Clinical parameters in 74 consecutive patients shunt operated for normal pressure hydrocephalus

Classification of Chronic Hydrocephalus in Adults: A Systematic Review and Analysis

BACKGROUND

Chronic hydrocephalus in adults (CHiA) includes all nonacute forms of hydrocephalus occurring in adulthood. It covers a spectrum of disorders. Some of these have relatively agreed on definitions, while others are less well characterized. The existing medical classification systems lack adequate structure and are neither clinically oriented nor easy to use, which severely hampers research and clinical care efforts.

METHODS

A systematic literature review and data analysis were performed, focusing on the terms "adult hydrocephalus" and "classification," using the PubMed, Scopus, and Cochrane Library databases. Data on terminology, definitions, patient demographics, symptom duration, and clinical presentations were extracted, analyzed, and compiled. A Delphi process was followed to define CHiA disorders.

RESULTS

A total of 33 studies collectively used 48 terms to define various CHiA disorders. Different terms were used to describe similar conditions. CHiA disorders were found to be clustered into 7 distinctive clinical entities based on the clinical characteristics.

CONCLUSIONS

An evidence-based new clinical classification for CHiA is suggested. Our review identified gaps in knowledge and areas for further research.

Impact of Shunt Placement on CSF Dynamics

BACKGROUND

CSF dynamics are disturbed in chronic hydrocephalus (NPH). We hypothesise that these alterations reflect a disturbance of intracranial compliance. The aim of our study is to investigate the variations in intracranial hydrodynamics in NPH after ventricular shunt surgery.

PATIENTS AND METHOD

We included 14 patients with definite NPH. All patients improved after ventriculoperitoneal shunting. The patients underwent an analysis of intracranial haemodynamics by phase-contrast MRI (pcMRI) preoperatively, at 6 months postoperatively, and at 1 year postoperatively. We analysed the dynamics of intraventricular CSF at the level of the aqueduct of Sylvius (SVAQU) and CSF at the level of the high cervical subarachnoid spaces (SVCERV). We calculated the ratio between SVAQU and SVCERV, called CSFRATIO, which reflects the participation of intraventricular pulsatility in overall intracranial CSF pulsatility.

RESULTS

SVAQU significantly (p = 0.003) decreased from 240 ± 114 μL/cc to 214 ± 157 μL/cc 6 months after shunt placement. Six months after shunt placement, SVCERV significantly (p = 0.007) decreased from 627 ± 229 μL/cc to 557 ± 234 μL/cc. Twelve months after shunt placement, SVCERV continued to significantly (p = 0.001) decrease to 496 ± 234 μL/cc. CSFRATIO was not changed by surgery.

CONCLUSIONS

CSF dynamics are altered by shunt placement and might be a useful marker of the shunt's effectiveness-especially if pressure values start to rise again. The detection of changes in CSF dynamics would require a reference postoperative pcMRI measurement for each patient.

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.

Failure of Internal Cerebrospinal Fluid Shunt: A Systematic Review and Meta-Analysis of the Overall Prevalence in Adults

OBJECTIVE

Reported rates of failures of internal cerebrospinal fluid shunt (ICSFS) vary greatly from less than 5% to more than 50% and no meta-analysis to assess the overall prevalence has been performed. We estimated the failure rate after ICSFS insertion and searched for associated factors.

METHODS

Six databases were searched from January 1990 to February 2022. Only original articles reporting the rate of adult shunt failure were included. Random-effects meta-analysis with a generalized linear mixed model method and logit transformation was used to compute the overall failure prevalence. Subgroup analysis and meta-regression were implemented to search for associated factors.

RESULTS

Of 1763 identified articles, 46 were selected, comprising 70,859 ICSFS implantations and 13,603 shunt failures, suggesting an accumulated incidence of 19.2%. However, the calculated pooled prevalence value and its 95% confidence interval (CI) were 22.7% (95% CI, 19.8-5.8). The CI of the different estimates did not overlap, indicating a strong heterogeneity confirmed by a high I² of 97.5% (95% CI, 97.1-97.8; P < 0.001; τ² = 0.3). Ninety-five percent prediction interval of shunt failure prevalence ranged from 8.75% to 47.36%. A meta-regression of prevalence of publication found a barely significant decreasing failure rate of about 2% per year (-2.11; 95% CI, -4.02 to -0.2; P = 0.031).

CONCLUSIONS

Despite being a simple neurosurgical procedure, ICSFS insertion has one of the highest risk of complications, with failure prevalence involving more than 1 patient of 5. Nonetheless, all efforts to lower this high level of shunt failure seem to be effective.

Idiopathic normal pressure hydrocephalus: postoperative patient perspective and quality of life

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible disease. Surgical results have been well described in the literature, but only a few studies investigated the subjective outcome. This study aimed to investigate the patient's expectations about surgery, the perceived improvement after treatment, and its impact on the quality of life (QoL).

METHODS

A new dedicated survey was created to investigate subjectively different aspects of the treatment pathway of iNPH (diagnosis, symptoms, expectations from surgery, surgical operation, surgical results, and postoperative QoL), together with the SF-12 and EQ-5D as validated, standardized tools.

RESULTS

Forty-five patients were included. Forty-three percent of cases received the diagnosis after at least 1 year, with symptoms worsening in 73%, and frustration in 93%. Reaching a diagnosis was important for 100% of patients, with high expectations from surgery; 86% of them hoped to return to a normal life. Seventy-two percent of patients reported a significant postoperative improvement (walking 68%, mood 57%). Memory and incontinence did not improve in 64% of cases. Subjectively, QoL improved in 72% of cases. The SF-12 score is comparable to controls >75 years, but lower than the 65-75 years group. The EQ-5D index was 0.66 (lower than those of the 65-75 years group = 0.823, and >75 years group = 0.724). Pain and discomfort, instead, were lower compared to the healthy population (43% vs 56%). The idea of having an implanted device and of long-term follow-up is not worrying for 80% of patients; approximately two-thirds of them reported a regained control of their lives.

CONCLUSIONS

The importance of early diagnosis and patients' perspective, alongside clinical evaluation, is highlighted. The self-reported evaluations on symptoms and QoL, along with the balance between postoperative worries and benefits, should be discussed preoperatively with patients and relatives, and included postoperatively to comprehensively assess the surgical outcome.

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.

Using smartphone-based accelerometers to gauge postoperative outcomes in patients with NPH: Implications for ambulatory monitoring

Background

The surgical treatment of normal pressure hydrocephalus (NPH) with shunting remains controversial due to the difficulty in distinguishing such pathology from other neurological conditions that can present similarly. Thus, patients with suspected NPH should be carefully selected for surgical intervention. Historically, clinical improvement has been measured by the use of functional grades, alleviation of symptoms, and/or patient/family-member reported surveys. Such outcome analysis can be subjective, and there is difficulty in quantifying cognition. Thus, a push for a more quantifiable and objective investigation is warranted, especially for patients with idiopathic NPH (INPH), for which the final diagnosis is confirmed with postoperative clinical improvement. We aimed to use Apple Health (Apple Inc., Cupertino, CA) data to approximate physical activity levels before and after shunt placement for NPH as an objective outcome measurement. The patients were contacted and verbally consented to export Apple Health activity data. The patient's physical activity data were then analyzed. A chart review from the patient's EMR was performed to understand and better correlate recovery.

Case Description

Our first patient had short-term improvements in activity levels when compared to his preoperative activity. The patient's activity level subsequently decreased at 6 months and onward. This decline was simultaneous to new-onset lumbar pain. Our second patient experienced sustained improvements in activity levels for 12 months after his operation. His mobility data were in congruence with his subjectively reported improvement in clinical symptoms. He subsequently experienced a late-decline that began at 48-months. His late deterioration was likely confounded by exogenous factors such as further neurodegenerative diseases coupled with old age.

