Lumboperitoneal shunt surgery for idiopathic normal pressure hydrocephalus (SINPHONI-2): an open-label randomised trial

Risk Variants Associated With Normal Pressure Hydrocephalus: Genome-Wide Association Study in the FinnGen Cohort

BACKGROUND AND OBJECTIVES

Large-scale genome-wide studies of chronic hydrocephalus have been lacking. We conducted a genome-wide association study (GWAS) in normal pressure hydrocephalus (NPH).

METHODS

We used a case-control study design implementing FinnGen data containing 473,691 Finns with genotypes and nationwide health records. Patients with NPH were selected based on ICD-10 G91.2 diagnosis. To select patients with idiopathic NPH (iNPH) for sensitivity analysis, we excluded patients with a potentially known etiology of the condition using an algorithm on their disease history. The controls were the remaining non-hydrocephalic participants. For a replication analysis, the NPH cohort from UK Biobank (UKBB) was used.

RESULTS

We included 1,522 patients with NPH (mean age 72.2 years, 53% women) and 451,091 controls (mean age 60.5 years, 44% women). In the GWAS comparing patients with NPH with the controls, we identified 6 gene regions significantly (p < 5.0e-8) associated with NPH that replicated in a meta-analysis with UKBB (NPH n = 173). The top loci near the following genes were rs7962263, SLCO1A2 (odds ratio [OR] 0.71, 95% CI 0.65-0.78, p = 1.0e-14); rs798495, AMZ1/GNA12 (OR 1.29, 95% CI 1.20-1.39, p = 2.9e-12); rs10828247, MLLT10 (OR 0.77, 95% CI 0.71-0.83, p = 1.5e-11); rs561699566 and rs371919113, CDCA2 (OR 0.76, 95% CI 0.70-0.82, p = 1.5e-11); rs56023709, C16orf95 (OR 1.24, 95% CI 1.16-1.33, p = 3.0e-9); and rs62434144, PLEKHG1 (OR 1.23, 95% CI 1.14-1.32, p = 1.4e-8). In the sensitivity analysis comparing only patients with iNPH (n = 1,055) with the controls (n = 451,091), 4 top loci near the following genes remained significant: rs7962263, SLCO1A2 (OR 0.70, 95% CI 0.63-0.78, p = 2.1e-11); rs10828247, MLLT10 (OR 0.74, 95% CI 0.62-0.82, p = 4.6e-10); rs798511, AMZ1/GNA12 (OR 1.28, 95% CI 1.17-1.39, p = 1.7e-8); and rs56023709, C16orf95 (OR 1.28, 95% CI 1.17-1.39, p = 1.7e-8).

DISCUSSION

We identified 6 loci significantly associated with NPH in the thus far largest GWAS in chronic hydrocephalus. The genes near the top loci have previously been associated with blood-brain barrier and blood-CSF barrier function and with increased lateral brain ventricle volume. The effect sizes and allele frequencies remained similar in NPH and iNPH cohorts, indicating the identified loci are risk determinants for iNPH and likely not explained by associations with other etiologies. However, the exact role of these loci is still unknown, warranting further studies.

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.

An Interdisciplinary Protocol for Ventriculoperitoneal Shunt Patient Selection in Normal Pressure Hydrocephalus

BACKGROUND

Normal pressure hydrocephalus can be treated with ventriculoperitoneal shunt (VPS) placement, but no broadly implemented indication for VPS exists.

METHODS

Our protocol consists of physical therapy and occupational therapy practitioners administering validated tests of gait, balance, and cognition before and after lumbar drain placement. Specific tests include: Timed "Up & Go", Tinetti Gait and Balance Assessment, Berg Balance Scale, Mini Mental Status Exam, Trail Making Test Part B, and the Rey Auditory and Visual Learning Test. Minimal clinically important difference values for each test were determined from literature review. A retrospective review of patients treated under this protocol was performed. The primary outcomes were candidacy for VPS based on the protocol and patient-reported symptomatic improvement after VPS placement.

RESULTS

A total of 48/75 (64%) patients received VPS. A total of 43/48 (89.6%) of those shunted reported improved symptoms at 6-week follow-up. However, 10/22 (45.5%) reported worsening symptoms at 1-year follow-up. The mean Tinetti score significantly increased after lumbar drain in patients who improved with VPS compared to the no shunt group (4.27 vs. -0.48, P < 0.001). A total of 6/33 (18%) patients with postoperative imaging had a subdural fluid collection identified and 3/49 (6%) had other complications, including 1 seizure, 1 intracerebral hemorrhage, and 1 stroke.

CONCLUSIONS

Standardized assessment of gait, balance, and cognition before and after temporary cerebrospinal fluid diversion identifies patients with normal pressure hydrocephalus likely to benefit from VPS placement with a low complication rate. One year after VPS, approximately one half of patients had symptoms recurrence.

Efficacy and safety of shunt surgery in patients with idiopathic normal-pressure hydrocephalus: can we predict shunt response by preoperative magnetic resonance imaging (MRI)?

AIM

The aim of this study was to identify preoperative magnetic resonance imaging (MRI) findings that can predict the shunt responsiveness in idiopathic normal-pressure hydrocephalus (iNPH) patients and to investigate postoperative outcome and complications.

MATERIALS AND METHODS

A total of 192 patients with iNPH who underwent shunt at our hospital between 2000 and 2021 were included to investigate complications. Of these, after exclusion, 127 (1-month postoperative follow-up) and 77 (1-year postoperative follow-up) patients were evaluated. The preoperative MRI features (the presence of tightness of the high-convexity subarachnoid space, Sylvian fissure enlargement, Evans' index, and callosal angle) of the shunt-response and nonresponse groups were compared, and a systematic review was conducted to evaluate whether preoperative MRI findings could predict shunt response.

RESULTS

Postoperative complications within one month after surgery were observed in 6.8% (13/192), and the most common complication was hemorrhage. Changes in corpus callosum were observed in 4.2% (8/192). The shunt-response rates were 83.5% (106/127) in the 1-month follow-up group and 70.1% (54/77) in 1-year follow-up group. In the logistic regression analysis, only Evans' index measuring >0.4 had a significant negative relationship with shunt response at 1-month follow-up; however, no significant relationship was observed at 1-year follow-up. According to our systematic review, it is still controversial whether preoperative MRI findings could predict shunt response.

CONCLUSION

Evans' index measure of >0.4 had a significant relationship with the shunt response in the 1-month follow-up group. In systematic reviews, there is ongoing debate about whether preoperative MRI findings can accurately predict responses to shunt surgery. Postoperative corpus callosal change was observed in 4.2% of iNPH patients.

Lumbar Lordosis is a Risk Factor for Lumbar Catheter Fracture of Lumboperitoneal Shunt

OBJECTIVE

This study aimed to investigate the causes of lumboperitoneal (LP) shunt failure and determine risk factors for lumbar catheter fracture.

METHODS

We retrospectively investigated 149 patients who underwent LP shunting in our hospital between January 2012 and March 2023. Shunt reconstruction occurred in 22 patients (14.8%). Among these, cause of failure was lumbar catheter fracture in 5 (22.7%). Patient backgrounds, cause of LP shunt failure, surgical technique factors, and anatomical characteristics were extracted for comparative analysis and risk factors of lumbar catheter fracture were analyzed.

RESULTS

Compared with the no reoperation group (n = 127), patients in the lumbar catheter fracture tended to be younger (63 ± 20 vs. 72 ± 11 years) and favorable neurologic status (modified Rankin scale score ≤2) after initial LP shunt; however, the differences were not significant. Lumbar lordosis was significantly higher in the lumbar catheter fracture group (52.7°± 14.8° vs. 37.1°± 12.3°; P = 0.0067).

CONCLUSIONS

Excessive lumbar lordosis is a risk factor for lumbar catheter fracture in patients undergoing LP shunting. Younger age and higher level of postoperative activities of daily living might also be associated with lumbar catheter fracture.

Improvement in gait velocity variability after cerebrospinal fluid elimination and its relationship to clinical symptoms in patients with idiopathic normal pressure hydrocephalus

AIM

This study aimed to investigate the improvement in gait velocity variability after cerebrospinal fluid (CSF) elimination, and the association between gait velocity variability and gait and cognitive impairment in patients with idiopathic normal pressure hydrocephalus.

METHODS

The gait velocity of 44 patients with idiopathic normal pressure hydrocephalus was measured using the Timed Up and Go Test (TUG) for a total of 10 times over 3 days each before and after CSF elimination. The coefficient of variation (CV) in the time required for the sequence of actions in TUG (TUG-CV) was calculated using 10 TUG data, and used for measuring intraindividual gait velocity variability. Gait quality was evaluated with the Gait Status Scale Revised (GSSR), and cognitive function was evaluated with the Mini-Mental State Examination and the Frontal Assessment Battery.

