Tap Test Research Articles

Factors Affecting the Patency of Radiocephalic Arteriovenous Fistulas Based on Clinico-Radiological Parameters.

Arteriovenous fistulas are an important means of vascular access for long-term haemodialysis in patients with end-stage renal disease (ESRD). We evaluated the outcome of radiocephalic arteriovenous fistulas (RCAVFs) in 55 patients operated upon in our hospital in southern India. We studied the outcome of RCAVF surgery with the demographic factors, duration of diabetes, the diameter of the radial artery and cephalic vein, and any signs of atherosclerosis in the radial artery. We found that a small cephalic vein size of ≤ 2 mm, a negative cephalic vein tap test, a thickened, non-compressible, calcified radial artery on palpation, and evidence of atherosclerosis on radiological investigations were associated with a significant chance of RCAVF failure. A clinico-radiological grading of atherosclerosis for peripheral arteries is also proposed. Any patient presenting to the microsurgeon with a small cephalic vein size, a negative cephalic vein tap test, a thickened, non-compressible, calcified vessel on palpation, and tram-track calcification or whole vessel calcification or severely atherosclerotic vessel on radiological evaluation must be approached with caution regarding RCAVF creation and must be prepared for an arteriovenous fistula (AVF) creation at a higher level.

Damage Detection in Composite Materials Using Tap Test Technique and Neural Networks

The wind energy sources promote the generation of electricity, being environmentally safe, clean and its use has been growing in Brazil, especially in the northeastern states with the implementation of new wind farms. Wind turbines, however, are subject to weather, risk of animal shocks, materials carried by the wind, and the vibrations of the system itself. The blade is the most important component of a wind turbine and is the one with the greatest risk of failure. They are usually made of a composite fiber-reinforced polymer matrix and balsa wood as structural reinforcement. As the material composing this blade has heterogeneous and anisotropic characteristics, conventional inspection techniques are not considered effective. The non-destructive Tap Test technique can be a safe option in composite materials because it does not suffer from these limitations. The objective of this work is to inspect composite plates of polymeric resin used in wind turbines with discontinuities using the non-destructive Tap Test technique, where regions with and without defect were analyzed. The collected signals from an accelerometer and a microphone were processed, to allow the extraction of features and the recognition of discontinuities with the aid of a neural network.

Optical Coherence Tomography Revealing Ganglion Cell Loss in Idiopathic Normal Pressure Hydrocephalus

Although there may theoretically be a disturbance in the eye or the visual pathways due to abnormal cerebrospinal fluid (CSF) dynamics in idiopathic normal pressure hydrocephalus (iNPH), it has not been studied systemically. Optical coherence tomography (OCT) is a noninvasive, reproducible procedure for quantitative and qualitative analysis of retinal morphology. OCT was used to study the eye fundus before and after a CSF tap test in patients with iNPH compared with healthy individuals (HIs). Twelve patients with iNPH (6 females and 6 males) with a median age of 76 years (64-84 years) and 21 HIs (11 females and 10 males) with a median age of 73 years (64-79 years) were included. The patients underwent neurological, cognitive, and physiotherapeutic evaluation. Brain magnetic resonance imaging, CSF tap test via lumbar puncture, and subsequently CSF analysis were performed. OCT was performed before and after CSF removal. HIs underwent OCT once. The patients had significantly reduced retinal ganglion cell layer thickness 71 μm (56-81 μm) compared with the HIs, 79.5 μm (72-90 μm) (P = 0.001), but no significant changes were observed before or after the CSF tap test. All patients improved in motor function in a 10-m walk test after the CSF tap test. The median CSF pressure was 15 and 1 cm H2O, respectively, before and after lumbar puncture with removal of median 43.5 mL CSF. This pilot study shows OCT findings that differ from HIs and implies a rational for becoming a valuable tool in the diagnosis of iNPH. Further studies are warranted to elucidate the pathology of the retina in iNPH.

