Risk Analysis Index as a preoperative frailty tool for elective ventriculoperitoneal shunt surgery for idiopathic normal pressure hydrocephalus

OBJECTIVE

Idiopathic normal pressure hydrocephalus (iNPH) predominantly occurs in older patients, and ventriculoperitoneal shunt (VPS) placement is the definitive surgical treatment. VPS surgery carries significant postoperative complication rates, which may tip the risk/benefit balance of this treatment option for frail, or higher-risk, patients. In this study, the authors investigated the use of frailty scoring for preoperative risk stratification for adverse event prediction in iNPH patients who underwent elective VPS placement.

METHODS

The Nationwide Readmissions Database (NRD) was queried from 2018 to 2019 for iNPH patients aged ≥ 60 years who underwent VPS surgery. Risk Analysis Index (RAI) and modified 5-item Frailty Index (mFI-5) scores were calculated and RAI cross-tabulation was used to analyze trends in frailty scores by the following binary outcome measures: overall complications, nonhome discharge (NHD), extended length of stay (eLOS) (> 75th percentile), and mortality. Area under the receiver operating characteristic curve analysis was performed to assess the discriminatory accuracy of RAI and mFI-5 for primary outcomes.

RESULTS

A total of 9319 iNPH patients underwent VPS surgery, and there were 685 readmissions (7.4%), 593 perioperative complications (6.4%), and 94 deaths (1.0%). Increasing RAI score was significantly associated with increasing rates of postoperative complications: RAI scores 11-15, 5.4% (n = 80); 16-20, 5.6% (n = 291); 21-25, 7.6% (n = 166); and ≥ 26, 11.6% (n = 56). The discriminatory accuracy of RAI was statistically superior (DeLong test, p < 0.05) to mFI-5 for the primary endpoints of mortality, NHD, and eLOS. All RAI C-statistics were > 0.60 for mortality within 30 days (C-statistic = 0.69, 95% CI 0.68-0.70).

CONCLUSIONS

In a nationwide database analysis, increasing frailty, as measured by RAI, was associated with NHD, 30-day mortality, unplanned readmission, eLOS, and postoperative complications. Although the RAI outperformed the mFI-5, it is essential to account for the potentially reversible clinical issues related to the underlying disease process, as these factors may inflate frailty scores, assign undue risk, and diminish their utility. This knowledge may enhance provider understanding of the impact of frailty on postoperative outcomes for patients with iNPH, while highlighting the potential constraints associated with frailty assessment tools.

Freezing of gait in idiopathic normal pressure hydrocephalus

BACKGROUND

Reports of freezing of gait (FoG) in idiopathic normal pressure hydrocephalus (iNPH) are few and results are variable. This study's objective was to evaluate the frequency of FoG in a large cohort of iNPH patients, identify FoG-associated factors, and assess FoG's responsiveness to shunt surgery.

METHODS

Videotaped standardized gait protocols with iNPH patients pre- and post-shunt surgery (n = 139; median age 75 (71-79) years; 48 women) were evaluated for FoG episodes by two observers (Cohens kappa = 0.9, p < 0.001). FoG episodes were categorized. Mini-mental state examination (MMSE) and MRI white matter hyperintensities (WMH) assessment using the Fazekas scale were performed. CSF was analyzed for Beta-amyloid, Tau, and Phospho-tau. Patients with and without FoG were compared.

RESULTS

Twenty-two patients (16%) displayed FoG at baseline, decreasing to seven (8%) after CSF shunt surgery (p = 0.039). The symptom was most frequently exhibited during turning (n = 16, 73%). Patients displaying FoG were older (77.5 vs. 74.6 years; p = 0.029), had a slower walking speed (0.59 vs. 0.89 m/s; p < 0.001), a lower Tinetti POMA score (6.8 vs. 10.8; p < 0.001), lower MMSE score (21.3 vs. 24.0; p = 0.031), and longer disease duration (4.2 vs. 2.3 years; p < 0.001) compared to patients not displaying FoG. WMH or CSF biomarkers did not differ between the groups.

CONCLUSIONS

FoG is occurring frequently in iNPH patients and may be considered a typical feature of iNPH. FoG in iNPH was associated with higher age, longer disease duration, worse cognitive function, and a more unstable gait. Shunt surgery seems to improve the symptom.

Cerebrospinal fluid shunt surgery reduces the risk of developing dementia and Alzheimer's disease in patients with idiopathic normal pressure hydrocephalus: a nationwide population-based propensity-weighted cohort study

BACKGROUND

Patients with idiopathic normal-pressure hydrocephalus (iNPH) are predisposed to developing dementing disorders. Cerebrospinal fluid (CSF) shunt implantation is a treatment used to improve the motor and cognitive disabilities of these patients; however, its effect on the risk of developing dementing disorders remains unclear. We conducted a population-based propensity-weighted cohort study to investigate whether CSF shunt surgery may reduce the risk of subsequently developing dementia, Alzheimer's disease (AD), and vascular dementia in iNPH patients.

METHODS

Patients aged ≥ 60 years who were diagnosed with iNPH (n = 2053) between January 2001 and June 2018 were identified from the Taiwan National Health Insurance Research Database. Various demographic characteristics (age, sex, and monthly income) and clinical data (incidence year, comorbidities, and Charlson comorbidity index) were collected and divided into the shunt surgery group (SSG) and the non-shunt surgery group (NSSG). Stabilized inverse probability of treatment weighting by using the propensity score was performed to achieve a balanced distribution of confounders across the two study groups. The cumulative incidence rate and risk of dementing disorders were estimated during a 16-year follow-up period.

RESULTS

After weighting, the data of 375.0 patients in SSG and 1677.4 patients in NSSG were analyzed. Kaplan-Meier curve analysis indicated that the cumulative incidence rate of AD (p = 0.009), but not dementia (p = 0.241) and vascular dementia (p = 0.761), in SSG was significantly lower than that in NSSG over the 16-year follow-up period. Cox proportional hazards regression analysis revealed that SSG had a reduced hazard ratio (HR) for developing AD [HR (95% CI) 0.17 (0.04-0.69)], but not for dementia [HR (95% CI) 0.83 (0.61-1.12)] and vascular dementia [HR (95% CI) 1.18 (0.44-3.16)], compared with NSSG. Further Fine-Gray hazard regression analysis with death as a competing event demonstrated that SSG had a reduced subdistribution HR (sHR) for developing dementia [sHR (95% CI) 0.74 (0.55-0.99)] and AD [sHR (95% CI) 0.15 (0.04-0.61)], but not for vascular dementia [sHR (95% CI) 1.07 (0.40-2.86)].