RESULTS

The TUG, TUG-CV, GSSR and Frontal Assessment Battery results improved significantly after CSF elimination. The analyses using pre-CSF elimination results showed that the TUG-CV significantly and positively correlated with the TUG and GSSR results, and negatively with Mini-Mental State Examination results, but not with age and the Frontal Assessment Battery results. The stepwise multiple regression analysis indicates that the TUG, GSSR and Mini-Mental State Examination results were significant predictors of the TUG-CV. The analysis using data of change after CSF elimination showed that ΔTUG and ΔGSSR were significant predictors of ΔTUG-CV.

CONCLUSIONS

Gait velocity variability improved after CSF elimination, and gait velocity variability was associated with gait disturbances and cognitive impairment in patients with idiopathic normal pressure hydrocephalus. Geriatr Gerontol Int 2024; 24: 693-699.

Idiopathic normal pressure hydrocephalus: Validation of the DESH score as a prognostic tool for shunt surgery response

OBJECTIVE

Several radiological markers have been linked to clinical improvement after shunt surgery for idiopathic normal pressure hydrocephalus (iNPH). However, iNPH has no pathognomonic feature, and patients are still diagnosed as probable, possible, or unlikely cases based on clinical symptoms, imaging findings, and invasive supplementary tests. The predictive value of the disproportionately enlarged subarachnoid space hydrocephalus (DESH) score is not yet conclusively determined, but it might offer a more accurate diagnostic method. The aim of the present retrospective cohort study was to validate the predictive power of the DESH score for clinical improvement after shunt surgery in iNPH patients.

METHODS

We retrospectively obtained presurgical MRI and/or CT scans from 71 patients with iNPH who underwent ventriculoperitoneal shunt surgery. Radiological images were evaluated for Evans index (EI), corpus callosal angle (CA), tight high convexity (THC), Sylvian fissure dilation, and focal sulci dilation. These markers were aggregated to determine the DESH score. Patient journal entries were used to subjectively determine the extent of improvement in gait function, urinary incontinence, and/or cognition as a measure of shunt surgery response.

RESULTS

Multiple logistic regression analysis, controlling for age and sex (α = 0.05), showed that DESH score was significantly correlated (OR 1.77) with subjective shunt-surgery response at a minimum of 1-month follow-up. Patients with higher DESH scores were more likely to have a favorable response to shunt surgery.

CONCLUSION

Aggregating radiological markers into the DESH score is useful for predicting shunt responders among iNPH patients and can aid the selection of patients for surgery. These findings provide further support for the DESH score as a diagnostic tool for iNPH.

Prediction of Surgical Outcomes in Normal Pressure Hydrocephalus by MR Elastography

BACKGROUND AND PURPOSE

Normal pressure hydrocephalus is a treatable cause of dementia associated with distinct mechanical property signatures in the brain as measured by MR elastography. In this study, we tested the hypothesis that specific anatomic features of normal pressure hydrocephalus are associated with unique mechanical property alterations. Then, we tested the hypothesis that summary measures of these mechanical signatures can be used to predict clinical outcomes.

MATERIALS AND METHODS

MR elastography and structural imaging were performed in 128 patients with suspected normal pressure hydrocephalus and 44 control participants. Patients were categorized into 4 subgroups based on their anatomic features. Surgery outcome was acquired for 68 patients. Voxelwise modeling was performed to detect regions with significantly different mechanical properties between each group. Mechanical signatures were summarized using pattern analysis and were used as features to train classification models and predict shunt outcomes for 2 sets of feature spaces: a limited 2D feature space that included the most common features found in normal pressure hydrocephalus and an expanded 20-dimensional (20D) feature space that included features from all 4 morphologic subgroups.

RESULTS

Both the 2D and 20D classifiers performed significantly better than chance for predicting clinical outcomes with estimated areas under the receiver operating characteristic curve of 0.66 and 0.77, respectively (P < .05, permutation test). The 20D classifier significantly improved the diagnostic OR and positive predictive value compared with the 2D classifier (P < .05, permutation test).

CONCLUSIONS

MR elastography provides further insight into mechanical alterations in the normal pressure hydrocephalus brain and is a promising, noninvasive method for predicting surgical outcomes in patients with normal pressure hydrocephalus.

Oblique Angled Retractor for Lumboperitoneal Shunt Implantation via Lateral Abdominal Laparotomy

BACKGROUND

 A normal retractor often interferes with the ribs and/or thighs of the ipsilateral side when the skin and abdominal muscles are towed while performing the lumboperitoneal shunt (LPS) procedure in the lateral position. To overcome this, we developed an obtuse-angled retractor.

METHODS

 We modified the traditional retractors into oblique-angled retractors. The blade of the new retractors was bent to 60 degrees, the entire blade was thinned, and the tip of the blade was tapered.

RESULTS

 To date, we have performed approximately 30 LPS procedures in the lateral position using the new oblique-angled retractor and confirmed its usefulness.

CONCLUSION

 An oblique-angled retractor helps confirm the accurate placement of the tip of the retractor blades, even in obese patients in whom the retractor often interferes with the ribs and/or thighs.

Utility of cortical tissue analysis in normal pressure hydrocephalus

Clinical improvement following neurosurgical cerebrospinal fluid shunting for presumed idiopathic normal pressure hydrocephalus is variable. Idiopathic normal pressure hydrocephalus patients may have undetected Alzheimer's disease-related cortical pathology that confounds diagnosis and clinical outcomes. In this study, we sought to determine the utility of cortical tissue immuno-analysis in predicting shunting outcomes in idiopathic normal pressure hydrocephalus patients. We performed a pooled analysis using a systematic review as well as analysis of a new, original patient cohort. Of the 2707 screened studies, 3 studies with a total of 229 idiopathic normal pressure hydrocephalus patients were selected for inclusion in this meta-analysis alongside our original cohort. Pooled statistics of shunting outcomes for the 229 idiopathic normal pressure hydrocephalus patients and our new cohort of 36 idiopathic normal pressure hydrocephalus patients revealed that patients with Aβ + pathology were significantly more likely to exhibit shunt nonresponsiveness than patients with negative pathology. Idiopathic normal pressure hydrocephalus patients with Alzheimer's disease -related cortical pathology may be at a higher risk of treatment facing unfavorable outcomes following cerebrospinal fluid shunting. Thus, cortical tissue analysis from living patients may be a useful diagnostic and prognostic adjunct for patients with presumed idiopathic normal pressure hydrocephalus and potentially other neurodegenerative conditions affecting the cerebral cortex.

Late intrathecal retraction of a lumboperitoneal shunt

Background

Lumboperitoneal (LP) shunt placement is a good option for treating elderly patients with communicating normal pressure hydrocephalus (NPH) who are also on antiplatelet therapy following endovascular treatment of unruptured bilateral internal carotid artery aneurysms. Here, in an 80-year-old male with an LP shunt, the catheter was "pinched" between adjacent spinous processes, resulting in laceration of the catheter and intrathecal catheter migration.

Case Description

An 80-year-old male was treated with a LP shunt for NPH 1 year after undergoing endovascular treatment of unruptured bilateral internal carotid artery aneurysms. The lumbar catheter was placed at the L2-3 level. Six months later, when he clinically deteriorated, the follow-up computed tomography showed recurrent ventricular enlargement. Further, studies additionally confirmed intrathecal migration of the lumbar catheter, warranting secondary ventriculoperitoneal shunt placement.

Conclusion

Patients with LP shunts may develop lumbar catheter lacerations secondary to a "pinching" effect from adjacent spinous processes, resulting in intrathecal catheter migration.

Predictive Ability of Frontal Assessment Battery for Cognitive Improvement After Shunt Surgery in Individuals With Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

The predictive ability of the Frontal Assessment Battery (FAB) for postoperative cognitive improvement in idiopathic normal pressure hydrocephalus (iNPH) is unstudied.

OBJECTIVE

To compare the predictive ability of the FAB and the Mini-Mental State Examination (MMSE) for postoperative cognitive improvement in individuals with iNPH after shunt surgery.

METHOD

We retrospectively reviewed the medical records of individuals with iNPH who had shunt surgery between January 2016 and October 2018. Individuals had completed the tap test and clinical evaluations (FAB, MMSE, Timed Up and Go [TUG]) both before and 24-48 hours after CSF tapping and after surgery. We excluded individuals without complete clinical evaluations and those with shunt surgery performed >6 months after CSF tapping. Factors associated with postoperative FAB and MMSE improvement as per the 2011 iNPH guidelines were extracted using univariate and multivariate logistic regression analyses. Independent variables were baseline FAB and MMSE scores, FAB and MMSE score changes and TUG amelioration rate after CSF tapping, Evans index, age, and days from CSF tapping to surgery and from surgery to postoperative assessment.