A elderly case of late-onset aqueductal membranous occlusion was denied idiopathic normal pressure hydrocephalus by tap test

A elderly case of late-onset aqueductal membranous occlusion was denied idiopathic normal pressure hydrocephalus by tap test

Идиопатическая гидроцефалия взрослых: современное состояние проблемы

The term "idiopathic hydrocephalus" in adults is a broader concept that includes larger spectrum of patients compared to "idiopathic normotensive hydrocephalus". It includes both young and elderly patients with various forms of the disease, patients with various levels of obstruction. Th ere is no general classification and general approach to treat patients with such a pathology. Endoscopic triventriculostomy in idiopathic aqueductal stenosis and cerebrospinal fluid shunting after a positive test of cerebrospinal fluid (tap test) evacuation in idiopathic normotensive hydrocephalus are proved to be effective. In patients with other forms of cerebrospinal fluid pathway obstruction, treatment approach is represented by the opinions of some surgeons. At the same time, most surgeons consider the use of cerebrospinal fluid shunting operations to be effective and justified, and they use endoscopic techniques as an option for examining ventricular system and for performing auxiliary manipulations. The high frequency of various complications of bypass surgery and slightly lower efficiency of endoscopic operations indicates the need to systematize patients; to improve selection criteria and to expand the indications for the use of endoscopic surgical techniques.

Clinical tips in diagnosing idiopathic normal pressure hydrocephalus: a new concept beyond the cerebrospinal fluid tap test.

Accurate diagnosis of idiopathic normal pressure hydrocephalus is important to manage patients with idiopathic normal pressure hydrocephalus more appropriately. Based on the clinical features and brain magnetic resonance imaging findings, the idiopathic normal pressure hydrocephalus diagnosis is made up. However, most clinicians do not recommend the shunt operation to their patients with presumed idiopathic normal pressure hydrocephalus unless any patients with idiopathic normal pressure hydrocephalus show a considerable improvement through the cerebrospinal fluid tap test. The cerebrospinal fluid tap test is an invasive method and has some limitations to diagnose idiopathic normal pressure hydrocephalus. Therefore, we suppose that a new diagnostic approach of idiopathic normal pressure hydrocephalus is necessary. Various magnetic resonance imaging findings suggesting idiopathic normal pressure hydrocephalus have been applied to diagnose idiopathic normal pressure hydrocephalus. Besides, advances in neuroimaging techniques, including dopamine transporter imaging, and amyloid imaging may allow clinicians to exclude the potential misdiagnosis including Parkinsonian disorders and Alzheimer's disease in patients with presumed idiopathic normal pressure hydrocephalus. Herein, we suggest a neuroimaging-supportive algorithm for the diagnosis of idiopathic normal pressure hydrocephalus. We suspect that this is the time to change the classical approach of diagnosing idiopathic normal pressure hydrocephalus.

Normal-Pressure Hydrocephalus - Patient Evaluation and Decision-Making.

Normal-pressure hydrocephalus (NPH) presents with the triad of gait difficulty, urinary incontinence, and cognitive decline. However, the definitive diagnosis and treatment may be challenging at times due to secondary causes of NPH (sNPH) versus idiopathic NPH (iNPH), co-existing other degenerative, vascular, and metabolic causes of similar clinical presentations. The objective of this narrative review is to outline the approach to patient evaluation and decision-making in cases where there is clinical suspicion of iNPH. This review article intends to provide a practical approach to the patients with a suspected diagnosis of iNPH. The cardinal clinical features with a guide from investigations like magnetic resonance imaging (MRI) brain and cerebrospinal fluid (CSF) analysis, and CSF tap assessment have been outlined. The interpretation of conflicting MRI brain findings or CSF analysis may need resolution by further tests. The decision algorithm following the examination and investigations has been included to address the dilemma in the case of a non-supportive MRI and/or CSF tap test. iNPH is a treatable cause of the cognitive decline and gait disorder. While neurodegenerative causes may accompany iNPH, any patient with improvement after CSF drainage deserves therapeutic intervention.

