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.

Erythritol is a sugar alcohol produced by Aureobasidium sp. from glucose. It is 75–80% as sweet as sucrose and is also nonhygroscopic. The aim of this study was to evaluate this sugar substitute from a cariological point of view. Erythritol was neither utilized as a substrate for the lactic acid production nor for plaque formation of mutans streptococci (serotypes a-h) and certain oral microorganisms. It was not utilized for water-insoluble glucan synthesis or cellular adherence by glucosyltransferase from Streptococcus mutans PS-14 (c) and Streptococcus sobrinus 6715 (g). Finally, a significantly lower caries score (3.1 ± 0.5; mean ± SEM) was observed in specific pathogen-free rats infected with S. sobrinus 6715 and fed with a diet containing 26% erythritol, as compared to control rats fed with a diet containing 26% sucrose (60.5 ± 2.0). Also, rats provided a diet containing 56% erythritol chocolate (23.8% erythritol) and challenged with S. mutans PS-14 exhibited a significantly lower caries score (6.7 ± 0.8) compared to the sucrose chocolate group (82.8 ± 2.8). The main conclusion from this study is therefore that erythritol is a promising sugar substitute from a cariological point of view.

The indications for shunt operation in patients with idiopathic normal pressure hydrocephalus accompanied by brain atrophy (atypical idiopathic normal pressure hydrocephalus: AINPH) were investigated in 25 patients who satisfied the diagnostic criteria and underwent ventriculoperitoneal (VP) shunting. All patients had no apparent history of intra- or extracranial disease; dementia and gait disturbance as the main complaints; moderate to severe cerebral atrophy and ventricular dilatation and at least periventricular low density around the anterior horn on computed tomography; normal cerebrospinal fluid (CSF) pressure and filling of ventricles or cortical surface space with contrast medium at 24 hours on cisternography. The 15 male and 10 female patients were aged 47-83 years (mean 60.4 years). VP shunting was effective in 12 improved patients and not effective in 13 unimproved patients according to NPH grading. Pathological pressure wave on epidural pressure monitoring was observed in eight of 12 improved patients, but none of 13 unimproved patients. CSF outflow resistance was 35.33 +/- 11.16 mmHg/ml/min in improved patients and 9.12 +/- 3.51 mmHg/ml/min in unimproved patients. Preoperative serum alpha-1-antichymotrypsin value (alpha-1-ACT) was 42.02 +/- 8.64 mg/dl in improved patients and 61.72 +/- 11.03 mg/dl in unimproved patients. Alpha-1-ACT over 55 mg/dl occurred only in unimproved patients. Cerebral arteriovenous difference of oxygen content value (c-AVDO2) before and after surgery was 6.34 +/- 0.9 ml% and 5.91 +/- 0.78 ml% in improved patients and 4.75 +/- 1.85 ml% and 4.81 +/- 1.73 ml% in unimproved patients, respectively. The two cases with preoperative c-AVDO2 value over 8.5 ml% were both unimproved. Mean cerebral blood flow value before and after surgery was 23.51 +/- 4.20 ml/100 g/min and 45.22 +/- 8.11 ml/100 g/min in improved patients and 21.77 +/- 5.12 ml/100 g/min and 24.82 +/- 4.97 ml/100 g/min in unimproved patients, respectively. Cerebral atrophy in improved patients is caused by a cerebral circulation disturbance defined as a cerebral blood flow of penumbra or more due to cerebral arteriosclerosis, etc. A flow-chart of indications of shunt surgery for AINPH was prepared based on the results of the present study.

This study was conducted to elucidate the pathologic conditions of cerebral circulatory disorders in idiopathic normal pressure hydrocephalus (iNPH). Among 44 possible iNPH patients, 40 patients underwent shunt surgery based on diagnostic flow charts plotted by the Southern Tohoku method and were evaluated to be shunt-effective at the end of the first post-surgical month. The cerebral blood flow (CBF) was measured by N-isopropyl-( 123 I)-P-iodo-amphetamine single photon emission computed tomography (mean, mCBF; cortical region, cCBF; thalamus-basal ganglia region, tbCBF on autoradiography [ARG] method) and the perfusion patterns of the cerebral cortex were measured based on threedimensional stereotactic surface projection (3D-SSP) Z-score images, before and 1 month after the surgery in all 40 subjects. The mCBF rose significantly from 32.1 ± 2.74 ml/100 g/min before surgery to 39.8 ± 3.02 ml/100 g/min after surgery (p º 0.03). Investigation of the change of CBF revealed reductions in the cCBF (3 cases), tbCBF (9 cases), and cCBF ＋ tbCBF (28 cases), with the reduced-cCBF group totaling 31 cases and the reduced-tbCBF group totaling 37 cases. Investigation of cerebral cortex hypoperfusion by 3D-SSP Z-score revealed 31 cases with hypoperfusion (frontal lobe type [19 cases], occipitotemporal lobe type [5 cases], mixed type [7 cases]) and nine cases with cortical normoperfusion (N). The pattern of reduction of the cortical blood flow on ARG method was favorably correlated with the pattern of hypoperfusion of the cerebral cortex on 3D-SSP Z-score images before surgery. A reduction of blood flow was found in the thalamus-basal ganglia region of all N type cases. The blood flow improved in 19 of 31 (61.3%) cases of the reduced-cCBF group and in 32 of 37 (86.5%) cases of the reducedtbCBF group. All of the cases without detectable improvement exhibited increased blood flow in nonreduction areas. Investigation of the hypoperfusion patterns of the cerebral cortex on 3D-SSP Z-score images, revealed a reduction or disappearance of the hypoperfusion site in 19 of 31 (61.3%) cases, either no-change or a shift of the hypoperfusion site in 12 of 31 (38.7%) cases, and a correlation between the pattern of cortical blood flow reduction on ARG method and the pattern of cerebral cortex hypoperfusion on 3D-SSP Z-score images after surgery. Cerebral circulatory disorders in iNPH manifest as either of two pathophysiological conditions: the``circulatory disorder of the cerebral cortical region'' and thè`c irculatory disorder of the thalamus-basal ganglia region.'' Various patterns develop according to the disease stage.

A total of 482 operated idiopathic normal pressure hydrocephalus (iNPH) patients were divided into those aged <80 years at the time of surgery (group A: 400 cases; and male-to-female ratio, 259:141) and ≥80 years (group B: 82 cases; male-to-female ratio, 43:39) and comparatively investigated based on the following variables: (1) temporal changes in shunt efficacy rates, and (2) temporal changes in each symptom, including the patient’s fall frequency and preoperative modified Rankin Scale (mRS) score and during follow-up at 3, 6 months, 1–4 years postoperatively. (1) The shunt efficacy rates at 3 months and 4 years postoperatively were 93% and 82%, respectively, in group A and 92.3% and 70.7%, respectively, in group B. This demonstrates a decrease in shunt efficacy at 4 years postoperatively, regardless of the persistence of shunt function or adjustments in setting pressure. This trend was particularly observed in group B. In group A, 41 (9.8%) cases had decreased efficacy rate, compared with 21 (25.6%) cases in group B, which occurred due to complications with an extracranial or intracranial disease. (2) Gait disturbance ( G ) and urinary incontinence ( U ) showed signs of improvement in the early postoperative stage, while dementia ( D ) and mRS score began to gradually improve from 6 months postoperatively. Patient’s fall frequency tended to become higher until 6 months postoperatively than the preoperative rate. In group A, symptom improvement was comparatively maintained until 4 years postoperatively, while in group B, all symptoms and mRS tended to gradually deteriorate beginning at 3 years postoperatively.