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. 2021 Apr 7;18(1):18.
doi: 10.1186/s12987-021-00252-5.

Evaluating the cerebrospinal fluid tap test with the Hellström iNPH scale for patients with idiopathic normal pressure hydrocephalus

Johanna Rydja  1 , Andreas Eleftheriou  2 , Fredrik Lundin  2
Affiliations

Evaluating the cerebrospinal fluid tap test with the Hellström iNPH scale for patients with idiopathic normal pressure hydrocephalus

Johanna Rydja et al. Fluids Barriers CNS. .

Abstract

Background: The cerebrospinal fluid tap test (CSF TT) is used for selecting shunt surgery candidates among patients with idiopathic normal pressure hydrocephalus (iNPH). We aimed to evaluate the predictive value of the CSF TT, by using the Hellström iNPH scale for shunted iNPH patients with a standardized method.

Methods: One hundred and sixteen shunt-operated iNPH patients were retrospectively included in this study. The gait and balance domains in the iNPH scale were used as outcome measures for the CSF TT and the total iNPH scale score as the postoperative outcome. A positive response to CSF TT was defined as a change of ≥ 5 points in the gait domain and ≥ 16 points in the balance domain. Differences between CSF TT responders and non-responders, sensitivity, specificity, positive and negative predictive values, accuracy, and correlations between changes from baseline to post CSF TT and from baseline to the postoperative follow-up, were calculated.

Results: In the CSF TT there were 63.8% responders in the gait domain and correspondingly 44.3% in the balance domain. CSF TT responders had a significantly better postoperative outcome in the total scale score (gait P ≤ 0.001, balance P ≤ 0.012) and gait CSF TT responders improved more in gait (P ≤ 0.001) and balance CSF TT responders in balance (P ≤ 0.001). No differences between CSF TT gait or balance responders could be found in neuropsychological or urinary continence assessments postoperatively. The sensitivity and specificity of the CSF TT and the outcome of the total iNPH scale score postoperatively were 68.1% and 52.0% for gait and 47.8% and 68.0% for balance, respectively.

Conclusions: The CSF TT, with the Hellström iNPH scale as the outcome measure, has clear limitations in predicting postoperative results. The gait domain may be used to predict outcomes for gait, but the balance domain is too insensitive.

Keywords: CSF TT; Idiopathic normal pressure hydrocephalus; Outcome; Sensitivity; Specificity.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Flow chart of inclusion and exclusion of 116 iNPH patients with results from CSF TT and follow-up evaluation
Fig. 2
Fig. 2
The ordinal grading steps for gait and balance in the Hellström iNPH scale [15]
Fig. 3
Fig. 3
Correlation between changes from baseline at the CSF TT in the gait domain on the iNPH scale and change in the total iNPH scale score postoperatively, Spearman’s rho, r = 0.28, p ≤ 0.01. Distribution of true and false, positive and negative outcomes in the CSF TT with bold lines at the five-point levels of improvement. N = 116
Fig. 4
Fig. 4
Correlation between changes from baseline at the CSF TT in the gait domain on the iNPH scale and change in the gait domain postoperatively, Spearman’s rho, r = 0.48, p ≤ 0.01. Distribution of true and false, positive and negative outcomes in the CSF TT with bold lines at the five-point levels of improvement. N = 116
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References

    1. Relkin N, Marmarou A, Klinge P, Bergsneider M, Black PML. INPH guidelines, part II: Diagnosing idio-pathic normal-pressure hydrocephalus. Neurosurgery. 2005 doi: 10.1227/01.NEU.0000168185.29659.C5. - DOI - PubMed
    1. Bergsneider M, Black PM, Klinge P, Marmarou A, Relkin N. Surgical management of idiopathic normal-pressure hydrocephalus. neurosurgery. 2005;57 suppl_3:S2-29-S2-39. 10.1227/01.NEU.0000168186.45363.4D. - PubMed
    1. Malm J, Graff-Radford NR, Ishikawa M, Kristensen B, Leinonen V, Mori E, et al. Influence of comorbidities in idiopathic normal pressure hydrocephalus research and clinical care. A report of the ISHCSF task force on comorbidities in INPH. Fluids Barriers CNS. 2013 doi: 10.1186/2045-8118-10-22. - DOI - PMC - PubMed
    1. Wikkelsö C, Andersson H, Blomstrand C, Lindqvist G, Svendsen P. Predictive value of the cerebrospinal fluid tap-test. Acta Neurol Scand. 1986;73:566–573. doi: 10.1111/j.1600-0404.1986.tb04601.x. - DOI - PubMed
    1. Sand T, Bovim G, Grimse R, Myhr G, Helde G, Cappelen J. Idiopathic normal pressure hydrocephalus: the CSF tap-test may predict the clinical response to shunting. Acta Neurol Scand. 1994;89:311–316. doi: 10.1111/j.1600-0404.1994.tb02640.x. - DOI - PubMed

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