CONCLUSION

CSF shunt surgery is associated with reduced risks of the subsequent development of dementia and AD in iNPH patients. Our findings may provide valuable information for assessing the benefit-to-risk profile of CSF shunt surgery.

In vivo assessment of the ocular biomechanical properties in patients with idiopathic normal pressure hydrocephalus

PURPOSE

Idiopathic normal pressure hydrocephalus (iNPH) is associated with an increased prevalence of open-angle glaucoma, attributed to variations of the pressure gradient between intraocular and intracranial compartments at the level of the lamina cribrosa (LC). As ocular biomechanics influence the behavior of the LC, and a lower corneal hysteresis (CH) has been associated to a higher risk of glaucomatous optic nerve damage, in this study we compared ocular biomechanics of iNPH patients with healthy subjects.

METHODS

 Twenty-four eyes of 24 non-shunted iNPH patients were prospectively recruited. Ocular biomechanical properties were investigated using the ocular response analyzer (Reichert Instruments) for the calculation of the CH, corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc). Results were compared with those of 25 eyes of 25 healthy subjects.

RESULTS

 In iNPH eyes, the median CH value and interquartile range (IQR) were 9.7 mmHg (7.8-10) and 10.6 mmHg (9.3-11.3) in healthy controls (p = 0.015). No significant differences were found in IOPcc [18.1 mmHg (14.72-19.92) vs. 16.4 mmHg (13.05-19.6)], IOPg [15.4 mmHg (12.82-19.7) vs. 15.3 mmHg (12.55-17.35)], and CRF [9.65 mmHg (8.07-11.65) vs. 10.3 mmHg (9.3-11.5)] between iNPH patients and controls.

CONCLUSIONS

 In iNPH patients, the CH was significantly lower compared to healthy subjects. This result suggests that ocular biomechanical properties may potentially contribute to the risk of development of glaucomatous optic nerve damage in iNPH patients.

[Preoperative Predictors of Outcomes of Cerebrospinal Fluid Shunt Surgery in Patients with Idiopathic Normal Pressure Hydrocephalus]

The disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings on cranial images are useful to predict cerebrospinal fluid (CSF) shunt responsiveness to some extent in patients with idiopathic normal-pressure hydrocephalus (iNPH). However, recent studies show that patients with iNPH often have concomitant Alzheimer's or Lewy body disease regardless of DESH findings, which may be associated with poor outcomes of CSF shunt surgery. Moreover, long-term outcomes after CSF shunt surgery in patients with iNPH, which is one of the most important issues to be addressed for effective treatment of iNPH, remain unknown.

[Neuropathology of Idiopathic Normal Pressure Hydrocephalus: A Study of Three Autopsy Cases and a Literature Review]

We present neuropathological findings in three autopsy brains from patients diagnosed clinically with idiopathic normal pressure hydrocephalus (iNPH) in Japan; still, specific findings of iNPH remain unclear. Comorbid atherosclerosis and hypertensive microvascular diseases, including arterio- and arteriolosclerosis and ischemic changes in the brain parenchyma, are frequently (65%) observed in autopsy brain tissue from patients with iNPH, which has drawn attention to the clinicopathological similarities and differences between iNPH and Binswanger's disease. Additionally, Aβ protein deposition and phosphorylated tau-positive neurofibrillary tangles and neuropil threads are observed in cerebral cortical biopsy specimens obtained during intracranial pressure monitoring or shunt surgery among a subset of patients with iNPH. These findings are as frequent as those reported in autopsy data of the age-matched general population. Alterations in aquaporin-4 expression in the cerebral cortex have also been reported, suggestive of a possible association with altered volume or composition of the interstitial fluid in the microenvironment, particularly in the vicinity of capillaries, or glymphatic system dysfunction and consequent altered interstitial fluid drainage. Greater understanding of the normal anatomical structures and pathways involved in cerebrospinal fluid circulation, particularly in absorption and drainage, in the craniospinal region is essential for better clarity regarding iNPH neuropathology.

[Recent Developments in Diagnostic Imaging for Idiopathic Normal Pressure Hydrocephalus]

Idiopathic normal pressure hydrocephalus (iNPH), a syndrome characterized by cognitive impairment, gait abnormalities, and urinary incontinence attributable to cerebrospinal fluid circulatory insufficiency, is associated with an obscure etiology. Several methodologies and imaging analysis techniques, including visualization of cerebral hemodynamics and diffusion tensor imaging have emerged in recent years to determine functional alterations in cases of iNPH. These advancements have led to more comprehensive understanding of the pathophysiological mechanisms underlying iNPH. In this article, we discuss the historical evolution of imaging modalities for iNPH and contemporaneous imaging techniques designed to acquire deeper insight into this disease.

Intraventricular Shunt Catheter Placement of Adult Normal Pressure Hydrocephalus Using an AxiEMTM Electromagnetic Neuronavigation System: A Single-Center Experience

AIM

To prove the superiority of the electromagnetic (EM) neuronavigation technique to increase the accuracy of intraventicular shunt catheter placement, and to reduce accompanying complications.

MATERIAL AND METHODS

A total of 21 patients with hydrocephalus [age range (years): 53-84] were studied. All of them had undergone thin-slice, navigation-compatible, computed tomography (CT) preoperatively. Shunt surgery was performed under the guidance of EM neuronavigation technology. All patients underwent follow-up CT the next day to evaluate catheter tip placement and were followed up at 1, 3, 6, and 12 months.

RESULTS

All catheter tips were placed properly in front of the foramen of Monro in the desired position, except in one case in which the tip migrated to the perimesencephalic cistern and underwent reoperation in the early postoperative period. No complications due to infection and obstruction were observed in the medium- and long-term follow-ups. The complication rate due to the incorrect catheter positioning was 4.76% of the total cases.

CONCLUSION

The placement of the ventricular catheter under EM-guided navigation technology reduces the proximal-end failure caused by malpositioning, obstruction, and infection.