The Tatar-Russian Bilingualism in Early Childhood

The paper presents findings from psycholinguistic research with normally developing preschool Tatar-Russian bilingual children between the age of 4;0 to 6;0 years old. Forty children in total- twenty children between the age of 4;0 -5;0, and twenty children between the age of 5;0-6;0 were tested. Children with language impairment and mental disabilities were excluded from the study. All children attend a polylingual kindergarten, where the children learn in organized way the following three languages: their mother tongue - the state language of the Tatarstan - the Tatar language, Russian - the official language of the Russian Federation to which Tatarstan belongs, and English. The children were tested with two types of language tests: Syntactic test (wh-complement tests) and mix Tatar-Russian vocabulary test (comprehension and production). They were also tested with a psychological non-verbal Knock Tap test. All children were tested individually in a separate room by a native Tatar speaking and Russian speaking researcher. In order to avoid the influence of the language of testing on the results half of the children were tested with part of the tests in Tatar language and the other part in Russian language. The next day they were changing the languages and the tests. The research question we try to answer is: Do the children develop balanced bilingualism in the kindergarten age having in mind the educational system they are involved in or they are dominant in one of the two languages. The results of the children are analyzed with the ANOVA and SPSS Statistics. They show that the older children are better in all test. Regarding the language the younger children show poor results in Tatar and better results in Russian. The older children show equally good results in both languages. The paper discusses the classical theory of Skutnabb-Kangas (1981) and newest findings of Bialystok (2020) regarding the bilingualism and bilingual education from early ages and which factors play important role in successful development of balanced bilingualism from early age.

Endoscopic third ventriculostomy in post traumatic hydrocephalus- Institutional experience

Introduction: Hydrocephalus is a known sequelae in traumatic brain injury patients. It may occur early or late and presents with dementia, urinary incotinence and difficulty in walking as described by Hakim and Adams. There are two distinct types of normal pressure hydrocephalus one is idiopathic most commonly seen in the elderly age groups and the other is secondary due to a cerebro vascular accident, trauma or surgery. The idiopathic type may not respond to the CSF diversion procedure, but the secondary type which responds to CSF diversion procedure. Our study aims at exploring the option of ETV in these patients not making them shunt dependent. Materials and Methods: The patients with traumatic brain injury admitted in the dept. of neurosurgery between January 2012 and January 2018 were included into the study. Congenital hydrocephalus and secondary hydrocephalus due to spontaneous SAH and tumours were excluded. 14 patients were identified and if there was some improvement in their condition after CSF tap test were planned for endoscopic third ventriculostomy. Results: Out of the 14 patients 2 were females and the remaining 12 were males. 2 did not improve at all. 12 had some improvement out of which 3 had a failure and underwent a v-p shunt. Hence there were 5 failures out of 14 which made 35.7%. Mitchel et al and Michelangelo et al reported 72-75% success rates in their study which is similar to our results. Conclusion: ETV is an option which can be offered to patients with secondary hydrocephalus. The chances of failure though present the procedure is minimally invasive and improves CSF dynamics. Keywords: Secondary hydrocephalus due to trauma, Endoscopic third ventriculostomy, Trauma induced hydrocephalus.

Dynamic functional networks in idiopathic normal pressure hydrocephalus: Alterations and reversibility by CSF tap test.

Idiopathic Normal Pressure Hydrocephalus (iNPH)—the leading cause of reversible dementia in aging—is characterized by ventriculomegaly and gait, cognitive and urinary impairments. Despite its high prevalence estimated at 6% among the elderlies, iNPH remains underdiagnosed and undertreated due to the lack of iNPH‐specific diagnostic markers and limited understanding of pathophysiological mechanisms. INPH diagnosis is also complicated by the frequent occurrence of comorbidities, the most common one being Alzheimer's disease (AD). Here we investigate the resting‐state functional magnetic resonance imaging dynamics of 26 iNPH patients before and after a CSF tap test, and of 48 normal older adults. Alzheimer's pathology was evaluated by CSF biomarkers. We show that the interactions between the default mode, and the executive‐control, salience and attention networks are impaired in iNPH, explain gait and executive disturbances in patients, and are not driven by AD‐pathology. In particular, AD molecular biomarkers are associated with functional changes distinct from iNPH functional alterations. Finally, we demonstrate a partial normalization of brain dynamics 24 hr after a CSF tap test, indicating functional plasticity mechanisms. We conclude that functional changes involving the default mode cross‐network interactions reflect iNPH pathophysiological mechanisms and track treatment response, possibly contributing to iNPH differential diagnosis and better clinical management.

