Diagnosis of normal-pressure hydrocephalus

Idiopathic normal pressure hydrocephalus: historical context and a contemporary guide

Idiopathic normal pressure hydrocephalus (NPH) was described in 1965 as a syndrome in which hydrocephalus develops but with a normal cerebrospinal fluid (CSF) pressure, causing shunt-responsive gait apraxia, cognitive impairment and urinary incontinence. Not all patients respond to shunting despite having the clinical syndrome with appropriate radiological features. This has led to considerable debate over subsequent decades regarding idiopathic NPH. It is now understood that asymptomatic communicating hydrocephalus can develop in many healthy older people, and that over time this can develop into a symptomatic state that sometimes responds to CSF shunting, but to a variable extent. This review looks at the historical background of NPH, the use of predictive tests, the current state of clinical evidence for the diagnosis and treatment of idiopathic NPH and the possible underlying causes, to provide a contemporary practical guide for assessing patients with the radiological features of idiopathic NPH.

Radiological biomarkers of idiopathic normal pressure hydrocephalus: new approaches for detecting concomitant Alzheimer's disease and predicting prognosis

Idiopathic normal pressure hydrocephalus (iNPH) is a clinical syndrome characterized by cognitive decline, gait disturbance, and urinary incontinence. As iNPH often occurs in elderly individuals prone to many types of comorbidity, a differential diagnosis with other neurodegenerative diseases is crucial, especially Alzheimer's disease (AD). A growing body of published work provides evidence of radiological methods, including multimodal magnetic resonance imaging and positron emission tomography, which may help noninvasively differentiate iNPH from AD or reveal concurrent AD pathology in vivo. Imaging methods detecting morphological changes, white matter microstructural changes, cerebrospinal fluid circulation, and molecular imaging have been widely applied in iNPH patients. Here, we review radiological biomarkers using different methods in evaluating iNPH pathophysiology and differentiating or detecting concomitant AD, to noninvasively predict the possible outcome postshunt and select candidates for shunt surgery.

Callosal Angle Sub-Score of the Radscale in Patients with Idiopathic Normal Pressure Hydrocephalus Is Associated with Positive Tap Test Response

The aim of the present study was the implementation of the composite imaging “Radscale” in patients with idiopathic normal pressure hydrocephalus (iNPH) and the evaluation of its score, as well as absolute stroke volume and peak flow velocity of cerebrospinal fluid (CSF) in aqueduct as indicators of a positive response following a tap test. Forty-five patients with iNPH were included. Clinical evaluation involved the 10 m timed walk test before and every 24 h for 3 consecutive days after evacuative lumbar puncture (LP). Neuropsychological evaluation comprised a mini mental state examination (MMSE), frontal assessment battery (FAB), 5-word test (5WT) and CLOX drawing test 1 and 2, which were carried out before and 48 h after LP. The tap test’s response was defined as a ≥20% improvement in gait and/or a ≥10% improvement in neuropsychological tests. All scores of neuropsychological and clinical variables, except for immediate 5WT and CLOX-1, differed significantly before and 48 h after LP. Improvement in time and steps of a 10 m timed walk test differed significantly between female and male patients. Out of 45 total patients, 19 were tap test responders and 26 non-responders. The total score of Radscale and CSF flow parameters did not differ between responders and non-responders. However, “Callosal angle” sub-score differed significantly between these two groups. A greater “callosal angle” sub-score, meaning more acute callosal angle, was associated with a positive tap test response, rendering it a useful measurement in the stratification of iNPH patients that will potentially respond to CSF shunting.

Poroelastic Mechanical Properties of the Brain Tissue of Normal Pressure Hydrocephalus Patients During Lumbar Drain Treatment Using Intrinsic Actuation MR Elastography

RATIONALE AND OBJECTIVES

Hydrocephalus (HC) is caused by accumulating cerebrospinal fluid resulting in enlarged ventricles and neurological symptoms. HC can be treated via a shunt in a subset of patients; identifying which individuals will respond through noninvasive imaging would avoid complications from unsuccessful treatments. This preliminary work is a longitudinal study applying MR Elastography (MRE) to HC patients with a focus on normal pressure hydrocephalus (NPH).

MATERIALS AND METHODS

Twenty-two ventriculomegaly patients were imaged and subsequently received a lumbar drain placement for cerebrospinal fluid (CSF) drainage. NPH lumbar drain responders and NPH syndrome nonresponders were categorized by clinical presentation. Displacement images were acquired using intrinsic activation (IA) MRE and poroelastic inversion recovered shear stiffness and hydraulic conductivity values. A stable IA-MRE inversion protocol was developed to produce unique solutions for both recovered properties, independent of initial estimates.

