The neuropsychology of normal pressure hydrocephalus

Although dementia is described as one of the constituent characteristics of normal pressure hydrocephalus (NPH),alongside gait disturbances and urinar y incontinence, there is a rather limited number of controlled studies conc erning neuropsychological deficits in the disease. A wide range of psychopa thologically relevant symptoms have been described, but the common features of most cases include mental and mator slowing, apathy, emotional indiffer ence, anosognosia, memory and attentional impairment. A number of other fun ctional deficits such as dyslexia, dysgraphia, acalculia, apraxia can also frequently be found. Some emphasis is put on the work of J, de Mol (Brussel s) which appears to be most important for the study of neuropsychological s ymptoms in NPH patients. The methodological standard of a number of studies has been found to be rather low, and yet a sound neuropsychological invest igation may be of utmost importance for the diagnosis and neurosurgical out come assessment. Concerning morphological correlates of the functional defi cits in NPH,various hypotheses have been formulated, but it is argued that symptoms can neither be described as predominantly "diffuse" in nature, nor can they be reduced to unilocular dysfunctions. Recommendations for future research strategies are formulated.