A comprehensive clinico-radiological, neuropsychological and biomechanical analysis approach to patients with idiopathic normal pressure hydrocephalus

BackgroundA systematic approach to patients with suspected idiopathic normal pressure hydrocephalus (iNPH) is essential to recognize the subset of patients who may benefit from ventriculoperitoneal shunt surgery (VPS). Quantitative biomechanical analysis of gait and balance (QBAGB) may help objectify the response to the cerebrospinal fluid tap test (CSF-TT) and VPS outcome after 3 months and support identification of candidates for VPS. MethodsWe retrospectively reviewed data from all patients with probable iNPH who 1) underwent clinico-radiological and neuropsychological assessments using validated scales (iNPH Scale and iNPH Radscale) at our centre in the period from January to December 2018; and 2) had completed QBAGB before CSF-TT (‘baseline’), shortly after CSF-TT, and at three months after either VPS or conservative treatment. ResultsAt the time-points ‘after CSF-TT’ and ‘3 months’, patients with iNPH and VPS (n = 11) significantly improved on the Kiefer Scale score, iNPH Scale total score and gait domain score, as well as in gait velocity and step length measured by QBAGB. In contrast, patients without surgery (n = 10) had unchanged iNPH Scale scores and motor performance throughout. Using data from all patients, we calculated cut-off levels for substantial improvements in gait velocity, step length, and the iNPH Scale domain gait score at the time-point ‘after CSF-TT’. ConclusionQBAGB helps to objectify the response to CSF-TT to select candidates for VPS and corroborates clinico-radiological and neuropsychological data derived from validated scales. The QBAGB cut-off values for substantial improvement after CSF-TT need further elucidation in larger, preferably prospective studies.

Two‐point dynamic observation of Alzheimer’s disease cerebrospinal fluid biomarkers in idiopathic normal pressure hydrocephalus

AbstractBackgroundExtensive research into cerebrospinal fluid (CSF) biomarkers was performed in patients with idiopathic normal pressure hydrocephalus (iNPH). Most prior research into CSF biomarkers has been one‐point observation.ObjectiveTo investigate dynamic changes in CSF biomarkers during routine tap test in iNPH patients.MethodsWe analyzed CSF concentrations of tau, amyloid‐β (Aβ) 42 and 40, and leucine rich α‐2‐glycoprotein (LRG) in 88 consecutive potential iNPH patients who received a tap test. We collected two‐point lumbar CSF separately at the first 1 ml (First Drip (FD)) and at the last 1 ml (Last Drip (LD)) during the tap test and 9 patients who went on to receive ventriculo‐peritoneal shunt surgery each provided 1 ml of ventricular CSF (VCSF).ResultsTau concentrations were significantly elevated in LD and VCSF compared to FD (LD/FD = 1.22, p = 0.003, VCSF/FD = 2.76, p = 0.02). Conversely, Aβ42 (LD/FD = 0.80, p < 0.001, VCSF/FD = 0.38, p = 0.03) and LRG (LD/FD = 0.74, p < 0.001, VCSF/FD = 0.09, p = 0.002) concentrations were significantly reduced in LD and VCSF compared to FD. Gait responses to the tap test and changes in cognitive function in response to shunt were closely associated with LD concentrations of tau (p = 0.02) and LRG (p = 0.04), respectively.ConclusionsDynamic changes were different among the measured CSF biomarkers, suggesting that LD of CSF as sampled during the tap test reflects an aspect of VCSF contributing to the pathophysiology of iNPH. CSF circulation is disturbed in iNPH and old style one‐point CSF biomarker observation can be misestimated. This study detected dynamic changes of CSF biomarkers in iNPH during routine tap test and revealed the linkage between 1ml Last Drip of lumbar CSF and ventricular CSF.

