Idiopathic hydrocephalic dementia in aging brain the neurosurgical approach.

On the basis of our 16 years' experience, we have treated 36 patients by extrathecal shunt for idiopathic normal pressure hydrocephalus. All patients were submitted to clinical evaluation, neuroradiological, and neuropsychological (Mini Mental Test) tests. Seventy-six per cent of patients showed a significant clinical improvement. No change was found in 24% of them, including two patients who died. In a group of 13 patients we measured the level of main neurotransmitter metabolites (MHPG, HVA, 5-HIAA) in order to evaluate the functional status of encephalic monoaminergic system. If care is taken to make a correct diagnosis and give adequate treatment with a shunt, hydrocephalic dementia has a good prognosis.