[Neuropsychological symptomatology in normal pressure hydrocephalus].

The neuropsychological observations of 63 patients undergoing surgery for "normal pressure hydrocephalus" (NPH) have been analyzed retrospectively. To make a semiological picture of mental disturbances in NPH, the level of consciousness, behaviour and cognitive functions were studied. A neuropsychological investigation of the main cognitive functions (language, gnosis, praxis, calculation, memory) enables us to specify the characteristics of dementia shown by these patients. A mental picture of the most frequent neuropsychological signs is described. The mental syndrome which characterized NPH reveals an alteration of alertness and concentration, a deficiency in memory, a disorganization of graphism (writing and drawing), a dyscalculia and behaviour problems (bradypsychy, apathy, indifference). Such a syndrome points out a bilateral frontal lesion. On the other hand, the less frequent signs are largely verbal and show different stages of aphasia. These signs can usually be found in patients who don't improve after ventricular drainage and are more suggestive of a degenerative disease of the Alzheimer type. The results are compared with the psychometric and neuropsychological data of the literature. More specific attention is accorded to differential diagnosis.