RESULTS

The mean number of days from CSF tapping to surgery and from surgery to postoperative assessment were 77.5 (SD = 36.0) and 42.0 (SD = 14.5), respectively. Logistic regression analyses showed significant associations in the univariate analyses of postoperative FAB improvement with baseline FAB scores ( P = 0.043) and with FAB score changes after CSF tapping ( P = 0.047).

CONCLUSION

The FAB may help predict postoperative cognitive improvement after shunt surgery better than the MMSE.

Brain blood flow pulse analysis may help to recognize individuals who suffer from hydrocephalus

BACKGROUND

Normal pressure hydrocephalus (NPH) is often associated with altered cerebral blood flow. Recent research with the use of the ultrasonic method suggests specific changes in the shape of cardiac-related cerebral arterial blood volume (CaBV) pulses in NPH patients. Our study aims to provide a quantitative analysis of the shape of CaBV pulses, estimated based on transcranial Doppler ultrasonography (TCD) in NPH patients and healthy individuals.

METHODS

The CaBV pulses were estimated using TCD cerebral blood flow velocity signals recorded from probable NPH adults and age-matched healthy individuals at rest. The shape of the CaBV pulses was compared to a triangular shape with 27 similarity parameters calculated for every reliable CaBV pulse and compared between patients and volunteers. The diagnostic accuracy of the most prominent parameter for NPH classification was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

The similarity parameters were calculated for 31 probable NPH patients (age: 59 years (IQR: 47, 67 years), 14 females) and 23 healthy volunteers (age: 54 years (IQR: 43, 61 years), 18 females). Eighteen of 27 parameters were different between healthy individuals and NPH patients (p < 0.05). The most prominent differences were found for the ascending slope of the CaBV pulse with the AUC equal to 0.87 (95% confidence interval: 0.77, 0.97, p < 0.001).

CONCLUSIONS

The findings suggest that in NPH, the ascending slope of the CaBV pulse had a slower rise, was more like a straight line, and generally was less convex than in volunteers. Prospective research is required to verify the clinical utility of these findings.

Rare complication of lumboperitoneal shunt with distal catheter migration into the inguinal hernia sac in two adults: A case report

Background

Despite the proven benefits of lumboperitoneal shunt (LPS) for idiopathic normal-pressure hydrocephalus, complications such as catheter migration remain a problem. Inguinal complications of the distal catheter are rare in adults, and their management is uncertain. Herein, we present two cases of distal catheter migration into the inguinal hernia sac after LPS in adults and recommend their management.

Case Description

An 86-year-old man presented with inguinal swelling. In another 82-year-old man who did not show any improvement after LPS, shunt angiography revealed LPS dysfunction due to lumbar catheter occlusion and distal LPS catheter in the right inguinal hernia sac, and lumbar catheter reconstruction was performed. Both patients did not have any symptoms, except inguinal swelling, and were followed up. After 2 weeks and 4 days, the distal catheter moved into the peritoneal cavity.

Conclusion

Inguinal complications due to the migration of the distal catheter into the inguinal hernia sac are rare in LPS because frequent movements of the distal catheter due to trunk rotation dislodge it from the inguinal hernia sac for a short period. Urgent surgery was not recommended because the catheter was moved in a short period and the patients did not wish to undergo hernia repair.

Health-Related Quality of Life and Role of Surgical Treatment in Idiopathic Normal Pressure Hydrocephalus: A Systematic Review

OBJECTIVE

Although shunting has been shown to ameliorate symptoms in idiopathic normal pressure hydrocephalus (iNPH), its impact on health-related quality of life (HRQoL) has yet to be fully elucidated. Patient and caregiver subjective life satisfaction and HRQoL represent crucial indicators for assessing the well-being of individuals facing chronic illnesses, including iNPH. This study aimed to systematically analyze the existing data about HRQoL in iNPH-treated patients to evaluate the role of surgical treatment in such a scenario.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the literature in the PubMed/Medline, Web of Science, and Scopus databases was searched. Fourteen studies met our inclusion criteria. The Joanna Briggs Institute critical appraisal tool was used to assess the risk of bias.

RESULTS

Overall, HRQoL improved significantly within 1 year after shunt placement although patients with iNPH reported worse HRQoL values compared with healthy-matched individuals. Up to 5 years after shunting, a sustained heterogeneity exists on published data showing improved scores across all domains for at least 21 months after shunting. Further, although surgical treatment can improve HRQoL, long-term follow-up showed that it remained lower than that of healthy controls. These data suggest a significant decrease of HRQoL in patients with iNPH over time after shunting, probably due to aging, comorbidities, and disease progression.

CONCLUSIONS

Despite that iNPH has been recognized as a potentially reversible neurological disorder, the available data about the impact of shunting on the HRQoL are unsatisfactory. To improve the well-informed clinical decision-making, it is essential to reach additional high-quality evidence regarding the effect of shunting on HRQoL. New prospective studies, using validated instruments specifically tailored for assessing HRQoL in patients with iNPH, and improved reporting standards are needed. Current evidence suggests that although shunting can provide initial benefits, affected patients may experience long-term impairment in HRQoL.

Association of gait and cognition after surgery in patients with idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a treatable disease in older adults. The association between gait and cognition has recently become a topic of interest. Sequential changes in this association were investigated in patients with iNPH using a newly developed statistical method. Data were extracted from the SINPHONI-2 multicenter study on iNPH. Fifty patients who underwent shunt surgery were included in this study. Gait and cognition were assessed using the Timed Up and Go (TUG) and Mini-Mental State Examination (MMSE) tests. In addition to the MMSE total score, changes in the sub-item scores were examined. The ordinal sub-items of the MMSE are usually treated as continuous or categorical; however, both are unsuitable. An ordinal smoothing penalty with a generalized additive model enables precise statistical inference of ordinal and binary predictors. The TUG time improved significantly at 3, 6, and 12 months after surgery. The MMSE total scores increased without statistical significance. Preoperatively, there was no association between TUG time and MMSE sub-items. At 3 months, the "Registration," "3-step command," "Read," and "Copy" sub-items were statistically significant. The number of significant sub-items increased after 12 months. Thus, the association between gait and cognition gradually increased after surgery in patients with iNPH.

Predictive value of spinal CSF volume in the preoperative assessment of patients with idiopathic normal-pressure hydrocephalus

Introduction

The pathophysiology, diagnosis, and management of idiopathic normal pressure hydrocephalus (iNPH) remain unclear. Although some prognostic tests recommended in iNPH guidelines should have high sensitivity and high predictive value, there is often no positive clinical response to surgical treatment.

Materials and methods

In our study, 19 patients with clinical and neuroradiological signs of iNPH were selected for preoperative evaluation and possible further surgical treatment according to the guidelines. MR volumetry of the intracranial and spinal space was performed. Patients were exposed to prolonged external lumbar drainage in excess of 10 ml per hour during 3 days. Clinical response to lumbar drainage was assessed by a walk test and a mini-mental test.

Results

Twelve of 19 patients showed a positive clinical response and underwent a shunting procedure. Volumetric values of intracranial space content in responders and non-responders showed no statistically significant difference. Total CSF volume (sum of cranial and spinal CSF volumes) was higher than previously published. No correlation was found between spinal canal length, CSF pressure, and CSF spinal volume. The results show that there is a significantly higher CSF volume in the spinal space in the responder group (n = 12) (120.5 ± 14.9 ml) compared with the non-responder group (103.1 ± 27.4 ml; n = 7).

Discussion

This study demonstrates for the first time that CSF volume in the spinal space may have predictive value in the preoperative assessment of iNPH patients. The results suggest that patients with increased spinal CSF volume have decreased compliance. Additional prospective randomized clinical trials are needed to confirm our results.

High prevalence of lumbar spinal stenosis in cases of idiopathic normal-pressure hydrocephalus affects improvements in gait disturbance after shunt operation

Objective

Idiopathic normal-pressure hydrocephalus (iNPH) is characterized by symptoms of dementia, urinary incontinence, and gait disturbance; however, gait disturbance tends to persist after shunt surgery. Gait disturbance and urinary dysfunction are also major symptoms of lumbar spinal stenosis (LSS). Currently, the epidemiology of the complications of LSS in iNPH is unclear. Here, we evaluated the coexistence rate of LSS in iNPH cases.

Methods

This was a retrospective case-control study. Between 2011 and 2017, 224 patients with a median age of 78 years, including 119 males, were diagnosed with iNPH and underwent lumboperitoneal shunts or ventriculoperitoneal shunts. LSS was diagnosed with magnetic resonance imaging by two spine surgeons. Age, sex, body mass index (BMI), Timed Up and Go (TUG) test, Mini Mental State Examination (MMSE) score, and urinary dysfunction were examined. We compared the changes in these variables in the group of patients with iNPH without LSS versus those with both iNPH and LSS.

Results

Seventy-three iNPH patients (32.6%) with LSS had significantly higher age and BMI. The existence of LSS did not alter the postoperative improvement rates of MMSE and urinary dysfunction; however, TUG improvement was significantly impaired in the LSS-positive group.

