Mutism and Pseudobulbar Symptoms after Resection of Posterior Fossa Tumors in Children: Incidence and Pathophysiology and Transient Cerebellar Mutism after Posterior Fossa Surgery in Children

To the Editor: I read with great interest the articles by Pollack et al.(3) and Van Calenbergh et al. (4). I agree with the comment by Hoffman that this condition is unfrequent in the cases previously reported (2). I observed only one other such case. The patient was a 3-year-old girl who was operated on for a posterior fossa ependymoma. She had presented with transient mutism (≈3 wk) and then experienced a period of dysarthric speech. I think that there is a complex anatomic involvement associated with this unusual transient condition, mainly with bilateral impairment of the dentatothalamo (ventrolateral nucleus)-cortical (supplementary motor area) pathway (1), but the temporariness of the mutism suggests that the anatomic damage is transient or incomplete or that other uncertain pathways could supply the main, bilaterally damaged one. Moreover, the dysarthria that often occurs after the phase of mutism confirms the presence of a severe cerebellar damage. However, the observation of patients with large posterior fossa neoplasms is frequent and the possible bilateral damage of the cerebellar nuclei and of the white matter could provoke mutism in many cases. Thus, I continue to think that mutism in children and adult patients operated on for posterior fossa tumors may have both a functional basis (negativism) and an organic basis(anatomic bilateral cerebellar damage). It is likely that both sets of factors are involved at the same time. Luciano Mastronardi Rome, Italy