Mutism: elective or selective, and acquired

When a child does not speak, this may be because there is no wish to do so (elective or selective mutism), or the result of lesions in the brain, part icularly in the posterior fossa. The characteristics of the former children are described, especially their shyness; and it is emphasized that mild fo rms are quite common and a definitive diagnosis should only be made if the condition is significantly affecting the child and family. In the case of m utism due to organic causes, the commonest of these is trauma to the cerebe llum. Operations on the cerebellum to remove rumours can be followed by mut ism, often after an interval of a few days, and it may last for several mon ths or longer, to be followed by dysarthria. Other rarer causes are discuss ed, and also the differential diagnosis. The so-called posterior fossa synd rome consists of mutism combined with ataxia, cranial nerve palsies, bulbar palsies, hemiparesis, cognitive impairment and emotional lability, bur the post-operative symptoms are often dominated by the lack of speech. The mos t accepted cause for the condition is vascular spasm with involvement of th e dentate nucleus and the dentatorubrothalamic tracts to the brain-stem, an d subsequently to the cortex. Diaschisis map be involved in causing the los s of higher cerebral functions, and possibly, complicating hydrocephalus. T he treatment of elective mutism is reviewed, either using a psychotherapeut ic approach or a variety of drugs, or both. These may well be ineffective, and it must be remembered that the condition often resolves on its own. The former treatment must concentrate on the training of social skills and act ivities of daily life and must be targeted to both the child, the family, a nd the school. Also, all kinds of punishment and insistence on speech must be discouraged. The drug, which seems to be most effective, is fluoxetine. Discovering more about the causes of mutism due to organic causes may well depend on studies using such techniques as magnetic resonance imaging and s ingle photon emission tomography. (C) 2001 Elsevier Science B.V. All rights reserved.