Conclusions

LSS affects improvements in gait disturbance of iNPH patients after shunt operation. Because our results revealed that one-third of iNPH patients were associated with LSS, gait disturbance observed in iNPH patients should be considered a potential complication of LSS.

Age-Related Changes in Cerebrospinal Fluid Dynamics in the Pathogenesis of Chronic Hydrocephalus in Adults

Cerebrospinal fluid (CSF) dynamics has dramatically changed in this century. In the latest concept of CSF dynamics, CSF is thought to be produced mainly from interstitial fluid excreted from the brain parenchyma and is absorbed in the meningeal lymphatics. Moreover, CSF does not always flow from the ventricles to the subarachnoid space unidirectionally through the foramina of Magendie and Luschka. In an environment of increased intracranial CSF in idiopathic normal pressure hydrocephalus, CSF freely moves through the inferior choroidal point of the choroidal fissure, which interfaces between the inferior horn of the lateral ventricles and the ambient cistern and through the velum interpositum between the third ventricle and the quadrigeminal cistern. The structure of the hippocampus adjacent to the inferior part of the choroidal fissure may be important in preventing the accumulation of waste products in the hippocampus. A recent imaging technology for CSF dynamics, such as four-dimensional flow and intravoxel incoherent motion magnetic resonance imaging, can visualize and quantify the pulsatile complex CSF motion in clinical usage. We present the current concepts of CSF dynamics with advanced magnetic resonance imaging techniques, which will be helpful in the management and understanding of the pathogenesis of chronic hydrocephalus in adults.

Lumboperitoneal Shunt Surgery under Spinal Anesthesia on Idiopathic Normal Pressure Hydrocephalus Patients

Since the publication of guidelines for managing idiopathic normal pressure hydrocephalus (iNPH) in 2004, an increasing number of patients with iNPH have been undergoing shunt surgery in Japan. However, shunt surgeries for iNPH can be challenging because the procedures are performed on elderly patients. General anesthesia-related risks, such as postoperative pneumonia or delirium, are higher in the elderly. To decrease these risks, we applied spinal anesthesia on a lumboperitoneal shunt (LPS). Herein, we analyzed our methods focusing on the postoperative outcomes. We retrospectively analyzed 79 patients who underwent LPS at our institution with more than one year of follow-up. The patients were divided into two groups based on the anesthetic approach, that is, 1) general anesthesia and 2) spinal anesthesia, and were examined in terms of postoperative complications, delirium, and postoperative hospital stay. In the general anesthesia group, two patients had respiratory complications after the surgery. The postoperative delirium score using the intensive care delirium screening checklist (ICDSC) was 0 (2) (median [interquartile range]), and the length of postoperative hospital stay was 11 (4) days. In the spinal anesthesia group, no patients had respiratory complications. The postoperative mean ICDSC was 0 (1), and the length of postoperative hospital stay was 10 (3) days. Although there was no significant difference regarding postoperative delirium existed, LPS under spinal anesthesia decreased respiratory complications and significantly shortened the postoperative hospital stay. LPS under spinal anesthesia could be an alternative to general anesthesia in elderly patients with iNPH and possibly lessen the general anesthesia-related risks.

Treatment of Idiopathic Normal Pressure Hydrocephalus with a Novel Programmable Valve: Prospective Evaluation of Costs, Efficacy, and Safety

Objective  Programmable valves provide an equal or superior neurological outcome when compared with fixed pressure ones, with fewer complications, in treating idiopathic normal pressure hydrocephalus (iNPH) patients. Long-term costs of these treatments have not been properly compared in literature. We sought to compare costs, efficacy, and safety of 1-year treatment of iNPH patients with programmable valve Sphera Pro and a fixed pressure valve. Materials and Methods  A prospective cohort of iNPH patients treated with programmable valve was compared with a historical cohort of iNPH patients treated with fixed pressure valve. Our primary outcome was mean direct cost of treating iNPH up to 1 year. Efficacy in treating iNPH and safety were assessed as secondary outcomes. Statistical Analysis  Proportions were compared using chi-square or Fisher's exact tests. Normally distributed variables were compared using the Student's t -test or the Mann-Whitney's U test. Differences in the evolution of the variables over time were assessed using generalized estimating equations. All tests were two-sided, with an α of 0.05. Results  A total of 19 patients were analyzed in each group (mean age 75 years, the majority male). Comorbidities and clinical presentation were similar between groups. Both fixed pressure and programmable valve patients had neurological improvement over time ( p  < 0.001), but no difference was seen between groups ( p  = 0.104). The fixed pressure valve group had more complications than the programmable valve group (52.6% vs. 10.5%, respectively, p  = 0.013). Annual treatment cost per patient was US$ 3,820 ± 2,231 in the fixed pressure valve group and US$ 3,108 ± 553 in the programmable valve group. Mean difference was US$712 (95% confidence interval, 393-1,805) in favor of the programmable valve group. Conclusion  The Sphera Pro valve with gravitational unit had 1 year treatment cost not higher than that of fixed pressure valve, and resulted in similar efficacy and fewer complications.

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.

Plasma and cerebrospinal fluid concentrations of neurofilament light protein correlate in patients with idiopathic normal pressure hydrocephalus

BACKGROUND

Neurofilament light chain protein (NFL), a marker of neuronal axonal degeneration, is increased in cerebrospinal fluid (CSF) of patients with idiopathic normal pressure hydrocephalus (iNPH). Assays for analysis of NFL in plasma are now widely available but plasma NFL has not been reported in iNPH patients. Our aim was to examine plasma NFL in iNPH patients and to evaluate the correlation between plasma and CSF levels, and whether NFL levels are associated with clinical symptoms and outcome after shunt surgery.

METHODS

Fifty iNPH patients with median age 73 who had their symptoms assessed with the iNPH scale and plasma and CSF NFL sampled pre- and median 9 months post-operatively. CSF plasma was compared with 50 healthy controls (HC) matched for age and gender. Concentrations of NFL were determined in plasma using an in-house Simoa method and in CSF using a commercially available ELISA method.

RESULTS

Plasma NFL was elevated in patients with iNPH compared to HC (iNPH: 45 (30-64) pg/mL; HC: 33 (26-50) (median; Q1-Q3), p = 0.029). Plasma and CSF NFL concentrations correlated in iNPH patients both pre- and postoperatively (r = 0.67 and 0.72, p < 0.001). We found only weak correlations between plasma or CSF NFL and clinical symptoms and no associations with outcome. A postoperative NFL increase was seen in CSF but not in plasma.

CONCLUSIONS

Plasma NFL is increased in iNPH patients and concentrations correlate with CSF NFL implying that plasma NFL can be used to assess evidence of axonal degeneration in iNPH. This finding opens a window for plasma samples to be used in future studies of other biomarkers in iNPH. NFL is probably not a very useful marker of symptomatology or for prediction of outcome in iNPH.

Current research of idiopathic normal pressure hydrocephalus: Pathogenesis, diagnosis and treatment

Idiopathic normal pressure hydrocephalus (iNPH) is caused by impaired cerebrospinal fluid absorption in the elderly; it is a surgically treatable form of dementia. Gait disturbance, dementia, and urinary incontinence are the triad of signs for iNPH. In addition to these clinical findings, imaging studies show characteristic ventricular enlargement. High Evans Index and ‘disproportionately enlarged subarachnoid hydrocephalus’ are other well-known imaging findings of iNPH. If the tap test shows improved symptoms, shunt surgery is performed. The disease was first described by Hakim and Adams in 1965, followed by the publication of the first, second, and third editions of the guidelines in 2004, 2012, and 2020, respectively. Recent studies signal the glymphatic system and classical cerebrospinal fluid (CSF) absorption from the dural lymphatics as aetiological mechanisms of CSF retention. Research is also underway on imaging test and biomarker developments for more precise diagnosis, shunting technique options with fewer sequelae and complications, and the influence of genetics. Particularly, the newly introduced ‘suspected iNPH’ in the third edition of the guidelines may be useful for earlier diagnosis. However, less well-studied areas remain, such as pharmacotherapy in non-operative indications and neurological findings other than the triadic signs. This review briefly presents previous research on these and future issues.

Novel cerebrospinal fluid biomarkers correlating with shunt responsiveness in patients with idiopathic normal pressure hydrocephalus

BACKGROUND

Idiopathic Normal pressure hydrocephalus (iNPH) is a form of adult hydrocephalus that is clinically characterized by progressive gait impairment, cognitive dysfunction, and urinary incontinence. The current standard method of treatment involves surgical installation of a CSF diversion shunt. However, only a fraction of patients shows an alleviation of symptoms from shunt surgery. Thus, the purpose of this prospective explorative proteomic study was to identify prognostic CSF biomarkers to predict shunt responsiveness in iNPH patients. Further, we evaluated the ability of the core Alzheimer's disease (AD) CSF biomarkers phosphorylated (p)-tau, total (t)-tau, and amyloid-β 1-42 (Aβ1-42) to serve as predictors of shunt response.