RESULTS

Property images showed significantly increased shear modulus (p = 0.003 in periventricular region, p = 0.005 in remaining cerebral tissue) and hydraulic conductivity (p = 0.04 in periventricular region) in ventriculomegaly patients compared to healthy volunteers. Baseline MRE imaging did not detect significant differences between NPH lumbar drain responders and NPH syndrome nonresponders; however, MRE time series analysis demonstrated consistent trends in average poroelastic shear modulus values over the course of the lumbar drain process in responders (initial increase, followed by a later decrease) which did not occur in nonresponders.

CONCLUSION

These findings are indicative of acute mechanical changes in the brain resulting from CSF drainage in NPH patients.

Anterior Callosal Angle: A New Marker of Idiopathic Normal Pressure Hydrocephalus?

OBJECTIVE

Diagnosing idiopathic normal pressure hydrocephalus (iNPH) still remains a clinical challenge. The callosal angle (CA) is a widely used neuroradiologic marker for iNPH. However, the relationship of the CA to clinical features has not been well investigated. We hypothesize that iNPH symptoms might better correlate with a variant of the CA (anterior callosal angle [ACA]). We aim to establish the validity of the ACA measurement for the diagnosis of iNPH and compare it with current radiologic parameters.

METHODS

The multidisciplinary BOLOGNA PRO-HYDRO Study Group performed a retrospective review of consecutive iNPH patients. Magnetic resonance imaging studies for these patients were collected, as well as magnetic resonance imaging studies from Alzheimer disease and healthy control patients. The CA, ACA, and Evans Index were measured by 2 blinded members of the study team based on magnetic resonance images for each of these populations.

RESULTS

The ACA shows high accuracy, sensitivity, and specificity in distinguishing iNPH patients from healthy control and Alzheimer disease patients. The optimal pathologic diagnostic cut-off value for the ACA is 119 degrees. The diagnostic accuracy of the ACA is not significantly different from the CA.

CONCLUSIONS

The ACA could be a valid radiologic parameter in the diagnostic armamentarium for iNPH.

Is endoscopic third ventriculostomy safe and efficient in the treatment of obstructive chronic hydrocephalus in adults? A prospective clinical and MRI study

BACKGROUND

In case of suspected normal pressure hydrocephalus, MRI is performed systematically and can sometimes highlight an obstruction of the flow pathways of the CSF (aqueductal stenosis or other downstream obstruction). It seems legitimate for these patients to ask the question of a treatment with endoscopic third ventriculostomy (ETV), even if the late decompensation of an obstruction may suggest an association with a CSF resorption disorder. The aim of this study was to evaluate clinical and radiological evolution after ETV in a group of elderly patients with an obstructive chronic hydrocephalus (OCH).

METHODS

ETV was performed in 15 patients with OCH between 2012 and 2017. Morphometric (callosal angle, ventricular surface, third ventricular width, and Evans' index) and velocimetric parameters (stroke volume of the aqueductal (SVa) CSF) parameters were measured prior and after surgery with brain MRI. The clinical score (mini-mental status examination (MMSE) and the modified Larsson's score, evaluating walking, autonomy, and incontinence) were performed pre- and postoperatively.

RESULTS

SVa was less than 15 μL/R-R in 12 out of the 15 patients; in the other three cases, the obstruction was located at a distance from the middle part of the aqueduct. Fourteen out of 15 patients were significantly improved: mean Larsson's score decreased from 3.8 to 0.6 (P ≤ 0.01) and mean MMSE increased from 25.7 to 28 (P = 0.084). Evans' index and ventricular area decreased postoperatively and the callosal angle increased (P ≤ 0.01). The mean follow-up lasted 17.9 months. No postoperative complications were observed.

CONCLUSION

ETV seems to be a safe and efficient alternative to shunt for chronic hydrocephalus with obstruction; the clinical improvement is usual and ventricular size decreases slightly.

Ventriculomegaly in the Elderly: Who Needs a Shunt? A MRI Study on 90 Patients

OBJECTIVE

In the case of ventriculomegaly in the elderly, it is often difficult to differentiate between communicating chronic hydrocephalus (CCH) and brain atrophy. The aim of this study is to describe the MRI criteria of CCH, defined by a symptomatic patient with ventriculomegaly and that improved after shunt placement.

