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Results for “Hydrocephalus, Normal Pressure”

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PubMed1990

Angiotensin converting enzyme inhibition, CBF autoregulation, and ICP in patients with normal-pressure hydrocephalus.

Fourteen patients with normal pressure hydrocephalus had the autoregulation of cerebral blood flow (CBF) and intracranial pressure (ICP) investigated. In 8 of the patients the effect of Captopril on ICP and CBF was also investigated. The mean arterial blood pressure (MABP) was 109 mmHg (intra-arterially), and ICP was 11 mmHg (intraventricularly). Changes in global CBF were estimated by the arterio-venous oxygen difference method. The autoregulation of CBF was present in 13 of the patients (p less than 0.01). The lower limit of CBF autoregulation was 86% of the baseline perfusion pressure. One hour after 50 mg of captopril perorally, MABP was reduced 16 mmHg, and ICP and CBF were unchanged. The autoregulation was maintained and the lower limit was decreased 19 mmHg. Thus patients would be expected to benefit from captopril treatment in hypotensive anaesthesia.

Administration, Oral↗

PubMed1990

Cerebral hemodynamics in patients with normal pressure hydrocephalus: correlation between cerebral circulation time and dementia.

Regional cerebral blood flow and regional cerebral circulation time were measured in 13 demented patients with chronic hydrocephalus, mostly normal pressure hydrocephalus. The average hemispheric, frontal, and temporal cerebral blood flows were significantly reduced. The average regional cerebral circulation time values were significantly prolonged in the frontal, temporal, and thalamic regions, most markedly in the frontal white matter, where periventricular lucency was observed on computed tomography. Clinical improvement was obtained in all patients after operation. While postoperative regional cerebral blood flow values did not change compared with preoperative ones, postoperative regional cerebral circulation time values were significantly reduced in all the regions measured, and most markedly in the frontal white matter. The present results suggest that microcirculation in the frontal lobe is closely correlated with dementia in association with pressure exerted on the nerve fibers in the frontal white matter in patients with normal pressure hydrocephalus.

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PubMed1994

[Idiopathic normal pressure hydrocephalus in the aged].

Continuous lumbar cerebrospinal fluid pressure measurement was made in 19 cases of aged patients suspected of idiopathic normal pressure hydrocephalus. Based on the pressure study, they were divided into high pressure group (H group) and normal pressure group (N group). H group was composed of 11 cases and N group of 8 cases. Baseline pressures in H group and N group were 16.3 +/- 3.0 mmHg, 9.6 +/- 1.7 mmHg, respectively and the difference was statistically significant. Pulse pressure was high in H group and frequency of pressure waves was also significantly high in H group. There were no significant differences in clinical symptoms and CT findings between the two groups, except for clinical improvement after cerebrospinal fluid removal, which was noted in all of 6 cases examined in H group. No difference between them was noted on CT cisternography and cerebral blood flow measurement. Shunt surgery was carried out in the cases of H group and it was effective in 8 of 11 cases (72.7%). Thus, continuous lumbar cerebrospinal fluid measurement was useful for selection of idiopathic normal pressure hydrocephalus in the aged.

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PubMed2004

Relationship between valve opening pressure, body position, and intracranial pressure in normal pressure hydrocephalus: paradigm for selection of programmable valve pressure setting.

OBJECTIVE: There is little scientific basis for guidance in selecting the optimal valve for the treatment of normal pressure hydrocephalus. The aim of this study was to determine the programmable valve opening pressure setting that would result in a slight reduction in intracranial pressure (ICP) after a ventriculoperitoneal shunt is implanted. We also assessed whether shunt-induced ICP could be predicted on the basis of a simple hydrodynamic equation. METHODS: In this prospective study of 11 patients with normal pressure hydrocephalus, ICP was measured before and after implantation of a shunt incorporating a programmable valve without an antisiphon device. Pressure measurements, including intraperitoneal pressure, were recorded at body angles ranging from 0 to 55 degrees and at valve settings ranging from 30 to 200 mm H(2)O. Measured ICP values were compared with values computed using a simple hydrodynamic equation. RESULTS: Even at a valve setting greater than the mean baseline ICP (200 mm H(2)O), the supine ICP was significantly lower than the baseline value (baseline ICP, 164 +/- 64 mm H(2)O; postoperative ICP, 125 +/- 69 mm H(2)O, P = 0.04). Valve pressure did not equate 1:1 with the measured postoperative ICP. Comprehensive ICP measurements at upright body positions demonstrated a stepwise reduction in ICP rather than a precipitous decline as a result of so-called siphoning. CONCLUSION: This study indicates that very high valve opening pressure settings may be optimal for the initial treatment of normal pressure hydrocephalus. The relationship between ICP and opening pressure valves is linear but not predicted by simple hydrodynamics.

