Hydrocephalus

===Other===
[[File:BrainAtrophy(exvacuo).png|thumb|Hydrocephalus ''ex vacuo'' from vascular dementia as seen on MRI]]
* [[Normal pressure hydrocephalus]] (NPH) is a particular form of chronic communicating hydrocephalus, characterized by enlarged cerebral ventricles, with only intermittently elevated cerebrospinal fluid pressure. Characteristic triad of symptoms are; dementia, apraxic gait and urinary incontinence. The diagnosis of NPH can be established only with the help of continuous intraventricular pressure recordings (over 24 hours or even longer), since more often than not instant measurements yield normal pressure values. Dynamic compliance studies may be also helpful. Altered compliance ([[wikt:elastic#Adjective|elasticity]]) of the ventricular walls, as well as increased [[viscosity]] of the cerebrospinal fluid, may play a role in the pathogenesis.<ref>{{cite journal | vauthors = Martin BA, Loth F | title = The influence of coughing on cerebrospinal fluid pressure in an in vitro syringomyelia model with spinal subarachnoid space stenosis | journal = Cerebrospinal Fluid Research | volume = 6 | issue = 1 | pages = 17 | date = December 2009 | pmid = 20043856 | pmc = 2806373 | doi = 10.1186/1743-8454-6-17 | doi-access = free }}</ref>
* ''Hydrocephalus ex vacuo'' also refers to an enlargement of cerebral ventricles and subarachnoid spaces, and is usually due to brain [[atrophy]] (as it occurs in [[dementia]]s), post-[[traumatic brain injury|traumatic brain injuries]], and even in some psychiatric disorders, such as [[schizophrenia]].<ref name=":0">{{Cite book|title=Complications in neuroanesthesia| vauthors = Hemanshu P |isbn=9780128040751|oclc=939553425|date = 2016-02-29| publisher = Elsevier Science }}</ref> As opposed to hydrocephalus, this is a compensatory enlargement of the CSF-spaces in response to brain [[parenchyma]] loss; it is not the result of increased CSF pressure.<ref name=":0" />