A pilot study on the positive rate of multi‐time point and multiple domain evaluation in cerebrospinal fluid tap test of patients with normal pressure hydrocephalus

AbstractBackgroundThe CSF tap test evaluation vary a lot in different medical center, which result in the wide range of sensitivity. Our study aimed to explore the effect of multi time point and multiple domain evaluation on the determination of CSF tap test results in patients with normal pressure hydrocephalus.MethodA total of 150 outpatients with NPH 2013‐2018 from the Department of Neurology of Peking Union Medical College Hospital were enrolled in this study. All patients underwent detailed neuropsychological (MMSE, MOCA, Trail Making Test , Digital Symbol, Stroop‐c test, Grooved pegboard test) and walking ability (10 meter walking test, 5 meter up and go test), and head MRI examination. Patients who did not complete the four time point’s evaluation of CSF tap test to eliminate severe dementia and various reasons. The positive criteria were that the performance of either time or steps in walking test was 20% higher than the baseline level, or both were 10% higher. In the cognitive test, the score of any test is 20% higher than the baseline as a positive criterion. According to this standard, the positive rates of each evaluation test and three evaluation time points were calculated and compared.ResultThe positive rate of 5 meter up and go test on 8 hours, 24 hours and 72 hours after CSF tap test was 40.6%, 42.0%, 48.9%, the positive rate of 10‐meter walking test was 35.8%, 30.9%, 40.7% respectively; the positive rate of Digital Symbol was 23.8%, 38.1%, 42.9% respectively; the positive rate of Trail Making T test was 38.7%, 45%, 57.9%; the positive rates of Stroop‐c performance were 27.0%, 39.3% and 49.1% respectively; the positive rates of Grooved pegboard test on 8 hours, 24 hours and 72 hours after CSF tap test were 25%, 27.9% and 39.7%.ConclusionThe positive rate of 5 meter up and go test is higher than that of 10 meter walking test, and the positive rate of 24‐hour and 72 hour comprehensive evaluation combined with walk and cognitive evaluation is higher.

The changing of cognitive function and the influence of learning effect on the results before and after the CSF tap test in patients with normal pressure hydrocephalus

AbstractBackgroundThe CSF tap test evaluation needs repetitive test of walking ability and cognition. Our study aimed to explore the changes of cognitive function and the influence of learning effect on the results in CSF tap test when evaluating the patients with normal pressure hydrocephalus (NPH).MethodCSF tap test was carried out in 134 patients with NPH 2013‐2018 in neurology clinic of Peking Union Medical College Hospital. All patients underwent detailed neuropsychological evaluation (MMSE, MOCA, Trail Making test, Digital symbol, Stroop‐c test) and walking ability (10 meter walking test, up and go test), and head MRI examination. Patients who did not complete the four time point evaluations of CSF tap test due to severe dementia or any other reasons were excluded. Nonparametric test was used to test the difference of z‐scores of executive function (including connection test, number sign and shop‐c test) between the baseline and the four time points after CSF tap test. According to the baseline MMSE scores, the subjects were divided into MMSE > = 26 and MMSE < 26 groups. The changes of z‐scores of three executive function tests were observed in the group.ResultCompared with the baseline, the Z‐score of executive function began to improve at 24 hours and 72 hours, and there was a statistically significant difference (P 0.001 and 0.000, respectively). Within the MMSE > = 26 group, there was a significant improvement in executive function at 24 hours and 72 hours compared with baseline (P <0.05). In the group with MMSE < 26, the executive function Z‐score at 72 hours was significantly improved compared with that at baseline (P = 0.000), while the improvement at 8 hours and 24 hours was not significant.ConclusionIt was found that the executive function of CSF was improved with different evaluation points. According to the classification of MMSE scores, it was found that patients with different cognitive states had different characteristics of executive function curve, which could not be explained by learning effect.

