Vascular factors in suspected normal pressure hydrocephalus: A population-based study

The contribution of cerebral small vessel disease in idiopathic normal pressure hydrocephalus: Insights from a prospective cohort study

INTRODUCTION

Idiopathic normal pressure hydrocephalus (iNPH) and cerebral small vessel disease (CVSD) are age-related diseases, but their prevalence and clinical relationship are unclear.

METHODS

This prospective cohort study enrolled 95 patients with probable iNPH in China and evaluated their CSVD burden using magnetic resonance imaging. Linear regression models were used to analyze the association between CSVD scores and clinical outcomes.

RESULTS

The results showed 78% of the patients had at least one CSVD imaging marker, and higher total CSVD scores were significantly associated with declines in attention, executive function, psychomotor speed, and gait performance after multivariate adjustments. However, the preoperative CSVD score did not affect the post-shunt improvement in modified Rankin scale or iNPH grading scale scores.

DISCUSSION

Our findings suggest that CSVD is prevalent in patients with iNPH and is associated with more severe symptoms, but it may not affect shunt outcomes. Future studies are needed to elucidate the underlying mechanisms.

HIGHLIGHTS

We found that 78% of the patients with idiopathic normal pressure hydrocephalus (iNPH) had at least one type of cerebral small vessel disease (CSVD) imaging marker. The CSVD burden aggravates cognitive and gait impairments in patients with iNPH but may not affect shunt outcomes. The effects of different imaging markers of CSVD on cognition and gait are different and worthy of further investigation.

Survival After Shunt Therapy in Normal-Pressure Hydrocephalus: A Meta-Analysis of 1614 Patients

BACKGROUND

Ventriculoperitoneal (VP) shunt therapy is a crucial intervention for normal-pressure hydrocephalus (NPH). This meta-analysis delves into survival time and the impact of baseline symptom burden on survival after VP shunt therapy for NPH, employing reconstructed pooled survival curves and a one-stage meta-analysis.

METHODS

IPD regarding overall survival (OS) were acquired from published Kaplan-Meier charts, utilizing the R package IPDfromKM in R (Version 4.3.1, the R Foundation for Statistical Computing). Reconstructed Kaplan-Meier charts were then generated from the pooled IPD data. Both one-stage and two-stage meta-analyses were executed, with hazard ratios (HRs) employed as metrics to evaluate effectiveness.

RESULTS

From the initial screening of 216 records, five articles encompassing 1614 patients met the eligibility criteria for inclusion. In two of the five included studies, overall survival was stratified by gait score (1-4 vs. ≥4) in 1043 patients, continence score (1-3 vs. ≥4) in 1022 patients, and mRS (0-2 vs. ≥3) in 956 patients. Patients with good gait demonstrated a mean survival of 8.24 years, while those with poor gait had a mean survival of 6.19 years (log-rank test: p < 0.001). The HR for gait was 2.25 (95% CI: 1.81-2.81, p < 0.001). Continence score stratification revealed a significant difference in survival time (log-rank test: p < 0.001), with an HR of 1.66 (95% CI: 1.33-2.06, p < 0.001). Similarly, mRS stratification demonstrated a significant survival difference (log-rank test: p < 0.001), with an HR of 2.21 (95% CI: 1. 74-2.80, p < 0.001). The reconstructed survival curves for all NPH patients treated with VP shunt therapy, pooling data from five studies, revealed a median survival time of 8.82 years (95% CI: 8.23-9.40). Survival rates at 1, 3, 5, 7, 9, 11, and 13 years were 95.7%, 83.8%, 70.5%, 59.5%, 48.7%, 35.8%, and 25.4%, respectively. Comparison with a general control population showed an HR of 1.79 (95% CI: 1.62-1.98, p < 0.001).

CONCLUSIONS

This comprehensive meta-analysis underscores the influence of baseline symptom burden on survival after VP shunt therapy in NPH. Therapy in the early stages for those without significant comorbidities may enhance survival.

Blood-brain barrier-associated biomarker correlated with cerebral small vessel disease and shunt outcome in normal pressure hydrocephalus: a prospective cohort study

BACKGROUND

Blood-brain barrier (BBB) breakdown is associated with neurodegeneration and cognitive impairment. Cerebral small vessel disease (CSVD) is also common in idiopathic normal pressure hydrocephalus (iNPH). Biomarkers in the cerebrospinal fluid (CSF) may reflect the severity of neuropathological damage and indicate a relationship between BBB integrity and iNPH and its surgical outcome. The authors investigated the association of CSVD and comorbidity-related CSF biomarkers with shunt outcomes in iNPH.

MATERIALS AND METHODS

This prospective cohort study recruited 53 patients with iNPH, who were subgrouped by CSVD severity. CSF proteins were analyzed, including soluble platelet-derived growth factor receptor-β (sPDGFR-β), Alzheimer's disease biomarkers, neurofilament light chain (NfL), and triggering receptor expressed on myeloid cells 2 (Trem2). We assessed symptom improvement, investigated its association with biomarkers levels, calculated protein cutoffs for surgical outcomes using receiver operating characteristic (ROC) curves, and compared model predictions using different proteins through hierarchical regression analysis.

RESULTS

Among patients with iNPH, 74% had comorbid CSVD. Patients with severe CSVD exhibited significantly higher sPDGFR-β levels ( P =0.019) and better postoperative performance (β=0.332, t=2.174, P =0.039; r =0.573, P =0.001). Analysis of the predictive potential of the biomarkers showed that sPDGFR-β was predictive of surgical outcomes (area under curve=0.82, sensitivity=66.8%, specificity=94.7%). A Comparison of the models revealed a greater effect of sPDGFR-β (Adjusted R 2 =0.247, ∆R 2 =0.160, ∆F(1, 37)=8.238, P =0.007) on cognitive improvement.

CONCLUSION

This study highlighted the relevance of CSF biomarkers in assessing CSVD severity and predicting iNPH surgical outcomes. CSF shunt surgery may provide an alternative treatment for neurodegenerative diseases with BBB breakdown and dysfunctional CSF clearance.

A Bidirectional Mendelian Randomization Study of the Causal Association Between Ischemic Stroke, Coronary Heart Disease, and Hydrocephalus

BACKGROUND

The association among coronary heart disease, ischemic stroke, and hydrocephalus remains ambiguous.

OBJECTIVES

There is a need for a Mendelian randomization study to evaluate the underlying causality between coronary heart disease, ischemic stroke, and hydrocephalus.

METHODS

The data source utilized genome-wide association studies, employing a threshold of p < 5 × 10-8 to identify single nucleotide polymorphisms strongly linked to ischemic stroke and coronary heart disease as instrumental variables (IVs). Five methods-inverse variance weighted (IVW), Mendelian randomization (MR) Egger, Weighted Median, Weighted mode, and Simple mode-utilized the selected IVs to estimate the causality between ischemic stroke, coronary heart disease, and hydrocephalus.

RESULTS

The IVW demonstrated that ischemic stroke and coronary heart disease serve as risk factors for hydrocephalus (odds ratio [OR] = 1.650, 95% CI: 1.066-2.554, p = 0.025; OR = 1.307, 95% CI: 1.023-1.668, p = 0.032). Both the MR-Egger intercept test and Cochran's Q test affirmed the relative reliability of the IVW analysis results. However, no evidence of a reverse causation was observed between hydrocephalus and coronary heart disease or ischemic stroke.

CONCLUSIONS

Coronary heart disease and Ischemic stroke may increase the risk of hydrocephalus.

[Causal relationship between sleep phenotype and idiopathic normal pressure hydrocephalus: a two-sample bidirectional Mendelian randomization study]

OBJECTIVE

To explore the causal relationship between sleep phenotype and idiopathic normal pressure hydrocephalus (iNPH) using two-sample bidirectional Mendelian randomization.

METHODS

The exposure data including 8 sleep phenotypes used in this study were obtained from GWAS catalog, FinnGenR10 and MRCIEU GWAS. The outcome data for idiopathic normal-pressure hydrocephalus were obtained from FinnGen R10. We used the inverse-variance weighted (IVW) method to perform the principal analyses. Cochrane Q-statistics test was used to assess the heterogeneity and MR Egger‑intercept test performed to evaluate the pleiotropy for sensitivity analyses.

RESULTS

IVW result showed that frequent daytime nap was associated with higher odds of iNPH (OR=3.3393, 95 CI% : 1.0646-10.4742, P=0.0270). Cochrane Q-statistics test and MR Egger‑intercept test showed that the MR analysis had no pleiotropy or heterogeneity (P > 0.05). The external validation reproduced this result (OR=2.5660, 95 CI% : 1.1680-5.6373, P=0.0189; OR=4.0424, 95 CI% : 1.5709-10.4024, P=0.0038). Reverse Mendelian randomization suggested that iNPH did not have significant impact on sleep phenotype.

CONCLUSION

The frequency of daytime naps is causally associated with iNPH, and reducing the frequency of weekly daytime naps can reduce the risk of iNPH in the elderly population.

Shunting for idiopathic normal pressure hydrocephalus

BACKGROUND

Normal pressure hydrocephalus (NPH) occurs when the brain ventricles expand, causing a triad of gait, cognitive, and urinary impairment. It can occur after a clear brain injury such as trauma, but can also occur without a clear cause (termed idiopathic, or iNPH). Non-randomised studies have shown a benefit from surgically diverting ventricular fluid to an area of lower pressure by cerebrospinal fluid (CSF)-shunting in iNPH, but historically there have been limited randomised controlled trial (RCT) data to confirm this.

OBJECTIVES

To determine the effect of CSF-shunting versus no CSF-shunting in people with iNPH and the frequency of adverse effects of CSF-shunting in iNPH.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group's register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid SP), Embase (Ovid SP), PsycINFO (Ovid SP), CINAHL (EBSCOhost), Web of Science Core Collection (Clarivate), LILACS (BIREME), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform on 15 February 2023.