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PubMed1990

The effect of nimodipine on ICP and CBF in patients with normal-pressure hydrocephalus.

Eight patients with normal-pressure hydrocephalus (NPH) were studied. The resting mean arterial blood pressure (MABP) was 100 (90-125) mmHg and the mean intracranial pressure (ICP) was 11 (5-17) mmHg. ICP and MABP were continuously measured intraventricularly and intra-arterially, respectively. Changes in global cerebral blood flow (CBF) were estimated by the arteriovenous oxygen difference method. Intravenous nimodipine (15 microgram/kg/hour) was given in the first 2 hours and 30 microgram/kg/hour in the next 2 hours. MABP was reduced 23 (4-47) mmHg (p less than 0.05). ICP was increased 3 (0-10) mmHg (p less than 0.05). CBF was unchanged in the group on the whole, but in 4 of patients a major drop in perfusion pressure was seen, and CBF decreased 6, 11, 23 and 34%, respectively. Thus these findings underline the importance of maintaining the perfusion pressure under treatment with nimodipine.

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PubMed2003

Multi-modal MRI in normal pressure hydrocephalus identifies pre-operative haemodynamic and diffusion coefficient changes in normal appearing white matter correlating with surgical outcome.

Magnetic resonance techniques were used to investigate haemodynamic abnormalities and their consequences in normal pressure hydrocephalus (NPH) and to assess changes in these parameters following surgery. Eleven patients with NPH were studied pre- and post-operatively using perfusion and diffusion weighted imaging and compared with ten age-matched controls. Pre-operative periventricular relative cerebral blood volume (rCBV) was reduced in patients (0.76+/-0.11) compared with control (1.16+/-0.16, P<0.01). There was no difference between outcome groups and no change in haemodynamic parameters following surgery. The periventricular apparent diffusion coefficient (ADC) was elevated in the poor outcome group (1.67+/-0.3 x 10(-3) mm(2) s(-1)) compared with both controls (1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) and the good outcome group (0.99+/-0.3 x 10(-3) mm(2) s(-1), P<0.05) despite appearing normal on conventional imaging. In white matter hyperintensities (WMH), rCBV was reduced (0.70+/-0.12 vs. 1.00+/-0.10, P<0.01), and the ADC was increased (1.98+/-0.6 vs. 1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) compared with the same anatomical location in controls. As low rCBV and high ADC is characteristic of chronic infarction, the findings in WMH regions suggest they are irreversibly damaged. Normal appearing periventricular tissue rCBV was reduced, implying that significant haemodynamic consequences contribute to symptoms in NPH. The elevated pre-operative ADC of the same region, was correlated with poor outcome, and may, therefore, be useful in selecting patients for surgery.

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PubMed1977

Spontaneous improvement in "normal" pressure hydrocephalus.

A patient is presented with "normal" pressure hydrocephalus including dementia, incontinence, and apraxic gait. He had a normal lumbar CSF pressure, hydrocephalus with lack of air over the convexities on pneumoencephalography, and ventricular filling with prolonged retention on cisternography. He did not receive a shunt and, nevertheless, showed spontaneous improvement in his mental function over the next few years. This cases emphasizes the necessity for a controlled study of shunting for "normal" pressure hydrocephalus.

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PubMed2004

Decreases in ventricular volume correlate with decreases in ventricular pressure in idiopathic normal pressure hydrocephalus patients who experienced clinical improvement after implantation with adjustable valve shunts.

OBJECTIVE: This retrospective study examined whether changes in ventricular volume correspond with changes in adjustable valve pressure settings in a cohort of patients who received shunts to treat idiopathic normal pressure hydrocephalus. We also examined whether these pressure-volume curves and other patient variables would co-occur with a positive clinical response to shunting. METHODS: We selected 51 patients diagnosed with idiopathic normal pressure hydrocephalus who had undergone implantation of a Codman Hakim programmable valve (Medos S.A., Le Locle, Switzerland). Clinical data were gathered from the patients' records and clinical notes by an investigator blinded to patients' ventricular volumes. Ventricular volume was measured using 3D Slicer, an image analysis and interactive visualization software package developed and maintained at the Surgical Planning Laboratory at Brigham and Women's Hospital. RESULTS: Eighty-six percent of patients with gait disturbance at presentation showed improvement of this symptom, 70% experienced improvement in incontinence, and 69% experienced improvement in dementia. For the group showing 100% clinical improvement, the correlation coefficient of average changes in valve pressure over time (delta P/delta T) and average changes in ventricular volume over time (delta V/delta T) were high at 0.843 (P < 0.05). For the group experiencing no or only partial improvement, the correlation coefficient was 0.257 (P = 0.32), indicating no correlation between average delta V/delta T and average delta P/delta T for each patient. CONCLUSION: This was a carefully analyzed modeling study of idiopathic normal pressure hydrocephalus treatment made possible only by adjustable valve technology. With careful volumetric analysis, we found that changes in ventricular volume correlated with adjustments in valve pressure settings for those patients who improved clinically after shunting. This suggests that positive clinical responders retained parenchymal elasticity, emphasizing the importance of dynamic changes in this cohort.