Conclusion

The use of objective activity data offers a number of key benefits in the analysis of shunted patients with NPH/INPH. In this distinctive patient population, detailed functional outcome analysis is imperative because the long-term prognosis can be affected by comorbid factors or life expectancy. The benefits from using smartphone-based accelerometers for objective outcome metrics are abundant and such an application can serve as a clinical aid to better optimize surgical and recovery care.

Increased plasma levels of chitinase 3-like 1 (CHI3L1) protein in patients with idiopathic normal-pressure hydrocephalus

Idiopathic normal-pressure hydrocephalus (iNPH) is an uncommon neurological disorder with no known pathological hallmarks. INPH may share common degenerative pathways with other neurological diseases, such as Alzheimer's disease (AD). However, the reversible properties of iNPH may share differing pathophysiological mechanisms with other diseases. This study aimed at assessing the diagnostic value of plasma chitinase 3-like 1 (CHI3L1) protein levels as a disease-specific biomarker for iNPH. We selected both iNPH and AD patients as well as normal and disease control subjects from an enrolled dementia registry. A total of 121 AD, 80 iNPH, 13 idiopathic Parkinson's disease, and 23 mild cognitive impairment patients with 83 healthy controls were included in the final analysis. The Aβ42, total tau, and phosphorylated tau levels within the cerebrospinal fluid, as well as plasma levels of CHI3L1, were measured using commercially available enzyme-linked immunosorbent assay kits. CHI3L1 levels for iNPH patients were higher than those of the other groups. Analysis of covariance adjusting for age showed significantly increased plasma CHI3L1 levels in iNPH patients than in the controls (p < 0.001). CHI3L1 plasma levels may be useful in differentiating iNPH patients from healthy individuals.

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition): Endorsed by the Japanese Society of Normal Pressure Hydrocephalus

Among the various disorders that manifest with gait disturbance, cognitive impairment, and urinary incontinence in the elderly population, idiopathic normal pressure hydrocephalus (iNPH) is becoming of great importance. The first edition of these guidelines for management of iNPH was published in 2004, and the second edition in 2012, to provide a series of timely, evidence-based recommendations related to iNPH. Since the last edition, clinical awareness of iNPH has risen dramatically, and clinical and basic research efforts on iNPH have increased significantly. This third edition of the guidelines was made to share these ideas with the international community and to promote international research on iNPH. The revision of the guidelines was undertaken by a multidisciplinary expert working group of the Japanese Society of Normal Pressure Hydrocephalus in conjunction with the Japanese Ministry of Health, Labour and Welfare research project. This revision proposes a new classification for NPH. The category of iNPH is clearly distinguished from NPH with congenital/developmental and acquired etiologies. Additionally, the essential role of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in the imaging diagnosis and decision for further management of iNPH is discussed in this edition. We created an algorithm for diagnosis and decision for shunt management. Diagnosis by biomarkers that distinguish prognosis has been also initiated. Therefore, diagnosis and treatment of iNPH have entered a new phase. We hope that this third edition of the guidelines will help patients, their families, and healthcare professionals involved in treating iNPH.

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.

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.

Lumbar drain trial outcomes of normal pressure hydrocephalus: a single-center experience of 254 patients

OBJECTIVE

A short-term lumbar drain (LD) trial is commonly used to assess the response of normal pressure hydrocephalus (NPH) patients to CSF diversion. However, it remains unknown whether the predictors of passing an LD trial match the predictors of improvement after ventriculoperitoneal shunting. The aim of this study was to examine outcomes, complication rates, and associations between predictors and outcomes after an LD trial in patients with NPH.

METHODS

The authors retrospectively reviewed the records of 254 patients with probable NPH who underwent an LD trial between March 2008 and September 2017. Multivariate regression models were constructed to examine predictors of passing the LD trial. Complications associated with the LD trial procedure were recorded.

RESULTS

The mean patient age was 77 years and 56.7% were male. The mean durations of gait disturbance, cognitive decline, and urinary incontinence were 29 months, 32 months, and 28 months, respectively. Of the 254 patients, 30% and 16% reported objective and subjective improvement after the LD trial, respectively. Complications included a sheared LD catheter, meningitis, lumbar epidural abscess, CSF leak at insertion site, transient lower extremity numbness, slurred speech, refractory headaches, and hyponatremia. Multivariate analyses using MAX-R revealed that a prior history of stroke predicted worse outcomes, while disproportionate subarachnoid spaces (uneven enlargement of supratentorial spaces) predicted better outcomes after the LD trial (r2 = 0.12, p < 0.05).

CONCLUSIONS

The LD trial is generally safe and well tolerated. The best predictors of passing the LD trial include a negative history of stroke and having disproportionate subarachnoid spaces.

Idiopathic Normal-Pressure Hydrocephalus: Diagnostic Accuracy of Automated Sulcal Morphometry in Patients With Ventriculomegaly

BACKGROUND

Idiopathic normal-pressure hydrocephalus (iNPH) is a treatable cause of gait and cognitive impairment. iNPH should be differentiated from ventriculomegaly secondary to brain atrophy to choose the best therapeutic option (ventriculoperitoneal shunt vs medical management).

OBJECTIVE

To determine the diagnostic accuracy of automated sulcal morphometry to differentiate patients with iNPH from patients with ventriculomegaly of neurodegenerative origin.

METHODS

Thirty-eight consecutive patients with iNPH (shunt responsive n = 31, nonresponsive n = 7), 35 with vascular cognitive disorder, and 25 age- and sex-matched healthy controls were prospectively included and underwent cognitive evaluation and 3T brain magnetic resonance imaging. Sulcal opening of 10 sulci of interest was retrospectively measured using an automated surface-based approach from the 3-dimensional T1-weighted images. Receiver-operating characteristic curve analyses determined the best parameter to identify iNPH patients.

RESULTS

The best parameter to discriminate shunt-responsive iNPH from patients with vascular cognitive disorder and healthy controls was the ratio between calcarine sulcus and cingulate sulcus opening with an area under the curve of 0.94 (95% CI: 0.89, 0.99). A cut-off value of 0.95 provided the highest sensitivity (96.8%) and specificity (83.3%).

CONCLUSION

This preliminary study showed that automated sulcal morphometry may help the neurosurgeon to identify iNPH patients and to exclude other causes of ventriculomegaly.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cerebrospinal Fluid Levels of β-Amyloid 40 and β-Amyloid 42 are Proportionately Decreased in Amyloid Positron-Emission Tomography Negative Idiopathic Normal-Pressure Hydrocephalus Patients

BACKGROUND AND PURPOSE

Cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) could be misleading in idiopathic normal-pressure hydrocephalus (iNPH). We therefore investigated the CSF biomarkers in 18F-florbetaben amyloid-negative positron-emission tomography (PET) [amyloid PET(-)] iNPH, amyloid-positive PET [amyloid PET(+)] AD, and cognitively normal (CN) subjects.

METHODS

Ten amyloid PET(+) AD patients (56.7±5.6 years old, mean±standard deviation), 10 amyloid PET(-) iNPH patients (72.8±4.5 years old), and 8 CN subjects (61.2±6.5 years old) were included. We measured the levels of β-amyloid (Aβ)40, Aβ42, total tau (t-tau) protein, and phosphorylated tau (p-tau) protein in the CSF using enzyme-linked immunosorbent assays.