SELECTION CRITERIA

We included only RCTs of people who had symptoms of gait, cognitive, or urinary impairment with communicating hydrocephalus (Evans index of > 0.3) and normal CSF pressure. Control groups included those with no CSF shunts or those with CSF shunts that were in 'inactive' mode.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Where necessary, we contacted study authors requesting data not provided in the papers. We assessed the overall certainty of the evidence using GRADE.

MAIN RESULTS

We included four RCTs, of which three were combined in a meta-analysis. The four RCTs included 140 participants (73 with immediate CSF-shunting and 67 controls who had delayed CSF-shunting) with an average age of 75 years. Risk of bias was low in all parallel-group outcomes evaluated apart from gait speed, cognitive function (general cognition and Symbol Digit Test) (some concerns) and adverse events, which were not blind-assessed. CSF-shunting probably improves gait speed at less than six months post-surgery (standardised mean difference (SMD) 0.62, 95% confidence interval (CI) 0.24 to 0.99; 3 studies, 116 participants; moderate-certainty evidence). CSF-shunting may improve qualitative gait function at less than six months post-surgery by an uncertain amount (1 study, 88 participants; low-certainty evidence). CSF-shunting probably results in a large reduction of disability at less than six months post-surgery (risk ratio 2.08, 95% CI 1.31 to 3.31; 3 studies, 118 participants; moderate-certainty evidence). The evidence is very uncertain about the effect of CSF-shunting on cognitive function at less than six months post-CSF-shunt surgery (SMD 0.35, 95% CI -0.04 to 0.74; 2 studies, 104 participants; very low-certainty evidence). The evidence is also very uncertain about the effect of CSF-shunt surgery on adverse events (1 study, 88 participants; very low-certainty evidence). There were no data regarding the effect of CSF-shunting on quality of life.

AUTHORS' CONCLUSIONS

We found moderate-certainty evidence that CSF-shunting likely improves gait speed and disability in iNPH in the relative short term. The evidence is very uncertain regarding cognition and adverse events. There were no longer-term RCT data for any of our prespecified outcomes. More studies are required to improve the certainty of these findings. In addition, more information is required regarding patient ethnicity and the effect of CSF-shunting on quality of life.

Beat-to-Beat Blood Pressure Variability Within 24 Hours of Ischemic Stroke Onset: A Potential Predictor of Functional Prognosis

BACKGROUND

Beat-to-beat blood pressure variability (BPV) is based on each heartbeat and represents a dynamic equilibrium process modulated by artery and cardiac involvement of pressure-receptive reflexes. To date, there remains a lack of prospective studies illustrating the clinical value of beat-to-beat BPV within 24 hours of acute ischemic stroke onset.

METHODS AND RESULTS

This study prospectively monitored beat-to-beat blood pressure and heart rate in patients with acute ischemic stroke within 24 hours of onset using a noninvasive plethysmograph and calculated beat-to-beat BPV, heart rate variability, and the cross-correlation baroreflex sensitivity. A modified Rankin Scale score of ≥2 at 90 days was defined as an unfavorable prognosis. Multivariate logistic regression was performed, and the nomogram model was developed by adding the beat-to-beat BPV to the traditional model for predicting prognosis. Beat-to-beat BPV increased significantly in the unfavorable outcome group (P<0.05) compared with that in the favorable outcome group, whereas no difference was observed in beat-to-beat heart rate variability and cross-correlation baroreflex sensitivity between both groups (P>0.05). Furthermore, beat-to-beat BPV within 24 hours of acute ischemic stroke onset was independently associated with unfavorable outcome at 90 days (P<0.005). The addition of beat-to-beat BPV to the traditional model for predicting prognosis enhanced the area under the receiver operating characteristic curve from 0.816 to 0.830.

CONCLUSIONS

Increased beat-to-beat BPV within 24 hours of acute ischemic stroke onset was independently associated with a poor prognosis at 90 days and may be a potential predictor for discriminating unfavorable prognosis.

Symptoms and signs did not predict outcome after surgery: a prospective study of 143 patients with idiopathic normal pressure hydrocephalus

OBJECTIVE

To determine the utility of symptoms, signs, comorbidities and background variables for the prediction of outcome of treatment in iNPH.

METHODS

A prospective observational study of consecutively included iNPH patients, who underwent neurological, physiotherapeutic and neuropsychological assessments before and after shunt surgery. The primary outcome measure was the total change on the iNPH scale, and patients were defined as improved postoperatively if they had improved by at least five points on that scale.

RESULTS

143 iNPH patients were included, and 73% of those were improved after surgery. None of the examined symptoms or signs could predict which patients would improve after shunt surgery. A dominant subjective complaint of memory problems at baseline was predictive of non-improvement. The reported comorbidities, duration of symptoms and BMI were the same in improved and non-improved patients. Each of the symptom domains (gait, neuropsychology, balance, and continence) as well as the total iNPH scale score improved significantly (from median 53 to 69, p < 0.001). The proportions of patients with shuffling gait, broad-based gait, paratonic rigidity and retropulsion all decreased significantly.

DISCUSSION

This study confirms that the recorded clinical signs, symptoms, and impairments in the adopted clinical tests are characteristic findings in iNPH, based on that most of them improved after shunt surgery. However, our clinical data did not enable predictions of whether patients would respond to shunt surgery, indicating that the phenotype is unrelated to the reversibility of the iNPH state and should mainly support diagnosis. Absence of specific signs should not be used to exclude patients from treatment.

Modeling cerebrospinal fluid dynamics across the entire intracranial space through integration of four-dimensional flow and intravoxel incoherent motion magnetic resonance imaging

BACKGROUND

Bidirectional reciprocal motion of cerebrospinal fluid (CSF) was quantified using four-dimensional (4D) flow magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) MRI. To estimate various CSF motions in the entire intracranial region, we attempted to integrate the flow parameters calculated using the two MRI sequences. To elucidate how CSF dynamics deteriorate in Hakim's disease, an age-dependent chronic hydrocephalus, flow parameters were estimated from the two MRI sequences to assess CSF motion in the entire intracranial region.

METHODS

This study included 127 healthy volunteers aged ≥ 20 years and 44 patients with Hakim's disease. On 4D flow MRI for measuring CSF motion, velocity encoding was set at 5 cm/s. For the IVIM MRI analysis, the diffusion-weighted sequence was set at six b-values (i.e., 0, 50, 100, 250, 500, and 1000 s/mm2), and the biexponential IVIM fitting method was adapted. The relationships between the fraction of incoherent perfusion (f) on IVIM MRI and 4D flow MRI parameters including velocity amplitude (VA), absolute maximum velocity, stroke volume, net flow volume, and reverse flow rate were comprehensively evaluated in seven locations in the ventricles and subarachnoid spaces. Furthermore, we developed a new parameter for fluid oscillation, the Fluid Oscillation Index (FOI), by integrating these two measurements. In addition, we investigated the relationship between the measurements and indices specific to Hakim's disease and the FOIs in the entire intracranial space.

RESULTS

The VA on 4D flow MRI was significantly associated with the mean f-values on IVIM MRI. Therefore, we estimated VA that could not be directly measured on 4D flow MRI from the mean f-values on IVIM MRI in the intracranial CSF space, using the following formula; e0.2(f-85) + 0.25. To quantify fluid oscillation using one integrated parameter with weighting, FOI was calculated as VA × 10 + f × 0.02. In addition, the FOIs at the left foramen of Luschka had the strongest correlations with the Evans index (Pearson's correlation coefficient: 0.78). The other indices related with Hakim's disease were significantly associated with the FOIs at the cerebral aqueduct and bilateral foramina of Luschka. FOI at the cerebral aqueduct was also elevated in healthy controls aged ≥ 60 years.

CONCLUSIONS

We estimated pulsatile CSF movements in the entire intracranial CSF space in healthy individuals and patients with Hakim's disease using FOI integrating VA from 4D flow MRI and f-values from IVIM MRI. FOI is useful for quantifying the CSF oscillation.

10-year mortality, causes of death and cardiovascular comorbidities in idiopathic normal pressure hydrocephalus

OBJECTIVE

The objective was to investigate 10-year mortality, causes of death and cardiovascular comorbidity in idiopathic normal pressure hydrocephalus (iNPH) and to evaluate their mutual associations.

METHODS

This prospective cohort study included 176 CSF-shunted iNPH patients, and 368 age- and sex-matched controls. At inclusion, participants were medically examined, had blood analyzed and answered a questionnaire. The vascular comorbidities investigated were smoking, diabetes, body mass index, blood pressure (BP), hyperlipidemia, kidney function, atrial fibrillation and, cerebro- and cardiovascular disease.

RESULTS

Survival was observed for a mean period of 10.3 ± 0.84 years. Shunted iNPH patients had an increased risk of death compared to controls (hazard ratio (HR) = 2.5, 95% CI 1.86-3.36; p < 0.001). After 10 years, 50% (n = 88) of iNPH patients and 24% (n = 88) of the controls were dead (p < 0.001). The risk of dying from cardiovascular disease, falls and neurological diseases were higher in iNPH (p < 0.05). The most common cause of death in iNPH was cardiovascular diseases (14% vs 7% for controls). Seven out of nine iNPH dying from falls had subdural hematomas. Systolic BP (HR = 0.985 95% CI 0.972-0.997, p = 0.018), atrial fibrillation (HR = 2.652, 95% CI 1.506-4.872, p < 0.001) and creatinine (HR = 1.018, 95% CI 1.010-1.027, p < 0.001) were independently associated with mortality for iNPH.

DISCUSSION

This long-term and population-matched cohort study indicates that in spite of CSF-shunt treatment, iNPH has shorter life expectancy. It may be important to treat iNPH in supplementary ways to reduce mortality. Both cardiovascular comorbidities and lethal falls are contributing to the excess mortality in iNPH and reducing these preventable risks should be an established part of the treatment plan.