MATERIALS AND METHODS

Magnetic resonance imaging was prospectively evaluated in 90 patients with ventriculomegaly. Patients were classified into three groups: patients without clinical signs of CCH (control, n = 47), patients with CCH treated by shunt placement with clinical improvement (responders, n = 36), and patients with CCH treated using a shunt without clinical improvement (nonresponders, n = 7). MRI parameters of the two groups of interest (responders vs. controls) were compared.

RESULTS

Compared with controls, Evans' index (p = 0.029), ventricular area (p < 0.01), and volume (p = 0.0001) were higher in the responders. In this group, the callosal angle was smaller (p ≤ 0.0001) and the aqueductal stroke volume (SVa) of CSF was higher (p ≤ 0.0001) than in controls. On the ROC curves, the optimal cut-off values for differentiating between responders and controls were a ventricular area >33.5 cm², a callosal angle <90.8° and a SVa > 136.5 μL/R-R. In multivariate analysis, responders remained associated with SVa and callosal angle, with a c-statistic of 0.90 (95%CI, 0.83-0.98).

CONCLUSION

On suspicion of CCH, a large ventricular area, a small callosal angle, and an increased aqueductal stroke volume are important MRI arguments that can be associated with the clinical evaluation and dynamic testing of CSF to confirm the indication for a shunt.

Alzheimer's disease pathology and shunt surgery outcome in normal pressure hydrocephalus

We aimed to determine whether presence of AD neuropathology predicted cognitive, gait and balance measures in patients with idiopathic normal pressure hydrocephalus (iNPH) after shunt surgery. This is a prospective study of gait and balance measured by Timed Up and Go (TUG) and Tinetti tests, and cognitive function measured by Mini Mental Status Exam (MMSE), before and after shunt surgery in participants 65 years and older with iNPH at the Johns Hopkins University. Random effects models were used and adjusted for confounders. 88 participants were included in the analysis with a median (IQR) time of 104 (57–213) days between surgery and follow-up. 23 (25%) participants had neuritic plaques present (NP+) and were significantly older [76.4 (6.0) years], but were otherwise similar in all demographics and outcome measures, when compared to the group without neuritic plaques (NP-). NP- and NP+ participants equally improved on measures of TUG (β = -3.27, 95% CI -6.24, -0.30, p = 0.03; β = -2.37, 95% CI -3.90, -0.86, p = 0.02, respectively), Tinetti-total (β = 1.95, 95% CI 1.11, 2.78, p<0.001; β = 1.72, 95% CI 0.90, 2.53, p<0.001, respectively), -balance (β = 0.81, 95% CI 0.23, 1.38, p = 0.006; β = 0.87, 95% CI 0.40, 1.34, p<0.001, respectively) and -gait (β = 1.03, 95% CI 0.61, 1.45, p<0.001; β = 0.84, 95% CI 0.16, 1.53, p = 0.02, respectively), while neither NP- nor NP+ showed significant improvement on MMSE (β = 0.10, 95% CI -0.27, 0.46, p = 0.61, β = 0.41, 95% CI -0.27, 1.09, p = 0.24, respectively). In summary, 26% of participants with iNPH had coexisting AD pathology, which does not significantly influence the clinical response to shunt surgery.

VEGF: a potential target for hydrocephalus

Growth factors are primarily responsible for the genesis, differentiation and proliferation of cells and maintenance of tissues. Given the central role of growth factors in signaling between cells in health and in disease, it is understandable that disruption of growth factor-mediated molecular signaling can cause diverse phenotypic consequences including cancer and neurological conditions. This review will focus on the specific questions of enlarged cerebral ventricles and hydrocephalus. It is also well known that angiogenic factors, such as vascular endothelial growth factor (VEGF), affect tissue permeability through activation of receptors and adhesion molecules; hence, recent studies showing elevations of this factor in pediatric hydrocephalus led to the demonstration that VEGF can induce ventriculomegaly and altered ependyma when infused in animals. In this review, we discuss recent findings implicating the involvement of biochemical and biophysical factors that can induce a VEGF-mimicking effect in communicating hydrocephalus and pay particular attention to the role of the VEGF system as a potential pharmacological target in the treatment of some cases of hydrocephalus. The source of VEGF secretion in the cerebral ventricles, in periventricular regions and during pathologic events including hydrocephalus following hypoxia and hemorrhage is sought. The review is concluded with a summary of potential non-surgical treatments in preclinical studies suggesting several molecular targets including VEGF for hydrocephalus and related neurological disorders.

Morphologic features and flow void phenomenon in normal pressure hydrocephalus and other dementias: are they really significant?