RESULTS

The level of Aβ42 and the Aβ42/Aβ40 ratio in the CSF were significantly lower in AD than in iNPH or CN subjects. The Aβ40 level did not differ significantly between AD and iNPH (p=1.000), but it did between AD and CN subjects (p=0.032). The levels of both t-tau and p-tau were higher in AD than in iNPH or CN subjects. The levels of Aβ42, Aβ40, t-tau, and p-tau were lower in iNPH than in CN subjects, but there was no significant difference after controlling for age.

CONCLUSIONS

Our results suggest that the mechanism underlying low CSF Aβ levels differs between amyloid PET(-) iNPH and amyloid PET(+) AD subjects. The lower levels of all CSF biomarkers in iNPH patients might be due to reduced clearances from extracellular fluid and decreased brain metabolism of the periventricular zone in iNPH resulting from glymphatic dysfunction.

Neuropsychiatric Manifestations of Cognitively Advanced Idiopathic Normal Pressure Hydrocephalus

Background

Neuropsychiatric manifestations of patients with idiopathic normal pressure hydrocephalus (iNPH) have not been studied in a systematic way.

Aim

To study the spectrum of neuropsychiatric abnormalities in patients with iNPH.

Patient Selection and Evaluation

Patients attending 3 different tertiary care centers during three consecutive time periods spanning from 2010 to 2015 were analyzed for neuropsychiatric manifestations. Patients diagnosed as having probable or possible iNPH as per the consensus criteria were included in the study. Neuropsychiatric manifestations were captured by a comprehensive inventory (Cambridge Behavioral Inventory, CBI).

Results

The CBI score was available for 41 patients. The mean Mini-Mental State Examination score was 15.37 (SD 7.2) and the Addenbrooke's Cognitive Examination score was 34.95 (SD 19.67), thereby indicating cognitively advanced iNPH. All patients had impairment in one or more items on the CBI. The mean score was 55.46 (SD 27) out of 180, thereby indicating a mild degree of impairment. Among the subscores, impairment with motivation was the most observed abnormality followed by memory impairment. When the CBI total score and subscores were compared, all of them (except motivation) were higher for Alzheimer's disease; however, none was statistically significant. Even though the motivation score was higher for iNPH, the difference did not reach statistical significance.

Conclusions

It can be concluded that neurobehavioral abnormalities are common in patients with cognitively advanced normal pressure hydrocephalus. However, the intensity of involvement appeared less when compared to Alzheimer's disease. Apathy appears to be the most common impairment.

Epilepsy, headache, and abdominal pain after shunt surgery for idiopathic normal pressure hydrocephalus: the INPH-CRasH study

OBJECTIVE

Adverse events related to shunt surgery are common and might have a negative effect on outcome in patients with idiopathic normal pressure hydrocephalus (INPH). The authors’ objectives were to establish the frequencies of epilepsy, headache, and abdominal pain and determine their impact on patient quality of life (QOL), in long-term follow-up after shunt surgery for INPH.

METHODS

One hundred seventy-six shunt-treated patients with INPH (mean age 74 years) and 368 age- and sex-matched controls from the population were included. The mean follow-up time after surgery was 21 months (range 6–45 months). Each participant answered a questionnaire regarding present frequency and severity of headache and abdominal pain. Confirmed diagnoses of epilepsy and all prescriptions for antiepileptic drugs (AEDs) before and after shunt surgery for INPH were gathered from national registries. Equivalent presurgical and postsurgical time periods were constructed for the controls based on the date of surgery (the division date for controls is referred to as virtual surgery). All registry data covered a mean period of 6 years (range 3–8 years) before surgery/virtual surgery and 4 years (range 2–6 years) after surgery/virtual surgery. Provoked epileptic seizures were excluded. Patient QOL was assessed with the EuroQoL 5-dimension 5-level instrument.

RESULTS

Epilepsy was more common in shunt-treated patients with INPH than in controls (4.5% vs 1.1%, respectively; p = 0.023), as was treatment with AEDs (14.8% vs 7.3%, respectively; p = 0.010). No difference was found between the populations before surgery/virtual surgery (epilepsy, 2.3% [INPH] vs 1.1% [control], p = 0.280; AED treatment, 8.5% [INPH] vs 5.4% [control], p = 0.235). New-onset epilepsy and new AED treatment after surgery/virtual surgery were more common in INPH (epilepsy, 2.3% [INPH] vs 0.0% [control], p = 0.011; AED, 8.5% [INPH] vs 3.3% [control], p = 0.015). At follow-up, more patients with INPH than controls experienced headache several times per month or more often (36.1% vs 11.6%, respectively; p < 0.001). Patients with INPH and unilateral headache had more right-sided headaches than controls (p = 0.038). Postural headache was experienced by 16% (n = 27 of 169) of the patients with INPH. Twenty percent (n = 35) of the patients with INPH had persistent abdominal pain. Headache was not correlated to lower QOL. The study was underpowered to draw conclusions regarding QOL in patients with INPH who had epilepsy and abdominal pain, but the finding of no net difference in mean QOL indicates that no correlation between them existed.

CONCLUSIONS

Epilepsy, headache, and abdominal pain are common in long-term follow-up in patients after shunt surgery for INPH and are more common among patients with INPH than in the general population. All adverse events, including mild and moderate ones, should be considered during postoperative follow-ups and in the development of new methods for shunt placement.

The phenotype of idiopathic normal pressure hydrocephalus-a single center study of 429 patients

INTRODUCTION

Idiopathic Normal Pressure Hydrocephlaus (iNPH) is, despite a vastly improved knowledge of the disorder since its first description still underdiagnosed and undertreated. Because of this, there is a need for further large studies describing the typical symptomatology and reversibility of symptoms in iNPH, which was the aim of this study.

METHODS

In all, 429 patients (mean age 71 years) were included. Detailed pre- and postoperative examinations of symptoms and signs were analyzed. A composite outcome measure was constructed.

RESULTS

Sixty-eight % improved after surgery. Preoperatively, 72% exhibited symptoms from three or four of the assessed domains (gait, balance, neuropsychology and continence) while 41% had symptoms from all four domains. Ninety % had gait disturbances, of which 75% had broad-based gait, 65% shuffling gait and 30% freezing of gait. These disturbances coexisted in most patients preoperatively, but were more likely to appear as isolated findings after surgery. Impaired balance was seen in 53% and retropulsion in 46%. MMSE <25 was seen in 53% and impaired continence in 86%. Improvements were seen in all symptom domains postoperatively.

CONCLUSIONS

The iNPH phenotype is characterized by a disturbance in at least 3/4 symptom domains in most patients, with improvements in all domains after shunt surgery. Most patients present with a broad-based and shuffling gait as well as paratonia. Present symptoms in all domains and a shuffling gait at the time of diagnosis seem to predict a favorable postoperative outcome, whereas symptom severity does not.

Relationship between gait parameters and MR imaging in idiopathic normal pressure hydrocephalus patients after shunt surgery

BACKGROUND

A few previous studies have reported a change in gait motion in idiopathic normal pressure hydrocephalus (iNPH) patients after shunt surgery compared with before shunt surgery; however, there has been no detailed quantitative investigation of gait, including kinetic and kinematic parameters. Furthermore, the relationship between gait parameters and magnetic resonance (MR) imaging has not been confirmed.

RESEARCH QUESTION

We investigated the gait motion in patients with iNPH, and evaluated the relationship between kinetic gait parameters and MR imaging before and after shunt surgery.

METHODS

The subjects were 12 patients with iNPH who could walk 10 m without aids. A three-dimensional motion analysis system was used to obtain the spatiotemporal, kinetic, and kinematic parameters before and after surgery. Relationships between each gait parameter and MR imaging were assessed.

