Neuroanatomical Mechanism of Cerebellar Mutism After Stroke

Abstract

Cerebellar mutism (CM) is a rare neurological condition characterized by lack of speech due to cerebellar lesions. CM is often reported in children. We describe a rare case of CM after spontaneous cerebellar hemorrhage. The patient showed mutism, irritability, decreased spontaneous movements and oropharyngeal apraxia. Diffusion tensor imaging revealed significant volume reduction of medial frontal projection fibers from the corpus callosum. In Tracts Constrained by UnderLying Anatomy (TRACULA) analysis, forceps major and minor and bilateral cingulum-angular bundles were not visualized. Cerebello-frontal pathway reconstructed from the FMRIB Software Library showed continuity of fibers, with decreased number of fibers on qualitative analysis. These results suggest that cerebello-frontal disconnection may be a neuroanatomical mechanism of CM. Damage of brain network between occipital lobe, cingulate and cerebellum caused by hemorrhage may also have role in the mechanism of CM in our case.

Quantitative MRI in post-operative paediatric cerebellar mutism syndrome

“…Reduced FA and increased MD were seen in the region corresponding to the left SCPin keeping with disruption of the presumed underlying fibre tractand visual comparison of the fibre orientation distribution functions showed less coherent directionality in the left SCP. Another case report of a 20 year old female with cerebellar mutism following arteriovenous malformation-related cerebellar haemorrhage utilised an automated tool to reconstruct white matter pathways from dMRI data [66]. Qualitative analysis of the results showed an equivocal reduction in "fibres" between the right cerebellum and left frontal cortex, and apparent loss of callosal "fibres" in the patient compared to a healthy control.…”

Mutism resulting from heterochronic bilateral cerebellar hemorrhages – A case report

“…There have been six previous case reports of CM after cerebellar hemorrhage [Table 1]. [3,5,8,10,13,15] Although the sites of cerebellar hemorrhage were unilateral in five of six reports, all of the hematomas were so massive that they invaded beyond the midline structures, requiring surgical interventions in most cases. Either the massive hematoma and/or the surgical intervention would injure both the unilateral dentate nuclei and the brainstem, including the contralateral superior cerebellar peduncle.…”

“…[6] CM rarely occurs in children after surgery for posterior fossa midline tumors[2] such as medulloblastoma. [17] CM also occurs following trauma,[9] stroke , [3,5,8,10,11,13,15,16] and infections. [14]…”