RATIONALE AND OBJECTIVE

The aim of this study was to determine the distinctive features of normal-pressure hydrocephalus (NPH) and other dementias on routine T1-weighted and T2-weighted magnetic resonance (MR) images. Also, the contribution of these parameters to the diagnosis and treatment of NPH was investigated.

MATERIALS AND METHODS

Routine MR images were used to investigate the morphologic features (dilatation of Sylvian cisterns, narrowness of convexity sulci, thickness of corpus callosum (TCC), and dilatation of perihippocampal fissures) and the flow void phenomenon (FVP) in patients with idiopathic NPH (INPH) and other dementias. Routine MR images of 18 patients with INPH, 11 with dementias other than INPH, and 20 controls were retrospectively examined. Morphologic features and the FVP were graded subjectively. The TCC was measured quantitatively. Morphologic parameters, the FVP, and the shunt response were assessed using Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

The mean FVP score was significantly higher in patients with INPH (2.89 +/- 0.75) than in controls and patients with other dementias (1.1 +/- 0.85 and 1.09 +/- 0.83, respectively) (P < .001). There was significant difference in terms of TCC between patients with INPH (3 +/- 0.7 mm), those with other dementias (1.9 +/- 0.7 mm), and controls (5.2 +/- 0.8 mm) (P < .001). Significant differences in terms of other morphologic features were found between patients with INPH and those with other dementias (P < .05). No significant difference was found between morphologic parameters and the FVP and the outcome of cerebrospinal fluid diversion (P > .05).

CONCLUSIONS

Intense FVP is a signature of but is not pathognomonic for INPH. The morphologic analysis of MR images can be distinctive for the diagnosis of INPH or dementias other than INPH. Detailed evaluation of morphologic features and the FVP in routine MR workup of dementia will be useful for accurate diagnosis.

Shunts in normal-pressure hydrocephalus: do we place too many or too few?

OBJECT

The average 65-year-old patient with moderate dementia can look forward to only 1.4 quality-adjusted life years (QALYs), that is, longevity times quality of life. Some of these patients suffer from normal-pressure hydrocephalus (NPH) and respond dramatically to shunt insertion. Currently, however, NPH cannot be diagnosed with certainty. The authors constructed a Markov decision analysis model to predict the outcome in patients with NPH treated with and without shunts.

METHODS

Transition probabilities and health utilities were obtained from a review of the literature. A sensitivity analysis and Monte Carlo simulation were applied to test outcomes over a wide range of parameters. Using shunt response and complication rates from the literature, the average patient receiving a shunt would gain an additional 1.7 QALYs as a result of automatic shunt insertion. Even if 50% of patients receiving a shunt have complications, the shunt response rate would need to be less than 5% for empirical shunt insertion to do more harm than good. Authors of most studies have reported far better statistics.

CONCLUSIONS

In summary, many more patients with suspected NPH should be considered for shunt insertion.

Tau protein is a potential biological marker for normal pressure hydrocephalus

A biological marker for normal pressure hydrocephalus (NPH) is beneficial for evaluation of its severity and of indications for shunt operation. Tau protein was initially considered as a biological marker in cerebrospinal fluid (CSF) from Alzheimer's patients. Recently, it has been demonstrated that degeneration in the brain causes elevation of tau in CSF. Therefore, the tau level in CSF from NPH patients was evaluated. Tau levels in CSF from NPH patients were significantly higher than that in controls. The tau levels were correlated with the severity of dementia, urinary incontinence, and gait disturbance in NPH. These results suggest that CSF tau may be useful as a biological marker for NPH to determine the level of neuronal degeneration.

Disturbances of cerebrospinal fluid (CSF) circulation--neuropsychiatric symptoms and neuroradiological contribution

The present study aimed at relating dementia, pseudo-neurasthenic and affective organic brain syndromes to underlying type of CSF flow disorder and to subsequent alteration of anatomy. T2*-weighted magnetic resonance imaging (MRI) in the midsagittal plane permitted an analysis of aqueductal CSF flow phenomena and hydrocephalus-induced elevation, thinning and dorsal impingement of the corpus callosum. Furthermore, the width of the third ventricle was measured on the transverse scout images. 72 patients with communicating hydrocephalus (increased aqueductal CSF pulsations) and 26 patients with aqueductal stenosis (absence of aqueductal flow phenomena) were compared with 22 controls. Dementia and affective disorders were distributed equally among both CSF flow subgroups whereas pseudo-neurasthenic syndromes were observed more frequently in non-communicating hydrocephalus (p < 0.03). Alzheimer-type and multiinfarct dementia syndromes were found more frequently in communicating hydrocephalus whereas non-classifiable dementia showed some predilection for non-communicating hydrocephalus. Callosal height, area and third ventricular width did not predict affective or pseudoneurasthenic disorder whereas third ventricular width (p < 0.01) and callosal area (p < 0.05) discriminated between demented and non-demented patients. Dorsal impingement of the corpus callosum by the falx was a non-specific finding.