RESULTS

The post-shunt walking speed and step length were increased compared with pre-shunt values. The post-shunt evaluation showed increased range of motion of the hip, knee, and ankle joints in the sagittal plane during the gait cycle. The peak flexion moment of the hip during the stance phase was greater after shunt surgery. The improvement rate of the Evans index was significantly correlated with the improvement rate of walking speed, and the total ranges of motion of the hip and ankle joints in the sagittal plane.

SIGNIFICANCE

The propulsive force of the hip and ankle joints was regained after shunt surgery. Normalization of the Evans index could predict improvement in propulsive force after shunt surgery in iNPH.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Quantitative analysis of cerebrospinal fluid dynamics at phase contrast cine-MRI: predictivity of neurosurgical "Shunt" responsiveness in patients with idiopathic normal pressure hydrocephalus

BACKGROUND

Aqueductal stroke volume (ACSV) measured by phase-contrast cine (PCC)-MRI has been proposed with controversy as a tool for the selection of patients with normal pressure hydrocephalus (NPH) as candidates for shunt-surgery. The aim of this study was to assess if PCC-MRI scan measurements of ACSV could select properly these patients.

METHODS

We retrospectively reviewed charts and MRI of 38 shunted patients (72.16±6.16 years). ACSV measurements were performed 7-30 days before shunt and at the first and sixth months after surgery. Normally distributed variables were compared in the two groups (improved/unimproved) by t-test for baseline values and with repeated measures analysis of variance.

RESULTS

Twenty-six patients (68,4%) improved after VPS (mean time of symptom onset was 8.15±7.19 months). Mean preoperative ACSV value was 271.85±143.03, which decreased by 21.6% (mean 213±125.14) at the first month and 40.3% sixth months after VPS (mean 162.15±91.5). Twelve patients (31.6%) did not improve (mean time of symptom onset was 29±5.62 months). Mean preoperative ACSV value was 79.83±31.24, decreased to 8.7% (mean 72.83±28.66) at first month after VPS. 21.2% (mean 62.83±31.12) after six months. We found statistical difference between preoperative ACSV of improved and unimproved patients (P<0.01), onset time of symptoms (P<0.01) and the changes in ACSV after one and six months in both groups (P<0.001).

CONCLUSIONS

ACSV is useful to stratify patients with NPH after surgery (improved /not improved) suggesting to proceed with serial ACSV measurements before deciding treatment.

Lumbar Puncture Test in Normal Pressure Hydrocephalus: Does the Volume of CSF Removed Affect the Response to Tap?

BACKGROUND AND PURPOSE

There is limited evidence to support the use of high-volume lumbar taps over lower-volume taps in the diagnosis of normal pressure hydrocephalus. The purpose of this study is to detect whether the volume of CSF removed from patients undergoing high-volume diagnostic lumbar tap test for normal pressure hydrocephalus is significantly associated with post-lumbar tap gait performance.

MATERIALS AND METHODS

This retrospective study included 249 consecutive patients who underwent evaluation for normal pressure hydrocephalus. The patients were analyzed both in their entirety and as subgroups that showed robust response to the lumbar tap test. The volume of CSF removed was treated as both a continuous variable and a discrete variable. Statistical tests were repeated with log-normalized volumes.

RESULTS

This study found no evidence of a relationship between the volume of CSF removed during the lumbar tap test and subsequent gait test performance in the patient population (Pearson coefficient r = 0.049-0.129). Log normalization of the volume of CSF removed and controlling for age and sex failed to yield a significant relationship. Subgroup analyses focusing on patients who showed greater than 20% improvement in any of the gait end points or who were deemed sufficiently responsive clinically to warrant surgery also yielded no significant relationships between the volume of CSF removed and gait outcomes, but there were preliminary findings that patients who underwent tap with larger-gauge needles had better postprocedure ambulation among patients who showed greater than 20% improvement in immediate time score (P = .04, n = 62).

CONCLUSIONS

We found no evidence to support that a higher volume of CSF removal impacts gait testing, suggesting that a high volume of CSF removal may not be necessary in a diagnostic lumbar tap test.

Revisiting secondary normal pressure hydrocephalus: does it exist? A review

OBJECTIVE There are several etiologies that can lead to the development of secondary normal pressure hydrocephalus (sNPH). The aim of this study was to evaluate the etiology, diagnosis, treatment, and outcome in patients with sNPH and to highlight important differences between the separate etiologies. METHODS A comprehensive review of the literature was performed to identify studies conducted between 1965 and 2015 that included data regarding the etiology, treatment, diagnosis, and outcome in patients with sNPH. Sixty-four studies with a total of 1309 patients were included. The inclusion criteria of this study were articles that were written in English, included more than 2 patients with the diagnosis of sNPH, and contained data regarding the etiology, diagnosis, treatment, or outcome of NPH. The most common assessment of clinical improvement was based on the Stein and Langfitt grading scale or equivalent improvement on other alternative ordinal grading scales. RESULTS The main etiologies of sNPH were subarachnoid hemorrhage (SAH) in 46.5%, head trauma in 29%, intracranial malignancies in 6.2%, meningoencephalitis in 5%, and cerebrovascular disease in 4.5% of patients. In 71.9% of patients the sNPH was treated with ventriculoperitoneal shunt placement, and 24.4% had placement of a ventriculoatrial shunt. Clinical improvement after shunt placement was reported in 74.4% and excellent clinical improvement in 58% of patients with sNPH. The mean follow-up period after shunt placement was 13 months. Improvement was seen in 84.2% of patients with SAH, 83% of patients with head trauma, 86.4% of patients with brain tumors, 75% of patients with meningoencephalitis, and 64.7% of patients with NPH secondary to stroke. CONCLUSIONS Secondary NPH encompasses a diverse group of clinical manifestations associated with a subset of patients with acquired hydrocephalus. The most common etiologies of sNPH include SAH and traumatic brain injury. Secondary NPH does indeed exist, and should be differentiated from idiopathic NPH based on outcome and on clinical, pathophysiological, and epidemiological characteristics, but should not be considered as a separate entity.

Cerebrospinal Fluid Lumbar Tapping Utilization for Suspected Ventriculoperitoneal Shunt Under-Drainage Malfunctions

Objective

The diagnosis of shunt malfunction can be challenging since neuroimaging results are not always correlated with clinical outcomes. The purpose of this study was to evaluate the efficacy of a simple, minimally invasive cerebrospinal fluid (CSF) lumbar tapping test that predicts shunt under-drainage in hydrocephalus patients.

Methods

We retrospectively reviewed the clinical and radiological features of 48 patients who underwent routine CSF lumbar tapping after ventriculoperitoneal shunt (VPS) operation using a programmable shunting device. We compared shunt valve opening pressure and CSF lumbar tapping pressure to check under-drainage.

Results

The mean pressure difference between valve opening pressure and CSF lumbar tapping pressure of all patients were 2.21±24.57 mmH₂O. The frequency of CSF lumbar tapping was 2.06±1.26 times. Eighty five times lumbar tapping of 41 patients showed that their VPS function was normal which was consistent with clinical improvement and decreased ventricle size on computed tomography scan. The mean pressure difference in these patients was −3.69±19.20 mmH₂O. The mean frequency of CSF lumbar tapping was 2.07±1.25 times. Fourteen cases of 10 patients revealed suspected VPS malfunction which were consistent with radiological results and clinical symptoms, defined as changes in ventricle size and no clinical improvement. The mean pressure difference was 38.07±23.58 mmH₂O. The mean frequency of CSF lumbar tapping was 1.44±1.01 times. Pressure difference greater than 35 mmH₂O was shown in 2.35% of the normal VPS function group (2 of 85) whereas it was shown in 64.29% of the suspected VPS malfunction group (9 of 14). The difference was statistically significant (p=0.000001). Among 10 patients with under-drainage, 5 patients underwent shunt revision. The causes of the shunt malfunction included 3 cases of proximal occlusion and 2 cases of distal obstruction and valve malfunction.