Abnormal thickening and thinning of the cerebral cortex in idiopathic normal‐pressure hydrocephalus

AbstractBackgroundWe investigated differences in cortical thickness utilizing automated surface‐based cortical thickness analysis in 2 groups: idiopathic normal‐pressure hydrocephalus (INPH) patients who had a positive response to the cerebrospinal fluid tap test and healthy controls. We also explored whether a relationship exists between cortical thinning and gait disturbance in INPH patients. We hypothesized that INPH patients might show a characteristic pattern of cortical thickness change and that there may be unique relationships between cortical thinning and gait disturbance in INPH patients.MethodForty‐nine INPH patients and 26 healthy controls were imaged with MRI, including 3‐dimensional volumetric images, for automated surface‐based cortical thickness analysis across the entire brain. Gait disturbance features related to INPH were determined using the Gait Status Scale (GSS).ResultCompared with age‐ and gender‐matched healthy controls, unexpectedly, INPH patients showed statistically significant cortical thickening mainly in areas located in the high convexity of the frontal, parietal, and occipital regions. Additionally, cortical thinning mainly in temporal and orbitofrontal regions was observed in the INPH group relative to the control group. The GSS scores were negatively correlated with cortical thickness in the medial orbital part of the superior frontal gyrus, gyrus rectus, superior temporal gyrus, temporal pole, and insula.ConclusionA distinctive pattern of cortical thickness changes was found in INPH patients. We cautiously suggest that cortical thickening in INPH can result from reactive gliosis. Further, our results support the hypothesis that cortical thinning in INPH can result from neuronal degeneration. In addition, cortical thinning can play an important role in gait disturbances in INPH patients.

Can the radiological scale “iNPH Radscale” predict tap test response in idiopathic normal pressure hydrocephalus?

BackgroundIdiopathic normal pressure hydrocephalus (iNPH) presents typical radiological signs that have been summarised in a semi-quantitative scale named the iNPH Radscale. However, the iNPH Radscale's predictive value for response to cerebrospinal fluid (CSF) tap test has never been studied. This study aims to investigate if the iNPH Radscale can predict locomotion improvement after CSF tap test. MethodsA total of 100 patients with iNPH (age: 76.3 ± 7.9, gender: 36% female) were included in this retrospective study. Two raters, blinded to the response of the CSF tap test, evaluated the iNPH Radscale and its seven subitems (Evan's index, callosal angle, size of temporal horns, narrow high-convexity sulci, dilated Sylvian fissures, focally dilated sulci, and periventricular hypodensities). Locomotion improvement was assessed by the Timed Up and Go (TUG) performed before, and 24 h after, the CSF tap test. ResultsThe iNPH Radscale (total score) was similar between the CSF tap test responders and non-responders (responders: 8.31 ± 1.96, non-responders: 9.18 ± 2.51, p = 0.128). However, the temporal horns score was smaller in the responders group (1.66 ± 0.57 versus 1.94 ± 0.24, p = 0.045), even after adjusting for age, gender, education level, white matter changes, and global cognition (β: -0.250, C.I. 95%: [−3.185; −0.161], p = 0.031). ConclusionThe iNPH Radscale (total score) does not predict locomotion improvement after CSF tap test, while a smaller temporal horns score at baseline is associated with a positive tap test responder status.

Acute Presentation of Normal Pressure Hydrocephalus After Transcatheter Aortic Valve Implantation: A Novel Interaction Between the First and Third Circulations

Idiopathic normal pressure hydrocephalus (iNPH) negatively affects gait and cognition abilities and urine continence in the elderly. It is associated with systemic hypertension, although the exact pathophysiology is still unknown. A correlation to increased intracranial pulsatility and decreased compliance was suggested. Transcatheter aortic valve implantation (TAVI) is increasingly used in the treatment of severe AS. New-onset systemic hypertension affects some patients after TAVI. To identify any association between aortic valve replacement and the development of NPH. A cohort was created retrospectively of all patients who were evaluated for NPH with cerebrospinal fluid (CSF) tap test at a single institute during 2014-2019. Patients were reviewed for a past medical history of aortic valvular disease or aortic valve replacement. A total of 242 patients underwent evaluations for NPH. Of these patients, 133 were considered to have iNPH. Six patients underwent aortic valve replacement before the initial symptoms of NPH: 1 surgical and 5 TAVI. The time from aortic valve replacement to the initial NPH symptoms was <6 months in 3 patients (as low as 1 month in 2 of them). Two patients had functional improvement after CSF tap test and proceeded to receive a shunt, 4 and 6 months after TAVI, respectively. Two patients developed hypertension after TAVI. Pulse pressure increased by >10 mm Hg in 3 patients after TAVI. This is the first case series of symptomatic NPH after TAVI. In this unique subgroup, NPH symptoms can develop rapidly. Post-TAVI iNPH represents a novel interaction between the blood and CSF circulations.