Association between dietary total choline and abdominal aorta calcification among older US adults: A cross-sectional study of the National Health and Nutrition Examination Survey

BACKGROUND

Numerous studies indicate a potential bidirectional association between dietary choline intake and its derivative, betaine, and subclinical atherosclerosis. However, little research has been conducted on the relationship between dietary choline and severe abdominal aortic calcification (SAAC).

METHODS

This cross-sectional study analyzed population-based data from the National Health and Nutrition Examination Survey (2013-2014). Choline intake and food sources were measured using two 24-h dietary-recall interviews. The abdominal aortic calcification score was measured using a dual-emission x-ray absorptiometry scan. To assess the relationship between choline intake and SAAC, the study utilized restricted cubic spline and a multivariable logistic regression model.

RESULTS

Among the 2640 individuals included in the study, 10.9% had SAAC. After adjusting for all selected covariates, compared with the lowest quartile of dietary choline, the odds ratios of SAAC for the second-quartile, third-quartile, and fourth-quartile dietary choline intake were 0.63 (95% confidence interval [CI], 0.43-0.93), 0.63 (95% CI, 0.42-0.94), and 0.77 (95% CI, 0.5-1.16), respectively. The study found an L-shaped relationship between dietary choline and SAAC in the dose-response analysis. Subgroup analyses did not demonstrate any statistically significant interaction effects for any subgroup.

CONCLUSION

The study found that a higher intake of dietary choline is associated with a lower prevalence of SAAC. The dose-response analysis revealed an L-shaped relationship between dietary choline and SAAC. However, further studies are warranted to investigate the direct role of choline in the development of SAAC.

Observational study of intracranial pressure instability in patients with pseudotumour cerebri syndrome

Introduction

A fixed CSF pressure (CSFp) of 25 cmH2O (18 mmHg) has been utilised to date to define and classify pseudotumour cerebri syndrome (PTCS). Furthermore, ICP monitoring, and CSF infusion tests have not been frequently performed in this group of patients.

Research question

We aimed to report typical, unusual and unstable patterns of ICP in patients with PTCS.

Material and methods

We reviewed the recordings of CSF infusion tests and overnight ICP monitoring of patients with suspected or confirmed IIH between January 2003-December 2020.We excluded all patients with a shunt in situ and selected recordings that represented unstable patterns of ICP changes in PTCS.

Results

463 CSF infusion tests and 26 ICP monitorings of PTCS patients had been performed in this timeframe. We divided results of observed pattern into two group: those with known venous sinus measurements (Group A) and those without (Group B). Observed recordings formed a total of 5 and 4 different patterns respectively, based on the behaviour of ICP and slow waves at rest, overnight, and during infusion as well as in relationship to the clinical presentation of each patient.

Discussion and conclusion

Accurate monitoring of ICP in PTCS is quintessential. Full understanding of each element of its pathophysiology and their interaction would be essential and include quantification of the CSF pressure not only as a number, but also with consideration of its dynamic contents. Cerebral venous pressure measurements and/or monitoring may be useful. Consideration of the presence or absence of papilloedema in the context of disturbed CSF dynamics could reveal further diagnostic and therapeutic insights.

Application of LRG mechanism in normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a prevalent type of hydrocephalus, including secondary normal pressure hydrocephalus (SNPH) and idiopathic normal pressure hydrocephalus (INPH). However, its clinical diagnosis and pathological mechanism are still unclear. Leucine-rich α-2 glycoprotein (LRG) is involved in various human diseases, including cancer, diabetes, cardiovascular disease, and nervous system diseases. Now the physiological mechanism of LRG is still being explored. According to the current research results on LRG, we found that the agency of LRG has much to do with the known pathological process of NPH. This review focuses on analyzing the LRG signaling pathways and the pathological mechanism of NPH. According to the collected literature evidence, we speculated that LRG probably be involved in the pathological process of NPH. Finally, based on the mechanism of LRG and NPH, we also summarized the evidence of molecular targeted therapies for future research and clinical application.

CWH43 Variants Are Associated With Disease Risk and Clinical Phenotypic Measures in Patients With Normal Pressure Hydrocephalus

Background and Objectives

Variants in the CWH43 gene have been associated with normal pressure hydrocephalus (NPH). We aimed to replicate these findings, identify additional CWH43 variants, and further define the clinical phenotype associated with CWH43 variants.

Methods

We determined the prevalence of CWH43 variants by whole-genome sequencing (WGS) in 94 patients with NPH. The odds of having CWH43 variant carriers develop NPH were determined through comparison with 532 Mayo Clinic Biobank volunteers without a history of NPH. For patients with NPH, we documented the head circumference, prevalence of disproportionate enlargement of subarachnoid hydrocephalus (DESH), microvascular changes on MRI quantified by the Fazekas scale, and ambulatory response to ventriculoperitoneal shunting.

Results

We identified rare (MAF <0.05) coding CWH43 variants in 15 patients with NPH. Ten patients (Leu533Terfs, n = 8; Lys696Asnfs, n = 2) harbored previously reported predicted loss-of-function variants, and combined burden analysis confirmed risk association with NPH (OR 2.60, 95% CI 1.12-6.03, p = 0.027). Additional missense variations observed included Ile292Thr (n = 2), Ala469Ser (n = 2), and Ala626Val (n = 1). Though not quite statistically significant, in single variable analysis, the odds of having a head circumference above the 75th percentile of normal controls was more than 5 times higher for CWH43 variant carriers compared with that for noncarriers (unadjusted OR 5.67, 95% CI 0.96-108.55, p = 0.057), and this was consistent after adjusting for sex and height (OR 5.42, 95% CI 0.87-106.37, p = 0.073). DESH was present in 56.7% of noncarriers and only 21.4% of carriers (p = 0.016), while sulcal trapping was also more prevalent among noncarriers (67.2% vs 35.7%, p = 0.030). All 8 of the 15 variant carriers who underwent ventriculoperitoneal shunting at our institution experienced ambulatory improvements.

Discussion

CWH43 variants are frequent in patients with NPH. Predicted loss-of-function mutations were the most common; we identified missense mutations that require further study. Our findings suggest that congenital factors, rather than malabsorption or vascular dysfunction, are primary contributors to the CWH43-related NPH clinical syndrome.

[Coincidence of normal pressure hydrocephalus and Alzheimer`s disease: therapeutic implications and open questions]

Normal pressure hydrocephalus (NPH) is prevalent in aging patient populations. Despite its clinical relevance, many patients with NPH may not receive adequate treatment. Because of the frequency of Alzheimer`s disease in these patients, there could be overlapping pathophysiological mechanisms that are as yet incompletely understood. Cerebral comorbidities seem to have negative effects on therapeutic response to ventriculoperitoneal shunting. In order to avoid unnecessary and unsuccessful surgery in highly vulnerable elderly patients, they have to be taken into consideration in the diagnostic process.

Vascular risk factors for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

Objective

Idiopathic normal-pressure hydrocephalus (iNPH) is a treatable cause of dementia; however, its etiology and pathogenesis remain poorly understood. The objective of this study was to investigate the prevalence and impact of vascular risk factors in patients with iNPH compared to a control cohort to better understand the potential mechanisms and preventive measures.

Methods

We systematically searched PubMed, Web of Science, Embase, and the Cochrane Library (from inception to December 20, 2022) for studies reporting vascular risk factors for the development of iNPH. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using random-effects models.

Results

After screening 1,462 articles, 11 case-control studies comprising 1,048 patients with iNPH and 79,668 cognitively unimpaired controls were included in the meta-analysis. Our data showed that hypertension (N = 991, OR = 2.30, 95% CI 1.64 to 3.23, I2= 64.0%), diabetes mellitus (DM) (N = 985, OR = 3.12, 95% CI 2.29 to 4.27, I2= 44.0%), coronary heart disease (CHD; N = 880, OR = 2.34, 95% CI 1.33 to 4.12, I2= 83.1%), and peripheral vascular disease (N = 172, OR = 2.77, 95% CI 1.50 to 5.13, I2= 0.0%) increased the risk for iNPH, while overweight was a possible factor (N = 225, OR = 2.01, 95% CI 1.34 to 3.04, I2= 0.0%) based on the sensitivity analysis. Smoking and alcohol consumption were not associated with iNPH.

Conclusions

Our study suggested that hypertension, DM, CHD, peripheral vascular disease, and overweight were associated with iNPH. These factors might be involved in the pathophysiological mechanisms promoting iNPH. These findings require further investigation in future studies.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42022383004.

Tightened Sulci in the High Convexities as a Noteworthy Feature of Idiopathic Normal Pressure Hydrocephalus

OBJECTIVE

The presence of tightened sulci in the high-convexities (THC) is a key morphological feature for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH), but the exact localization of THC has yet to be defined. The purpose of this study was to define THC and compare its volume, percentage, and index between iNPH patients and healthy controls.

METHODS

According to the THC definition, the high-convexity part of the subarachnoid space was segmented and measured the volume and percentage from the 3D T1-weighted and T2-weighted magnetic resonance images in 43 patients with iNPH and 138 healthy controls.

RESULTS

THC was defined as a decrease in the high-convexity part of the subarachnoid space located above the body of the lateral ventricles, with anterior end on the coronal plane perpendicular to the anterior commissure-posterior commissure (AC-PC) line passing through the front edge of the genu of corpus callosum, the posterior end in the bilateral posterior parts of the callosomarginal sulci, and the lateral end at 3 cm from the midline on the coronal plane perpendicular to the AC-PC line passing through the midpoint between AC and PC. Compared to the volume and volume percentage, the high-convexity part of the subarachnoid space volume per ventricular volume ratio < 0.6 was the most detectable index of THC on both 3D T1-weighted and T2-weighted magnetic resonance images.