Conclusion

Under-drainage of CSF should be suspected if CSF lumbar tapping pressure is 35 mmH₂O higher than the valve opening pressure and shunt malfunction evaluation or adjustment of the valve opening pressure should be made.

A review of cognitive impairment and differential diagnosis in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a complex and still underestimated pathology. In the early stages, the cognitive profile is characterized mainly by impairments of attention, psychomotor speed and memory, suggesting frontal involvement; patients with more advanced iNPH show overall cognitive deterioration. The memory impairment, however, seems to be milder than that seen in Alzheimer's disease (AD). Clinical and neuroimaging data are crucial for the diagnosis of iNPH, but the presence of different variables, such as comorbidities, and the possible overlapping with other neurodegenerative diseases, AD in particular, make the differential diagnosis difficult. To date studies seeking to identify possible biological markers have provided inconclusive results; moreover reliable indices predictive of a good response to surgery are still lacking. There is a need for further studies with longer follow-ups and for closer interaction among the different professionals involved.

The effect of shunt surgery on neuropsychological performance in normal pressure hydrocephalus: a systematic review and meta-analysis

We conducted a systematic review of the literature and used meta-analytic techniques to evaluate the impact of shunt surgery on neuropsychological performance in patients with normal pressure hydrocephalus (NPH). Twenty-three studies with 1059 patients were identified for review using PubMed, Web of Science, Google scholar and manual searching. Inclusion criteria were prospective, within-subject investigations of cognitive outcome using neuropsychological assessment before and after shunt surgery in patients with NPH. There were statistically significant effects of shunt surgery on cognition (Mini-Mental State Examination; MMSE), learning and memory (Rey Auditory Verbal Learning Test; RAVLT, total and delayed subtests), executive function (backwards digit span, phonemic verbal fluency, trail making test B) and psychomotor speed (trail making test A) all in the direction of improvement following shunt surgery, but with considerable heterogeneity across all measures. A more detailed examination of the data suggested robust evidence for improved MMSE, RAVLT total, RAVLT delayed, phonemic verbal fluency and trail making test A only. Meta-regressions revealed no statistically significant effect of age, sex or follow-up interval on improvement in the MMSE. Our results suggest that shunt surgery is most sensitive for improving global cognition, learning and memory and psychomotor speed in patients with NPH.

Validation of a noninvasive test routinely used in otology for the diagnosis of cerebrospinal fluid shunt malfunction in patients with normal pressure hydrocephalus

OBJECT

Ventriculoperitoneal shunting is the first-line treatment for normal pressure hydrocephalus. Noninvasive auditory tests based on recorded otoacoustic emissions were assessed, as currently used for universal neonatal hearing screenings, for the diagnosis of cerebrospinal fluid shunt malfunction. The test was designed based on previous works, which demonstrated that an intracranial pressure change induces a proportional, characteristic, otoacoustic-emission phase shift.

METHODS

Forty-four patients with normal pressure hydrocephalus (23 idiopathic and 21 secondary cases) were included in this prospective observational study. The male:female sex ratio was 1.44, the age range was 21–87 years (mean age 64.3 years), and the range of the follow-up period was 1–3 years (mean 20 months). Patients were implanted with a Sophy SU8 adjustable-pressure valve as the ventriculoperitoneal shunt. The phase shifts of otoacoustic emissions in response to body tilt were measured preoperatively, immediately postoperatively, and at 3–6 months, 7–15 months, 16–24 months, and more than 24 months postoperatively. Three groups were enrolled: Group 1, 19 patients who required no valve opening-pressure adjustment; Group 2, 18 patients who required valve opening-pressure adjustments; and Group 3, 7 patients who required valve replacement.

RESULTS

In Group 1, phase shift, which was positive before surgery, became steadily negative after surgery and during the follow-up. In Group 2, phase shift, which was positive before surgery, became negative immediately after surgery and increasingly negative after a decrease in the valve-opening pressure. In Group 3, phase shift was positive in 6 cases and slightly negative in 1 case before revision, but after revision phase shift became significantly negative in all cases.

CONCLUSIONS

Otoacoustic emissions noninvasively reflect cerebrospinal fluid shunt function and are impacted by valve-opening pressure adjustments. Otoacoustic emissions consistently diagnosed shunt malfunction and predicted the need for surgical revision. The authors’ diagnostic test, which can be repeated without risk or discomfort by an unskilled operator, may address the crucial need of detecting valve dysfunction in patients with poor clinical outcome after shunt surgery.

CSF tap test - Obsolete or appropriate test for predicting shunt responsiveness? A systemic review

OBJECTIVES

There is no accurate test for diagnosing normal pressure hydrocephalus or for screening for patients who will benefit from shunt surgery. Additional tests, such as cerebrospinal fluid tap test (CSF-TT), are often used in practice to provide further predictive value in detecting suitable patients for shunting. We performed a systematic review of the literature to evaluate the CSF-TT's effect on the outcome of main symptoms and on validity parameters in screening patients suitable for shunting.

METHODS

In February 2015 we searched electronic databases from their inception to the current date, using the following key words: normal pressure hydrocephalus, idiopathic normotensive hydrocephalus, shunt operation, CSF tap test, predictive value, validity. The search retrieved 8 articles explicitly addressing the topic.

RESULTS

There was a very high positive predictive value of CSF-TT: 92% (range from 73% to 100%) but a low negative predictive value: 37% (18%-50%). Also, the CSF-TT has high specificity: 75% (33%-100%) but average sensitivity: 58% (26%-87%). The overall accuracy of the test was 62% (45%-83%).

CONCLUSIONS

This systematic review did not provide unambiguous validity of the CSF-TT in the screening of patients for shunting. The validity of the CSF-TT is good for patient inclusion for shunting due to the fact that the positive response to the test is very reliable. Unfortunately, the negative response to the test does not reliably make these patients ineligible for shunting. Further studies are needed to improve and standardize the methodology in order to optimize the detection power of the test.

Should ventriculoatrial shunting be the procedure of choice for normal-pressure hydrocephalus?

Object

Ventriculoatrial (VA) shunting is rarely used for patients with normal-pressure hydrocephalus (NPH), likely due to surgeon technical preference and case reports indicating cardiopulmonary complications. However, these complications have typically been limited to adults in whom VA shunts had been placed when they were children. Few studies have directly compared VA shunting to ventriculoperitoneal (VP) shunting in cases of NPH.

Methods

The authors retrospectively analyzed all NPH patients treated by a single surgeon at their center from January 2002 through December 2011. Thirty patients were treated with VA shunts (14 male) and 157 with VP shunts (86 male). The patients' mean age (± SD) at surgery was 73.7 ± 9.4 years for VA shunting and 76.0 ± 8.2 years for VP shunting; the median durations of follow-up were 42.0 months (IQR 19.2–63.6 months) and 34.2 months (IQR 15.8–67.5), respectively. Statistical analysis was performed using chi-square tests and Wilcoxon rank-sum tests.

Results

Perioperative and postoperative complications for VA and VP shunting cohorts, respectively, included distal revision (2.7% vs 6.6%, p = 0.45), proximal revision (2.7% vs 2.5%, p = 0.97), and postoperative seizure (2.7% vs 1.5%, p = 0.62). Shunt drainage–related subdural hematomas/hygromas developed in 8.1%/27.0% of VA shunt–treated patients versus 6.6%/26.4% of VP shunt–treated patients (p = 0.76/0.98) and were nearly always successfully managed with programmable-valve adjustment. Symptomatic intracerebral hemorrhage (1.5%) and shunt infection (2.0%) were only observed in those who underwent VP shunting. Of note, no cardiovascular complications were observed in any patient, and there were no cases of distal occlusion of the VA shunt.

