Cerebellar mutism syndrome: From pathophysiology to rehabilitation

Abstract

Cerebellar mutism syndrome (CMS) is a common complication following surgical resection of childhood tumors arising in the posterior fossa. Alteration of linguistic production, up to muteness and emotional lability, generally reported at least 24 h after the intervention, is the hallmark of post-operative CMS. Other associated traits include hypotonia and other cerebellar motor signs, cerebellar cognitive-affective syndrome, motor deficits from the involvement of the long pathways, and cranial neuropathies. Recovery usually takes 6 months, but most children are burdened with long-term residual deficits. The pathogenic mechanism is likely due to the damage occurring to the proximal efferent cerebellar pathway, including the dentate nucleus, the superior cerebellar peduncle, and its decussation in the mesencephalic tegmentum. Proven risk factors include brain stem invasion, diagnosis of medulloblastoma, midline localization, tumor size, invasion of the fourth ventricle, invasion of the superior cerebellar peduncle, left-handedness, and incision of the vermis. Currently, rehabilitation is the cornerstone of the treatment of patients with cerebellar mutism syndrome, and it must consider the three main impaired domains, namely speech, cognition/behavior, and movement.

Keywords: cerebellar mutism syndrome; cerebellum; language; pediatric tumor; posterior fossa.

FIGURE 1

Some terms found in the literature to describe CMS. CCAS highlights behavioral changes, whereas TCMSD focuses on mutism and CS indicates the typical motoric cerebellar signs that can be observed both pre- and post-operatively.CMS, cerebellar mutism syndrome; CCAS, cerebellar cognitive-affective syndrome; TCMSD, transient mutism and subsequent dysarthria; CS, cerebellar syndrome.

FIGURE 2

Rehabilitation of pediatric patients with CMS must consider the three main impaired domains, namely speech, cognition/behavior, and movement.