Brain imaging techniques in the diagnosis of dementia

Various recently developed brain imaging techniques used to assist in the diagnosis of dementia are reviewed. The methods reviewed are x-ray computed tomography scan imaging, magnetic resonance imaging, positron emission tomography, and the older techniques of pneumoencephalography and radioisotope cisternography. It was concluded that while these techniques often offer excellent diagnostic information, none of them provides a definitive characteristic image for Alzheimer's disease.

Normal pressure hydrocephalus in geriatric medicine: a challenge

Normal pressure hydrocephalus (NPH) in elderly patients is reviewed. Since the clinical signs that characterize NPH--incontinence, difficulty walking, and dementia--occur frequently in the elderly in association with a wide variety of disorders, attention is paid to the differential diagnosis of NPH on the basis of both clinical findings and laboratory tests. Success rates for treatment of NPH using surgical shunting are discussed, as are mortality rates and complication rates for this type of surgery in the elderly. Factors that may be of value in predicting which NPH patients are most likely to benefit from surgical intervention are reviewed, and the need for the development of pharmacological alternatives to surgery for elderly NPH patients is emphasized. As one of the most treatable causes of dementia in the elderly, NPH should be considered in the diagnosis of demented elderly patients with continence and gait disturbances, and it merits further research.

Normal-pressure hydrocephalus associated with spinal cord tumor

While the association of spinal cord tumor and high-pressure hydrocephalus is well known, only 5 cases of spinal cord tumor associated with normotensive hydrocephalus have been reported. Two further cases are described here, discussing the possible pathophysiological mechanism. It is suggested that these patients go through a subclinical stage of high-pressure hydrocephalus and become normotensive later on, a process which might influence the surgical results.

Evaluation of treatment of normal-pressure hydrocephalus

Ten patients with dementia due to normal-pressure hydrocephalus were evaluated prospectively according to a planned, longitudinal protocol for 4 to 12 months. Information recorded at each visit included clinical history, medical and neurological examination, psychometric scoring by Mini-Mental Status Questionnaire, measurement of ventricular size and local cerebral blood flow, and partition coefficients (local lambda changes) (1 lambda) by xenon contrast computerized tomography scanning. Cerebrospinal fluid shunting was carried out in eight cases. Serial evaluations were repeated at intervals up to 8 months after shunting, and demonstrated that the ventricles decreased in size and periventricular hypodensities decreased. White matter 1 lambda values and blood flows and cortical gray matter flows progressively increased for 3 months after shunting, and remained increased except for one case complicated by chronic alcoholism. Clinical recovery correlated with improved cerebral perfusion. There were returns of urinary continence and improvements in gait and usually in activities of daily living. Mentation was the last factor to improve. Factors negatively influencing cerebral perfusion and clinical recovery were shunt failures and various contributing causes of dementia.

The syndrome of normal-pressure hydrocephalus

A series of 40 patients with the syndrome of normal-pressure hydrocephalus is presented. Diagnosis was based on clinical and computerized tomography (CT) scan criteria and was followed by the insertion of a ventriculoperitoneal shunt in every instance. All patients responded favorably to treatment (four of them had a fair outcome), and this response was maintained. There was one postoperative death, but no other serious complications. This study demonstrates that it is possible to diagnose the syndrome of normal-pressure hydrocephalus on the basis of clinical and CT scan criteria without any other invasive investigations. Such patients should respond favorably to an adequately functioning shunting system.

[Normal-pressure hydrocephalus and cerebellar hematoma. Report of a case with necropsy]

The authors report the case of a 64-year-old man who presented normal pressure hydrocephalus in the course of hypertensive and arteriosclerotic vasculopathy confirmed by postmortem examination. A blood clot was found on the central area of the left cerebellar hemisphere. The clinical features and the pathogenesis of normal pressure hydrocephalus and cerebellar hemorrhage are reviewed and discussed.