Conclusions

The authors found no significant differences in complication rates between VA and VP shunting, and VA shunting was not associated with any cardiopulmonary complications. Thus, in the authors' experience, VA shunting is at least as safe as VP shunting for treating NPH.

Evaluation of coexistence of Alzheimer's disease in idiopathic normal pressure hydrocephalus using ELISA analyses for CSF biomarkers

BACKGROUND

We investigated levels of the β-amyloid 1-42 (Aβ42), total tau protein (T-tau) and tau phosphorylated at position threonine 181 (P-tau) in cerebrospinal fluid (CSF) of idiopathic normal pressure hydrocephalus (iNPH) patients and tried to find their clinical implications in the evaluation and treatment of iNPH.

METHOD

Twenty-five possible iNPH patients were prospectively enrolled and their CSF was collected to analyze levels of Aβ42, T-tau and P-tau using ELISA method. Gait disturbance, urinary incontinence, and cognitive impairment were semi-quantified and detailed neuropsychological (NP) test was performed.

RESULT

Eight iNPH patients were classified into the lower CSF Aβ42 group and 17 patients were classified into the higher CSF Aβ42 group. There was no difference in the iNPH grading score and its improvement after LP between the two groups. The lower CSF Aβ42 group showed more deficits in attention, visuospatial function and verbal memory in the baseline NP test and less improvement in phonemic categorical naming and frontal inhibitory function after LP.

CONCLUSIONS

Our study suggested that concomitant AD in iNPH patients might contribute to lumbar puncture or shunt unresponsiveness, especially in the field of cognitive dysfunction.

Gravity assisted vs. medium pressure valves for communicating hydrocephalus show similar valve-revision rates

BACKGROUND

Two common valve types used to treat hydrocephalus include gravity assisted valves (GAV) and medium pressure valves (MPV). Despite their different mechanism of action, differentiated surgical indications per type are not well defined. One could assume that due to a higher complexity of the GAV system, it may be more prone to valve-related malfunction. The purpose of this retrospective study was to compare the valve-related complication rates of GAV and MPV in patients with communicating hydrocephalus.

METHOD

Patients aged 16 years or older undergoing their first shunt implantation using GAV or MPV were included. We recorded demographic data, implantation diagnosis, outcome, complications, valve type and valve adjustments. Symptoms were documented at discharge and follow-up. Valve-related malfunctions were distinguished from other shunt complications.

RESULTS

N = 252 patients (range 16.6-88.4, mean 65.0 years, 116 male and 136 female) underwent shunt placement for the first time. N = 122 GAV (48.4 %) and n = 130 MPV were implanted (51.6 %) over a period of 5 years. The most frequent diagnoses were normal pressure hydrocephalus (NPH) in 86 cases (34.1 %) and posthemorrhagic hydrocephalus in 114 cases (45.2 %). About two thirds of patients were free of hydrocephalus-related symptoms at follow-up. N = 66 subjects (26.2 %) underwent at least one shunt revision. N = 29 revisions (11.5 %) were due to valve-related malfunction. Valve-related revisions were the main cause for revision in 18/37 cases (48.6 %) in the GAV group and in 11/29 (37.9 %) in the MPV group. Neither clinical improvement nor valve-related malfunctions were found to be statistically different among groups.

CONCLUSIONS

Despite their technical differences, GAV and MPV show similar valve-related revision rates in the treatment of communicating hydrocephalus.

Slight elevation of baseline intracranial pressure after fluid infusion into CSF space in patients with hydrocephalus

OBJECTIVE

To investigate the elevation of resting cerebrospinal fluid (CSF) pressure recorded after a CSF infusion test in patients with hydrocephalus.

MATERIAL AND METHODS

Fifty patients (30 men and 20 women, mean age 68 +/- 13 years) with ventriculomegaly and clinical symptoms of normal pressure hydrocephalus have been studied. Lumbar (56%) or intraventricular (44%) computerized infusion studies were performed to investigate the hydrodynamics of CSF. After infusion, the fall in ICP was recorded until a steady-state level was achieved and the difference between pre- and post-infusion resting ICP was calculated (DeltaICP).

RESULTS

A positive difference (>2 mm Hg) between post- and pre-infusion resting ICP was identified in 31 infusion tests (62%). The mean value of the difference was 6.7 with an SD of 3.5 mm Hg. The patients who demonstrated this phenomenon had a greater elastance coefficient (p>0.05); DeltaICP was positively correlated with age (R=0.27; p=0.03), with the size of the brain's ventricles (R=0.63, p=0.03) and inversely with the severity of clinical impairment (Stein-Langfitt score R=-0.61, p=0.02; normal pressure hydrocephalus score: R=0.54; p<0.05). DeltaICP was independent of the site of infusion (lumbar or ventricular).

CONCLUSION

In patients with a 'stiffer' brain, ICP returns to the resting level after the infusion test at a slightly higher level than before the test. The magnitude of this increase is greater when ventricles are more dilated and clinical symptoms are less severe.

A randomised trial of high and low pressure level settings on an adjustable ventriculoperitoneal shunt valve for idiopathic normal pressure hydrocephalus: results of the Dutch evaluation programme Strata shunt (DEPSS) trial

BACKGROUND

In treating idiopathic normal pressure hydrocephalus (INPH) with a shunt there is always a risk of underdrainage or overdrainage. The hypothesis is tested whether patients treated using an adjustable valve preset at the highest opening pressure leads to comparable good clinical results with less subdural effusions than in a control group with an opening pressure preset at a low pressure level.

METHODS

A multicentre prospective randomised trial was performed on a total of 58 patients suspected of INPH. Thirty patients were assigned to (control) group 1 and received a Strata shunt (Medtronic, Goleta, USA) with the valve preset at a performance level (PL) of 1.0, while 28 patients were assigned to group 2 and received a Strata shunt with the valve preset at PL 2.5. In this group the PL was allowed to be lowered until improvement or radiological signs of overdrainage were met.

RESULTS

Significantly more subdural effusions were observed in the improved patients of group 1. There was no statistically significant difference in improvement between both groups overall.

CONCLUSIONS

On the basis of this multicentre prospective randomised trial it is to be recommended to treat patients with INPH with a shunt with an adjustable valve, preset at the highest opening pressure and lowered until clinical improvement or radiological signs of overdrainage occur although slower improvement and more shunt adjustments might be the consequence.

Influence of comorbidities in idiopathic normal pressure hydrocephalus - research and clinical care. A report of the ISHCSF task force on comorbidities in INPH

Idiopathic normal pressure hydrocephalus (INPH) is a syndrome of ventriculomegaly, gait impairment, cognitive decline and incontinence that occurs in an elderly population prone to many types of comorbidities. Identification of the comorbidities is thus an important part of the clinical management of INPH patients. In 2011, a task force was appointed by the International Society for Hydrocephalus and Cerebrospinal Fluid Disorders (ISHCSF) with the objective to compile an evidence-based expert analysis of what we know and what we need to know regarding comorbidities in INPH. This article is the final report of the task force. The expert panel conducted a comprehensive review of the literature. After weighing the evidence, the various proposals were discussed and the final document was approved by all the task force members and represents a consensus of expert opinions. Recommendations regarding the following topics are given: I. Musculoskeletal conditions; II. Urinary problems; III. Vascular disease including risk factors, Binswanger disease, and white matter hyperintensities; IV. Mild cognitive impairment and Alzheimer disease including biopsies; V. Other dementias (frontotemporal dementia, Lewy body, Parkinson); VI. Psychiatric and behavioral disorders; VII. Brain imaging; VIII. How to investigate and quantify. The task force concluded that comorbidity can be an important predictor of prognosis and post-operative outcome in INPH. Reported differences in outcomes among various INPH cohorts may be partly explained by variation in the rate and types of comorbidities at different hydrocephalus centers. Identification of comorbidities should thus be a central part of the clinical management of INPH where a detailed history, physical examination, and targeted investigations are the basis for diagnosis and grading. Future INPH research should focus on the contribution of comorbidity to overall morbidity, mortality and long-term outcomes.