Adolescent↗

PubMedDate not supplied

Association of deep white matter infarction with chronic communicating hydrocephalus: implications regarding the possible origin of normal-pressure hydrocephalus.

The coexistence of cerebrovascular disease leading to deep white matter infarction and normal-pressure hydrocephalus has been noted previously in clinical studies, as both diseases can present with the triad of gait disturbance, dementia, and incontinence. The purpose of this MR study was to determine if the two diseases demonstrated a statistical association. Evidence of patchy periventricular hyperintensity representing presumed deep white matter infarction was sought in 20 patients shunted for normal-pressure hydrocephalus and in 35 additional consecutive patients with clinical symptoms and MR findings consistent with normal-pressure hydrocephalus. Deep white matter infarction was also sought in 62 consecutive age-matched control subjects. There was a statistically significant (p less than .001) higher association (58%) of marked infarction in the 55 patients with normal-pressure hydrocephalus than in the age-matched controls (24%). MR findings of communicating hydrocephalus (ventriculomegaly and increased aqueductal CSF flow void) were sought in 78 consecutive patients with presumed deep white matter infarction, and the degree of severity of the two diseases was also found to be statistically significant (p less than .05). In view of this association, the possibility that the two diseases are related was considered. A potential mechanism is discussed whereby deep white matter infarction leading to decreased periventricular tensile strength could result in communicating hydrocephalus. It is plausible that normal-pressure hydrocephalus may result from a number of different insults to the brain.

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PubMed1994

Cognitive recovery in idiopathic normal pressure hydrocephalus: a prospective study.

Idiopathic normal-pressure hydrocephalus remains difficult to treat. Controversy exists as to whether or not shunting can really improve cognitive functions and whether quantified intracranial pressure monitoring (ICP-Mo) can predict postoperative improvement rates. Several studies have drawn attention to the lack of a prospective study concerning the surgical outcome of this condition. We have performed such a study on idiopathic normal-pressure hydrocephalus patients shunted on the basis of ICP-Mo when "high" waves (amplitude > 9 mm Hg) were present. Twenty-three patients underwent surgery. The preoperative and postoperative clinical states were assessed by a quantitative procedure blind to the ICP-Mo results. A clear postshunting improvement was seen in 96% of the patients at 1 year with a statistically significant correlation between high wave relative frequency and the grade of improvement (P < 0.05). At the same time, 66.6% of shunted patients showed a significant improvement in cognitive functions. Complications of shunting were successfully managed without residual deficits in this series. We recommend the use of quantitative ICP-Mo as a criterion for surgery and to predict the improvement grade.

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PubMed1996

The effect of ketanserin on ICP and CBF in patients with normal-pressure hydrocephalus.

Eight patients with normal-pressure hydrocephalus were studied. Intracranial pressure (ICP) and mean arterial blood pressure (MAP) were measured continuously before and during administration of ketanserin i.v. (10 mg bolus followed by an infusion of 3 mg over a 60-min period, 6 mg over the next 30 min, and 12 mg over the last 30 min). The mean baseline MAP and ICP were 103 and 8 mm Hg, respectively. Five minutes after the bolus dose, the maximum decrease in MAP occurred (mean, 17 mm Hg; p < 0.05). The maximum ICP (10 mm Hg) occurred at 5 min and at 100 min after the bolus dose but was not significantly different from the baseline value. There was no change in relative global cerebral blood flow (CBF) expressed as 1/(arteriovenous oxygen difference). It is concluded that ketanserin in a clinically recommended dose decreases blood pressure without significantly influencing the ICP or CBF.

Adult↗

PubMed2003

Is there a correlation between operative results and change in ventricular volume after shunt placement? A study of 60 cases of idiopathic normal-pressure hydrocephalus.