METHODS

We conducted a tandem mass tag (TMT) proteomic analysis of lumbar CSF from 68 iNPH patients, sampled pre-shunt surgery. Tryptic digests of CSF samples were labelled with TMTpro reagents. The TMT multiplex samples were fractionated in 24 concatenated fractions by reversed-phase chromatography at basic pH and analysed by liquid chromatography coupled to mass spectrometry (LC-MS) on an Orbitrap Lumos mass spectrometer. The relative abundances of the identified proteins were correlated with (i) iNPH grading scale (iNPHGS) and (ii) gait speed change 1 year after surgery from baseline to identify predictors of shunt responsiveness.

RESULTS

We identified four CSF biomarker candidates which correlated most strongly with clinical improvement on the iNPHGS and were significantly changed in shunt-responsive compared to shunt-unresponsive iNPH patients 1 year post-surgery: FABP3 (R = - 0.46, log2(fold change (FC)) = - 0.25, p < 0.001), ANXA4 (R = 0.46, log2(FC) = 0.32, p < 0.001), MIF (R = -0.49, log2(FC) =  - 0.20, p < 0.001) and B3GAT2 (R = 0.54, log2(FC) = 0.20, p < 0.001). In addition, five biomarker candidates were selected based on their strong correlation with gait speed change 1 year after shunt installation: ITGB1 (R = - 0.48, p < 0.001), YWHAG (R = - 0.41, p < 0.01), OLFM2 (R = 0.39, p < 0.01), TGFBI (R = - 0.38, p < 0.01), and DSG2 (R = 0.37, p < 0.01). Concentrations of the CSF AD core biomarkers did not differ significantly with shunt responsiveness.

CONCLUSION

FABP3, MIF, ANXA4, B3GAT2, ITGB1, YWHAG, OLFM2, TGFBI and DSG2 in CSF are promising prognostic biomarker candidates to predict shunt responsiveness in iNPH patients.

Refractory Delayed Pneumocephalus after Transsphenoidal Cyst Drainage for Rathke's Cleft Cyst in a Patient with a Cerebrospinal Fluid Shunt

A 75-year-old man presented with bilateral lower limb weakness to our hospital from another clinic. Radiological examinations implied the possibilities of idiopathic normal pressure hydrocephalus (iNPH) and a suprasellar cyst, but both were observed conservatively at that time. Due to the progressive gait disturbance, a lumboperitoneal shunt was implanted 1 year later. The clinical symptoms improved, but the cyst had grown after another year, causing visual impairment. Transsphenoidal drainage of the cyst was performed, but delayed pneumocephalus occurred. Repair surgery was performed with temporary suspension of shunt function, but pneumocephalus relapsed two and a half months after the resumption of shunt flow. In the second repair surgery, the shunt was removed because it was assumed that it would prevent closure of the fistula by lowering intracranial pressure. Two and a half months later, after confirming involution of the cyst and no pneumocephalus, a ventriculoperitoneal shunt was implanted, and cerebrospinal fluid (CSF) leakage has not relapsed since then. The coexistence of idiopathic normal pressure hydrocephalus (iNPH) and Rathke's cleft cyst (RCC) is rare, but it can occur. RCC can be cured by simple drainage, but delayed pneumocephalus can occur in cases whose intracranial pressure decreases due to CSF shunting. When simple drainage without sellar reconstruction for RCC is attempted after CSF shunting for coexistent iNPH, attention should be paid to changes in intracranial pressure, and it is desirable to stop the flow of the shunt for a certain period.

Normal Pressure Hydrocephalus Following Cranial Radiation: Identification of Shunting Responders

BACKGROUND

We examined cognitive, brain MRI, and lumbar infusion test (LIT) features to identify predictors of response to ventriculoperitoneal shunting (VPS) in long-term cancer survivors with suspected normal pressure hydrocephalus (NPH) following cranial radiotherapy (RT).

METHODS

Patients who completed cranial RT at least 2 years before with clinically suspected NPH and an Evans' index (EI) ≥ 0.30 underwent a cognitive and a cerebrospinal fluid (CSF) volumetric (MRI) analysis (n = 36). For those in whom VPS was placed (n = 14), we explored whether adding a CSF volumetric analysis to classical MRI and LIT (Tap Test) features would better identify VPS responders.

RESULTS

Nearly 80% exhibited cognitive impairment. The CSF volume at NPH diagnoses was significantly larger in the group of VPS responders (p = 0.04). The addition of CSF volume to NPH diagnoses increased accuracy to 93%, with a positive and negative predictive value of 91% and 100%, respectively.

CONCLUSION

The addition of a quantitative MRI analysis of CSF volume to classical MRI and LIT NPH criteria, along with a high clinical suspicion of NPH, may help to identify VPS responders, thus improving the clinical management and prognosis of long-term survivors.

Idiopathic normal pressure hydrocephalus: historical context and a contemporary guide

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

Effectiveness and safety of ventriculoperitoneal shunt versus lumboperitoneal shunt for communicating hydrocephalus: A systematic review and meta-analysis with trial sequential analysis

INTRODUCTION

The current standard surgical treatment for cerebrospinal fluid diversion is a ventriculoperitoneal shunt (VPS) implantation. Lumboperitoneal shunts (LPS) are an alternative treatment for communicating hydrocephalus. Prior studies comparing these two included a limited number of participants.

METHODS

We performed a meta-analysis determined the treatment failure, complications and effectiveness of lumboperitoneal shunt for communicating hydrocephalus. We reviewed studies with clinical and imaging diagnoses of communicating hydrocephalus, all causes and subtypes of communicating hydrocephalus, and studies that analyzed the primary and secondary outcomes listed below. We included randomized controlled trials (RCTs), non-RCTs and retrospective studies. We performed the meta-analysis in R, using a random-effects model and reporting 95% confidence intervals.

RESULTS

Data from 25 studies, including 3654 patients, were analyzed. The total complication rates were 12.98% (188/1448) for lumboperitoneal shunt and 23.80% (398/1672) for ventriculoperitoneal shunt. The odds ratio for lumboperitoneal shunt versus ventriculoperitoneal shunt complication rates was 0.29 (95% CI 0.19 to 0.45, p < 0.0001), and the I² was 72%. The shunt obstruction/malfunction rate was 3.99% (48/1204) for lumboperitoneal shunt and 8.31% (115/1384) for ventriculoperitoneal shunt (Odds ratio 0.54, 95% CI 0.37 to 0.79, p = 0.002, I²  = 0%). Based on the Modified Rankin Scale score, there were no differences in effectiveness between lumboperitoneal shunt and ventriculoperitoneal shunt. Nevertheless, lumboperitoneal shunt improved radiological outcomes.

CONCLUSIONS

This analysis demonstrated that lumboperitoneal shunt is a safe and equally effective choice for treating communicating hydrocephalus. More studies are needed to confirm the safety of lumboperitoneal shunt.

Thecoperitoneal Shunts—Our 20 Years Experience

Introduction The thecoperitoneal shunt is a modality of cerebrospinal fluid (CSF) diversion used to treat various clinical conditions such as idiopathic intracranial hypertension (IIH), normal pressure hydrocephalus (NPH), and CSF leaks. There is a wide variability in the data regarding the utility and complications associated with it. We thus reviewed the outcomes and complications of the shunt done in our setting.

Methodology The study is a retrospective review of all the thecoperitoneal shunts performed at NIMHANS (National Institute of Mental Health and Neurosciences) from January 2000 to December 2020. The demographic details, clinical profile, indications for the shunt, magnetic resonance imaging, follow-up and complications, and shunt revisions were collected and analyzed.

Results Three-hundred twelve patients underwent shunt primarily at our institute. The mean follow-up of the patients was 5.2 years. The indications include pseudomeningocele in 31.4%, CSF leak from surgical site in 25.3%, IIH in 17.6%, and NPH in 7.3% patients.

The shunt was more effective in pseudomeningocele in up to 95% and CSF leaks in 91% compared to 64‰ in IIH, though it is not significant (p > 0.05). The complication rate was 17% that included shunt block, wound CSF leak, infection, and subdural hygromas. The shunt malfunction was seen in 14.69% patients who underwent revision.

Conclusion Thecoperitoneal shunt is a useful treatment option for various pathologies including IIH, NPH, and wound CSF leaks. They have good clinical outcomes and acceptable revision rates especially in conditions with slit ventricle. The complications such as low-pressure headache can be overcome by using adjuncts as programmable valve or antisiphon device.

Clinical Outcome and Safety of Lumboperitoneal Shunt in the Treatment of Non-Obstructive Hydrocephalus

Objective

This study aimed to evaluate the functional outcomes of lumboperitoneal (LP) shunt for the treatment of non-obstructive hydrocephalus.

