With the rapid aging of Japanese society, medical care of the elderly has become an important social issue. Among various disorders manifesting dementia, gait disturbance, and urinary incontinence in the elderly population, normal pressure hydrocephalus (NPH), especially of idiopathic type (iNPH), is becoming noteworthy. The Guidelines for management of iNPH in Japan are created in compliance with the evidence-based medicine methods and published in 2004. This English version is made to show the diagnosis and treatment of iNPH with reference to the socio-medical background in Japan and to promote the international research on iNPH. They propose three diagnostic levels; possible, probable, and definite. They indicate the diagnostic importance of high convexity tightness and dilated sylvian fissure with mild to moderate ventriculomegaly on coronal magnetic resonance imaging. The cerebrospinal fluid tap test is regarded as an important diagnostic test because of its simplicity to perform and high predictability of the shunt efficacy. The use of programmable valves at shunt surgeries is recommended. Flowcharts for diagnosis, preoperative assessment, and prevention for complications of shunt surgery are made to promote a wide use of them.

Cystoperitoneal shunting is a valid method of achieving obliteration of the cyst and clinical improvement and seems to feature low operative risk and few complications. It should be noted, however, that some patients experience shunt dependency after cystoperitoneal shunting.

Autoregulation of cerebral blood flow ("CBF15") was tested in a series of 26 pediatric patients (mean age 13.2 years) with severe head injury (average Glasgow Coma Scale (GCS) score 5.5) in the acute stage. A baseline 133Xe CBF measurement was performed and then repeated, after blood pressure was increased by 29% with intravenous phenylephrine or decreased by 26% with intravenous trimethaphan camsylate. Correlations were made between CBF and clinical condition, outcome, time after injury, intracranial pressure (ICP), and pressure-volume index (PVI) changes, and the site of injury (hemispheres, diencephalon, or brain stem). The site of injury was determined with multimodality evoked potential measurements. Autoregulation was intact in 22 (59%) of 37 measurements. There was no correlation with GCS score, outcome, time after injury, site of injury, or way of testing (decreasing or increasing blood pressure). Autoregulation was statistically significantly more often impaired when CBF was either below normal -2 standard deviations (SD) (reduced flow) or above normal +2 SD (absolute hyperemia). In cases with intact autoregulation, mean ICP decreased from 17.5 to 15.0 mm Hg with higher blood pressure and increased from 19.0 to 21.3 mm Hg with lower blood pressure. When PVI was measured during the blood pressure manipulations, it was found to change in a direction opposite to the ICP change. The consequences of these findings in the management of ICP problems with blood pressure control are discussed.

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A 41-year-old female presented with a meningioma of the craniocervical junction manifesting as tetraparesis and vesicourethral dysfunction. Neuroradiological examinations showed a homogeneous enhanced mass lesion extending from the foramen magnum to the upper aspect of the second vertebral body. The tumor was totally removed via the transcondylar fossa approach, which is one type of the lateral approach. She was discharged without neurological deficits. The transcondylar approach is often utilized for lesions that occupy the ventral portion around the foramen magnum. The transcondylar fossa approach, a variation of the transcondylar approach, is a refined technique which obtains a closely similar surgical working field. Use of the transcondylar fossa approach remains controversial when treating patients with little brain stem dislocation, a small condylar fossa, and a protruding occipital condyle, but the approach can easily be converted to the transcondylar approach. The transcondylar fossa approach could become a standard method to access the craniocervical junction.

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Identical twins who both presented with progressively enlarging heads in their first year of life are reported. Neuroimaging demonstrated morphological similarities in the cerebral cortex. The CSF space, including ventricular system, and subarachnoid space were dilated, suggesting external hydrocephalus. Cerebral blood flow velocity in the anterior cerebral artery monitored by Doppler sonogram indicated the two had similar flow patterns and velocities. Simultaneous recording of ICP waves and intracranial biomechanical properties, that is, pressure buffering capacity (pressure volume index: PVI) and CSF outflow resistance (Ro) measured by the bolus saline injection technique, objectively indicated that all these biomechanical factors were also quite similar in the twins. These results indicate that identical twins with external hydrocephalus have very similar intracranial environments, both anatomically and biomechanically.

Analysis of cerebrospinal fluid (CSF) flow and motion at the craniospinal junction was conducted by magnetic resonance velocity imaging with phase encoding followed by motion velocity integration. Thirteen normal subjects classified into two groups were studied: an infant group with open sutures and fontanel, and a noninfant group with closed sutures and fontanel. Predominance in CSF to-and-fro motion was recognized in the ventral subarachnoid space, and a maximum caudad motion velocity of 7.5 +/- 2.4 mm/s was recorded in the infant group and one of 14.9 +/- 6.2 mm/s in the noninfant group. The average bulk flow velocity in all cases was 86.7 +/- 81.6 (means +/- SD) mm/min. The difference in flow velocity between the infant group (19.7 +/- 28.2 mm/min) and the noninfant group (116.5 +/- 80 mm/min) suggested that the CSF circulation around the cervical spine may vary at different ages.