Rey Auditory Verbal Learning Test in idiopathic normal pressure hydrocephalus and Alzheimer's disease

Objective: This study aims to evaluate the ability of the Rey Auditory Verbal Learning Test (RAVLT), to separate the early stages of idiopathic normal pressure hydrocephalus (iNPH) from Alzheimer's disease (AD), both in comparison to each other and to healthy individuals (HI). Method: The RAVLT performance regarding learning, recall and recognition, was analyzed in three matched samples comprising 30 HI, 84 participants with AD and 84 with iNPH. The clinical samples were divided into two subgroups based on scores on the MMSE, High performers (27-30 points, n = 30) and Medium performers (18-26 points, n = 54). Results: Memory performance was significantly impaired in both clinical samples relative to HI, even in the comparisons with the subgroups consisting of only High-MMSE performers. Despite similar results on measures capturing learning, the iNPH patients outperformed AD patients on measures of recall and recognition. Conclusions: Learning impairment occurs early in iNPH and AD alike, when MMSE performance is still within normal limits. RAVLT measures of delayed recall and recognition are less affected in iNPH than in AD and may serve as differential diagnostic neuropsychological markers.

A role for mutations in AK9 and other genes affecting ependymal cells in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is an enigmatic neurological disorder that develops after age 60 and is characterized by gait difficulty, dementia, and incontinence. Recently, we reported that heterozygous CWH43 deletions may cause iNPH. Here, we identify mutations affecting nine additional genes (AK9, RXFP2, PRKD1, HAVCR1, OTOG, MYO7A, NOTCH1, SPG11, and MYH13) that are statistically enriched among iNPH patients. The encoded proteins are all highly expressed in choroid plexus and ependymal cells, and most have been associated with cilia. Damaging mutations in AK9, which encodes an adenylate kinase, were detected in 9.6% of iNPH patients. Mice homozygous for an iNPH-associated AK9 mutation displayed normal cilia structure and number, but decreased cilia motility and beat frequency, communicating hydrocephalus, and balance impairment. AK9+/- mice displayed normal brain development and behavior until early adulthood, but subsequently developed communicating hydrocephalus. Together, our findings suggest that heterozygous mutations that impair ventricular epithelial function may contribute to iNPH.

Use of cortical volume to predict response to temporary CSF drainage in patients with idiopathic normal pressure hydrocephalus

OBJECTIVE

Temporary drainage of CSF with lumbar puncture or lumbar drainage has a high predictive value for identifying patients with suspected idiopathic normal pressure hydrocephalus (iNPH) who may benefit from ventriculoperitoneal shunt insertion. However, it is unclear what differentiates responders from nonresponders. The authors hypothesized that nonresponders to temporary CSF drainage would have patterns of reduced regional gray matter volume (GMV) as compared with those of responders. The objective of the current investigation was to compare regional GMV between temporary CSF drainage responders and nonresponders. Machine learning using extracted GMV was then used to predict outcomes.

METHODS

This retrospective cohort study included 132 patients with iNPH who underwent temporary CSF drainage and structural MRI. Demographic and clinical variables were examined between groups. Voxel-based morphometry was used to calculate GMV across the brain. Group differences in regional GMV were assessed and correlated with change in results on the Montreal Cognitive Assessment (MoCA) and gait velocity. A support vector machine (SVM) model that used extracted GMV values and was validated with leave-one-out cross-validation was used to predict clinical outcome.

RESULTS

There were 87 responders and 45 nonresponders. There were no group differences in terms of age, sex, baseline MoCA score, Evans index, presence of disproportionately enlarged subarachnoid space hydrocephalus, baseline total CSF volume, or baseline white matter T2-weighted hyperintensity volume (p > 0.05). Nonresponders demonstrated decreased GMV in the right supplementary motor area (SMA) and right posterior parietal cortex as compared with responders (p < 0.001, p < 0.05 with false discovery rate cluster correction). GMV in the posterior parietal cortex was associated with change in MoCA (r2 = 0.075, p < 0.05) and gait velocity (r2 = 0.076, p < 0.05). Response status was classified by the SVM with 75.8% accuracy.

CONCLUSIONS

Decreased GMV in the SMA and posterior parietal cortex may help identify patients with iNPH who are unlikely to benefit from temporary CSF drainage. These patients may have limited capacity for recovery due to atrophy in these regions that are known to be important for motor and cognitive integration. This study represents an important step toward improving patient selection and predicting clinical outcomes in the treatment of iNPH.

Idiopathic normal pressure hydrocephalus possibly affects the occurrence of proximal femoral fracture

AIMS

The clinical triad of idiopathic normal pressure hydrocephalus (iNPH) includes gait disturbance, dementia, and urinary incontinence. These symptoms are also frequently observed in patients with proximal femoral fracture (PFF). The aim of this study was to investigate the relationship between PFF and iNPH retrospectively.

PATIENTS AND METHODS

Of the130 patients over 80-years-old with PFF included in this study, 48 were assigned to the PFF group. Forty-eight patients with peripheral vertigo matched with the PFF group for age and sex were included in the control group. We compared the Evans' index (EI), which is a head computed tomography finding of iNPH, and the percentages of patients with EI>0.3 between the two groups. The PFF group was further divided into two subgroups depending on whether EI was higher or lower than 0.3 (the higher or lower subgroup, respectively). We compared the patient's gait abilities before PFF, causes of PFF, cognitive functions, and occurrence of urinary incontinence between both groups.

RESULTS

The mean value of EI in the PFF group was significantly higher than that in the control group (PFF group, 0.301; control group, 0.284; p=0.008). The percentages of patients with EI>0.3 in the PFF and control groups were 62.5% and 35.4%, respectively (p=0.014). In subgroup analyses, the gait ability before injury was worse in the higher subgroup than that in the lower subgroup and was prominent among individuals who could walk only with human assistance (p=0.018). There were no significant differences in other parameters.

CONCLUSION

Elderly patients with PFF may have underlying idiopathic normal pressure hydrocephalus.

LEVEL OF EVIDENCE

III; case-control comparative study.

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.

A - 20 Do Alzheimer's Disease Biomarkers Impact Normal Pressure Hydrocephalus Lumbar Drain Trial Outcomes

OBJECTIVE

Distinguishing normal pressure hydrocephalus (NPH) from Alzheimer's disease (ad) would aid patient selection for lumbar drain trials (LDT). Cerebrospinal fluid (CSF) ad biomarkers are altered in NPH, limiting interpretation. This study examines the utility of CSF ad biomarkers in predicting gait and cognitive outcomes in patients undergoing LDT.

METHODS

127 patients underwent LDT. CSF ad biomarkers from Mayo Clinic Laboratories (MCL) or Athena Diagnostics were used to classify patients as ad, non-ad, or indeterminate. MCL indeterminate results were further classified as suspected ad, non-ad, or suspected NPH (sNPH) using a derived p-tau threshold (>15 pg/mL & Aß42 <=1026 pg/mL)1. Cognitive improvement was determined using reliable change indices for Trail Making Test A&B and Hopkins Verbal Learning Test-Revised. Physical therapists (PT) utilized the Berg Balance Scale and/or the Timed Up and Go to determine gait improvements. Chi-square tests investigated relationships between diagnostic groups, PT and cognitive improvements, and eventual shunting for the whole sample and then stratified by the two laboratory assays.