Methods

We retrospectively studied the clinical surgical results of 172 adult patients with hydrocephalus who underwent LP shunt surgery between June 2014 and June 2019. Data regarding the following were collected: pre- and postoperative symptom status, third ventricle width changes, Evans index, and postoperative complications. Additionally, the baseline and follow-up Glasgow Coma Scale (GCS) score, Glasgow Outcome Scale (GOS), and Modified Rankin Scale (mRS) scores were investigated. All patients were followed up for ≥12 months using clinical interview and braining imaging using computed tomography (CT) scan or magnetic resonance imaging (MRI).

Results

Majority of patients presented with normal pressure hydrocephalus as the etiology of their disease (48.8%), followed by cardiovascular accident (28.5%), trauma (19.7%), and brain tumor (3%). The mean GCS, GOS, and mRS improved postoperatively. The average period from symptomatic onset to surgery was 402 days. The average width of the third ventricle on CT scan or MRI was 11.43 mm preoperatively and 10.8 mm postoperatively (P<0.001). The Evans index improved from 0.258 to 0.222 after operation. The symptomatic improvement score was 7.0, with a complication rate of 7%.

Conclusion

Significant improvement was observed in the functional score and brain image after LP shunt placement. Moreover, the satisfaction with symptomatic improvement after surgery remains high. LP shunt operation is a viable alternative in the treatment of non-obstructive hydrocephalus due to the low complication rate, fast recovery, and high satisfaction.

Rehabilitation effects in idiopathic normal pressure hydrocephalus: a randomized controlled trial

BACKGROUND

Gait-balance disturbances are core symptoms of idiopathic normal pressure hydrocephalus (iNPH). However, the rehabilitation effects of cerebrospinal fluid (CSF) shunting along with other treatment or no further treatment (natural course [NC]) for iNPH are unknown.

OBJECTIVES

This study evaluated whether dynamic equilibrium gait training (DEGT) can improve gait-balance functions after CSF shunting of patients with iNPH compared to standard exercise (SE) and NC. Furthermore, it investigated the incidence of falls.

METHODS

A total of 70 patients with iNPH who underwent CSF shunting were randomly assigned to 6 weeks of DEGT (n = 23), 6 weeks of SE (n = 23), or NC (n = 24). Evaluation was performed at baseline (preoperatively) and at 1 week, 7 weeks (postintervention), and 6 months postoperatively (follow-up). Outcomes were measured using the functional gait assessment (FGA), 10-m walk test, timed up-and-go test, life-space assessment (LSA), and fall incidence.

RESULTS

A total of 65 participants completed the study. During the intention-to-treat analysis, the DEGT group demonstrated significant recovery of gait-balance functions according to only the FGA at postintervention and follow-up compared to the SE and NC groups; however, recovery of the SE group did not differ from that of the NC group. The DEGT group had a significantly lower fall incidence than the other groups at follow-up. Significantly better LSA results were observed for all groups at follow-up compared to baseline; however, no difference in LSA results were observed between groups.

CONCLUSIONS

DEGT in addtion to CSF shunting can facilitate the recovery of gait-balance function and reduce the fall incidence of iNPH patients.

Ventriculoperitoneal Shunt Failure 3-year after Shunt Surgery Caused by Migration of Detached Ventricular Catheter into the Cranium: A Case Study of Idiopathic Normal-pressure Hydrocephalus

Idiopathic normal-pressure hydrocephalus (iNPH) is a neurological disorder that typically presents with gait disturbance, cognitive impairment, and urinary incontinence. Although most patients respond to cerebrospinal-fluid shunting, some do not react well because of shunt failure. A 77-year-old female with iNPH underwent ventriculoperitoneal shunt implantation, and her gait impairment, cognitive dysfunction, and urge urinary incontinence improved. However, 3 years after shunting (at the age of 80), her symptoms gradually recurred for 3 months and she did not respond to shunt valve adjustment. Imaging studies revealed that the ventricular catheter detached from the shunt valve and migrated into the cranium. With immediate revision of the ventriculoperitoneal shunt, her gait disturbance, cognitive dysfunction, and urinary incontinence improved. When a patient whose symptoms have been relieved by cerebrospinal-fluid shunting experiences an exacerbation, it is important to suspect shunt failure, even if many years have passed since the surgery. Identifying the position of the catheter is crucial to determine the cause of shunt failure. Prompt shunt surgery for iNPH can be beneficial, even in elderly patients.

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

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

Creating of “fascial sheath” around subcutaneous lumboperitoneal shunt catheters largely prevents postoperative subcutaneous shunt catheter migration

Background:

Spinal catheter migration into the subcutaneous tissue is common after lumboperitoneal shunt (LPS) placement. This study proposed a new method (i.e., wrapping fascia around the catheter like a sheath) to prevent LPS spinal catheter migration.

Methods:

After a LPS spinal catheter was inserted under routine fluoroscopic guidance, and the paravertebral muscle fascia was closed, the fascia was sutured to wrap the catheter like a sheath using intermittent sutures.

Results:

Before the introduction of this technique, the rate of LPS spinal catheter subcutaneous migration was 4.6%. In this study, following LPS shunt placement in 18 consecutive patients with normal pressure hydrocephalus, no further spinal catheter migrations were observed.

Conclusion:

This novel method of “wrapping the LPS catheter with intermittent suture like a sheath” was found to be safe and effective for preventing further spinal catheter subcutaneous migration.

Safety and effectiveness of the assessment and treatment of idiopathic normal pressure hydrocephalus in the Adult Hydrocephalus Clinical Research Network

OBJECTIVE

The aim of this study was to describe the processes and outcomes associated with patients at five sites in the Adult Hydrocephalus Clinical Research Network (AHCRN) who had undergone evaluation and treatment for suspected idiopathic normal pressure hydrocephalus (iNPH) and had 1-year postoperative follow-up.

METHODS

Subjects with possible iNPH who had been prospectively enrolled in the AHCRN registry between November 19, 2014, and December 31, 2018, were evaluated by CSF drainage via either lumbar puncture or external lumbar drainage, consistent with recommendations of the international iNPH guidelines. Standardized clinical evaluations of gait, cognition, urinary symptoms, depression, and functional outcomes were conducted at baseline, before and after CSF drainage, and at 4-month intervals after shunt surgery. Complications of CSF drainage and shunt surgery were recorded.

RESULTS

Seventy-four percent (424/570) of patients with possible iNPH had CSF drainage, and 46% of them (193/424) underwent shunt surgery. The mean change in gait velocity with CSF drainage was 0.18 m/sec in patients who underwent shunt surgery versus 0.08 m/sec in patients who did not. For shunt surgery patients, gait velocity increased by 54% from 0.67 m/sec before CSF drainage to 0.96 m/sec 8-12 months after surgery, and 80% of patients had an increase of at least 0.1 m/sec by the first postoperative visit. Evaluation of cognition, urinary symptoms, depression, and functional outcomes also revealed improvement after shunt surgery. Of 193 patients who had undergone shunt surgery, 176 (91%) had no complications and 17 (9%) had 28 complications. Eleven patients (6%) had 14 serious complications that resulted in the need for surgery or an extended hospital stay. The 30-day reoperation rate was 3%.

CONCLUSIONS

Using criteria recommended by the international iNPH guidelines, the authors found that evaluation and treatment of iNPH are safe and effective. Testing with CSF drainage and treatment with shunt surgery are associated with a high rate of sustained improvement and a low rate of complications for iNPH in the 1st year after shunt surgery. Patients who had undergone shunt surgery for iNPH experienced improvement in gait, cognitive function, bladder symptoms, depression, and functional outcome measures. Gait velocity, which is an easily measured, objective, continuous variable, should be used as a standard outcome measure to test a patient's response to CSF drainage and shunt surgery in iNPH.

Value of MRI-based semi-quantitative structural neuroimaging in predicting the prognosis of patients with idiopathic normal pressure hydrocephalus after shunt surgery

OBJECTIVES

To explore the value of structural neuroimaging in predicting the prognosis of shunt surgery for idiopathic normal-pressure hydrocephalus (iNPH) using two different standard semi-quantitative imaging scales.

METHODS

A total of 47 patients with iNPH who underwent shunt surgery at our hospital between 2018 and 2020 were included in this study. The modified Rankin Scale (mRS) and iNPH grading scale (iNPHGS) were used to evaluate and quantify the clinical symptoms before and after shunt surgery. The disproportionately enlarged subarachnoid space hydrocephalus (DESH) and iNPH Radscale scores were used to evaluate the preoperative MR images. The primary endpoint was improvement in the mRS score a year after surgery, and the secondary endpoint was the iNPHGS after 1 year. The preoperative imaging features of the improved and non-improved groups were compared.

