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 urinary incontinence, there is a rather limited number of controlled studies concerning neuropsychological deficits in the disease. A wide range of psychopathologically relevant symptoms have been described, but the common features of most cases include mental and mator slowing, apathy, emotional indifference, anosognosia, memory and attentional impairment. A number of other functional deficits such as dyslexia, dysgraphia, acalculia, apraxia can also frequently be found. Some emphasis is put on the work of J, de Mol (Brussels) which appears to be most important for the study of neuropsychological symptoms in NPH patients. The methodological standard of a number of studies has been found to be rather low, and yet a sound neuropsychological investigation may be of utmost importance for the diagnosis and neurosurgical outcome assessment. Concerning morphological correlates of the functional deficits 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.