RESULTS

The sNPH group had the highest percentage of PT (63%-70%) and cognitive (9% -11%) improvement (see Table 1), while the ad group had the lowest (50% and 3%, respectively). The sNPH group underwent shunting more (56%-68%) compared to the ad and non-ad groups (47%). Relationships, however, were not statistically significant (p > 0.05).

CONCLUSION

Patients with sNPH CSF ad biomarker profiles demonstrated clinically meaningful physical improvements and underwent shunting more frequently than those with ad or non-ad biomarker profiles. This highlights the potential for CSF ad biomarkers in predicting NPH treatment response.

A - 99 Older Adult Male with Idiopathic Normal Pressure Hydrocephalus (iNPH): Neuropsychological Case Study

OBJECTIVE

Idiopathic normal pressure hydrocephalous (iNPH) is a potentially reversible syndrome characterized by ventriculomegaly. Parkinsonism is an often-overlooked clinical feature of iNPH. Mostile et al. (2022) argued that the diagnostic iNPH "triad" should be reconsidered as a "tetrad" including parkinsonism. This case will discuss iNPH presenting with parkinsonism. Patient is an 81-year-old male with a history of iNPH with Hakim's triad. His medical history includes hyperlipidemia, hypertension, deep vein thrombosis, benign prostatic hyperplasia, total knee replacement, and chronic depression. Presenting concerns were continued cognitive and gait impairments.

METHOD

Patient was referred from his physiatrist for evaluation of his cognitive functioning and assistance with discharge planning in an acute inpatient rehabilitation hospital. Patient was neuropsychologically evaluated to clarify the etiology of his cognitive presentation.

RESULTS

Patient's cognitive profile was impaired in areas of attention, executive functioning, processing speed, visuoperception, and displayed a subcortical memory profile. Patient had intact functioning in areas of oral reading, naming, and working memory. Motor examination was evident for apraxia, task-specific tremor, and micrographia.

CONCLUSIONS

This case report provides additive findings for common presentation of iNPH including parkinsonism presenting with comorbid psychiatric and medical confounders, highlighting the need for further research on neuropsychological profile of iNPH post shunt procedure. It also accentuates the need to accept parkinsonism as one of the common presentations of iNPH. Akinesia has been reported in nearly 70% of iNPH cases (Krauss et al, 1997), with bradykinesia and postural instability being the main parkinsonian features. Asymmetry and resting tremor were seen to be uncommon (Molde et al., 2017).

Idiopathic Intracranial Hypertension with Disproportionately Enlarged Subarachnoid Space Hydrocephalus on Imaging

The pathophysiology of idiopathic intracranial hypertension (IIH) and idiopathic normal-pressure hydrocephalus (iNPH) differs in terms of cerebrospinal fluid (CSF) pressure and imaging-related characteristics. A 51-year-old man presented with optic nerve papillary edema, visual disturbance, bilateral abducens nerve palsy, and a wide-based gait. Imaging showed characteristic findings of IIH and disproportionately enlarged subarachnoid space hydrocephalus (DESH) - characteristic of iNPH. A CSF examination revealed marked CSF hypertension. IIH with iNPH-like imaging features (DESH) was diagnosed, and ventriculoperitoneal shunt surgery was performed. Postoperatively, the visual acuity and visual field improved. This report also describes the distinct and overlapping pathophysiological mechanisms of IIH and iNPH.

Prevalence of Fecal Incontinence in Normal Pressure Hydrocephalus: A Prospective Evaluation of 100 Patients

BACKGROUND

Normal pressure hydrocephalus (NPH) is a frequent disease in elderly patients. The main symptoms are gait disturbance, urine incontinence, and cognitive decline. Fecal urgency and incontinence are described as rare additional symptoms; however, no exact numbers are known. The aim of this study was to investigate the prevalence of fecal disturbances in NPH patients.

METHODS

Patients who presented to our department with confirmed diagnosis of NPH between January and December 2021 were interviewed prospectively about fecal function. Additionally, the extent of gait disturbance, cognitive decline, ventriculomegaly (EvansIndex), disproportionate enlarged subarachnoid space hydrocephalus (DESH presence), age, gender, and length of history were documented. In those who were operated with a hydrocephalus shunt postoperative development of stool incontinence was followed up.

RESULTS

One hundred patients were evaluated (67 males, 33 females, medium age 77.5 years, medium Evans Index: 0.37; 87 with disproportionate enlarged subarachnoid space hydrocephalus). 97 patients showed gait disturbance, 84 cognitive decline, and 87 bladder dysfunctions. 78 patients had the complete Hakim triad. 32 patients complained about fecal incontinence (20 with urge incontinence, 12 with complete incontinence). Twenty nine patients were shunted, of which 17 (57%) recovered completely, 9 (31%) partially, and 3 (10%) did not show any change.

CONCLUSIONS

Fecal urgency and incontinence is a frequent finding in NPH (32%) and is essential for the quality of life. In the general population, fecal incontinence in elderly is found in up to 15%. The more than two-fold higher prevalence in NPH patients and the high percentage of postshunted improvement suggests that NPH causes often directly fecal disturbance.

Longitudinal post-shunt outcomes in idiopathic normal pressure hydrocephalus with and without comorbid Alzheimer's disease

OBJECTIVE

Alzheimer's disease (AD) is highly comorbid with idiopathic normal pressure hydrocephalus (iNPH) and may diminish the benefits of shunting; however, findings in this area are mixed. We examined postoperative outcomes, with emphases on cognition and utilization of novel scoring procedures to enhance sensitivity.

METHODS

Using participant data from an iNPH outcome study at Butler Hospital, a mixed effect model examined main and interaction effects of time since surgery (baseline, 3 months, 12 months, and 24-60 months) and AD comorbidity (20 iNPH and 11 iNPH+AD) on activities of daily living (ADLs) and iNPH symptoms. Regression modeling explored whether baseline variables predicted improvements 3 months postoperatively.

RESULTS

There were no group differences in gait, incontinence, and global cognition over time, and neither group showed changes in ADLs. Cognitive differences were observed postoperatively; iNPH patients showed stable improvements in working memory (p = 0.012) and response inhibition (p = 0.010), while iNPH + AD patients failed to maintain initial gains. Regarding predicting postoperative outcomes, baseline AD biomarkers did not predict shunt response at 3 months; however, older age at surgery predicted poorer cognitive outcomes (p = 0.04), and presurgical Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) (p = 0.035) and Mini-Mental Status Examination (MMSE) scores (p = 0.009) predicted improvements incontinence.