CONCLUSIONS

To improve the diagnostic accuracy of iNPH, the definition of THC was clarified, and high-convexity part of the subarachnoid space volume per ventricular volume ratio <0.6 proposed as the best index for THC detection in this study.

High homocysteine is associated with idiopathic normal pressure hydrocephalus in deep perforating arteriopathy: a cross-sectional study

BACKGROUND AND OBJECTIVE

The pathogenesis and pathophysiology of idiopathic normal pressure hydrocephalus (iNPH) remain unclear. Homocysteine may reduce the compliance of intracranial arteries and damage the endothelial function of the blood-brain barrier (BBB), which may be the underlying mechanism of iNPH. The overlap cases between deep perforating arteriopathy (DPA) and iNPH were not rare for the shared risk factors. We aimed to investigate the relationship between serum homocysteine and iNPH in DPA.

METHODS

A total of 41 DPA patients with iNPH and 49 DPA patients without iNPH were included. Demographic characteristics, vascular risk factors, laboratory results, and neuroimaging data were collected. Multivariable logistic regression analysis was performed to investigate the relationship between serum homocysteine and iNPH in DPA patients.

RESULTS

Patients with iNPH had significantly higher homocysteine levels than those without iNPH (median, 16.34 mmol/L versus 14.28 mmol/L; P = 0.002). There was no significant difference in CSVD burden scores between patients with iNPH and patients without iNPH. Univariate logistic regression analysis demonstrated that patients with homocysteine levels in the Tertile3 were more likely to have iNPH than those in the Tertile1 (OR, 4.929; 95% CI, 1.612-15.071; P = 0.005). The association remained significant after multivariable adjustment for potential confounders, including age, male, hypertension, diabetes mellitus, atherosclerotic cardiovascular disease (ASCVD) or hypercholesterolemia, and eGFR level.

CONCLUSION

Our study indicated that high serum homocysteine levels were independently associated with iNPH in DPA. However, further research is needed to determine the predictive value of homocysteine and to confirm the underlying mechanism between homocysteine and iNPH.

Association between vascular risk factors and idiopathic normal pressure hydrocephalus: a Mendelian randomization study

BACKGROUND AND OBJECTIVE

Patients with idiopathic normal pressure hydrocephalus (iNPH) have a higher prevalence of hypertension and diabetes. However, the causal effects of these vascular risk factors on iNPH remain unclear. This study aimed to explore the causal relationship between vascular risk factors (VRFs) and iNPH.

METHODS

We conducted the Mendelian randomization (MR) analysis of iNPH. We included nineteen vascular risk factors related to hypertension, diabetes, lipids, obesity, smoking, alcohol consumption, exercise, sleep, and cardiovascular events as exposure factors. We used the inverse-variance weighted method for causal effect estimation and weighted median, maximum likelihood, and MR Egger regression methods for sensitivity analyses.

RESULTS

We found that genetically predicting essential hypertension (OR = 1.608 (1.330-1.944), p = 0.013) and increased sleep duration (OR = 16.395 (5.624-47.799), p = 0.009) were associated with higher odds of iNPH. Type 1 diabetes (OR = 0.869 (0.828-0.913), p = 0.004) was associated with lower odds of iNPH. For the other 16 VRFs, there was no evidence that they were significantly associated with iNPH. Sensitivity analyses showed that essential hypertension and type 1 diabetes were significantly associated with iNPH.

CONCLUSION

In our MR study on VRFs and iNPH, we found essential hypertension to be a causal risk factor for iNPH. This suggests that hypertension may be involved in the pathophysiological mechanism of iNPH.

Association between dietary folate intake and cognitive impairment in older US adults: National Health and Nutrition Examination Survey

OBJECTIVE

To determine the association between dietary folate intake and low cognitive performance in older adults.

METHODS

In this cross-sectional observational study, 2011-2014 data from the 2010 National Health and Nutrition Examination Survey, including 2,524 adults aged 60 years and older, included 24-hour dietary intakes. Total folic acid intake was calculated as the sum of folic acid supplements and dietary folic acid. Cognitive function was assessed using three tests. The association between folate intake and cognitive function was assessed using a multivariate conditional logistic regression model.

RESULTS

2524 participants from two survey cycles (2011-2014) in the NHANES aged 60 years and over. In the multivariate logistic regression, the OR of developing folate was 0.96 (95% CI: 0.94∼0.98) in participants with Z test. Folate intake was negatively associated with cognitive function. Compared with Q1, Q4(≥ 616.3mg/day) in the AFT and DSST tests reduced the risk of cognitive impairment by 31% (OR = 0.69, 95% CI: 0.52-0.93) and 44% (OR = 0.56). 95% confidence interval: 0.44-0.7). In the comprehensive evaluation of IR and AFT scores, the association between dietary folate intake and low cognitive performance in US adults is linear. We also found a significant interaction between gender and cognitive ability (P value for the interaction was 0.021).

CONCLUSIONS

Dietary intake of folic acid may be inversely associated with cognitive impairment. The DSST study found an L-shaped association between dietary folate intake and cognitive decline in US adults, with an inflection point of approximately 510,383 mg/day.

Prevalence and development of idiopathic normal pressure hydrocephalus: A 16-year longitudinal study in Japan

OBJECTIVE

We previously investigated the preclinical state of idiopathic normal pressure hydrocephalus (iNPH): asymptomatic ventriculomegaly with features of iNPH on magnetic resonance imaging (AVIM) found in community inhabitants. The aim of the study was to determine how iNPH develops longitudinally.

MATERIALS AND METHODS

A previous longitudinal prospective community-based cohort study was initiated in 2000. The 271 70 year-old participants were followed up in 2016 at the age of 86 years. At this time, 104 participants could be reached for clinical examinations and brain magnetic resonance imaging (MRI). iNPH in this study was diagnosed if the participant had more than one symptom in the clinical triad and disproportionately enlarged subarachnoid space hydrocephalus (DESH) on MRI, fulfilling at least an Evans index >0.3 (ventricular enlargement, VE) and a narrowing of the subarachnoid space at the high convexity (tight high convexity, THC). Asymptomatic VE (AVE) plus THC were considered AVIM.

RESULTS

Longitudinally throughout 16 years, 11 patients with iNPH were found. The hospital consultation rate was only 9%. Five of the eight patients with AVIM (62.5%) and six of 30 with AVE (20.0%) developed iNPH. Cross-sectionally, eight patients had iNPH (8/104, 7.7% prevalence at the age of 86) in 2016. Disease development was classified into THC-preceding and VE-preceding iNPH. One VE-preceding iNPH case was considered a comorbidity of Alzheimer's dementia.

CONCLUSION

Idiopathic normal pressure hydrocephalus had a high prevalence among octogenarians in the evaluated community. iNPH developed not only via AVIM but also via AVE, the latter was also frequent in the elderly.

The demography of idiopathic normal pressure hydrocephalus: data on 3000 consecutive, surgically treated patients and a systematic review of the literature

OBJECTIVE

The objective of this study was to describe the demographic characteristics of patients with idiopathic normal pressure hydrocephalus (iNPH) through an analysis of 3000 consecutive, surgically treated Swedish patients and a systematic review of the literature.

METHODS

Data on age, sex, comorbidities, diagnostic delay, initial symptoms, and severity of symptoms at diagnosis were extracted from the Swedish Hydrocephalus Quality Registry. In addition, a systematic PRISMA-based review of the literature published from database inception until August 2019 was performed using the PubMed, Cochrane, and Scopus databases on the basis of two concepts: normal pressure hydrocephalus and demography and their association with related terms. Of 1020 unique articles, 16 were eligible for study inclusion and were assessed for quality using the Newcastle-Ottawa Scale. Mean and weighted mean values were calculated.

RESULTS

The mean patient age at the time of surgery was 74.4 years, 79% of patients were in their 70s, and 60% of the patients were men. Almost 50% of the patients had symptoms from four main domains (i.e., balance, gait, cognition, and urinary dysfunction) at disease onset. Patients aged < 60 years (2%) reported more headaches and fewer balance problems than those aged ≥ 60. Women were more impaired in function than men at the time of diagnosis. Dementia (Mini-Mental State Examination score < 25) was found in 47% of the patients. Men had more diabetes, heart disease, hypertension, and stroke than women, and comorbidity correlated with increased impairment. The incidence of surgery for iNPH was 20%-40% of the disease incidence according to survey and operation-based studies.

CONCLUSIONS

Most iNPH patients undergo surgery in their 70s. Those aged < 60 years show slightly different symptomatology and probably present with a specific disease entity, indicating that the lower age limit for iNPH should be 60 years. iNPH patients have severe impairment preceded by a long diagnostic delay. Even though the included study designs differed, the systematic review showed that the disorder has a very low treatment incidence. The importance of diagnosing and treating iNPH is further emphasized by the fact that iNPH may account for a considerable part of all cases of dementia.

Clinical Outcomes After Ventriculo-Peritoneal Shunting in Patients With Classic vs. Complex NPH

Objective

Normal pressure hydrocephalus (NPH) is a neurological condition characterized by a clinical triad of gait disturbance, cognitive impairment, and urinary incontinence in conjunction with ventriculomegaly. Other neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and vascular dementia share some overlapping clinical features. However, there is evidence that patients with comorbid NPH and Alzheimer's or Parkinson's disease may still exhibit good clinical response after CSF diversion. This study aims to evaluate clinical responses after ventriculo-peritoneal shunt (VPS) in a cohort of patients with coexisting NPH and neurodegenerative disease.

Methods

The study has two components; (i) a pilot study was performed that specifically focused upon patients with Complex NPH and following the inclusion of the Complex NPH subtype into consideration for the clinical NPH programme, (ii) a retrospective snapshot study was performed to confirm and characterize differences between Classic and Complex NPH patients being seen consecutively over the course of 1 year within a working subspecialist NPH clinic. We studied the characteristics of patients with Complex NPH, utilizing clinical risk stratification and multimodal biomarkers.

