The definition of normal pressure hydrocephalus (NPH), in adults, associates 
clinical signs (Adams and Hakim triad) involving gait disorders, urinary 
incontinence and dementia, associated with aspects on brain imaging that are 
consistent with this hypothesis and also normal or slightly increased 
intracranial pressure. The aim of this study was to clarify the techniques and 
methods facilitating the diagnosis of NPH. The literature review has been 
conducted from the Medline database without date limitation including the 
keywords "normal pressure hydrocephalus" and "diagnosis." They should appear in 
the article title. From the 43 initially sorted, only 13 have been selected 
using exclusion criteria. The proposed methods are very sparse and focused on 
the improvement after surgical shunt. This focus is independent from the 
diagnosis criteria proposed in 2005. This introduces an ambiguity in the 
interpretation of the results. In practice, the diagnosis of NPH is more 
difficult in the elderly population where differential diagnoses are frequent, 
particularly vascular lesions (notably microangiopathy) and Alzheimer's disease. 
The more invasive techniques as continuous spinal drainage (usually during 3 
days) or some features of CSF dynamics (Rout, compliance) seem to be the best 
predictors of after shunt improvement. However, these techniques are difficult 
to use in routine in the elderly. The combination of Evans index and corpus 
callosum angle on MRI is very useful to improve the differential diagnosis with 
cerebral atrophy. Spinal tap test (lumbar puncture with the removal of 40 mL of 
CSF) can be repeated two or three times for consecutive days to improve the 
predictive value before shunting. Gait and balance often improve after shunt, 
more than cognition and bladder disorders. In the elderly population, the 
prognosis after 3 years is non conclusive despite initial improvement. Poor 
prognosis seems to be due to associated pathologies in particular 
neurodegenerative diseases. This should be considered in decision-making of CSF 
shunt.