The clinical effect of lumbar puncture in normal pressure hydrocephalus

Owing to all the difficulties involved in selecting patients with normal pressure hydrocephalus for shunt-operation, a cerebrospinal fluid-tap-test (CSF-TT) is introduced. Psychometric and motor capacities of the patients are measured before and after lumbar puncture and removal of 40-50 ml CSF. Patients fulfilling criteria for normal pressure hydrocephalus were compared to patients with dementia and atrophy shown by computed tomography. Normal pressure hydrocephalus patients showed temporary improvement after lumbar puncture. The extent of the temporary improvement appeared to be well correlated with the improvement after shunt operation. Accordingly, the CSF-TT seems to be of value when selecting those patients who will probably benefit from a shunt operation.

Isotope cisternography and conductance to outflow of CSF in normal pressure hydrocephalus

In 50 patients with normal pressure hydrocephalus (NPH) the findings on lumbar isotope cisternography (IGG) were compared to the conductance to outflow of CSF (Cout) as measured by lumbo-ventricular perfusion. The purpose was to identify those ICG-characteristics that imply a low Cout and thus may indicate CSF shunting therapy. Normal ICG was found only in three patients, where Cout was not, or only moderately, decreased. There was a significant correlation between a low Cout and occurrence of ventricular retention and absent parasagittal accumulation at 24 hours or later, following injection. These findings may, however, also be present in patients with no, or only moderate, decreased Cout, where CSF shunting may seen unjustified. It is concluded, that the indication for CSF shunting cannot be based on the results of ICG alone.

Indications for the surgical treatment of hydrocephalic dementia

Eighteen patients with chronic hydrocephalic dementia who had a ventriculo-atrial or ventriculo-peritoneal shunt are reported. The indications for operating on this type of dementia are discussed on the basis of the clinical and instrumental protocol and the postoperative results.

Acquired hydrocephalus. II. Diagnostic and prognostic value of quantitative isotope ventriculography (QIV), lumbar isotope cisternography (LIC), pneumoencephalography, and continuous intraventricular pressure recording (CIP)

The diagnostic and prognostic values of quantitative isotope ventriculography (QIV), lumbar isotope cisternography (LIC), pneumoencephalography (PEG), and continuous intraventricular pressure recording (CIP) were assessed on the basis of the clinical course in 160 patients suspected of having acquired hydrocephalus. The diagnostic value of a given method is defined as its reliability in the diagnosis of hydrocephalus. The reliability in the selection of hydrocephalic patients who will improve on shunt operation is designated as the prognostic value of the method concerned. As the diagnoses are based on isotopic procedures, the diagnostic values of these procedures cannot be assessed. QIV is of greater prognostic value than the other methods of examination. The presence of plateau waves in CIP is a rare, but prognostically valuable sign. The prognostic value of B waves is also good, whereas their diagnostic value is slight. Both from diagnostic and prognostic points of view, PEG is of less value is communicating hydrocephalus on account of the many false findings.

Ventricular differences between hydrostatic hydrocephalus and hydrocephalus ex vacuo by computed tomography

Transaxial CT scans of 100 patients with hydrostatic hydrocephalus and 50 patients with hydrocephalus ex vacuo have been reviewed with respect to measurements of: frontal horn ratio, width of the temporal horns, width of the third ventricle, width of cerebral fissures and sulci. The diagnosis of hydrostatic hydrocephalus is probable when (a) both temporal tips are visualized and measure 2 mm or greater in width and the sylvian and interhemispheric fissures and cerebral sulci are not visible, or (b) there is visualization of temporal horn tips measuring 2 mm or greater in width and the lateral ventricles are symmetrically enlarged with the frontal horn ratio 0.50 or more.

Psychotic symptoms in normal-pressure hydrocephalus

Two patients with a psychiatric history of about 20 years, and clinical and neuroradiological signs of normal-pressure hydrocephalus (NPH) are reported. One had a periodic psychosis subsequent to a tuberculous meningitis, and this overshadowed the slight classical symptoms of NPH. She had received at least 120 treatments with electro-convulsive therapy. The second patient suffered from a paranoid psychosis; other signs of NPH were moderate though progressive. Both patients showed definite improvement of their NPH symptoms after ventriculo-atrial shunting, and psychotic symptoms ceased totally. Follow-up was 5 years for the patient with periodic psychosis. The other patient died from septicaemia 2.5 years after shunting. A large-scale screening of patients with psychiatric symptoms or dementia, particularly when combined with gait disturbance, should be done by using computerized tomography. Patients suspected of having NPH should then be referred for further examination with the aim of selecting patients suitable for shunting. These measures seem well motivated from humanitarian as well as economic points of view.