Programmable valve represents an efficient and safe tool in the treatment of idiopathic normal-pressure hydrocephalus patients

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by gait disturbance, dementia and /or urinary incontinence, dilation of the ventricular system and normal opening cerebrospinal fluid pressure. Shunt surgery is the standard treatment of iNHP. Diversions with programmable valves are recommended, once drainage pressure can be changed. However, well-defined protocols still lack guiding the steps to attain proper pressure for each patient. Methods: In our study, we reported the experience of shunting 24 patients with iNPH using Strata® (Medtronic) valve, following a protocol based on a positive Tap Test. Results: We observed clinical improvement in 20 patients and stability/worsening in 4 patients. Complications occurred in five patients, including one death. The results display improvement, and complications occurred at a lower rate than reported in other studies. Conclusions: The Strata® valve used in the proposed protocol represents an efficient and safe tool in the treatment of iNPH.

A new scale for assessment of severity and outcome in iNPH

OBJECTIVE

To present a new, continuous, calibrated and norm-based scale for the grading of severity and assessment of treatment outcome in idiopathic normal pressure hydrocephalus (iNPH).

PATIENTS AND METHODS

A scale designed for the assessment of the four domains, gait, neuropsychology, balance and continence, using ordinal ratings and continuous measures, was developed. Data from a series of 181 consecutive iNPH patients were used to calibrate the continuous parts of the scale and to describe the distributional properties of the ordinal ratings. Data from normative studies were used to determine the limits for normal scores.

RESULTS

The construction of the scale made it well equipped to separate iNPH patients at baseline, and the total scores assumed a bell-shaped, approximately normal distribution. All four domain scores correlated significantly with each other, underscoring the well-known syndromatic nature of iNPH, and justifying the use of a total score to describe the patients. Reliability [Cronbach's α for the total score = 0.74, and for the domains of gait and neuropsychology, 0.86 and 0.89, respectively) and validity estimates (convergent validity evaluated by Spearman rank correlations for the scale and the modified Rankin scale (ρ = -0.61) and the mini mental state examination (ρ = 0.57)] are satisfying.

CONCLUSION

The iNPH scale covers the four most important symptom domains and the full range of severity of the iNPH syndrome. The scale is sensitive, reliable, valid and feasible. We recommend that it should be used in future iNPH research.

One-year outcome in the European multicentre study on iNPH

OBJECTIVES

To assess the 1-year outcome after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH).

METHODS

Patients (n = 142) were prospectively included in the European multicentre study by 13 centres. Diagnoses were based solely on clinical and radiological findings. All received a programmable ventriculoperitoneal shunt. Re-examinations, 12 months after surgery, were performed in 115 patients, and the outcome was assessed by the modified Rankin scale (mRs) and a new iNPH grading scale. Improvement was defined as ≥1 step on the mRs and ≥5 points on the iNPH scale.

RESULTS

The scores on both scales were significantly improved after 1 year of shunt treatment (Ps < 0.001). Sixty-nine per cent of the patients were improved according to the mRs and 84% according to the iNPH scale. The proportion able to live independently (scores 0-2 on the mRs) was increased from 53% before to 82% 12 months after surgery (P < 0.001). Neither classification (typical or questionable) nor comorbidity affected the level of improvement. Patients not completing the study were worse off with regard to their clinical condition at entry than completers. Twenty-eight per cent of the patients experienced complications and were either conservatively (13%) or surgically (15%) treated.

CONCLUSION

The results of this prospective multicentre study on patients with iNPH diagnosed solely on clinical and radiological criteria support shunt surgery in patients presenting with symptoms and signs and MRI findings suggestive of iNPH.

Early evaluation of cerebral metabolic rate of glucose (CMRglu) with 18F-FDG PET/CT and clinical assessment in idiopathic normal pressure hydrocephalus (INPH) patients before and after ventricular shunt placement: preliminary experience

PURPOSE

We evaluated the relationships between the cerebral metabolic rate of glucose (CMRglu) measured by dynamic (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and the clinical and neuropsychological assessment before and after the surgical procedure in idiopathic normal pressure hydrocephalus (INPH) patients.

METHODS

Eleven selected INPH patients underwent clinical assessment (modified Rankin scale, Krauss scale, Larsson categorization system and Stein-Langfitt scale), cognitive evaluation (Mini-Mental State Examination, MMSE) and dynamic (18)F-FDG PET/CT scan 3 days before and 1 week after ventricular shunt placement.

RESULTS

After shunting, the global CMRglu significantly increased (2.95 ± 0.44 vs 4.38 ± 0.68, p = 10(-7)) in all INPH patients with a mean percentage value of 48.7%. After shunting, no significant change was found in the Evans ratio whereas a significant decrease in all clinical scale scores was observed. Only a slight reduction in the MMSE was found. After shunting, a significant correlation between the global CMRglu value and clinical assessment was found (R (2) = 0.75, p = 0.024); indeed all clinical scale scores varied (decreasing) and the CMRglu value also varied (increasing) in all INPH patients.

CONCLUSION

Our preliminary data show that changes in the CMRglu are promptly reversible after surgery and that there is a relationship between the early metabolic changes and clinical symptoms, independently from the simultaneous changes in the ventricular size. The remarkable and prompt improvement in the global CMRglu and in symptoms may also have important implications for the current concept of "neuronal plasticity" and for the cells' reactivity in order to recover their metabolic function.

Impact of duration of symptoms on CSF dynamics in idiopathic normal pressure hydrocephalus

OBJECTIVE

Cerebrospinal fluid (CSF) pressure-volume compensation may change over time as part of normal ageing, where the resistance to CSF outflow increases and the formation of CSF decreases with age. Is CSF compensation dependent on duration of symptoms in idiopathic normal pressure hydrocephalus (iNPH)?

METHODS

We investigated 92 patients presenting with iNPH. Mean age was 73 (range 47-86). There were 60 men and 32 women. They all presented with gait disturbance and ventricular dilatation. Memory deficit occurred in 72% and urinary incontinence in 52% of patients. All patients underwent computerized CSF infusion tests. Sixty-four shunted patients were available for follow-up, and their improvement was expressed using the NPH score.

RESULTS

Mean intracranial pressure (ICP) was 10.1±5.1 mmHg, and mean resistance to CSF outflow was 17.3±5.2 mmHg/(ml/min). Mean duration of symptoms was 24±19 months (range from 2 weeks to 86 months). Baseline ICP, magnitude of ICP pulse waveform, brain compliance and improvement after shunting (72% of patients improved) did not exhibit any dependency on the duration of symptoms. The resistance to CSF outflow showed a strong tendency to decrease in time with the duration of symptoms beyond 2 years (R= -0.702; P<0.005).

CONCLUSION

This is a preliminary observation, and it suggests that for patients with duration of symptoms longer than 2-3 years, the threshold for normal resistance to CSF outflow should be duration-adjusted.