RESULTS

The rates of the primary and secondary outcomes were 59.6% and 61.7%, respectively, 1 year after surgery. There were no significant differences in preoperative DESH score, iNPH Radscale, Evans' index (EI), or callosal angle (CA) between the improved and non-improved groups. Significant correlations were observed between the severity of gait disorder and EI and the CA.

CONCLUSIONS

The value of structural neuroimaging in predicting the prognosis of shunt surgery is limited, and screening for shunt surgery candidates should not rely only on preoperative imaging findings.

KEY POINTS

• Early shunt surgery can significantly improve the clinical symptoms and prognosis of patients with idiopathic normal-pressure hydrocephalus (iNPH). • Structural imaging findings have limited predictiveness for the prognosis of patients with iNPH after shunt surgery. • Patients should not be selected for shunt surgery based on only structural imaging findings.

Effect of comorbid Parkinson's disease and Parkinson's disease dementia on the course of idiopathic normal pressure hydrocephalus

OBJECTIVE

The objective of this study was to analyze the effect of concomitant Parkinson's disease (PD) and PD dementia (PD/PDD) on the course of idiopathic normal pressure hydrocephalus (iNPH), especially as related to the outcome of lumboperitoneal shunt (LPS) surgery.

METHODS

The authors retrospectively analyzed patients with iNPH without accompanying disorders (iNPH alone [iNPHa]) and iNPH concomitant with PD/PDD (iNPHc+PD/PDD) who had presented to their department between 2010 and 2019. The diagnosis of iNPHc+PD/PDD was established using the diagnostic criteria of the Movement Disorder Society. The effect of LPS surgery on clinical symptoms and striatum volumes was evaluated.

RESULTS

Thirty-three patients with iNPHa and 23 patients with iNPHc+PD/PDD were identified. Comorbid PD/PDD significantly worsened clinical outcome as measured by the iNPH grading scale, modified Rankin Scale (mRS), and Hoehn and Yahr (HY) scale. LPS surgery improved the iNPH score including gait disturbance (p < 0.01), cognitive impairment (p = 0.02), and urinary disturbance (p < 0.01) in iNPHa and improved gait disturbance (p = 0.01) and urinary disturbance (p = 0.03) in iNPHc+PD/PDD for 1 year. Comorbid synucleinopathies maintained worse mRS scores and HY stages for 3 years, and LPS surgery extended overall survival (p = 0.003), as well as the period of sustained mRS scores (p = 0.04) and HY stages (p = 0.004) in iNPHc+PD/PDD. Both caudate and putamen volumes were reduced in iNPHa (p < 0.01) compared to those in controls and in patients with iNPHc+PD/PDD compared to those in patients with PD/PDD (p < 0.01), and LPS surgery restored caudate volumes in both groups.

CONCLUSIONS

These results revealed that comorbid PD/PDD deteriorates the clinical course of iNPH and that LPS surgery is recommended regardless of this comorbidity.

Dynamic gait stability in patients with idiopathic normal pressure hydrocephalus with high and low fall-risk

BACKGROUND

This study aimed to investigate whether dynamic gait stability differs between idiopathic normal-pressure hydrocephalus with high- and low-fall-risk.

METHODS

Participants comprised 40 idiopathic normal-pressure hydrocephalus patients and 23 healthy-controls. Idiopathic normal-pressure hydrocephalus patients were divided into those with high-fall-risk (n = 20) and low-fall-risk (n = 20) groups using the cut-off score of ≤14/30 for fall-risk on the Functional Gait Assessment. Dynamic stability during gait was assessed by three-dimensional motion analysis. Dynamic stability was defined as the ability to maintain an extrapolated center of mass within the base of support at heel contact, with the distance between the two defined as the margin of stability. Conscious motor control was assessed by the Movement-Specific Reinvestment Scale.

FINDINGS

Anteroposterior and mediolateral margin of stabilities were significantly larger in both idiopathic normal-pressure hydrocephalus groups than in healthy-controls. The mediolateral margin of stability was significantly higher in the high-fall-risk group than in the low-fall-risk group; whereas, the anteroposterior margin of stability did not differ between idiopathic normal-pressure hydrocephalus groups. The Movement-Specific Reinvestment Scale was significantly higher in the high-fall-risk group than in the low-fall-risk group.

INTERPRETATION

Idiopathic normal-pressure hydrocephalus patients with have high forward and lateral dynamic stability during gait regardless of their fall-risk. In particular, idiopathic normal-pressure hydrocephalus patients with high-fall-risk may consciously maintain lateral dynamic stability to a greater extent than those with low-fall-risk. These findings highlight a conscious motor control component in the pathological gait of idiopathic normal-pressure hydrocephalus, and provide clues for rehabilitation and fall prevention strategies in idiopathic normal-pressure hydrocephalus patients.

Are preoperative phase-contrast CSF flow parameters ideal for predicting the outcome of shunt surgery in patients with idiopathic normal pressure hydrocephalus?

Purpose

Phase-contrast magnetic resonance (PC-MR) is widely used in patients with idiopathic normal pressure hydrocephalus (iNPH), but its role in predicting prognosis remains controversial. To evaluate the effectiveness of preoperative PC-MR CSF flow measurement in predicting the clinical response to shunt surgery in patients with iNPH.

Methods

Forty-six patients with definite iNPH were included between January 2018 and January 2022. PC-MR was used to evaluate CSF peak velocity (PV), average velocity, aqueductal stroke volume (ASV), net ASV, and net flow. The modified Rankin Scale (mRS), iNPH grading scale (iNPHGS), Mini-Mental State Examination (MMSE), and Timed 3-m Up and Go Test (TUG) were used for clinical assessment. The primary endpoint was the improvement in the mRS score 1 year after surgery, and the secondary endpoints were the iNPHGS, MMSE, and TUG scores at 1 year. Differences between shunt improvement and non-improvement groups, based on the clinical outcomes, were compared using the Mann-Whitney U-test, logistic regression models, and receiver operating characteristic curves. Correlations between CSF flow parameters and the baseline clinical outcomes were assessed using Spearman's correlation coefficient.

Results

No CSF parameters significantly differed between shunt improvement and non-improvement groups based on mRS and secondary outcomes. And all CSF parameters showed significant overlap in both shunt improvement and non-improvement groups based on mRS and secondary outcomes. Significant correlations between the mRS and iNPHGS scores, and PV, ASV, and net ASV were observed.

Conclusion

While some preoperative PC-MR CSF flow parameters reflected the symptom severity of iNPH to a certain extent, they alone might not be ideal markers of shunt responsiveness.

One-year outcome of a lumboperitoneal shunt in older adults with idiopathic normal pressure hydrocephalus

Background

Lumboperitoneal shunt (LPS) is now an effective surgical modality for idiopathic normal pressure hydrocephalus (iNPH), but there is still a lack of clinical data on LPS in older adult iNPH patients in China. We aim to report the shunt effect and the complications of older adult iNPH patients treated with LPS at a single center in Shanghai, China.

Methods

We conducted a retrospective study among adults over 60 years old who were diagnosed as iNPH and treated with LPS from September 2016 to December 2020. The shunt effect was evaluated from two dimensions of functional and symptomatic improvement 3 months and 1 year after surgery, respectively. The potential factors related to the shunt effect one year after surgery were explored by comparing the effect between different subgroups and conducting multivariate logistic regression analysis.

Result

A total of 85 patients were included in this study, ranging from 60 to 93 years old, with an average age of 74.7. The function and symptoms were better both 3 months and 1 year after surgery than before (P < 0.001). At the 1-year postoperation follow-up, the functional and symptomatic improvement rates were 72.9% and 90.6%, respectively. The symptomatic improvement rates of gait, urination, and cognition were 74.1%, 72.9%, and 60.0%, respectively. Multivariate logistic regression analysis showed that improvement in function was much more possible in patients with less than 24 months from symptom onset to surgery (OR = 24.57, P < 0.001) and those with disproportionately enlarged subarachnoid-space hydrocephalus (OR = 5.88, P = 0.048); improvement in gait was also more possible in patients with less than 24 months from symptom onset to surgery (OR = 5.29, P = 0.017); improvement in urination was more possible in patients with diabetes (OR = 4.76, P = 0.019), and improvement in cognition was more possible in patients with preoperative modified Rankin scale level lower than 4 (OR = 3.51, P = 0.040). Minor operation-related complications were seen in 27 patients (31.8%) and severe complications in 6 patients (7.1%).

Conclusion

LPS could improve the function and symptoms of older adult iNPH patients. Early detection, diagnosis, and treatment of the disease could improve the shunt effect of the patients. Older adult iNPH patients with higher age ranges could achieve comparable shunt results compared with younger adults.

