The behavioral features of four children with acquired neurologic mutism are reported from the Department of Neurology, University Hospital Rotterdam-Dijkzigt, Rotterdam; and Department of Medical Psychology, Ziekenhuis Walcheren, Vlissingen, The Netherlands. Neuropsychologic examinations revealed changes in phonation, orofacial movements, communicative behavior, and linguistic functions. Case 1, akinetic mutism, post severe head injury, hemorrhage in left fronto-parietal area, spastic quadriplegia, motionless except for slow eye movements and head turning when addressed, no orofacial movements except smacking of lips, recovered slow dysarthric speech after 15 months; word finding unimpaired; Case 2, aphasic mutism, post head injury coma and contusion of left hemisphere, right flaccid hemiparesis, mobility improved in 6 weeks, but aphasia persisted; Case 3, cortical deafness, post head trauma neglect for verbal and nonverbal auditory stimuli, recovery of awareness of language and sounds after 5 weeks, but unaware of meanings (auditory agnosia), responded to written words, complete recovery with normal language comprehension after 11 weeks; Case 4, posterior fossa mutism, post craniotomy and removal of medulloblastoma, recovery of speech after 5 weeks. 
COMMENT. The various etiologies of acquired mutism may be differentiated by a battery of neuropsychological tests for phonation, orofacial movements, communication, and linguistic functions. In addition to the neurologic examination and neuroimaging, an EEG should distinguish Landau-Kleffner syndrome, a further example of mutism in some cases.