Dementia infantilis with cortical dysrhythmia.

Dementia and the major psychoses are rare in children. Weygandt, in 1907, introduced the term dementia infantilis to describe cases of progressive mental deterioration of obscure causation, occurring in young children whose previous development had been normal. Since then many of the cases to which this description applies have been found to have a definite etiology in in-flammatory, degenerative or demyelinating diseases of the nervous system. By common consent the term has come to be applied to the rather diverse clinical group of cases described originally by Heller (1908). Attempts have been made by Zappert (1921) and others to limit it to a circumscribed syndrome, but, as Voigt (1919) has pointed out, Heller's cases differed considerably from one another and may well have had a varying etiology. It is perhaps better, therefore, to regard dementia infantilis in a wider sense as a clinical grouping from which more circumscribed syndromes will continue to be split off as investigation proceeds. It is one of the objects of this paper to describe a case which conforms clinically to this group and in which electroencephalographic study has yielded a clue to the underlying pathological state. The type of abnormal cortical activity found in this case may well have been present in some of the cases previously described. The clinical similarity between cases of the infantile dementia group in spite of a varied causation is not remarkable when it is considered that in general the kind of psychological disturbance seen in children in whom there is gross psychotic disturbance depends at least as much upon the stage of mental development at the time it occurs as upon the nature of the etiological process. It is probable for this reason that Heller's cases, whilst alike clinically, were 122