Development and in-vitro characterization of an implantable flow sensing transducer for hydrocephalus

An implantable transducer for monitoring the flow of Cerebrospinal fluid (CSF) for the treatment of hydrocephalus has been developed which is based on measuring the heat dissipation of a local thermal source. The transducer uses passive telemetry at 13.56 MHz for power supply and read out of the measured flow rate. The in vitro performance of the transducer has been characterized using artificial Cerebrospinal Fluid (CSF) with increased protein concentration and artificial CSF with 10% fresh blood. After fresh blood was added to the artificial CSF a reduction of flow rate has been observed in case that the sensitive surface of the flow sensor is close to the sedimented erythrocytes. An increase of flow rate has been observed in case that the sensitive surface is in contact with the remaining plasma/artificial CSF mix above the sediment which can be explained by an asymmetric flow profile caused by the sedimentation of erythrocytes having increased viscosity compared to artificial CSF. After removal of blood from artificial CSF, no drift could be observed in the transducer measurement which could be associated to a deposition of proteins at the sensitive surface walls of the packaged flow transducer. The flow sensor specification requirement of +-10% for a flow range between 2 ml/h and 40 ml/h. could be confirmed at test conditions of 37 degrees C.

Selection of patients with idiopathic normal-pressure hydrocephalus for shunt placement: a single-institution experience

OBJECT

The ability to predict outcome after shunt placement in patients with idiopathic normal-pressure hydrocephalus (NPH) represents a challenge. To date, no single diagnostic tool or combination of tools has proved capable of reliably predicting whether the condition of a patient with suspected NPH will improve after a shunting procedure. In this paper, the authors report their experience with 120 patients with the goal of identifying CSF hydrodynamics criteria capable of selecting patients with idiopathic NPH. Specifically, they focused on the comparison between CSF-outflow resistance (R-out) and intracranial elastance (IE).

METHODS

Between January 1977 and December 2005, 120 patients in whom idiopathic NPH had been diagnosed (on the basis of clinical findings and imaging) underwent CSF hydrodynamics evaluation based on an intraventricular infusion test. Ninety-six patients underwent CSF shunt placement: 32 between 1977 and 1989 (Group I) on the basis of purely clinical and radiological criteria; 44 between 1990 and 2002 (Group II) on the basis of the same criteria as Group I and because they had an IE slope > 0.25; and 20 between 2003 and 2005 (Group III) on the basis of the same criteria as Group II but with an IE slope > or = 0.30. Outcomes were evaluated by means of both Stein-Langfitt and Larsson scores. Patients' conditions were considered improved when there was a stable decrease (at 6- and 12-month follow-up) of at least 1 point in the Stein-Langfitt score and 2 points in the Larsson score.

RESULTS

Group I: while no statistically significant difference in mean R-out value between improved and unimproved cases was observed, a clear-cut IE slope value of 0.25 differentiated very sharply between unimproved and improved cases. Group II: R-out values in the 2 unimproved cases were 20 and 47 mm Hg/ml/min, respectively. The mean IE slope in the improved cases was 0.56 (range 0.30-1.4), while the IE slopes in the 2 unimproved cases were 0.26 and 0.27. Group III: the mean IE slope was 0.51 (range 0.31-0.7). The conditions of all patients improved after shunting. A significant reduction of the Evans ratio was observed in 34 (40.5%) of the 84 improved cases and in none of the unimproved cases.

CONCLUSIONS

Our strategy based on the analysis of CSF pulse pressure parameters seems to have a great accuracy in predicting surgical outcome in clinical practice.

A pressure adjustment protocol for programmable valves

OBJECTIVE

There is no definite adjustment protocol for patients shunted with programmable valves. Therefore, we attempted to find an appropriate method to adjust the valve, initial valve-opening pressure, adjustment scale, adjustment time interval, and final valve-opening pressure of a programmable valve.

METHODS

Seventy patients with hydrocephalus of various etiologies were shunted with programmable shunting devices (Micro Valve with RICKHAM(R) Reservoir). The most common initial diseases were subarachnoid hemorrhage (SAH) and head trauma. Sixty-six patients had a communicating type of hydrocephalus, and 4 had an obstructive type of hydrocephalus. Fifty-one patients had normal pressure-type hydrocephalus and 19 patients had high pressure-type hydrocephalus. We set the initial valve pressure to 10-30 mmH(2)O, which is lower than the preoperative lumbar tapping pressure or the intraoperative ventricular tapping pressure, conducted brain computerized tomographic (CT) scans every 2 to 3 weeks, correlated results with clinical symptoms, and reset valve-opening pressures.

RESULTS

Initial valve-opening pressures varied from 30 to 180 mmH(2)O (mean, 102 +/- 27.5 mmH(2)O). In high pressure-type hydrocephalus patients, we have set the initial valve-opening pressure from 100 to 180 mmH(2)O. We decreased the valve-opening pressure 20-30 mmH(2)O at every 2- or 3-week interval, until hydrocephalus-related symptoms improved and the size of the ventricle was normalized. There were 154 adjustments in 81 operations (mean, 1.9 times). In 19 high pressure-type patients, final valve-opening pressures were 30-160 mmH(2)O, and 16 (84%) patients' symptoms had nearly improved completely. However, in 51 normal pressure-type patients, only 31 (61%) had improved. Surprisingly, in 22 of the 31 normal pressure-type improved patients, final valve-opening pressures were 30 mmH(2)O (16 patients) and 40 mmH(2)O (6 patients). Furthermore, when final valve-opening pressures were adjusted to 30 mmH(2)O, 14 patients symptom was improved just at the point. There were 18 (22%) major complications : 7 subdural hygroma, 6 shunt obstructions, and 5 shunt infections.

CONCLUSION

In normal pressure-type hydrocephalus, most patients improved when the final valve-opening pressure was 30 mmH(2)O. We suggest that all normal pressure-type hydrocephalus patients be shunted with programmable valves, and their initial valve-opening pressures set to 10-30 mmH(2)O below their preoperative cerebrospinal fluid (CSF) pressures. If final valve-opening pressures are lowered in 20 or 30 mmH(2)O scale at 2- or 3-week intervals, reaching a final pressure of 30 mmH(2)O, we believe that there is a low risk of overdrainage syndromes.

White matter diffusion is higher in Binswanger disease than in idiopathic normal pressure hydrocephalus

OBJECTIVES

To explore diagnostic differences in periventricular white matter (PWM) and deep white matter (DWM) diffusion patterns in patients diagnosed with Binswanger disease (BD) and in patients diagnosed with probable idiopathic normal pressure hydrocephalus (INPH) using diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

Apparent diffusion coefficient (ADC) values were calculated in the PWM and DWM in patients with INPH (n = 14) and BD (n = 9) and in controls (n = 10) using an spin echo echo planar imaging single-shot diffusion sequence and region of interest (ROI) analysis.

RESULTS

Patients with BD had higher ADC values than patients with INPH in the PWM and DWM in the frontal and occipital regions (P < 0.05) and higher values than controls in the frontal PWM and DWM (P < 0.01). After shunt surgery, ADC values were reduced in the frontal PWM in patients with INPH (P < 0.05).

CONCLUSIONS

Increased diffusion in the PWM and DWM in patients with BD may reflect irreversible breakdown of axonal integrity caused by the subcortical ischaemic vascular disease. By contrast, the normal white matter diffusion in patients with INPH indicates structurally intact axons, compatible with the reversibility of this disorder. DWI may be an important non-invasive diagnostic tool for differentiating between INPH and BD and identifying shunt responders and reversible brain damage in patients with INPH. However, the overlap between patients with INPH and BD in this study restricts the predictive value of the method.