CONCLUSION

iNPH + AD may be linked with greater declines in aspects of executive functioning postoperatively relative to iNPH alone. While baseline AD pathology may not prognosticate shunt response, younger age appears linked with postsurgical cognitive improvement, and utilizing both brief and comprehensive cognitive measures may help predict improved incontinence. These results illustrate the potential benefits of surgery and inform postoperative expectations for those with iNPH + AD.

Cerebrospinal fluid amyloid beta and response of cognition to a tap test in idiopathic normal pressure hydrocephalus: a case-control study

OBJECTIVES

To examine the relationship between cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) and tap test response to elucidate the effects of comorbidity of AD in idiopathic normal-pressure hydrocephalus (iNPH).

DESIGN

Case-control study.

SETTING

Osaka University Hospital.

PARTICIPANTS

Patients with possible iNPH underwent a CSF tap test.

MEASUREMENTS

Concentrations of amyloid beta (Aβ) 1-40, 1-42, and total tau in CSF were measured. The response of tap test was judged using Timed Up and Go test (TUG), 10-m reciprocation walking test (10MWT), Mini-Mental State Examination (MMSE), and iNPH grading scale. The ratio of Aβ1-42 to Aβ1-40 (Aβ42/40 ratio) and total tau concentration was compared between tap test-negative (iNPH-nTT) and -positive (iNPH-pTT) patients.

RESULTS

We identified 27 patients as iNPH-nTT and 81 as iNPH-pTT. Aβ42/40 ratio was significantly lower (mean [SD] = 0.063 [0.026] vs. 0.083 [0.036], p = 0.008), and total tau in CSF was significantly higher (mean [SD] = 385.6 [237.2] vs. 293.6 [165.0], p = 0.028) in iNPH-nTT than in iNPH-pTT. Stepwise logistic regression analysis revealed that low Aβ42/40 ratio was significantly associated with the negativity of the tap test. The response of cognition was significantly related to Aβ42/40 ratio. The association between Aβ42/40 ratio and tap test response, especially in cognition, remained after adjusting for disease duration and severity at baseline.

CONCLUSIONS

A low CSF Aβ42/40 ratio is associated with a poorer cognitive response, but not gait and urinary response, to a tap test in iNPH. Even if CSF biomarkers suggest AD comorbidity, treatment with iNPH may be effective for gait and urinary dysfunction.

Cerebral Microbleeds-Long-Term Outcome After Cerebrospinal Fluid Shunting in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Cerebral microbleeds (CMBs) are common in idiopathic normal pressure hydrocephalus (INPH) and have been suggested as radiological markers of a brain prone to bleeding. The presence of CMBs might be relevant when selecting patients for shunt surgery.

OBJECTIVE

To evaluate whether CMBs increases long-term risk of hemorrhagic complications and mortality or affects outcomes after cerebrospinal fluid shunt surgery in a cohort of patients with INPH.

METHODS

One hundred and forty nine shunted patients with INPH (mean age, 73 years) were investigated with MRI (T2* or susceptibility-weighted imaging sequences) preoperatively. CMBs were scored with the Microbleed Anatomic Rating Scale. Patients were observed for a mean of 6.5 years (range 2 weeks to 13 years) after surgery. Hemorrhagic events and death were noted. Improvement in gait was evaluated 3 to 6 months after surgery.

RESULTS

At baseline, 74 patients (50%) had CMBs. During follow-up, 7 patients (5%) suffered a hemorrhagic stroke and 43 (29%) suffered a subdural hematoma/hygroma with a median time from surgery of 30.2 months (IQR 50). Overall, having CMBs was not associated with suffering a subdural hematoma/hygroma or hemorrhagic stroke during follow-up with 1 exception that an extensive degree of CMBs (≥50 CMB) was more common in patients suffering a hemorrhagic stroke ( P = .03). CMBs were associated with increased mortality ( P = .02, Kaplan-Meier, log-rank test). The presence of CMBs did not affect gait outcome ( P = .28).

CONCLUSION

CMBs were associated with hemorrhagic stroke and mortality. CMBs do not seem to reduce the possibility of gait improvement after shunt surgery or contribute to the risk of hemorrhagic complications regarding subdural hematoma or hygroma.

Enhanced recovery after surgery in patients with normal pressure hydrocephalus undergoing ventriculoperitoneal shunting procedures

OBJECTIVE

Patients with idiopathic normal pressure hydrocephalus (iNPH) who undergo ventriculoperitoneal shunt (VPS) placement often belong to an older demographic, putting them at increased risk of postoperative delirium and related complications. Recent literature documenting the use of Enhanced Recovery After Surgery (ERAS) protocols in various disciplines of surgery has shown improved clinical outcomes, faster discharge, and lower readmission rates. Early return to a familiar environment (i.e., discharged home) is a well-known predictor of reduced postoperative delirium. However, ERAS protocols are uncommon in neurosurgery, especially intracranial procedures. We developed a novel ERAS protocol for patients with iNPH undergoing VPS placement to gain further insight regarding postoperative complications, specifically delirium.

METHODS

We studied 40 patients with iNPH with indications for VPS. Seventeen patients were selected at random to undergo the ERAS protocol, and twenty-three patients underwent the standard VPS protocol. The ERAS protocol consisted of measures to reduce infection, manage pain, minimize invasiveness, confirm procedural success with imaging, and shorten the length of stay. Pre-operative American Society of Anesthesiologists (ASA) grade was collected for each patient to indicate baseline risk. Rates of readmission and postoperative complications, including delirium and infection, were collected at 48 h, 2 weeks, and 4 weeks postoperatively.

RESULTS

There were no perioperative complications among the 40 patients. There was no postoperative delirium in any of the ERAS patients. Postoperative delirium was observed in 10 of 23 non-ERAS patients. There was no statistically significant difference between the ASA grade between the ERAS and non-ERAS groups.

