfunction is a wellknown p h e n o m e n o n and, according to the study by Sakai et al [ 10], the main problem is disturbance in the articulation of syllables. In contrast, mutism is an unusual state after cerebellar damage, and can be regarded as the most extreme form of dysarthria, where the patient cannot articulate at all [2,3]. Only several reports of"cerebellar mutism" have been published so far [ 3 - 6 , 8 - 1 0 , 1 2 ] . Among the 15 traceable patients, including our present patient, ages ranged from 4 to 10 years, and neither sex was predominant. All patients had posterior fossa tumors: 6 medulloblastomas, 6 astrocytomas, 2 ependymomas, and 1 glioblastoma. Mutism occurred after re0090-3019/9I/$3.50
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Surg Neurol 1991;36:307-9
Figure 1. Preoperative C T scans demonstrating a midline tumor in the posterior fossa and triventricular dilatation.
Figure 2. Postoperative C T scans demonstrating no additional lesion other than that due to posterior fossa surgery.
Cerebellar Mutism
moval of the tumors. In 9 of the 15 cases, the patients were able to speak for 1 to 3 days after the operation (60%). Each patient was fully alert; receptive vocabulary understanding and the lower cranial nerves were not involved. The mutism continued for between 4 days and 4 months, with speech returning in all cases. Interestingly, Fraioli and Guidetti [4] reported two cases of mutism after stereotactic lesioning of the bilateral dentate nuclei. Therefore, destruction of these nuclei may play a role in the development ofmutism. Moreover, mutism has also occurred after bilateral thalamotomy for Parkinson's disease [ 11 ]. This may indicate the contribution of the superior cerebellar peduncles, which connect the dentate nucleus to the thalamus. Lechtenberg and Gilman [7] suggested that the site responsible for the development of dysarthria was the superior surface of the left cerebellar hemisphere, and they speculated that in a left-handed person, lateralization of speech function in the cerebellum was contralateral, ie, on the right side. Sakai et al [9,10] reported three cases of "cerebellar mutism" in which there was destruction of the superior vermis and the paravermian zone.
In addition to this direct damage, Ferrante et al [3t have suggested at least two hypothetical factors contributing to the occurrence of mutism [3]. One is the psychic factor: all the patients were children, and behavioral changes including mutism and refusal of food intake might have appeared when they felt betrayed. The other is postoperative spasm of the arteries supplying the cerebellum ~nd the brain stem, causing ischemia. This possibility may be supported by the fact that 60% of the reported patients were able to speak immediately after
Surg Neurol 1991;36:307-9
309
surgery when cerebellar perfusion was not disturbed. In any event, further investigation, including MRI, will be necessary to elucidate the mechanism of cerebellar mutism.
References 1. Benson DF. Aphasia, alexia and agraphia. New York: Churchill Livingstone, 1979:163-4. 2. Dow RS. Cerebellar syndromes. In: Vinken PJ, Bruyn GW (eds). Handbook of clinical neurology: localization in clinical neurology. Vol 2. Amsterdam: North-Holland, 1969:392-431. 3. Ferrante L, Mastronardi L, Acoui M, Fortuna A. Mutism after posterior fossa surgery in children. J Neurosurg 1990;72:959-63. 4. Fraioli B, Guidetti B. Effect of stereotactic lesions of the dentate nucleus of the cerebellum in man. Appl Neurophysiol 1975; 38:81-90. 5. Hirsch JF, Renier D, Czernichow P, Benveniste L, Pierre-Kahn A. Medulloblastoma in childhood: Survival and functional results. Acta Neurochir 1979;48:1-15. 6. Humphrey RP. Mutism after posterior fossa tumor surgery. In: Marlin AE (ed). Concepts in pediatric neurosurgery. Vol 9. Basel: Karger, 1989:57-64. 7. Lechtenberg R, Gilman S. Speech disorders in cerebellar disease. Ann Neurol 1978;3:285-90. 8. Rakate HL, Grubb RL, Aram DM, Hahn JF, Ratcheson RA. Muteness of cerebellar origin. Arch Neurol 1985;42:697-8. 9. Sakai H. Cerebellar dysarthria: historical background and new concept of functional localization. No-shinkei-geka 1980; 32:1235-45. 10. Sakai H, Sekino H, Nakamura N. Three cases of "cerebellar tourism." Shinkeinaika 1980;12:302-4. i 1. Siegfried J, Esslen E, Gretener U, Ketz E, Perret E. Functional anatomy of the dentate nucleus in the light of stereotactic operations. Confin Neurol 1970;32:1-10. 12. Volcan I, Cole GP, Johnston K. A case of muteness ofcerebellar origin. Arch Neurol 1986;43:313-14.