Acquired hydrocephalus. I. A clinical analysis of 160 patients studied for hydrocephalus

A total of 160 patients suspected of having acquired hydrocephalus were studied either by quantitative isotope ventriculography (QIV) or by lumbar isotope cisternography (LIC). Of these patients, 56 had hydrocephalus. Mental deterioration, gait disturbances, ataxia, spasticity, and incontinence were most frequently present in the hydrocephalic patients, but none of the signs or combinations thereof are pathognomonic of acquired hydrocephalus. These signs are independent of the intracranial pressure (ICP) and the type of hydrocephalus. Surgical shunt procedures were in most cases followed by the disappearance of mental deterioration, gait disturbances, ataxia, and spasticity.

Hydrocephalus-dementia-complex in Paget's disease

The clinical triad of gait disturbances, memory impairment and urinary incontinence is associated with a communicating hydrocephalus in the 'normal pressure hydrocephalus'-syndrome. The authors present a case of H.D.C. (hydrocephalus-dementia-complex) in Paget's disease with an identical syndrome, but with obstructive hydrocephalus, causing a triventricular dilatation. Today, each case of mental deterioration in Paget's disease, should be immediately observed and neurosurgical intervention kept in view. An X-ray of the skull, a CT-scan of the brain and a cisternography are performed as routine procedure. If there are indications of involvement of the basis of the skull, hydrocephalus and/or disturbed pattern of the tracer-migration around the convexities, associated with a certain degree of dementia, impaired gait or urinary incontinence, a ventriculo-subcutaneous drain should be inserted. If clinical improvement follows, a ventriculatrial shunt is indicated. The post-operative clinical outcome seems to be dependent on some clinical and technical factors. The most eventful outcome is observed in cases where the clinial triad, described in patients with a classical 'normal pressure hydrocephalus'-syndrome, is associated with an obstructive hydrocephalus, due to a stenosis of the Sylvian aqueduct.

Adult idiopathic communicating hydrocephalus with and without shunting

The outcome in 37 adult patients with idiopathic communicating hydrocephalus treated by ventriculoatrial shunting is presented. Only 33% showed definite improvement, and no diagnostic procedures accurately predicted the outcome of surgery. These were compared with a "control" group of 12 patients who were not shunted; 50% of these were stable for up to 36 months. These findings, and the high frequency of serious complications (35%), suggest caution in recommending a shunt procedure.

Recovery in hydrocephalic dementia after shunt operation

Twenty-three patients with hydrocephalic dementia were studied before and after shunt operation, and improvement was found in 12. Before operation, the improved cases showed more symptoms of confabulation, gait disturbance, urinary incontinence, lack of insight, and constructional apraxia. The improvement was also most marked in these symptoms. The significance of general versus specific symptoms, duration, and aetiology is discussed from a differential diagnostic standpoint, and we conclude that the adequate and early diagnosis of hydrocephalic dementia is essential for good outcome after shunt operation, and that psychiatric and psychometric evaluation enable such a diagnosis to be made.

Gastrins in cat and dog: evidence for a biosynthetic relationship between the large molecular forms of gastrin and heptadecapeptide gastrin

1. Extracts of antral, duodenal and jejunal mucosa contained the same concentrations and molecular forms of gastrin in cat and dog. In both species component III constituted 93%, component II 4% and components I and IV each 1% of the total immunoreactivity. 2. During electrical vagal stimulation or feeding in (a) anaesthetized cats with ligated kidney vessels and resected jejunum and ileum, (b) anaesthetized normal cats or (c) conscious normal cats, release of the large molecular forms of gastrin, components I and II, was not detectable. 3. Luminal perfusates of cat antrum contained only component III and occasionally less than 2% of component IV. 4. Intravenous injections into conscious cats of components I, II and III isolated from cat antrum revealed a significantly slower elimination of the large components (t1/2 approximately 4.2 and 4.0 min respectively) than of component III (t1/2 approximately 1.1 min). Thus the absence of components I and II in cat blood cannot be due to rapid degradation. 5. During feeding, components I and II constituted 20% of the total gastrin immunoreactivity in antral venous blood of dogs. This amount is sufficient to account for the predominance of large components in peripheral venous blood in dogs considering their slow metabolic clearance rates. 6. Luminal perfusates of dog antrum contained components I, II and III in proportions corresponding to those found in antrum. 7. The results indicate that components I and II are synthesized in the same proportions in gastrin cells of cat and dog. In the cat, components I and II are, however, never released from the cells. Since these components contain heptadecapeptide gastrin within their sequeaces, they probably represent biosynthetic precursors of the principal gastrin, the heptadecapeptide (component III). The predominance of component III in gastric juice suggests that the feline gastrin cell secretes only component III, which degrades to component IV in blood.