In patients with communicating or normal-pressure hydrocephalus, ventricular volume decreases following implantation of differential pressure valves. We implanted hydrostatic (Miethke dual-switch) valves in 60 patients with normal-pressure hydrocephalus (NPH) between September 1997 and December 2001. The patients underwent CT 1 year after operation, and we measured the Evans index. Although 83% of the patients showed no change in ventricular volume as assessed by this index, 72% nevertheless showed good to excellent and 16% satisfactory clinical improvement, while 12% showed no improvement. Moderate or marked reduction in ventricular size was observed in 17%, of whom 40% of these patients showed good to excellent and 20% satisfactory clinical improvement; 40% showed unsatisfactory improvement. The favourable outcome following implantation of a hydrostatic shunt thus did not correlate with decreased ventricular volume 1 year after operation, better outcomes being observed in patients with little or no alteration in ventricular size than in those with a marked decrease. Postoperative change in ventricular volume in NPH thus does not have the same significance as in patients with high-pressure hydrocephalus.

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PubMed1976

Normal-pressure hydrocephalus due to tentorial meningioma.

Normal-pressure hydrocephalus and the associated triad of dementia, apraxic gait and urinary incontinence may be casued by various, sometimes unsuspected, lesions, usually those that block the flow of cerebrospinal fluid (CSF) around the tentorium. A 58-year-old woman with insidious onset of behaviour and gait problems had occult, normal-pressure hydrocephalus and a tentorial meningioma, resection of which produced complete recovery. This case demonstrates that a distinction must be made between the syndrome of normal-pressure hydrocephalus resulting from disturbance in CSF dynamics and the pathophysiologic features of the underlying lesion.

Brain Neoplasms↗

PubMed1984

Experimental normal-pressure hydrocephalus is accompanied by increased transmantle pressure.

This research was directed at the pathophysiology of normal-pressure hydrocephalus. The experimental method consisted of accurate and simultaneous measurement of the pressure within the ventricle and over the cerebral convexity in cats with hydrocephalus but normal ventricular pressure. Hydrocephalus was induced by the intracisternal injection of kaolin. Prior to the induction of hydrocephalus, the difference between the ventricular pressure and the pressure over the convexity (the transmantle pressure) was small (0.27 +/- 0.31 cm saline, mean +/- standard deviation). After the induction of normal-pressure hydrocephalus in seven animals, there was a statistically significant elevation of the transmantle pressure to 3.4 +/- 3.9 cm saline (p less than 0.05, Student's paired t-test). There was no similar increase in animals injected with lactated Ringer's solution. This finding supports the theory that it is the transmantle pressure, and not the ventricular pressure, that is the physiological determinant of ventricular dilatation. The theory explains why hydrocephalus can develop and persist despite normal ventricular pressure.

Animals↗

PubMed2000

Diagnosis and management of normal-pressure hydrocephalus.

The syndrome of normal-pressure hydrocephalus (NPH) remains a diagnostic and therapeutic challenge, especially as many patients do not display the classical clinical and neuroimaging patterns of NPH, thus questioning the usefulness of a shunt. Gait impairment remains the cardinal symptom, while mental deterioration may be subtle and even unrecognized. NPH is rarely the cause of severe dementia, and substantial improvement in NPH-related mental deterioration is limited to 30-40% of shunted patients. Many ancillary investigations have been described that can increase the probability of selecting the appropriate candidates for a shunt. The reliability and reproducibility of these tests are limited. Unfortunately, the best predictive tests are technically complex and are used only in a few specialized centers. The best management is still to adhere to strict clinical and magnetic resonance imaging criteria and to rely on a positive - but not negative - CSF tap test and the occurrence of B-waves during at least 50% of the continuous intracranial pressure recording time, when this procedure is available.

Humans↗

PubMed1976

[Cerebral cortex in normal pressure hydrocephalus: an electron microscopy study (author's transl)].

A cortical biopsy was taken at the time when ventricular pressure was measured, or a ventriculo-atrial shunt placed, in 11 patients with Normal Pressure Hydrocephalus (N.P.H.), and was studied with the electron microscope. In 9 cases, a rather typical electron microscopic picture with marked increase of extracellular space in an otherwise normal cortical neuropil was observed. 2 patients did not exhibit this pattern and, coincendentally, did not benefit from the placing of the shunt. As a control, about 600 cortical biopsies that had been taken for other reasons were reviewed. In the group, there were only 3 cortices that had a pattern of increased extracellular space similar to the described in N.P.H. On review of the clinico-pathologic data of these cases, it was felt that all 3 probably represented cases of normal pressure hydrocephalus. It is concluded that the ultrastructure of the cerebral cortex is of at least nosological interest in the study of N.P.H.

Cerebral Cortex↗

PubMed1981

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.

Adult↗

PubMed2000

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.

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