A case report of nonsurgical idiopathic normal pressure hydrocephalus differentiated from Alzheimer's dementia: Levetiracetam was effective in symptomatic epilepsy

Background

Idiopathic normal pressure hydrocephalus (iNPH) is a common form of dementia that causes gait disturbance, cognitive impairment, and urinary incontinence. iNPH is a "treatable dementia" that can be treated with shunt surgery, but this can be ineffective in some cases and can be accompanied by complications. As a result, many patients with iNPH do not undergo surgery. However, there is insufficient evidence on effective treatments other than surgical therapy.

Case Presentation

A 75-year-old woman presented to our hospital with a chief complaint of cognitive decline. She showed reduced motivation and inactivity. Brain magnetic resonance imaging showed a high score on the Evans Index (maximum width between bilateral lateral ventricular anterior horns/maximum intracranial cavity in the same slice). The subarachnoid space was enlarged at and below the Sylvian fissure, and narrowed at the higher arcuate region. She was diagnosed with iNPH. However, no shunt surgery was performed; 11 months later, she had a generalized convulsive seizure with loss of consciousness. An electroencephalogram showed generalized epileptic discharges. The possibility of surgery for her iNPH was ruled out. Levetiracetam prevented seizure recurrence and cognitive functions such as spontaneity and motivation were improved.

Conclusion

It is often assumed that surgery is the only effective treatment for patients with iNPH. However, as in the present case, symptomatic epileptic seizures may be a factor in dementia. Even in the absence of surgical treatment, we should examine the cause of dementia in patients with iNPH and consider pharmacological treatment, including antiepileptic drugs.

Risk factors for unfavourable outcomes after shunt surgery in patients with idiopathic normal-pressure hydrocephalus

A number of vascular risk factors (VRFs) have been reported to be associated with idiopathic normal-pressure hydrocephalus (iNPH), but it remains unclear whether these VRFs are related to patient outcomes after shunt surgery. Therefore, we investigated the risk factors for unfavourable outcomes after shunt surgery in iNPH patients using two samples from Tohoku University Hospital and from a multicentre prospective trial of lumboperitoneal (LP) shunt surgery for patients with iNPH (SINPHONI-2). We enrolled 158 iNPH patients. We compared the prevalence of VRFs and clinical measures between patients with favourable and unfavourable outcomes and identified predictors of unfavourable outcomes using multivariate logistic regression analyses. The presence of hypertension, longer disease duration, more severe urinary dysfunction, and a lower Evans' index were predictors of unfavourable outcomes after shunt surgery. In addition, hypertension and longer disease duration were also predictors in patients with independent walking, and a lower Evans' index was the only predictor in patients who needed assistance to walk or could not walk. Our findings indicate that hypertension is the only VRF related to unfavourable outcomes after shunt surgery in iNPH patients. Larger-scale studies are needed to elucidate the reason why hypertension can affect the irreversibility of symptoms after shunt placement.

Addressing the Devil Within: Normal Pressure Hydrocephalus—A Narrative Review

Normal pressure hydrocephalus (NPH) is the most frequently occurring form of hydrocephalus among adults. It is characterized clinically by the classical triad, called Hakim's triad, comprising gait issues, cognitive impairment, and urinary problems. NPH may be primary or idiopathic (iNPH) or secondary. Characteristic neuroimaging features occur, which are vital to diagnosis. Diagnostic criteria in the form of Japanese guideline and Congress of Neurological Surgeons 2005 guidelines have been devised, and broadly, are based on a constellation of clinical and neuroimaging features, in association with cerebrospinal fluid (CSF) testing. CSF tap test, extended lumbar drainage, and CSF infusion tests are invasive diagnostic tests. CSF tap test and extended lumbar drainage are used to demonstrate clinical reversibility with CSF drainage, and patients who demonstrate this are candidates for CSF shunting. However, due to the low negative predictive value of these tests, potential response to shunting cannot be negated among patients who do not respond to CSF drainage. Various shunting procedures are used for treatment, including ventriculoperitoneal, lumboperitoneal, and ventriculoatrial shunts. Endoscopic third ventriculostomy has also been attempted with limited success. Among the clinical features, gait abnormalities are most responsive to shunting. Persistent long-term response to shunting has been reported. Patients need to be meticulously followed up after the shunting procedure, to assess clinical and neuroimaging response, and detect possible shunt-related complications, especially CSF over-drainage. Early treatment is associated with better prognosis, and it is crucial to recognize and treat this condition before the development of severe symptoms.

Dural sac shrinkage signs on spinal magnetic resonance imaging indicate overdrainage after lumboperitoneal shunt for idiopathic normal pressure hydrocephalus

Background:

We previously found the usefulness of dural sac shrinkage signs (DSSSs), which are the anterior shift of the spinal cord and dura mater behind the cord, detected by magnetic resonance imaging (MRI) at the thoracic level for the diagnosis of spontaneous intracranial hypotension (IH). This is a retrospective survey on the usefulness of DSSSs for the early detection of iatrogenic IH caused by overdrainage through a lumboperitoneal shunt (LPS) for patients with idiopathic normal pressure hydrocephalus (INPH).

Methods:

Forty-five INPH patients had an LPS using a pressure programmable valve equipped with an anti-siphon device.

Results:

Nine patients complained of orthostatic headache after the LPS, indicating IH due to overdrainage, which persisted for more than a week in three patients and 2–7days in six patients. The headache was transient/ nonorthostatic in ten patients and absent in 26 patients. The DSSSs and accompanying enlargement of the venous plexus were observed in all three patients with prolonged orthostatic headaches. Only the anterior shift of the dura mater was observed in 1 (4%) among 25 patients who had short-term orthostatic headache, transient/ nonorthostatic headache, or absent headache, and underwent spinal MRI. A patient with prolonged severe orthostatic headache with both DSSSs eventually developed intracranial subdural effusion and underwent tandem valve surgery, which provided a quick improvement of symptoms. The DSSSs on thoracic MRI also disappeared promptly.

Conclusion:

DSSSs may serve as objective signs for the diagnosis of IH due to overdrainage through an LPS for INPH.

Evaluation of Patients With Cognitive Impairment Due to Suspected Idiopathic Normal-Pressure Hydrocephalus at Medical Centers for Dementia: A Nationwide Hospital-Based Survey in Japan

Objective

Treatment of idiopathic normal-pressure hydrocephalus (iNPH) requires collaboration between dementia specialists and neurosurgeons. The role of dementia specialists is to differentiate patients with iNPH from patients with other dementia diseases and to determine if other dementia diseases are comorbid with iNPH. We conducted a nationwide hospital-based questionnaire survey on iNPH in medical centers for dementia (MCDs).

Methods

We developed a questionnaire to assess how physicians in MCDs evaluate and treat patients with cognitive impairment due to suspected iNPH and the difficulties these physicians experience in the evaluation and treatment of patients. The questionnaire was sent to all 456 MCDs in Japan.

Results

Questionnaires from 279 MCDs were returned to us (response rate: 61.2%). Patients underwent cognitive tests, evaluation of the triad symptoms of iNPH, and morphological neuroimaging examinations in 96.8, 77.8, and 98.2% of the MCDs, respectively. Patients with suspected iNPH were referred to other hospitals (e.g., hospitals with neurosurgery departments) from 78.9% of MCDs, and cerebrospinal fluid (CSF) tap test was performed in 44 MCDs (15.8%). iNPH guidelines (iNPHGLs) and disproportionately enlarged subarachnoid space hydrocephalus (DESH), a specific morphological finding, were used and known in 39.4% and 38% of MCDs, respectively. Logistic regression analysis with “Refer the patient to other hospitals (e.g., hospitals with neurosurgery departments) when iNPH is suspected.” as the response variable and (a) using the iNPHGLs, (b) knowledge of DESH, (c) confidence regarding DESH, (d) difficulty with performing brain magnetic resonance imaging, (e) knowledge of the methods of CSF tap test, (f) absence of physician who can perform lumbar puncture, and (g) experience of being told by neurosurgeons that referred patients are not indicated for shunt surgery as explanatory variables revealed that the last two factors were significant predictors of patient referral from MCDs to other hospitals.

Conclusion

Sufficient differential or comorbid diagnosis using CSF tap test was performed in a few MCDs. Medical care for patients with iNPH in MCDs may be improved by having dementia specialists perform CSF tap tests and share the eligibility criteria for shunt surgery with neurosurgeons.

Normal pressure hydrocephalus: an update

Normal pressure hydrocephalus (NPH) has been a topic of debate since its introduction in publications. More frequent in the elderly population, it is characterized by gait disturbance, urinary urge incontinence and cognitive decline. Therefore, it is a clinical-radiological entity with relatively common findings for the age group, which together may have greater specificity. Therefore, its diagnosis must be careful for an adequate selection of patients for treatment with ventricular shunt, since the symptoms are potentially reversible. The tap test has a high positive predictive value as a predictor of therapeutic response, but a negative test does not exclude the possibility of treatment. Scientific efforts in recent years have been directed towards a better understanding of NPH and this narrative review aims to compile recent data from the literature in a didactic way for clinical practice.