[Long-term follow-up study of the absorption of gas after encephalography in dilated intracranial cerebrospinal fluid spaces (author's transl)]

The absorption of gas after encephalography in different groups of patients was investigated in a long-term follow-up study. Group I (11 patients) showed no pathological findings in the encephalogram. Group II (8 patients) had encephalographic signs of diffuse cerebral atrophy. Group III (7 patients) demonstrated in the encephalogram characteristics of normal pressure hydrocephalus with variously located blocks of air in the subarachnoid space. In group I the gas located in the subarachnoid space had usually disappeared after 24 h, in some cases after 72 h. In group II the pattern of resorption was basically similar, although in one case cortical air could be seen at 96 h. In group III the absorption of air from the subarachnoid space began after 72 h in radiological relevant amounts. In none of the cases of group III could similar short times of resorption be seen in comparison to group I. It is considered that these two groups can be clearly distinguished from each other in the duration of resorption of air from the subarachnoid space. The importance of encephalography as a pathophysiological tool for investigation of both the disturbed resorption and circulation of the cerebrospinal fluid in normal pressure hydrocephalus is stressed.

Measurement of 111in DTPA clearance during radionuclide cisternography

A new preparation of 111In DTPA for intrathecal administration has been tested and found to be a safe and highly efficacious cisternographic agent. The rate of removal of 111In DTPA from the C.S.F. and from the whole body has been measured and has been found to be of no diagnostic value in the distinction between patients with cerebral atrophy and those with normotensive hydrocephalus. Long-term retention studies show no evidence of significant long-term retention of indium in the C.S.F. The absorbed radiation dose has been investigated and found to be in good agreement with previous estimates based upon extrapolated data.

The resistance to cerebrospinal fluid absorption in humans. A method of evaluation by lumbo-ventricular perfusion, with particular reference to normal pressure hydrocephalus

In order to measure the resistance to cerebrospinal fluid absorption in humans a lumbo-ventricular perfusion test, using several intraventricular pressure levels, has been developed. The test has been performed in 15 patients fulfilling criterias of normal pressure hydrocephalus. A considerable variation in the resistance to cerebrospinal fluid absorption revealed by the test indicates that clinical and pneumoencephalographic signs of normal pressure hydrocephalus are of little use in the selection of patients who may benefit from shunting procedures.

Mental impairment in the elderly: medical-legal assessment

As life expectancy has lengthened, research has been increasingly directed toward improving the quality of life in old age. Social agencies work in the field of socioeconomic factors, and medical research seeks the causes and remedies for mental deterioration. It is time to review the legal status of the mentally impaired elderly and to ensure that our lawmakers are cognizant of the changing situation. Before any characterization of mental capacity is made, a comprehensive investigation should be carried out to make sure that no potentially correctable physical disorder underlies perceived mental disabilities. In the past, the law has taken a global view of mental capacity. A person was adjudged either competent for all purposes or incompetent on a similar universal basis. A system is suggested to change this outdated approach and to assess separately the divisible components of mental capability. This would permit the courts to delineate their judgments and allow persons with partial mental incapacities to live a fuller life than if they had been declared totally incompetent.

Cerebrospinal fluid imaging using serial metrizamide CT cisternography

Twenty-five patients studied by serial metrizamide (Amipaque) CT cisternography were used to analyze CSF kinetics. Delayed CSF flow patterns were noted in 7 patients, while intermediate patterns occurred in 4. The abnormal cisternogram was characterized primarily by ventricular reflux and stasis and secondarily by diminution of the parasagittal blush and a periventricular rim of decreased absorption. The intermediate group had minimal ventricular stasis after 24 hours and a normal parasagittal blush. After clinical and biochemical evaluation of the patient with dementia, CT scanning is usually indicated. If a profile suggestive of communicating hydrocephalus emerges, CSF kinetics can be monitored dynamically by CT scanning with metrizamide enhancement.

Syndrome of normal pressure hydrocephalus: possible relation to hypertensive and arteriosclerotic vasculopathy

A patient with clinical features of idiopathic normal pressure hydrocephalus, who responded dramatically to shunting, was found a necropsy to have a severe hypertensive and arteriosclerotic vasculopathy with multiple lacunar infarcts. There was no pathological evidence of thickened leptomeninges, fibrosis of the arachnoid villi, or Alzheimer's disease. An abnormal absorption mechanism was demonstrated with cisternography and by an increase in the concentration of homovanillic acid in the cerebrospinal fluid. It is suggested that vascular changes may play an important role in the pathophysiology in some cases of normal pressure hydrocephalus.