OBJECTIVE: The objective was to determine the sensitivity, specificity, and positive and negative predictive values of the CSF Tap Test (CSF TT) and resistance to CSF outflow (Rout) for the outcome of shunting in a sample of patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS: 115 patients were included in this European multicentre study. Diagnosis was based on clinical symptoms and signs, and MRI changes. All patients were treated with programmable ventriculoperitoneal shunts and re-examined 12 months after surgery. Outcomes were measures with a newly developed iNPH Scale and the modified Rankin Scale (mRS). Before surgery, a CSF TT and measurement of Rout was performed, with the results blinded to all caregivers. The 12 month outcome was correlated with Rout and the result of the CSF TT. RESULTS: Rout and the results of the CSF TT showed no correlation with outcome measured by either domain, or with total iNPH score or mRS score. Only an increase in the gait task (10 m of walking at free speed) of the CSF TT correlated significantly (r=0.22, p=0.02) with improvement in iNPH score. The positive predictive value of both tests was >90% and the negative predictive value <20%. Rout >12 had an overall accuracy of 65% and the CSF TT 53%. Combining both tests did not improve their predictive power. No correlation was found between Rout and the results of the CSF TT. CONCLUSIONS: Rout and the results of the CSF TT did not correlate with outcome after 12 months. Rout and CSF TT can be used for selecting patients for shunt surgery but not for excluding patients from treatment. TRIAL REGISTRATION: The study has been registered at clinicaltrials.gov, identifier NCT00874198.
"Infusion studies showing an increased resistance to CSF outflow, or transient symptomatic improvement after CSF drainage predicts a good outcome after shunting [45,46]. However, a low resistance to outflow or a negative CSF drainage test may still be associated with improvement after shunting . The value of these prognostic tests in the context of comorbidities is unknown. "
[Show abstract][Hide abstract] ABSTRACT: 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.
Fluids and Barriers of the CNS 06/2013; 10(1):22. DOI:10.1186/2045-8118-10-22
[Show abstract][Hide abstract] ABSTRACT: A case of an 8-year-old-boy with shunt-dependent occlusive hydrocephalus after resection of a cerebellar medulloblastoma is presented, who experienced repeated episodes of severe neurologic deterioration with signs and symptoms of raised intracranial pressure after spinal tapping. However, intracranial pressure was recorded within low ranges, only up to the opening pressure of the implanted adjustable shunt valve. Multiple shunt revisions were performed, until the condition was recognized as acute normal pressure hydrocephalus. Either enforced recumbency and downadjustment of the valve system to 0 cm H2O alone or external ventricular drainage seems to be successful to resolve the critical condition, depending on severity of the symptoms. The case illustrates that acute pathologic enlargement of the ventricular system is not always associated with increased intracranial pressure, even when typical signs and symptoms are present. The very rare entity of acute normal pressure hydrocephalus by two separated compartments is postulated based on the pulsatile vector force theory of brain water circulation.
Child s Nervous System 05/2013; 29(12). DOI:10.1007/s00381-013-2173-x · 1.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Object:
The treatment of hydrocephalus requires insight into the intracranial dynamics in the patient. Resistance to CSF outflow (R0) is a clinically obtainable parameter of intracranial fluid dynamics that quantifies the apparent resistance to CSF absorption. It is used as a criterion for the selection of shunt candidates and serves as an indicator of shunt performance. The R0 is obtained clinically by performing 1 of 3 infusion tests: constant flow, constant pressure, or bolus infusion. Among these, the bolus infusion method has the shortest examination times and provides the shortest time of exposure of patients to artificially increased intracranial pressure (ICP) levels. However, for unknown reasons, the bolus infusion method systematically underestimates the R0. Here, the authors have tested and verified the hypothesis that this underestimation is due to lack of accounting for viscoelasticity of the craniospinal space in the calculation of the R0.
The authors developed a phantom model of the human craniospinal space in order to reproduce in vivo pressure-volume (PV) relationships during infusion testing. The phantom model followed the Marmarou exponential PV equation and also included a viscoelastic response to volume changes. Parameters of intracranial fluid dynamics, such as the R0, could be controlled and set independently. In addition to the phantom model, the authors designed a computational framework for virtual infusion testing in which viscoelasticity can be turned on or off in a controlled manner. Constant flow, constant pressure, and bolus infusion tests were performed on the phantom model, as well as on the virtual computational platform, using standard clinical protocols. Values for the R0 were derived from each infusion test by using both a standard method based on the Marmarou PV equation and a novel method based on a system identification approach that takes into account viscoelastic behavior.
Experiments with the phantom model confirmed clinical observations that both the constant flow and constant pressure infusion tests, but not the bolus infusion test, yield correct R0 values when they are determined with the standard method according to Marmarou. Equivalent results were obtained using the computational framework. When the novel system identification approach was used to determine the R0, all of the 3 infusion tests yielded correct values for the R0. CONCLUSIONS" The authors' investigations demonstrate that intracranial dynamics have a substantial viscoelastic component. When this viscoelastic component is taken into account in calculations, the R0, is no longer underestimated in the bolus infusion test.
Journal of Neurosurgery 09/2013; 119(6). DOI:10.3171/2013.8.JNS122497 · 3.74 Impact Factor
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