CONCLUSIONS

We described a novel ERAS protocol for patients with iNPH receiving VPS focusing on an early discharge. Our data suggest that ERAS protocols in VPS patients might reduce the incidence of delirium without increasing the risk of infection or other postoperative complications.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Normal pressure hydrocephalus: Neurophysiological and neuropsychological aspects: a narrative review

Idiopathic normal pressure hydrocephalus (NPH) is a syndrome that affects elderly people and is characterized by excessive accumulation of cerebrospinal fluid in the brain ventricles. Diagnosis is based on the evaluation of clinical symptoms, which consists of a classic triad (Hakim triad), gait disturbances, cognitive impairment, and urinary incontinence. However, this complete triad is not always seen; therefore, it is difficult to make the diagnosis. NPH can be divided into primary or idiopathic NPH and secondary NPH. Diagnostic criteria for NPH remain a topic of discussion; however, the development of diagnostic techniques has brought new opportunities for diagnosis. The aim of this review is to present an overview of neurophysiological and neuropsychological approaches to support the clinical evaluation of patients with NPH and contribute to the differential diagnosis of NPH and dementia, as the clinical symptoms of NPH may resemble other neurodegenerative disorders.

[Idiopathic Normal Pressure Hydrocephalus and Neurodegenerative Diseases: a Short Review of Differential Diagnosis]

There are a variety of neurodegenerative diseases that require differentiation from idiopathic normal pressure hydrocephalus(iNPH), including Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies, frontotemporal dementia, progressive supranuclear palsy, and corticobasal degeneration. As the clinical features and structural imaging findings of these diseases may overlap with iNPH, biomarkers reflecting disease-specific pathology are necessary for differential diagnosis. In addition, these diseases often coexist with iNPH in elderly patients, and it is important to confirm the coexistence of their pathology even in cases clinically diagnosed as iNPH. This review provides an overview of established and emerging biomarkers for neurodegenerative diseases.

Can Shunt Response in Patients with Idiopathic Normal Pressure Hydrocephalus Be Predicted from Preoperative Brain Imaging? A Retrospective Study of the Diagnostic Use of the Normal Pressure Hydrocephalus Radscale in 119 Patients

BACKGROUND AND PURPOSE

The Normal Pressure Hydrocephalus Radscale is a combined scoring of 7 different structural imaging markers on preoperative brain CT or MR imaging in patients with idiopathic normal pressure hydrocephalus: callosal angle, Evans Index, Sylvian fissure dilation, apical sulcal narrowing, mean temporal horn diameter, periventricular WM lesions, and focal sulcal dilation. The purpose of this retrospective study was to assess the performance of the Normal Pressure Hydrocephalus Radscale in distinguishing idiopathic normal pressure hydrocephalus shunt responders from nonresponders.

MATERIALS AND METHODS

The preoperative MR imaging and CT scans of 119 patients with idiopathic normal pressure hydrocephalus were scored using the Normal Pressure Hydrocephalus Radscale. A summary shunt-response score assessed within 6 months from ventriculoperitoneal shunt surgery, combining the effect on cognition, gait, and urinary incontinence, was used as a reference. The difference between the mean Normal Pressure Hydrocephalus Radscale for responders and nonresponders was tested using the Student t test. The area under the curve was calculated for the Normal Pressure Hydrocephalus Radscale to assess shunt response. To ascertain reproducibility, we assessed the interobserver agreement between the 2 independent observers as intraclass correlation coefficients for the Normal Pressure Hydrocephalus Radscale for 74 MR imaging scans and 19 CT scans.

RESULTS

Ninety-four (79%) of 119 patients were shunt responders. The mean Normal Pressure Hydrocephalus Radscale score for shunt responders was 8.35 (SD, 1.53), and for nonresponders, 7.48 (SD, 1.53) (P = .02). The area under the curve for the Normal Pressure Hydrocephalus Radscale was 0.66 (range, 0.54-0.78). The intraclass correlation coefficient for the Normal Pressure Hydrocephalus Radscale was 0.86 for MR imaging and 0.82 for CT.

CONCLUSIONS

The Normal Pressure Hydrocephalus Radscale showed moderate discrimination for shunt response but cannot, on its own, be used for selecting patients with idiopathic normal pressure hydrocephalus for shunt surgery.

A Rare Case of Neurosyphilis Presenting As Normal Pressure Hydrocephalus Syndrome

Neurosyphilis, a chronic infection of the nervous system by Treponema pallidum can present in all stages of syphilis. Recently, it is found that neurosyphilis presents with novel manifestations. Here, we report a young patient who had neurosyphilis presenting as Normal Pressure Hydrocephalus (NPH) with bilateral optic atrophy. The patient showed improvement with treatment for neurosyphilis. Hence, it is evident that in young patients presenting with NPH and associated features, secondary etiologies should be investigated.

Frontal Behavior Syndromes in Idiopathic Normal Pressure Hydrocephalus as a Function of Alzheimer's Disease Biomarker Status

OBJECTIVES

Cognitive impairment and apathy are well-documented features of idiopathic normal pressure hydrocephalus (iNPH). However, research examining other neuropsychiatric manifestations of iNPH is scant, and it is unknown whether the neuropsychiatric presentation differs for iNPH patients with comorbid Alzheimer's disease (AD) versus iNPH without AD. This study aims to advance our understanding of neuropsychiatric syndromes associated with iNPH.

METHODS

Fifty patients from Butler Hospital's Normal Pressure Hydrocephalus Clinic met inclusion criteria. Caregiver ratings on the Frontal Systems Behavior Scale (FrSBe) were examined to appraise changes in apathy, executive dysfunction, and disinhibition. Patients also completed cognitive tests of global cognition, psychomotor speed, and executive functioning. AD biomarker status was determined by either amyloid-beta (Aβ) positron emission tomography (PET) imaging or cerebrospinal fluid (CSF) total tau to Aβ-42 ratio.

RESULTS

Results revealed clinically significant elevations on the FrSBe's apathy and executive dysfunction scales and modest correlations among these scales and cognitive measures. Of the 44 patients with available neuroimaging or CSF draw data, 14 presented with comorbid AD. Relative to the iNPH-only group, the iNPH + AD group showed a larger increase from pre-illness to current informant ratings on the executive dysfunction scale, but not the apathy or disinhibition scales.

CONCLUSIONS

These results replicate and extend prior research by identifying apathy and executive dysfunction as prominent neuropsychiatric symptoms of iNPH and suggest comorbid AD exacerbates dysexecutive behaviors. Future research is warranted to examine the effects of comorbid AD pathology in response to shunt surgery for iNPH, neuropsychiatric symptom changes, and resultant caregiver burden.