307
Mutism After Removal of a Vermian Medulloblastoma: Cerebellar Mutism Kazuhiko
Nagatani, M.D., Shiro Waga, M.D., D.M.Sc., and Yutaka Nakagawa,
M.D.
Department of Neurosurgery, Mie University School of Medicine, Edobashi, Tsu, Japan
Nagatani K, Waga S, Nakagawa Y. Mutism after removal of a vermian medulloblastoma: cerebellar mutism. Surg Neurol 1991;36:307-9.
A case of mutism after removal of a vermian medulloblastoma from a 4-year-old girl is reported. Postoperatively, the patient was mute without disturbance of consciousness, language comprehension, or lower cranial nerve function. Computed tomography scans demonstrated no abnormal findings except for the surgical lesion in the posterior fossa. The mutism lasted for 78 days, followed by a period of dysarthria, but she gradually became fluent. The mechanism of"cerebellar mutism" is briefly discussed. KEY WORDS: Cerebellar mutism; Cerebellar tumors; Dysarthria; Medulloblastoma
Conditions causing complete absence of speech in a conscious patient, ie, mutism or muteness, have been described by Benson [1] as follows: (1) damage to Broca's area, (2) damage to the supplementary motor area of the dominant hemisphere, (3) damage to the reticular formation of the mesencephalon, (4) diffuse bilateral cerebral hemispheric damage causing pseudobulbar palsy, and (5) bilateral thalamotomy for Parkinson's disease. In addition, cerebellar damage has been known to produce mutism [ 3 - 6 , 8 - 1 0 , 1 2 ] . This type of mutism has some unique clinical characteristics: (1) most reported cases involve children; (2) the mutism occurs after extensive removal of posterior fossa tumors; (3) the tumors have a midline location; and (4) during the mutism, comprehension is preserved and lower cranial nerve function is intact. The cerebellar site responsible for mutism is controversial, probably because the previous cases were reported in the computed tomography (CT) era before magnetic resonance imaging (MRI) had become available, and possibly because psychic causes could not be completely ruled out in some cases [3].
Address reprint requests to." Kazuhiko Nagatani, M.D., Department of Neurosurgery, Mie University School of Medicine, 2-174 Edobashi, Tsu 514, Japan. Received January 2, 1991; accepted March 20, 1991.
© 199I by Elsevier Science Publishing Co., Inc.
Case Report A 4-year-old girl was admitted to our hospital on August 28, 1986, with a 2-week history of unstable gait and complaints of occasional vomiting for a period of several months. Neurological examination showed slight truncal ataxia and bilateral papilledema. Computed tomography scans revealed a large midline cerebellar tumor and triventricular dilatation (Figure 1). She underwent a midline suboccipital craniectomy. The inferior vermis was incised and the tumor was totally removed with a Cavitron ultrasonic surgical aspirator, using microsurgical technique. The floor of the fourth ventricle was not invaded by the tumor. Histological examination demonstrated that the tumor was a medulloblastoma. Twentyfour hours after the operation, the patient became completely alert, but did not speak. Although the gag reflex and other lower cranial nerve functions were normal, she refused to eat for about 1 month, and did not speak. The mutism continued for 78 days, followed by a period of dysarthria, which showed a slow monotonous pattern and was not explosive nor scanning. H e r speech returned slowly and gradually without any specific treatment. During the period of mutism, her language comprehension was normal, and CT scans demonstrated no abnormal findings except for the surgical lesion (Figure 2). She became fluent about 4 months after the operation.