Results

There was no significant difference between responders and non-responders to CSF diversion on comorbidity scales. After VPS insertion, significantly more Classic NPH patients had improved cognition compared to Complex NPH patients (p = 0.005). Improvement in gait and urinary symptoms did not differ between the groups. 26% of the Classic NPH group showed global improvement of the triad, and 42% improved in two domains. Although only 8% showed global improvement of the triad, all Complex NPH patients improved in gait.

Conclusions

Our study has demonstrated that the presence of neurodegenerative disorders co-existing with NPH should not be the sole barrier to the consideration of high-volume tap test or lumbar drainage via a specialist NPH programme. Further characterization of distinct cohorts of NPH with differing degrees of CSF responsiveness due to overlay from neurodegenerative or comorbidity risk burden may aid toward more precise prognostication and treatment strategies. We propose a simplistic conceptual framework to describe NPH by its Classic vs. Complex subtypes to promote the clinical paradigm shift toward subspecialist geriatric neurosurgery by addressing needs for rapid screening tools at the clinical-research interface.

White matter changes should not exclude patients with idiopathic normal pressure hydrocephalus from shunt surgery

Introduction

White matter changes (WMC) on brain imaging can be classified as deep white matter hyperintensities (DWMH) or periventricular hyperintensities (PVH) and are frequently seen in patients with idiopathic normal pressure hydrocephalus (iNPH). Contradictory results have been reported on whether preoperative WMC are associated with outcome after shunt surgery in iNPH patients. The aim of this study was to investigate any association between DWMH and PVH and shunt outcome in patients with iNPH, using magnetic resonance volumetry.

Methods

A total of 253 iNPH patients operated with shunt surgery and clinically assessed before and 12 months after surgery were included. All patients were investigated preoperatively with magnetic resonance imaging of the brain. The volumes of DWMH and PVH were quantified on fluid-attenuated inversion recovery images using an in-house semi-automatic volumetric segmentation software (SmartPaint). Shunt outcome was defined as the difference in symptom score between post- and preoperative investigations, measured on the iNPH scale, and shunt response was defined as improvement with ≥ 5 points.

Results

One year after shunt surgery, 51% of the patients were improved on the iNPH scale. When defining improvement as ≥ 5 points on the iNPH scale, there was no significant difference in preoperative volume of WMC between shunt responders and non-responders. If outcome was determined by a continuous variable, a larger volume of PVH was negatively associated with postoperative change in the total iNPH scale (p < 0.05) and negatively associated with improvement in gait (p < 0.01) after adjusting for age, sex, waiting time for surgery, preoperative level of symptoms, Evans’ index, and disproportionately enlarged subarachnoid space hydrocephalus. The volume of DWMH was not associated with shunt outcome.

Conclusions

An association between outcome after shunt surgery and volume of PVH was seen, but there was no difference between shunt responders and non-responders in the volumes of DWMH and PVH. We conclude that preoperative assessment of WMC should not be used to exclude patients with iNPH from shunt surgery.

Testing and validation of reciprocating positive displacement pump for benchtop pulsating flow model of cerebrospinal fluid production and other physiologic systems

BACKGROUND

The flow of physiologic fluids through organs and organs systems is an integral component of their function. The complex fluid dynamics in many organ systems are still not completely understood, and in-vivo measurements of flow rates and pressure provide a testament to the complexity of each flow system. Variability in in-vivo measurements and the lack of control over flow characteristics leave a lot to be desired for testing and evaluation of current modes of treatments as well as future innovations. In-vitro models are particularly ideal for studying neurological conditions such as hydrocephalus due to their complex pathophysiology and interactions with therapeutic measures. The following aims to present the reciprocating positive displacement pump, capable of inducing pulsating flow of a defined volume at a controlled beat rate and amplitude. While the other fluidic applications of the pump are currently under investigation, this study was focused on simulating the pulsating cerebrospinal fluid production across profiles with varying parameters.

METHODS

Pumps were manufactured using 3D printed and injection molded parts. The pumps were powered by an Arduino-based board and proprietary software that controls the linear motion of the pumps to achieve the specified output rate at the desired pulsation rate and amplitude. A range of 0.01 [Formula: see text] to 0.7 [Formula: see text] was tested to evaluate the versatility of the pumps. The accuracy and precision of the pumps' output were evaluated by obtaining a total of 150 one-minute weight measurements of degassed deionized water per output rate across 15 pump channels. In addition, nine experiments were performed to evaluate the pumps' control over pulsation rate and amplitude.

RESULTS

Volumetric analysis of a total of 1200 readings determined that the pumps achieved the target output volume rate with a mean absolute error of -0.001034283 [Formula: see text] across the specified domain. It was also determined that the pumps can maintain pulsatile flow at a user-specified beat rate and amplitude.

CONCLUSION

The validation of this reciprocating positive displacement pump system allows for the future validation of novel designs to components used to treat hydrocephalus and other physiologic models involving pulsatile flow. Based on the promising results of these experiments at simulating pulsatile CSF flow, a benchtop model of human CSF production and distribution could be achieved through the incorporation of a chamber system and a compliance component.

Pathophysiological Mechanisms Underlying Idiopathic Normal Pressure Hydrocephalus: A Review of Recent Insights

The pathophysiologic mechanisms underpinning idiopathic normal pressure hydrocephalus (iNPH), a clinically diagnosed dementia-causing disorder, continue to be explored. An increasing body of evidence implicates multiple systems in the pathogenesis of this condition, though a unifying causative etiology remains elusive. Increased knowledge of the aberrations involved has shed light on the iNPH phenotype and has helped to guide prognostication for treatment with cerebrospinal fluid diversion. In this review, we highlight the central role of the cerebrovasculature in pathogenesis, from hydrocephalus formation to cerebral blood flow derangements, blood-brain barrier breakdown, and glymphatic pathway dysfunction. We offer potential avenues for increasing our understanding of how this disease occurs.

Application of Evans Index in Normal Pressure Hydrocephalus Patients: A Mini Review

With an ever-growing aging population, the prevalence of normal pressure hydrocephalus (NPH) is increasing. Clinical symptoms of NPH include cognitive impairment, gait disturbance, and urinary incontinence. Surgery can improve symptoms, which leads to the disease's alternative name: treatable dementia. The Evans index (EI), defined as the ratio of the maximal width of the frontal horns to the maximum inner skull diameter, is the most commonly used index to indirectly assess the condition of the ventricles in NPH patients. EI measurement is simple, fast, and does not require any special software; in clinical practice, an EI >0.3 is the criterion for ventricular enlargement. However, EI's measurement methods, threshold setting, correlation with ventricle volume, and even its clinical value has been questioned. Based on the EI, the z-EI and anteroposterior diameter of the lateral ventricle index were derived and are discussed in this review.

Neuropathological findings in possible normal pressure hydro-cephalus: A post-mortem study of 29 cases with lifelines

Aims: There are very few detailed post-mortem studies on idiopathic normal-pressure hydrocephalus (iNPH) and there is a lack of proper neuropathological criteria for iNPH. This study aims to update the knowledge on the neuropathology of iNPH and to develop the neuropathological diagnostic criteria of iNPH. Methods: We evaluated the clinical lifelines and post-mortem findings of 29 patients with possible NPH. Pre-mortem cortical brain biopsies were taken from all patients during an intracranial pressure measurement or a cerebrospinal fluid (CSF) shunt surgery. Results: The mean age at the time of the biopsy was 70±8 SD years and 74±7 SD years at the time of death. At the time of death, 11/29 patients (38%) displayed normal cognition or mild cognitive impairment (MCI), 9/29 (31%) moderate dementia and 9/29 (31%) severe dementia. Two of the demented patients had only scarce neuropathological findings indicating a probable hydrocephalic origin for the dementia. Amyloid-β (Aβ) and hyperphosphorylated τ (HPτ) in the biopsies predicted the neurodegenerative diseases so that there were 4 Aβ positive/low Alzheimer's disease neuropathological change (ADNC) cases, 4 Aβ positive/intermediate ADNC cases, 1 Aβ positive case with both low ADNC and progressive supranuclear palsy (PSP), 1 HPτ/PSP and primary age-related tauopathy (PART) case, 1 Aβ/HPτ and low ADNC/synucleinopathy case and 1 case with Aβ/HPτ and high ADNC. The most common cause of death was due to cardiovascular diseases (10/29, 34%), followed by cerebrovascular diseases or subdural hematoma (SDH) (8/29, 28%). Three patients died of a postoperative intracerebral hematoma (ICH). Vascular lesions were common (19/29, 65%). Conclusions: We update the suggested neuropathological diagnostic criteria of iNPH, which emphasize the rigorous exclusion of all other known possible neuropathological causes of dementia. Despite the first 2 probable cases reported here, the issue of "hydrocephalic dementia" as an independent entity still requires further confirmation. Extensive sampling (with fresh frozen tissue including meninges) with age-matched neurologically healthy controls is highly encouraged.

Outcomes of Ventriculoperitoneal Shunt in Patients With Idiopathic Normal-Pressure Hydrocephalus 2 Years After Surgery

Objective: To evaluate the outcomes and prognostic factors of ventriculoperitoneal shunts (VP-shunts) in patients with idiopathic normal-pressure hydrocephalus (iNPH) at 6 months and 2 years after surgery.

Method: We retrospectively analyzed 68 patients admitted to our institute and diagnosed with probable iNPH from January 2017 to March 2021. All patients underwent VP-shunt surgery with a programmable valve, and their outcomes were assessed via the Krauss index and modified Rankin scale (mRS) at 6 months and 2 years post-surgery. Univariate and multivariate regression analysis was performed to identify the prognostic factors.

