This study evaluates the efficacy of shunt operation for idiopathic normal pressure hydrocephalus, and determines the diagnostic value of noninvasive procedures commonly practiced in the clinic.

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome characterized by ventricular dilatation due to disturbed cerebrospinal fluid (CSF) circulation, accompanied by gait disturbance, dementia and/or urinary incontinence without causative disorders. With the aging of Japanese society, the number of patients is increasing, requiring diagnostic and therapeutic guidelines for the improvement of the patients' quality of life and social care. Under such conditions, this project was made as the prospective study of iNPH on Neurological Improvement (SINPHONI ). This study aims 1) to establish methods for non-invasive diagnosis of iNPH, and 2) to demonstrate therapeutic outcome of shunting operation by Codman Hakim programmable valve (CHPV). In this protocol, the evaluation of validity on MRI, tap test, CT cisternography, and CBF (3D-SSP) will be done in the diagnosis, and manual of initial setting pressure in CHPV for prevention of overdrainage problems will be estimated by modified Rankin scale (as primary endpoint) and some another scales during 1 year.

Inclusion Criteria:

Patients who had at least one more points of the triad (gait disturbance, cognitive impairment, and urinary incontinence) in Japan NPH grading scale revised, and had disproportionate ventriculomegaly (Evans index >0.3) with closing of the CSF space at high convexity on MRI. These patients must be diagnosed clinically other causative disorders, and ventricular dilatation due to disturbance of the cerebrospinal fluid (CSF) circulation. Be able to give informed consent.

Exclusion Criteria:

1) Cannot have an MRI scan 2) Has a problem with bleeding tendency and other serological examination. (liver enzyme and renal dysfunction, blood coagulopathy, and etc.) 3) Is unable to understand the risks of the testing and surgical therapy. 4) is tolerable for one year follow up after shunting operation.