Contactless Finger Tapping Detection at C-Band

The rapid finger tap test is widely used in clinical assessment of dyskinesias in Parkinson's disease. In clinical practice, doctors rely on their clinical experience and use the Parkinson's Disease Uniform Rating Scale to make a brief judgment of symptoms. We propose a novel C-band microwave sensing method to evaluate finger tapping quantitatively and qualitatively in a non-contact way based on wireless channel information (WCI). The phase difference between adjacent antennas is used to calibrate the original random phase. Outlier filtering and smoothing filtering are used to process WCI waveforms. Based on the resulting signal, we define and extract a set of features related to the features described in UPDRS. Finally, the features are input into a support vector machine (SVM) to obtain results for patients with different severity. The results show that the proposed system can achieve an average accuracy of 99%. Compared with the amplitude, the average quantization accuracy of the phase difference on finger tapping is improved by 3%. In the future, the proposed system could assist doctors to quantify the movement disorders of patients, and it is very promising to be a candidate for clinical practice.

P-Tau as prognostic marker in long term follow up for patients with shunted iNPH

ABSTRACT Objective: Diagnosis of idiopathic Normal Pressure Hydrocephalus (iNPH) relies solely on clinical and radiological criteria while, unlike other neurological diseases, the analysis of cerebrospinal fluid markers is not used in clinical practice. Nevertheless, the overlapping of neurodegenerative diseases affects the long-term shunt efficacy and this occurrence should be detected before surgery. Therefore, we performed this study in order to assess the correlation between pre-surgical levels of CSF Beta Amyloid protein, Total Tau protein and Phospho-Tau protein with long-term clinical outcome. Methods: Between March 2012 and May 2016 we prospective evaluated all patients with iNPH according to guidelines criteria and we analysed CSF concentration of these proteins before and during surgery. Two years after surgery we evaluated iNPH score for all patients, grouping them in shunt responders and non-responders. Results: A total of 117 patients were included: Tap Test non-responders were 58 and at two years we had 35 shunt responders and 15 shunt non-responders. We found a significative difference between shunt-responders and shunt non-responders for pre surgical T-Tau (p: 0.02) and for P-Tau (p: 0.01). All the proteins were significantly associated with clinical outcome after surgery with different cut-off values; in particular, having a ‘low’ value of T-Tau, P-Tau and Aβ1-42 resulted in favourable outcome after surgery. Conclusions: Low level of P-Tau is a useful CSF biochemical prognostic factor for good clinical outcome at least two years after shunt; meanwhile a lower Aβ1-42 might suggest that the pathophysiology of iNPH could have something in common with other neurodegenerative diseases of the elderly.

Cerebrospinal fluid closing pressure-guided tap test for the diagnosis of idiopathic normal pressure hydrocephalus: A descriptive cross-sectional study.

Background: Tap test improves symptoms of idiopathic normal pressure hydrocephalus (iNPH); hence, it is widely used as a diagnostic procedure. However, it has a low sensitivity and there is no consensus on the parameters that should be used nor the volume to be extracted. We propose draining cerebrospinal fluid (CSF) during tap test until a closing pressure of 0 cm H2O is reached as a standard practice. We use this method with all our patients at our clinic.Methods: This is a descriptive cross-sectional study where all patients with presumptive diagnosis of iNPH from January 2014 to December 2019 were included in the study. We used a univariate descriptive analysis and stratified analysis to compare the opening pressure and the volume of CSF extracted during the lumbar puncture, between patients in whom a diagnosis of iNPH was confirmed and those in which it was discarded.Results: A total of 92 patients were included in the study. The mean age at the time of presentation was 79.4 years and 63 patients were male. The diagnosis of iNPH was confirmed in 73.9% patients. The mean opening pressure was 14.4 cm H2O mean volume of CSF extracted was 43.4 mL.Conclusion: CSF extraction guided by a closing pressure of 0 cm H2O instead of tap test with a fixed volume of CSF alone may be an effective method of optimizing iNPH symptomatic improvement and diagnosis.