Results: The mean age of the patients was 71.1 ± 8.4 (mean ± standard deviation) years. On the Krauss improvement index, 6-month follow-up results were available for 68 patients. Of these patients, 91.2% experienced attenuation of their preoperative symptoms, with a mean Krauss index of 0.58 ± 0.27, and 48 patients (70.6%) had a Krauss index ≥0.5. Two-year follow-up results were available for 33 patients; 90.9% of them had sustained improvement, with a Krauss index of 0.54 ± 0.31, and 21 patients (66.3%) had a Krauss index ≥0.5. Thirty-three patients (58%) were living independently after 2 years (mRS 0–2). The outcomes were worse for patients with multiple comorbidities. Neither an increased patient age nor a prolonged history of illness was statistically significant prognostic factors for adverse outcomes of VP-shunt surgery.

Conclusion: Surgical treatment was well-tolerated by patients with iNPH who received VP-shunts. Most patients experienced attenuation of their preoperative symptoms. Multiple concurrent comorbidities should be considered as adverse prognostic factors before shunt insertion in patients with iNPH.

Clinical comorbidities correlated with a response to the cerebrospinal fluid tap test in idiopathic normal-pressure hydrocephalus

AIMS

The mainstay of treatment for idiopathic normal-pressure hydrocephalus (iNPH) is spinal fluid shunting. A tap test (TT) is recommended as an indication of shunting. Patients with iNPH are often elderly and have multiple comorbidities affecting the shunting outcome. We investigated the factors affecting TT in patients with iNPH.

METHODS

Seventy-five patients with iNPH were admitted to our department for a TT from April 2010 to May 2021. The patients were divided into a responsive group and an unresponsive group according to the clinical outcomes after TT on the Timed Up and Go Test (TUG), Mini-Mental State Examination (MMSE), or iNPH grading scale. Factors affecting the TT were compared between the responders and nonresponders.

RESULTS

There were 38 patients (50.7%) in the TT responder group, and the prevalence of improvement was 82.9% in the TUG, 27.6% in the MMSE, and 76.3% in the iNPH grading scale. There were no significant differences in the vascular risk factors between the two groups. The prevalence of lumbar spondylosis, compression fracture, severe periventricular hyperintensity, deep and subcortical white matter hyperintensity (DSWMH), and old cerebral infarcts was significantly higher among the TT nonresponders. The logistic regression analysis showed that severe DSWMH and lumbar spondylosis were associated with a TT nonresponse (p < 0.001 and p = 0.003, respectively). Shunting was performed in 22 patients, 19 of whom were TT responders.

CONCLUSION

Severe DSWMH and lumbar spondylosis were associated with a poor response to the TT in iNPH patients. We should consider risk factors when selecting candidates for shunt surgery.

What Radiologists Should Know About Normal Pressure Hydrocephalus

BACKGROUND

 Normal pressure hydrocephalus is a disease in elderly patients and one of the most common causes of treatable dementia. It occurs frequently with microangiopathy and Alzheimer's disease, so that differential diagnosis plays an important role. This is crucially determined by imaging findings. Therapy consists of cerebrospinal fluid drainage through a shunt, which should be performed as early as possible to improve the chances of success.

METHOD

 This report is based on a summary of the relevant literature that has been reviewed in PubMed with reference to epidemiology, symptoms, pathophysiology, diagnostics, and therapy. The results were supplemented by the joint guidelines of the German Society of Neurology and the German Society of Neurosurgery.

RESULTS AND CONCLUSION

 The understanding of the pathophysiologic changes leading to normal pressure hydrocephalus has expanded significantly in recent years to include concepts explaining relevant comorbidities. Diagnosis is based on radiological and clinical indicators, although accurate differentiation with respect to comorbidities is not always possible. A high response rate to treatment can be achieved by good patient selection. Positive prognostic markers for therapeutic success include Disproportionately Enlarged Subarachnoid Space Hydrocephalus (DESH), short disease duration, predominant gait disturbance, and few comorbidities.

KEY POINTS

  · Normal pressure hydrocephalus mainly affects patients older than 65 years of age with high comorbidity rate for microangiopathy and Alzheimer's disease. · Radiologic findings play an important role in the diagnosis and follow-up after shunting. · The earlier a shunt is placed, the better the outcome.

CITATION FORMAT

· Illies T, Eckert B, Kehler U. What Radiologists Should Know About Normal Pressure Hydrocephalus. Fortschr Röntgenstr 2021; 193: 1197 - 1206.

Aquaporin-4 Mediates Permanent Brain Alterations in a Mouse Model of Hypoxia-Aged Hydrocephalus

Aquaporin-4 (AQP4) is the principal water channel in the brain being expressed in astrocytes and ependymal cells. AQP4 plays an important role in cerebrospinal fluid (CSF) homeostasis, and alterations in its expression have been associated with hydrocephalus. AQP4 contributes to the development of hydrocephalus by hypoxia in aged mice, reproducing such principal characteristics of the disease. Here, we explore whether these alterations associated with the hydrocephalic state are permanent or can be reverted by reexposure to normoxia. Alterations such as ventriculomegaly, elevated intracranial pressure, and cognitive deficits were reversed, whereas deficits in CSF outflow and ventricular distensibility were not recovered, remaining impaired even one month after reestablishment of normoxia. Interestingly, in AQP4^−/− mice, the impairment in CSF drainage and ventricular distensibility was completely reverted by re-normoxia, indicating that AQP4 has a structural role in the chronification of those alterations. Finally, we show that aged mice subjected to two hypoxic episodes experience permanent ventriculomegaly. These data reveal that repetitive hypoxic events in aged cerebral tissue promote the permanent alterations involved in hydrocephalic pathophysiology, which are dependent on AQP4 expression.

Incidental findings of typical iNPH imaging signs in asymptomatic subjects with subclinical cognitive decline

Background

The etiology of idiopathic normal pressure hydrocephalus (iNPH) remains unclear. Little is known about the pre-symptomatic stage. This study aimed to investigate the association of neuropsychological data with iNPH-characteristic imaging changes compared to normal imaging and unspecific atrophy in a healthy population.

Methods

We extracted data from the community-dwelling Austrian Stroke Prevention Family Study (ASPS-Fam) database (2006–2010). All subjects underwent a baseline and identical follow-up examination after 3–5 years with MR imaging and an extensive neuropsychological test battery (Trail Making Test B, short physical performance balance, walking speed, memory, visuo-practical skills, composite scores of executive function and g-factor). We categorized the subjects into “iNPH”-associated, non-specific “atrophy,” and “normal” based on the rating of different radiological cerebrospinal fluid (CSF) space parameters. We noted how the categories developed over time. We assessed the association of the image categories with the neuropsychological data, different demographic, and lifestyle parameters (age, sex, education, alcohol intake, arterial hypertension, hypercholesterolemia), and the extent of white matter hyperintensities. We investigated whether neuropsychological data associated with the image categories were independent from other parameters as confounders.

Results

One hundred and thirteen subjects, aged 50–70 years, were examined. The imaging category “iNPH” was only present at follow-up. A third of subjects with “atrophy” at baseline changed to the category “iNPH” at follow-up. More white matter hyperintensities (WMH) were present in later “iNPH” subjects. Subjects with “iNPH” performed worse than “normal” subjects on executive function (p = 0.0118), memory (p = 0.0109), and Trail Making Test B (TMT-B. p < 0.0001). Education, alcohol intake, diabetes, arterial hypertension, and hypercholesterolemia had no effect. Age, number of females, and the extent of white matter hyperintensities were higher in “iNPH” than in “normal” subjects but did not significantly confound the neuropsychological results.

Conclusions

Apparent asymptomatic subjects with “iNPH” imaging characteristics presented with subclinical cognitive decline and showed worse executive function, memory, and TMT-B results than “normal” subjects. WMH seem to play a role in the etiology before ventriculomegaly. Clinical screening of individuals with incidental iNPH-characteristic imaging and conspicuous results sof these neurocognitive tests needs further validation.

Novel Insight in Idiopathic Normal Pressure Hydrocephalus (iNPH) Biomarker Discovery in CSF

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurological disease, causing motor and cognitive dysfunction and dementia. iNPH and Alzheimer’s disease (AD) share similar molecular characteristics, including amyloid deposition, t-tau and p-tau dysregulation; however, the disease is under-diagnosed and under-treated. The aim was to identify a panel of sphingolipids and proteins in CSF to diagnose iNPH at onset compared to aged subjects with cognitive integrity (C) and AD patients by adopting multiple reaction monitoring mass spectrometry (MRM-MS) for sphingolipid quantitative assessment and advanced high-resolution liquid chromatography–tandem mass spectrometry (LC–MS/MS) for proteomic analysis. The results indicated that iNPH are characterized by an increase in very long chains Cer C22:0, Cer C24:0 and Cer C24:1 and of acute-phase proteins, immunoglobulins and complement component fragments. Proteins involved in synaptic signaling, axogenesis, including BACE1, APP, SEZ6L and SEZ6L2; secretory proteins (CHGA, SCG3 and VGF); glycosylation proteins (POMGNT1 and DAG1); and proteins involved in lipid metabolism (APOH and LCAT) were statistically lower in iNPH. In conclusion, at the disease onset, several factors contribute to maintaining cell homeostasis, and the protective role of very long chains sphingolipids counteract overexpression of amyloidogenic and neurotoxic proteins. Monitoring specific very long chain Cers will improve the early diagnosis and can promote patient follow-up.