Progressive Parkinsonism Three Years after Shunt Surgery in a Patient with Idiopathic Normal Pressure Hydrocephalus

An 86-year-old man, who had undergone a lumboperitoneal shunt for idiopathic normal pressure hydrocephalus (iNPH) implanted 4 years earlier showed progressive parkinsonism for the past year. His clinical symptoms, including resting tremor and rapid eye movement sleep behavior disorder, responsiveness to levodopa, and abnormal findings on ¹²³I-meta-iodobenzylguanidine myocardial scintigraphy and dopamine transporter imaging, indicated that his pathological background of parkinsonism included concomitant synucleinopathy, such as Parkinson's disease or dementia with Lewy bodies, in addition to iNPH. Clinicians should consider the possibility of concomitant proteinopathies and their treatments when clinical symptoms become evident after shunt operations in patients with iNPH.

Structural correlates of cognitive impairment in normal pressure hydrocephalus

OBJECTIVES

The pathological bases for the cognitive and neuropsychiatric symptoms in normal pressure hydrocephalus (NPH) have not been elucidated. However, the symptoms may indicate dysfunction of subcortical regions. Previously, volume reductions of subcortical deep grey matter (SDGM) structures have been observed in NPH patients. The present study used automated segmentation methods to investigate whether SDGM structure volumes are associated with cognitive and neuropsychiatric measures.

METHODS

Fourteen NPH patients and eight healthy controls were included in the study. Patients completed neuropsychological tests of general cognition, verbal learning and memory, verbal fluency and measures of apathy and depression pre- and postshunt surgery. Additionally, patients underwent 3 Tesla T1-weighted magnetic resonance imaging at baseline and 6 months postoperatively. Controls were scanned once. SDGM structure volumes were estimated using automated segmentation (FSL FIRST). Since displacement of the caudate nuclei occurred for some patients due to ventriculomegaly, patient caudate volumes were also estimated using manual tracing. Group differences in SDGM structure volumes were investigated, as well as associations between volumes and cognitive and neuropsychiatric measures in patients.

RESULTS

Volumes of the caudate, thalamus, putamen, pallidum, hippocampus and nucleus accumbens (NAcc) were significantly reduced in the NPH patients compared to controls. In the NPH group, smaller caudate and NAcc volumes were associated with poorer performance on neuropsychological tests and increased severity of neuropsychiatric symptoms, while reduced volume of the pallidum was associated with better performance on the MMSE and reduced apathy.

CONCLUSIONS

Striatal volume loss appears to be associated with cognitive and neuropsychiatric changes in NPH.

A Case of Simultaneous Mania and Idiopathic Normal Pressure Hydrocephalus: Etiology or Comorbidity?

Normal pressure hydrocephalus (NPH), typically associated with the triad of gait disturbance, dementia and urinary incontinence, rarely presents with symptoms of mania, depression or psychosis and psychiatric disorders may complicate the diagnosis. Few cases of NPH and psychiatric disease comorbidity have been reported so far. In most of these cases, NPH was associated with depression and psychotic symptoms. Mania symptoms were also reported in a few cases those of which were associated with a history of bipolar disorder (BPD) or subthreshold BPD symptoms. In this paper, we present a case of late-onset mania symptoms simultaneously presenting with NPH in a healthy individual without a history of psychiatric disorder.

Colour vision abnormality as the only manifestation of normal pressure hydrocephalus

CLINICAL CASE

The case is presented of a 73-year-old male patient who referred to having black and white vision. Computed tomography showed normal pressure hydrocephalus (NPH). Magnetic resonance imaging was not performed because the patient refused to undergo further examinations.

DISCUSSION

Achromatopsia may be the first or only NPH symptom. It may be prudent to ask patients with NPH regarding colour vision.

Change of Amyloid-β 1-42 Toxic Conformer Ratio After Cerebrospinal Fluid Diversion Predicts Long-Term Cognitive Outcome in Patients with Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Alzheimer's disease (AD) pathology in idiopathic normal pressure hydrocephalus (iNPH) contributes to poor shunt responses. Amyloid-β 1- 42 (Aβ42) toxic conformer was recently identified with features of rapid oligomerization, strong neurotoxicity and synaptotoxicity.

OBJECTIVE

This observational study points to Aβ42 toxic conformer as a biomarker for AD pathology and for poor postoperative prognosis in patients with iNPH.

METHODS

The first cohort consisted of patients with AD (n = 17) and iNPH (n = 17), and cognitively normal individuals (CN, n = 12). The second cohort, consisted of 51 patients with iNPH, was divided into two groups according to phosphorylated Tau (pTau) level (low- and high-pTau groups); the low-pTau group was further subdivided according to one-year postoperative change in Aβ42 toxic conformer ratio (%) [Aβ42 toxic conformer/Aβ42×100] (decreased- and increased-conformer subgroups). Enzyme-linked immunosorbent assay was used to measure pTau, Aβ42, and Aβ42 toxic conformer in cerebrospinal fluid. Outcomes were evaluated using neuropsychological tests one- and two-years postoperatively.

RESULTS

In the first cohort, Aβ42 toxic conformer ratio in the iNPH group (10.8%) was significantly higher than that in the CN group (6.3%) and significantly lower than that in the AD group (17.2%). In the second cohort, the high-pTau group showed cognitive decline two-years postoperatively compared to baseline. However, the low-pTau group showed favorable outcomes one-year postoperatively; furthermore, the increased-conformer subgroup showed cognitive decline two-years postoperatively while the decreased-conformer subgroup maintained the improvement.

CONCLUSIONS

Change in Aβ42 toxic conformer ratio predicts long-term cognitive outcome in iNPH, even in the low-pTau group.

An unusual case of temporal bone encephalomeningocele occurring together with normal pressure hydrocephalus

Temporal bone encephalomeningoceles are uncommon clinical entities that can be challenging to diagnose and treat. Common presenting complaints include symptoms of aural fullness, hearing loss, clear otorrhea and meningitis. Common etiologies are chronic middle ear disease and trauma. A significant proportion of cases are spontaneous, which occurs in relation to benign intracranial hypertension. Normal pressure hydrocephalus associated with temporal bone encepahomeningoceles has not been previously described. The authors present an unusual case of spontaneous right sided temporal bone encephalomeningocele associated with symptomatic normal pressure hydrocephalus. Surgical repair of the defect was successful. The diagnostic and management approach to this unique case are discussed.

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

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

The Prediction of Shunt Response in Idiopathic Normal-Pressure Hydrocephalus Based on Intracranial Pressure Monitoring and Lumbar Infusion

BACKGROUND

Intracranial pressure (ICP) monitoring and infusion studies have long been used in the preoperative workup of patients with suspected idiopathic normal-pressure hydrocephalus (iNPH). We have analysed the predictive values of different measures derived from both investigations, emphasising the differences between responders and nonresponders.

