[Post-traumatic dementia].

On the basis of a retrospective study concerning 63 cases of normal pressure hydrocephalus, the author examines the characteristics of patients with a traumatic aetiology who were not ameliorated by a ventricular derivation. Four of these patients suffering from a post-traumatic dementia are described. Reviewing the literature, several topics concerning post-traumatic dementia are considered: incidence, time delay before diagnosis, variation of pictures, aetiopathogenic explanations, medico-legal problems encountered with Alzheimer's of Pick's diseases. Finally the differential diagnostic characteristics between the curable and incurable forms of post-traumatic dementia syndromes are discussed.