Shunt-responsive idiopathic normal pressure hydrocephalus patient with delayed improvement after tap test

Diffusion tensor imaging helps identify shunt-responsive normal pressure hydrocephalus patients among probable iNPH cohort

The aim of this study was to investigate whether white matter changes as measured by diffusion tensor imaging (DTI) can help differentiate shunt-responsive idiopathic normal pressure hydrocephalus (iNPH) patients from patients with other causes of gait disturbances and/or cognitive decline with ventriculomegaly whose clinical symptoms do not improve significantly after cerebrospinal fluid derivation (non-iNPH). Between 2017 and 2022, 85 patients with probable iNPH underwent prospective preoperative magnetic resonance imaging (MRI) and comprehensive clinical workup. Patients with clinical symptoms of iNPH, positive result on lumbar infusion test, and gait improvement after 120-h lumbar drainage were diagnosed with iNPH and underwent shunt-placement surgery. Fractional anisotropy (FA) and mean diffusivity (MD) values for individual regions of interest were extracted from preoperative MRI, using the TBSS pipeline of FSL toolkit. These FA and MD values were then compared to results of clinical workup and established diagnosis of iNPH. An identical MRI protocol was performed on 13 age- and sex-matched healthy volunteers. Statistically significant differences in FA values of several white matter structures were found not only between iNPH patients and healthy controls but also between iNPH and non-iNPH patients. ROI that showed best diagnostic ability when differentiating iNPH among probable iNPH cohort was uncinate fasciculus, with AUC of 0.74 (p < 0.001). DTI methods of white matter analysis using standardised methods of ROI extraction can help in differentiation of iNPH patients not only from healthy patients but also from patients with other causes of gait disturbances with cognitive decline and ventriculomegaly.

CSF Dynamics for Shunt Prognostication and Revision in Normal Pressure Hydrocephalus

BACKGROUND

Despite the quantitative information derived from testing of the CSF circulation, there is still no consensus on what the best approach could be in defining criteria for shunting and predicting response to CSF diversion in normal pressure hydrocephalus (NPH).

OBJECTIVE

We aimed to review the lessons learned from assessment of CSF dynamics in our center and summarize our findings to date. We have focused on reporting the objective perspective of CSF dynamics testing, without further inferences to individual patient management.

DISCUSSION

No single parameter from the CSF infusion study has so far been able to serve as an unquestionable outcome predictor. Resistance to CSF outflow (Rout) is an important biological marker of CSF circulation. It should not, however, be used as a single predictor for improvement after shunting. Testing of CSF dynamics provides information on hydrodynamic properties of the cerebrospinal compartment: the system which is being modified by a shunt. Our experience of nearly 30 years of studying CSF dynamics in patients requiring shunting and/or shunt revision, combined with all the recent progress made in producing evidence on the clinical utility of CSF dynamics, has led to reconsidering the relationship between CSF circulation testing and clinical improvement.

CONCLUSIONS

Despite many open questions and limitations, testing of CSF dynamics provides unique perspectives for the clinician. We have found value in understanding shunt function and potentially shunt response through shunt testing in vivo. In the absence of infusion tests, further methods that provide a clear description of the pre and post-shunting CSF circulation, and potentially cerebral blood flow, should be developed and adapted to the bed-space.

The benefit of delayed reassessment post high-volume CSF removal in the diagnosis of shunt-responsive idiopathic normal-pressure hydrocephalus

The principle aim of the study was to demonstrate the value of performing delayed reassessment in the diagnosis of idiopathic normal-pressure hydrocephalus (iNPH) and selection of suitable candidates for ventriculoperitoneal shunting (VPS). Thirty-one consecutive patients underwent the NPH protocol at the Flinders Medical Centre between March 2017 and November 2018. The protocol involved mobility and cognitive testing with reassessment post high-volume cerebrospinal fluid (CSF) removal at 24 h and 48 h. The Assessment of Quality of Life 6D (AQoL-6D) questionnaire and International Consultation on Incontinence Questionnaire - Urinary Incontinence Short Form (ICIQ-UI SF) were completed and repeated again at 6 weeks and 6 months post shunting. Results were analysed to determine the significance of delayed reassessment. Twenty patients (64.5%) underwent insertion of a VPS on the basis of objective improvements and specific criteria. Of these, 6 patients (30%) were shunted based on delayed reassessment at 48 h post CSF removal. Continued improvements were seen for all mobility and cognitive tests from baseline to 48 h post CSF removal. At 6 weeks and 6 months post shunting, there was an overall mean improvement in AQoL-6D and ICIQ-UI SF for the cohort and the improvement was also observed in the subgroup of patients who met shunt criteria at 48 h post CSF removal. In the diagnosis of shunt-responsive idiopathic normal-pressure hydrocephalus, delayed reassessment post CSF removal improves sensitivity and is therefore important.

[Lower urinary tract dysfunction in normal pressure hydrocephalus: Review of the literature]

INTRODUCTION

Lower urinary tract dysfunction in normal pressure hydrocephalus has received little attention from the scientific community. The aim of this review article was to discuss diagnostic and therapeutic options for these patients.