Exploring mechanisms of ventricular enlargement in idiopathic normal pressure hydrocephalus: a role of cerebrospinal fluid dynamics and motile cilia

Idiopathic normal pressure hydrocephalus (iNPH) is considered an age-dependent chronic communicating hydrocephalus associated with cerebrospinal fluid (CSF) malabsorption; however, the aetiology of ventricular enlargement in iNPH has not yet been elucidated. There is accumulating evidence that support the hypothesis that various alterations in CSF dynamics contribute to ventricle dilatation in iNPH. This review focuses on CSF dynamics associated with ventriculomegaly and summarises the current literature based on three potential aetiology factors: genetic, environmental and hydrodynamic. The majority of gene mutations that cause communicating hydrocephalus were associated with an abnormal structure or dysfunction of motile cilia on the ventricular ependymal cells. Aging, alcohol consumption, sleep apnoea, diabetes and hypertension are candidates for the risk of developing iNPH, although there is no prospective cohort study to investigate the risk factors for iNPH. Alcohol intake may be associated with the dysfunction of ependymal cilia and sustained high CSF sugar concentration due to uncontrolled diabetes increases the fluid viscosity which in turn increases the shear stress on the ventricular wall surface. Sleep apnoea, diabetes and hypertension are known to be associated with the impairment of CSF and interstitial fluid exchange. Oscillatory shear stress to the ventricle wall surfaces is considerably increased by reciprocating bidirectional CSF movements in iNPH. Increased oscillatory shear stress impedes normal cilia beating, leading to motile cilia shedding from the ependymal cells. At the lack of ciliary protection, the ventricular wall is directly exposed to increased oscillatory shear stress. Additionally, increased oscillatory shear stress may be involved in activating the flow-mediated dilation signalling of the ventricular wall. In conclusion, as the CSF stroke volume at the cerebral aqueduct increases, the oscillatory shear stress increases, promoting motor cilia shedding and loss of ependymal cell coverage. These are considered to be the leading causes of ventricular enlargement in iNPH.

Early shunt surgery improves survival in idiopathic normal pressure hydrocephalus

BACKGROUND AND PURPOSE

To examine the effect of delayed compared to early planning of shunt surgery on survival, in patients with idiopathic normal pressure hydrocephalus (iNPH), a long-term follow-up case-control study of patients exposed to a severe delay of treatment was performed.

METHODS

In 2010-2011 our university hospital was affected by an administrative and economic failure that led to postponement of several elective neurosurgical procedures. This resulted in an unintentional delay of planning of treatment for a group of iNPH patients, referred to as iNPHDelayed (n = 33, waiting time for shunt surgery 6-24 months). These were compared to patients treated within 3 months, iNPHEarly (n = 69). Primary outcome was mortality. Dates and underlying causes of death were provided by the Cause of Death Registry. Survival was analysed by Kaplan-Meier plots and a Cox proportional hazard model adjusted for potential confounders.

RESULTS

Median follow-up time was 6.0 years. Crude 4-year mortality was 39.4% in iNPHDelayed compared to 10.1% in iNPHEarly (p = 0.001). The adjusted hazard ratio in iNPHDelayed was 2.57; 95% confidence interval 1.13-5.83, p = 0.024. Causes of death were equally distributed between the groups except for death due to malignancy which was not seen in iNPHDelayed  but in 4/16 cases in iNPHEarly (p = 0.044).

CONCLUSIONS

The present data indicate that shunt surgery is effective in iNPH and that early treatment increases survival.

Deficient visuomotor hand coordination in normal pressure hydrocephalus

Objective

To investigate if visuomotor coordination of hand movements is impaired in patients with normal pressure hydrocephalus (NPH) identified by dedicated testing procedures.

Methods

Forty-seven patients admitted for diagnostic workup for suspected NPH were studied prospectively with MRI, testing of cognitive and motor functions, lumbar puncture, and visuomotor coordination of hand movements using the PABLO^R-device before and after a spinal tap of 40–50 ml CSF. Statistical analyses were carried out with repeated measures ANOVA and non-parametric correlation analyses.

Results

Fourteen patients were found to suffer from ideopathic NPH. They were severely impaired in visuomotor control of intermittent arm movements in comparison to patients who were found not to be affected by NPH (n = 18). In the patients with NPH the deficient arm control was improved after the spinal tap in proportion to the improvement of gait. There was no improvement of cognitive and motor functions in the patients not affected by NPH, while the patients with possible NPH (n = 15) showed intermediate deficit and improvement patterns.

Interpretation: Our data underline the importance of a multiparametric assessment of NPH and provide evidence for a motor control deficit in idiopathic NPH involving leg and arm movements. It is suggested that this motor control deficit resulted from an affection of the output tracts from the supplementary motor area in the periventricular vicinity.

Risk factors, comorbidities, quality of life, and complications after surgery in idiopathic normal pressure hydrocephalus: review of the INPH-CRasH study

OBJECTIVE

Idiopathic normal pressure hydrocephalus (INPH) is a dementia treatable by insertion of a shunt that drains CSF. The cause of the disease is unknown, but a vascular pathway has been suggested. The INPH-CRasH (Comorbidities and Risk Factors Associated with Hydrocephalus) study was a modern epidemiological case-control study designed to prospectively assess parameters regarding comorbidities and vascular risk factors (VRFs) for INPH, quality of life (QOL), and adverse events in patients with shunted INPH. The objective of this review was to summarize the findings of the INPH-CRasH study.

METHODS

VRFs, comorbidities, QOL, and adverse events were analyzed in consecutive patients with INPH who underwent shunt placement between 2008 and 2010 in 5 of 6 neurosurgical centers in Sweden. Patients (n = 176, within the age span of 60–85 years and not having dementia) were compared to population-based age- and gender-matched controls (n = 368, same inclusion criteria as for the patients with INPH). Assessed parameters were as follows: hypertension; diabetes; obesity; hyperlipidemia; psychosocial factors (stress and depression); smoking status; alcohol intake; physical activity; dietary pattern; cerebrovascular, cardiovascular, or peripheral vascular disease; epilepsy; abdominal pain; headache; and clinical parameters before and after surgery. Parameters were assessed through questionnaires, clinical examinations, measurements, ECG studies, and blood samples.

RESULTS

Four VRFs were independently associated with INPH: hyperlipidemia, diabetes, obesity, and psychosocial factors. Physical inactivity and hypertension were also associated with INPH, although not independently from the other risk factors. The population attributable risk percent for a model containing all of the VRFs associated with INPH was 24%. Depression was overrepresented in patients with INPH treated with shunts compared to the controls (46% vs 13%, p < 0.001) and the main predictor for low QOL was a coexisting depression (p < 0.001). Shunting improved QOL on a long-term basis. Epilepsy, headache, and abdominal pain remained common for a mean follow-up time of 21 months in INPH patients who received shunts.

CONCLUSIONS

The results of the INPH-CRasH study are consistent with a vascular pathophysiological component of INPH. In clinical care and research, a complete risk factor analysis as well as screening for depression and a measurement for QOL should probably be included in the workup of patients with INPH. The effect of targeted interventions against modifiable VRFs and antidepressant treatment in INPH patients should be evaluated. Seizures, headache, and abdominal pain should be inquired about at postoperative follow-up examinations.

Treatment for secondary deterioration in idiopathic normal pressure hydrocephalus in the later course of the disease: a retrospective analysis

BACKGROUND

Cerebrospinal fluid (CSF) shunting is a highly effective treatment for idiopathic normal pressure hydrocephalus (iNPH). However, secondary deterioration can occur at a later time. Thus, the current study aimed to evaluate the incidence rate and causes of secondary deterioration.

METHODS

A retrospective analysis was conducted on all patients with iNPH who were treated with implantation of a CSF shunt since 1993. A meticulous shunt workup was recommended to all patients who presented to our department with secondary deterioration during their follow-up visits. Data about the proportion of patients with such deterioration and its causes, subsequent treatment, and clinical outcome were obtained.

RESULTS

A total of 169 patients were included, and the mean follow-up time was 69.2 months. In total, 119 (70.4%) patients presented with a total of 153 secondary deteriorations. In 9 cases (5.9%), the deterioration was caused by delayed subdural hematoma and in 27 (22.1%) cases, by shunt dysfunction. Invasive shunt testing was commonly required to validate shunt failure. Moreover, 19 of 27 patients experienced a satisfactory improvement after revision surgery. In total, 86 deteriorations were attributed to nonsurgical causes, and the valve pressure was decreased in 79 patients, with only 16.5% presenting with a satisfactory improvement after lowering of valve pressure.

CONCLUSIONS

Most patients with shunted iNPH presented with deterioration in the later course of the disease. Shunt dysfunction was considered a cause of secondary deterioration. Moreover, shunt revision surgery was a highly effective treatment, and patients with deterioration should undergo screening procedures for shunt dysfunction, including invasive shunt testing.

Gaps, Controversies, and Proposed Roadmap for Research in Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus is considered common but remains underinvestigated. There are no uniformly accepted diagnostic criteria and therapeutic guidelines. We summarize the accumulated evidence regarding the definition, pathophysiology, diagnosis, and treatment of idiopathic normal pressure hydrocephalus, highlighting the many gaps and controversies, including diagnostic challenges, the frequent association with neurodegeneration and vascular disease, and the many unknowns regarding patient selection and outcome predictors. A roadmap to fill these gaps and solve the controversies around this condition is also proposed. More evidence is required with respect to diagnostic criteria, the value of ancillary testing, prospective population-based studies and novel trial designs. Furthermore, a need exists to develop new advanced options in shunt technology. © 2020 International Parkinson and Movement Disorder Society.

Diabetes is associated with familial idiopathic normal pressure hydrocephalus: a case-control comparison with family members

BACKGROUND

The pathophysiological basis of idiopathic normal pressure hydrocephalus (iNPH) is still unclear. Previous studies have shown a familial aggregation and a potential heritability when it comes to iNPH. Our aim was to conduct a novel case-controlled comparison between familial iNPH (fNPH) patients and their elderly relatives, involving multiple different families.