MATERIALS AND METHODS

ICP monitoring and lumbar infusion studies were routinely performed during a 6-year period. Shunting was proposed when the resistance to cerebrospinal fluid outflow (ROUT) >12 mmHg/ml/min and/or a minimum 15 % of slow waves were detected. The outcome was evaluated 6 months after surgery. Recorded data from ICP monitoring were mean pressure and pulse amplitude, the total percentage of slow waves and the presence of different types of slow waves following the classification proposed by Raftopoulos et al. Recorded data from lumbar infusion studies were mean values of pressure and pulse amplitude during three epochs (basal, early infusion and plateau), ROUT and the pulsatility response to the increase in mean pressure during the infusion. This response was quantified by two pulse amplitude indexes: the pulse amplitude index during the early infusion stage (A1) and the pulse amplitude index during the plateau stage (A2).

RESULTS

Thirty shunted patients were evaluated at the end of the follow-up and 23 (76.7 %) of them improved. Differences in the percentage of slow waves, ROUT and both pulsatility indexes were not statistically significant. The proportion of patients with great symmetrical waves and pulse amplitude during the early infusion stage were higher in responders (p < 0.05). The predictive analysis yielded the highest accuracy, with ROUT and A1 as a logical "OR" combination.

CONCLUSION

The combined use of ICP monitoring and lumbar infusion to forecast the response to shunting in patients with suspected iNPH did not improve the accuracy provided by any of them alone.

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.

Spectrum of cognitive disorders in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome characterized by ventricular dilation accompanied by a progressive triad of a gait disturbance, "dementia" and incontinence. We retrospectively evaluated cognitive profile, and its relationship with disease variables, in 64 iNPH patients. The iNPH group performed significantly worse than the control group on all neuropsychological tests, except for verbal memory (within the normal range). The patients were subdivided into four groups: group 1 (42%: global cognitive impairment); group 2 (24%: frontosubcortical dysfunction); group 3 (17%: isolated deficit of a single cognitive domain); group 4 (17%: no cognitive impairment). Group 1 was older, with a significantly longer disease duration and more severe motor disease, while groups 3 and 4 were younger and presented milder motor impairment and a shorter disease duration. These data suggest parallel progression of cognitive and motor impairment in iNPH; early shunt surgery might prevent the development, in older age, of dementia in these patients.

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Zusammenfassung. Das Krankheitsbild des Normaldruckhydrocephalus ist seit 50 Jahren bekannt. Etwa genau so lange existiert mit der Möglichkeit einer internen Liquordrainage durch einen Liquorshunt die Möglichkeit einer effektiven Therapie. Moderne Shuntsysteme lassen sich sehr genau den Bedürfnissen der Patienten anpassen, und die operativen Eingriffe selbst haben nur noch eine sehr geringe Morbidität und Mortalität. Trotzdem wird nur ungefähr jeder zehnte Patient erkannt und einer Behandlung zugeführt. Bei Erfolgsaussichten von über 80% einer signifikanten Reduktion der Beschwerden entsteht für die unbehandelten Patienten, aber auch für die Gesellschaft, ein erheblicher Schaden durch den Verlust der Selbständigkeit und durch vermeidbare Pflegebedürftigkeit. Der Information über dieses Krankheitsbild und Aufklärung über die Abgrenzung gegenüber häufigen Differenzialdiagnosen kommt daher eine zentrale Bedeutung zu.

Early Idiopathic Normal Pressure Hydrocephalus Patients With Neuropsychological Impairment Are Associated With Increased Fractional Anisotropy in the Anterior Thalamic Nucleus

In this study, we aimed to investigate the reactive changes in diffusion tensor imaging (DTI)-derived diffusion metrics of the anterior thalamic nucleus (AN), a relaying center for the Papez circuit, in early idiopathic normal pressure hydrocephalus (iNPH) patients with memory impairment, as well as its correlation with the patients' neuropsychological performances. In total, 28 probable iNPH patients with symptom onset within 1 year and 17 control subjects were prospectively recruited between 2010 and 2013 for this institutional review board-approved study. Imaging studies including DTI and a neuropsychological assessment battery were performed in all subjects. Diffusion metrics were measured from the region of the AN using tract-deterministic seeding method by reconstructing the mammillo-thalamo-cingulate connections within the Papez circuit. Differences in diffusion metrics and memory assessment scores between the patient and control group were examined via the Mann-Whitney U test. Spearman correlation analyses were performed to examine associations between diffusion metrics of AN and neuropsychological tests within the patient group. We discovered that early iNPH patients exhibited marked elevations in fractional anisotropy, pure diffusion anisotropy, and axial diffusivity (all P < 0.01), as well as lower neuropsychological test scores including verbal and nonverbal memory (all P < 0.05) compared with normal control. Spearman rank correlation analyses did not disclose significant correlations between AN diffusion metrics and neuropsychological test scores in the patient group, whereas ranked scatter plots clearly demonstrated a dichotic sample distribution between patient and control samples. In summary, our study highlighted the potential compensatory role of the AN by increasing thalamocortical connectivity within the Papez circuit because memory function declines in early iNPH when early shunt treatment may potentially reverse the memory deficits.

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.

Quantitative evaluation of changes in gait after extended cerebrospinal fluid drainage for normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by gait instability, urinary incontinence and cognitive dysfunction. These symptoms can be relieved by cerebrospinal fluid (CSF) drainage, but the time course and nature of the improvements are poorly characterized. Attempts to prospectively identify iNPH patients responsive to CSF drainage by evaluating presenting gait quality or via extended lumbar cerebrospinal fluid drainage (eLCD) trials are common, but the reliability of such approaches is unclear. Here we combine eLCD trials with computerized quantitative gait measurements to predict shunt responsiveness in patients undergoing evaluation for possible iNPH. In this prospective cohort study, 50 patients presenting with enlarged cerebral ventricles and gait, urinary, and/or cognitive difficulties were evaluated for iNPH using a computerized gait analysis system during a 3day trial of eLCD. Gait speed, stride length, cadence, and the Timed Up and Go test were quantified before and during eLCD. Qualitative assessments of incontinence and cognition were obtained throughout the eLCD trial. Patients who improved after eLCD underwent ventriculoperitoneal shunt placement, and symptoms were reassessed serially over the next 3 to 15months. There was no significant difference in presenting gait characteristics between patients who improved after drainage and those who did not. Gait improvement was not observed until 2 or more days of continuous drainage in most cases. Symptoms improved after eLCD in 60% of patients, and all patients who improved after eLCD also improved after shunt placement. The degree of improvement after eLCD correlated closely with that observed after shunt placement.