The Japanese journal of neuropsychology

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ArticleTitle	Idiopathic normal pressure hydrocephalus: from the viewpoint of clinical syndrome
Language	J
AuthorList	Hiroaki Kazui
Affiliation	Department of Neuropsychiatry, Kochi Medical School, Kochi University
Publication	Japanese Journal of Neuropsychology: 36 (3), 109-118, 2020
Received
Accepted
Abstract	Idiopathic normal pressure hydrocephalus (iNPH) is a clinical syndrome in which excessive cerebrospinal fluid (CSF) accumulates in the skull due to various factors related to CSF circulation and absorption, resulting in cognitive impairment, gait disturbance, and urinary disorder (triad symptoms of iNPH). The risk factors for iNPH were reported to be aging and vascular factors including both arterial and venous systems. Recently, genetic risk factor for iNPH, a copy number loss within the SFMBT1 gene, was reported. The SFMBT1 protein is localized mainly in the arterial walls, the ependymal cells, and the epithelium of the choroid plexus, all of which play a crucial role in the CSF circulation. In Japan, patients with iNPH with the speciﬁc MRI features of tightness of the high convexity and medial subarachnoid spaces, and ventriculomegaly, designated disproportionately enlarged subarachnoid space hydrocephalus (DESH) is regarded as important in clinical settings, because patients with DESH are easy to be detected and show high responsiveness to shunt surgery. However, recent studies revealed that pathology related to Alzheimer's disease (AD) is highly prevalent in iNPH patients and reported the coexistence of AD pathology might reduce the postoperative improvement. Individuals with no triad symptoms of iNPH and ventriculomegaly with features of DESH are present and they are considered to be iNPH patients in the preclinical stage. Thus, it is important that after we find individuals with DESH but without triad symptoms, we see the individuals regularly. The manifestation of triad symptoms could be prevented by performing shunt surgery when the minimal triad symptoms of iNPH appear.
Keywords	idiopathic normal pressure hydrocephalus (iNPH), disproportionately enlarged subarachnoid-space hydrocephalus (DESH), study of idiopathic normal pressure hydrocephalus on neurological improvement (SINPHONI), asymptomatic ventriculomegaly with features of idiopathic NPH on MRI (AVIM), risk factor