METHODS

Questionnaires and phone interviews were used for collecting the data and categorising the iNPH patients into the familial (fNPH) and the sporadic groups. Identical questionnaires were sent to the relatives of the potential fNPH patients. Venous blood samples were collected for genetic studies. The disease histories of the probable fNPH patients (n = 60) were compared with their ≥ 60-year-old relatives with no iNPH (n = 49). A modified Charlson Comorbidity Index (CCI) was used to measure the overall disease burden. Fisher's exact test (two-tailed), the Mann-Whitney U test (two-tailed) and a multivariate binary logistic regression analysis were used to perform the statistical analyses.

RESULTS

Diabetes (32% vs. 14%, p = 0.043), arterial hypertension (65.0% vs. 43%, p = 0.033), cardiac insufficiency (16% vs. 2%, p = 0.020) and depressive symptoms (32% vs. 8%, p = 0.004) were overrepresented among the probable fNPH patients compared to their non-iNPH relatives. In the age-adjusted multivariate logistic regression analysis, diabetes remained independently associated with fNPH (OR = 3.8, 95% CI 1.1-12.9, p = 0.030).

CONCLUSIONS

Diabetes is associated with fNPH and a possible risk factor for fNPH. Diabetes could contribute to the pathogenesis of iNPH/fNPH, which motivates to further prospective and gene-environmental studies to decipher the disease modelling of iNPH/fNPH.

Normal Pressure Hydrocephalus Associated with Alzheimer's Disease

OBJECTIVE

The aim was to investigate whether neurodegenerative biomarkers in cerebrospinal fluid (CSF) differentiate patients with suspected normal pressure hydrocephalus (NPH) who respond to CSF drainage from patients who do not respond.

METHODS

Data from 62 consecutive patients who presented with magnetic resonance imaging changes indicative of NPH were studied with regard to cognitive and gait functions before and after drainage of 40-50ml of CSF. Additionally, S100 protein, neuron-specific enolase, β-amyloid protein, tau protein and phospho-tau were determined in CSF. Statistical analyses were carried out with ANOVA and multiple linear regression.

RESULTS

Patients with CSF constellations typical for Alzheimer's disease (n = 28) improved significantly in cognitive and gait-related functions after CSF drainage. In contrast, those patients without a CSF constellation typical for Alzheimer's disease (n = 34) did not improve in cognitive and gait-related functions after CSF drainage. In addition, positive CSF biomarkers for Alzheimer's disease predicted these improvements.

INTERPRETATION

Our data suggest an association between Alzheimer's disease and NPH changes, supporting the recently suggested dichotomy of a neurodegenerative NPH and a true idiopathic NPH, with the latter appearing to be rare. ANN NEUROL 2020;88:703-711.

Prevalence of possible idiopathic normal pressure hydrocephalus in older inpatients with schizophrenia: a replication study

BACKGROUND

We recently reported that older patients with schizophrenia (SZ) show possible idiopathic normal pressure hydrocephalus (iNPH) more frequently than the general population. In this study, we estimated the prevalence of iNPH in a larger number of older SZ patients and explored useful examination values for diagnosis in the SZ population.

METHODS

We enrolled older inpatients with SZ (n = 39, mean age = 68.6 ± 7.7 years) from several psychiatric hospitals in Ehime, Japan and acquired brain imaging data using computed tomography. We evaluated three iNPH symptoms (dementia, gait disturbance, and urinary incontinence). In addition, we combined these data with our previous data to elucidate the relationship between iNPH and characteristics of SZ symptoms.

RESULTS

In total, five (12.8%) patients were diagnosed with possible iNPH. Evans' index for patients with iNPH was significantly higher than for those without iNPH (p = 0.002). The number of disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings was significantly higher in patients with iNPH than in those without iNPH (p <  0.001). Using combined data, Drug-Induced Extra-pyramidal Symptoms Scale (DIEPSS) subscales of gait and bradykinesia showed an increasing trend in the SZ with iNPH group.

CONCLUSIONS

We reconfirmed that older inpatients with SZ experienced possible iNPH more frequently than the general population. We should pay attention to the DIEPSS subscales of gait and bradykinesia and DESH findings in addition to the three main symptoms of iNPH and Evans' index so as to not miss SZ patients with iNPH.

Role of psychiatric, cardiovascular, socioeconomic, and demographic risk factors on idiopathic normal pressure hydrocephalus: A retrospective case-control study

OBJECTIVES

Currently, predicting and preventing idiopathic normal pressure hydrocephalus (iNPH) remains challenging, especially for patients without a history of cerebrovascular disease. By exploring the role of cardiovascular and psychiatric history, demographics, and socioeconomic status in iNPH, will provide better direction for elucidating the etiology or addressing healthcare inequalities.

PATIENTS AND METHODS

To investigate iNPH with respect to the selected risk factors, we conducted a retrospective case-control study from a neuroscience institute in Hawaii with a patient pool of 25,843. After excluding patients with a history of cerebrovascular disease, we identified 29 cases which meet the American-European guidelines for iNPH diagnosis. Meanwhile, 116 controls matched to age, sex, and race were also randomly selected.

RESULTS

Median age at diagnosis was 83 (IQR: 74-88), with cases estimated 22 years older than controls (95 % CI: 14.00-29.00; p = 0.0000001). Patients with iNPH were more likely to be White (OR 4.01, 95 % CI: 1.59-10.11; p = 0.0042) and less likely Native Hawaiian and other Pacific Islander (OR 0.010, 95 % CI: 0.00-0.78; p = 0.014). Median household income was $2874 (95 % CI: 0.000089-6905; p = 0.088) greater amongst iNPH cases. Effect size amongst cardiovascular risk factors was not found statistically significant (i.e., body mass index, hyperlipidemia, type 2 diabetes mellitus, hypertension, coronary artery disease or prior myocardial infarction history, peripheral vascular disease, smoking status, congestive heart failure, atrial fibrillation/flutter, and history of prosthetic valve replacement). However, iNPH patients were more likely to have a history of alcohol use disorder (OR 8.29, 95 % CI: 0.99-453.87; p = 0.050) and history of a psychiatric disorder (OR 2.48; 95 % CI: 1.08-5.68; p = 0.029). Odds ratio for autoimmune disorder, thyroid disorder, glaucoma, and seizures did not reach statistical significance.

CONCLUSION

Patient race (i.e., White; Native Hawaiian or other Pacific Islander) was found associated with iNPH development. Meanwhile, after excluding those with cerebrovascular disease, cardiovascular risk factors were not found associated with iNPH. Lastly, iNPH cases were more inclined to have a history of alcohol use disorder and prior psychiatric disorder. Overall, this data reveals that a racial disparity exists amongst iNPH, as well as highlights the role of various cardiovascular and psychiatric risk factors, which can potentially provide direction in etiology elucidation.

Dopaminergic Degeneration and Small Vessel Disease in Patients with Normal Pressure Hydrocephalus Who Underwent Shunt Surgery

The diagnosis of idiopathic normal pressure hydrocephalus (iNPH) and the outcome of lumboperitoneal shunt treatment remains to be systematically explored. Here, we aim to evaluate whether the severity of dopaminergic degeneration and white matter small vessel disease could be predictors of outcome for iNPH patients subjected to lumboperitoneal shunt treatment. This is a single center retrospective study with 39 patients with probable iNPH undergoing programmable surgical lumboperitoneal shunt from June 2016 to March 2018 at Hualien Tzu Chi Hospital. In all patients, dopaminergic degeneration was determined with ^99mTc- TRODAT-1 SPECT scan, while white matter small vessel disease (Fazekas scale) was assessed with Brain MRI. The iNPH grading scale (iNPHGS) score and Karnofsky Performance Score (KPS) pre- and post-operation (6-month follow-up) were available for all patients. Linear regression was used to correlate the severities of dopaminergic degeneration and small vessel disease with lumboperitoneal shunt treatment outcomes. Their iNPHGS score improved significantly after surgery (pre-operatively, 7.8 ± 2.6; post-operatively, 5.7 ± 2.6 (26.9% improvement) (p < 0.05)). Moreover, the KPS was also improved significantly after surgery, by a mean of 24.6% from the baseline score (p < 0.05). A significant correlation was observed between the severity of dopaminergic degeneration and a poorer improvement of iNPHGS score (p = 0.03). However, improvement of the iNPHGS score was not correlated with white matter small vessel disease. Dopaminergic degeneration comorbidity neutralized the degree of improvement after surgery. Although white matter small vessel disease was correlated with iNPH incidence, it may not be a prognostic factor for shunt operation. These findings have implications for the use of dopaminergic imaging, as they might help predict the surgical outcome of patients with iNPH, while vascular mechanisms seem to be involved in iNPH pathophysiology.

Negative predictors of shunt surgery outcome in normal pressure hydrocephalus

OBJECTIVES

The prevalence of idiopathic normal pressure hydrocephalus (iNPH) and vascular comorbidity increases with age. It has not been clarified if high age and vascular disease are negative predictors of shunt surgery outcome in patients with iNPH. The aim of this study was to investigate the impact of high age and vascular comorbidity on outcome after shunt surgery in patients with iNPH.

METHODS

All 332 patients with iNPH who were treated with shunts between 2011 and 2015 at a single centre were consecutively included. Hellström iNPH scale, without the neuropsychological tests, was calculated preoperatively and at follow-up 12 months after shunt surgery. Outcome was defined as the difference between the post-operative and preoperative iNPH scale scores. A multivariable model was used to investigate the predictive effects of age and vascular comorbidity on shunt surgery outcome.

RESULTS

In a multivariable analysis of covariance (ANCOVA) with post-operative outcome as the dependent variable, increasing age (years, B = -0.63, P < .001) and history of ischaemic stroke (B = -10.06, P = .0038) were negative predictors of shunt surgery outcome after controlling for waiting time for surgery, symptom severity at preoperative control, presence of diabetes mellitus, hypertension, hyperlipidaemia, history of myocardial infarction, duration of symptoms and shunt complications.

CONCLUSIONS

High age and established cerebrovascular disease are associated with less favourable outcome after shunt surgery in patients with iNPH.