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Normal Pressure Hydrocephalus: Sensitivity and Specificity

Introduction: None written.

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Tags: Neurologic Tag this Diagnosis.

Prevalence

Population / CalculatorPrevalence Comments / Study / Link
people > 65 0.41% taken from a German town, confirmed by CT scan.

Arch Neurol. 1995 Oct;52(10):1017-22. PMID: 7575219

Patients shunted for presumed NPH 29% (i.e. percent responding to shunt)

J Neurol Neurosurg Psychiatry. 1993 Mar;56(3):251-6. PMID: 8459240

More, Edit...

The sensitivity and specificity of findings for Normal Pressure Hydrocephalus are listed below. See the left navigation bar to change the display.

Negative Findings

Finding SensitivitySpecificity Comments, Study
CSF Removal Edit 62%33%

"tap test" - large-volume (>30 ml) removal of CSF by LP. 'Gold standard' was improvement after VP shunt placement.

Study: Neurosurgery. 2005 Sep;57(3 Suppl):S17-28. PMID: 16160426

Poorly Diagnostic Findings

Finding SensitivitySpecificity Comments, Study
Clinical and CT Diagnosis Edit 54%84%

'probable' NPH by all of the following criteria:

  • Clinical: 1) Predominance of gait disturbances; 2) Mental impairment ranging from not clinically present to moderate; 3) Absence of another disease which might explain the clinical symptoms.
  • CT: 1) Rounded frontal horns; 2) At least moderate ventriculomegaly (FHi 0 40 or higher); 3) Absence of moderate or severe cortical atrophy, and 4) Absence of moderate or severe white matter lucencies.
  • Study: J Neurol Neurosurg Psychiatry. 1993 Mar;56(3):251-6. PMID: 8459240

    External Lumbar Drainage Edit 50%80%

    this involves placing a catheter in the spine and draining CSF over a longer time period (say, 72 hrs).

    Another study reported sens = 97% , spec = 60%.

    Study: Neurosurgery. 2005 Sep;57(3 Suppl):S17-28. PMID: 16160426

    CSF Outflow Resistance Edit 58%44%

    Another (lower class) study reported sens 100%, spec 92%.

    Study: Neurosurgery. 2005 Sep;57(3 Suppl):S17-28. PMID: 16160426