SOURCES

A literature review of MedLine publications on urinary incontinence in normal pressure hydrocephalus was conducted. The following keywords were used: "hydrocephalus, normal pressure" and "bladder dysfunction" or "urinary incontinence" or "overactive bladder" or "urinary bladder, neurogenic". Prospective and retrospective studies as well as previous reviews were analyzed.

RESULTS

Urinary symptoms in normal pressure hydrocephalus are mainly represented by overactive bladder, which is a significant burden for the concerned patients. Isolated overactive bladder is more frequent (64%) than urinary incontinence (57%). Detrusor overactivity is seen in 95.2% of the cases. Neuro-surgery is efficient on urinary symptoms for 61.5% of the patients. Bladder recovery after surgery relates with increased mid-cingulate perfusion, probably linked with a functional restoration of the mid-cingulate that normally inhibits the micturition reflex. Medical options, added or not to surgery, include anticholinergic drugs unable to pass through the blood-brain barrier, Transcutaneous Electrical Nerve Stimulation and sacral neuromodulation.

CONCLUSION

There is actually an insufficient concern about urinary symptoms in normal pressure hydrocephalus. This article highlights the importance of a harmonization of neuro-urological practices in the pre-therapeutic evaluation of patients suffering from normal pressure hydrocephalus.

Asymmetric and Upper Body Parkinsonism in Patients with Idiopathic Normal-Pressure Hydrocephalus

Background and Purpose

Our aims were to analyze the characteristics of parkinsonian features and to characterize changes in parkinsonian motor symptoms before and after the cerebrospinal fluid tap test (CSFTT) in idiopathic normal-pressure hydrocephalus (INPH) patients.

Methods

INPH subjects were selected in consecutive order from a prospectively enrolled INPH registry. Fifty-five INPH patients (37 males) having a positive response to the CSFTT constituted the final sample for analysis. The mean age was 73.7±4.7 years. The pre-tap mean Unified Parkinson's Disease Rating Scale motor (UPDRS-III) score was 24.5±10.2.

Results

There was no significant difference between the upper and lower body UPDRS-III scores (p=0.174). The parkinsonian signs were asymmetrical in 32 of 55 patients (58.2%). At baseline, the Timed Up and Go Test and 10-meter walking test scores were positively correlated with the total motor score, global bradykinesia score, global rigidity score, upper body score, lower body score, and postural instability/gait difficulties score of UPDRS-III. After the CSFTT, the total motor score, global bradykinesia score, upper body score, and lower body score of UPDRS-III significantly improved (p<0.01). There was a significant decrease in the number of patients with asymmetric parkinsonism (p<0.05).

Conclusions

In the differential diagnosis of elderly patients presenting with asymmetric and upper body parkinsonism, we need to consider a diagnosis of INPH. The association between gait function and parkinsonism severity suggests the involvement of similar circuits producing gait and parkinsonian symptoms in INPH.

[Hakim-Adams syndrome]

Hakim-Adams syndrome is little known, although quite common disease. The etiology is not fully clear. Pathogenetic mechanisms included the blockage of cerebrospinal fluid outflow along the upper lateral surface of the brain, development of hydrocephalus with the expansion of the brain ventricles while maintaining normotensive cerebrospinal fluid (CSF). Main manifestations are ataxia, apraxia, symptoms of dementia and urinary disturbances, up to incontinence. Diagnosis is based on clinical symptoms, exploratory lumbar and neuroimaging. Main treatment is ventriculoperitoneal (stomach) shunt placement for fluid drainage. Timely surgical intervention gives good results and improves quality of life of patients.

[Normal pressure hydrocephalus: A review and practical aspects]

Idiopathic normal pressure hydrocephalus is a chronic disorder affecting the elderly. It is defined by Adams and Hakim's triad in addition to ventricular dilation visible by brain imaging and normal cerebrospinal fluid pressure during lumbar puncture. The objective of this review was to propose a standard of care for idiopathic normal pressure hydrocephalus based on an extensive literature review conducted on 459 articles published over the last 10 years. Those articles were obtained by searching for the keywords "normal pressure hydrocephalus" in the PubMed database and selecting all the articles published in English or in French. The diagnosis of idiopathic normal pressure hydrocephalus is difficult because of commonly associated diseases, such as Alzheimer's disease and microangiopathy. Brain MRI is one of the key procedures to assist in the diagnosis of idiopathic normal pressure hydrocephalus. Indeed, the presence of certain MRI features is highly predictive of a positive tap test and shunt responsiveness. Nevertheless, tap test remains the standard of care for diagnosis. Continuous cerebrospinal fluid drainage test is an alternative because it improves the sensitivity of diagnosis (but is a more complicated test to perform). Alzheimer's biomarkers dosing in the cerebrospinal fluid seems interesting when diagnosis remains uncertain: the presence of Alzheimer's profile of the biological markers is predictive of a lower response to the tap test.