Discussion Dysarthria produced by cerebellar dysfunction is a wellknown p h e n o m e n o n and, according to the study by Sakai et al [ 10], the main problem is disturbance in the articulation of syllables. In contrast, mutism is an unusual state after cerebellar damage, and can be regarded as the most extreme form of dysarthria, where the patient cannot articulate at all [2,3]. Only several reports of"cerebellar mutism" have been published so far [ 3 - 6 , 8 - 1 0 , 1 2 ] . Among the 15 traceable patients, including our present patient, ages ranged from 4 to 10 years, and neither sex was predominant. All patients had posterior fossa tumors: 6 medulloblastomas, 6 astrocytomas, 2 ependymomas, and 1 glioblastoma. Mutism occurred after re0090-3019/9I/$3.50
308
Surg Neurol 1991;36:307-9
Figure 1. Preoperative C T scans demonstrating a midline tumor in the posterior fossa and triventricular dilatation.
Figure 2. Postoperative C T scans demonstrating no additional lesion other than that due to posterior fossa surgery.
Cerebellar Mutism
moval of the tumors. In 9 of the 15 cases, the patients were able to speak for 1 to 3 days after the operation (60%). Each patient was fully alert; receptive vocabulary understanding and the lower cranial nerves were not involved. The mutism continued for between 4 days and 4 months, with speech returning in all cases. Interestingly, Fraioli and Guidetti [4] reported two cases of mutism after stereotactic lesioning of the bilateral dentate nuclei. Therefore, destruction of these nuclei may play a role in the development ofmutism. Moreover, mutism has also occurred after bilateral thalamotomy for Parkinson's disease [ 11 ]. This may indicate the contribution of the superior cerebellar peduncles, which connect the dentate nucleus to the thalamus. Lechtenberg and Gilman [7] suggested that the site responsible for the development of dysarthria was the superior surface of the left cerebellar hemisphere, and they speculated that in a left-handed person, lateralization of speech function in the cerebellum was contralateral, ie, on the right side. Sakai et al [9,10] reported three cases of "cerebellar mutism" in which there was destruction of the superior vermis and the paravermian zone.
In addition to this direct damage, Ferrante et al [3t have suggested at least two hypothetical factors contributing to the occurrence of mutism [3]. One is the psychic factor: all the patients were children, and behavioral changes including mutism and refusal of food intake might have appeared when they felt betrayed. The other is postoperative spasm of the arteries supplying the cerebellum ~nd the brain stem, causing ischemia. This possibility may be supported by the fact that 60% of the reported patients were able to speak immediately after
Surg Neurol 1991;36:307-9
309
surgery when cerebellar perfusion was not disturbed. In any event, further investigation, including MRI, will be necessary to elucidate the mechanism of cerebellar mutism.
References 1. Benson DF. Aphasia, alexia and agraphia. New York: Churchill Livingstone, 1979:163-4. 2. Dow RS. Cerebellar syndromes. In: Vinken PJ, Bruyn GW (eds). Handbook of clinical neurology: localization in clinical neurology. Vol 2. Amsterdam: North-Holland, 1969:392-431. 3. Ferrante L, Mastronardi L, Acoui M, Fortuna A. Mutism after posterior fossa surgery in children. J Neurosurg 1990;72:959-63. 4. Fraioli B, Guidetti B. Effect of stereotactic lesions of the dentate nucleus of the cerebellum in man. Appl Neurophysiol 1975; 38:81-90. 5. Hirsch JF, Renier D, Czernichow P, Benveniste L, Pierre-Kahn A. Medulloblastoma in childhood: Survival and functional results. Acta Neurochir 1979;48:1-15. 6. Humphrey RP. Mutism after posterior fossa tumor surgery. In: Marlin AE (ed). Concepts in pediatric neurosurgery. Vol 9. Basel: Karger, 1989:57-64. 7. Lechtenberg R, Gilman S. Speech disorders in cerebellar disease. Ann Neurol 1978;3:285-90. 8. Rakate HL, Grubb RL, Aram DM, Hahn JF, Ratcheson RA. Muteness of cerebellar origin. Arch Neurol 1985;42:697-8. 9. Sakai H. Cerebellar dysarthria: historical background and new concept of functional localization. No-shinkei-geka 1980; 32:1235-45. 10. Sakai H, Sekino H, Nakamura N. Three cases of "cerebellar tourism." Shinkeinaika 1980;12:302-4. i 1. Siegfried J, Esslen E, Gretener U, Ketz E, Perret E. Functional anatomy of the dentate nucleus in the light of stereotactic operations. Confin Neurol 1970;32:1-10. 12. Volcan I, Cole GP, Johnston K. A case of muteness ofcerebellar origin. Arch Neurol 1986;43:313-14.
