Comparison of Continuous Noninvasive and Invasive Intracranial Pressure Measurement--Celda Infusion Subprotocol
Condition: Hydrocephalus; Shunt Malfunction
MeSH terms: Hydrocephalus
Study type: Interventional

Summary: 
      This research is being done to determine the accuracy of two noninvasive methods of measuring
      the pressure of the spinal fluid, also known as intracranial pressure (ICP).
    

Detailed description: 
      Recently, astronauts in long-duration spaceflight have been found to have a syndrome
      consisting of swelling of the optic nerve, impaired vision, and elevated cerebrospinal fluid
      pressure (also known as intracranial pressure [ICP]) via lumbar puncture (LP), which is
      similar to the syndrome of idiopathic intracranial hypertension (IIH). In astronauts, this
      syndrome is called Visual Impairment/Intracranial Pressure (VIIP). It is not possible to
      perform an LP on astronauts in space. Noninvasive methods of estimating ICP exist but have
      not been tested against continuous ICP methods in a patient cohort that is physiologically
      similar to that of astronauts.

      The primary objective of this study is to determine the validity, reliability, accuracy, and
      precision of two noninvasive methods of ICP measurement (tympanic membrane displacement (TMD,
      Marchbanks Measurements Systems, UK) and distortion product otoacoustic emissions (DPOAE) in
      comparison to a reference standard, invasive ICP measurement, in human subjects undergoing
      diagnostic cerebrospinal fluid (CSF) infusion testing.

      The two noninvasive methods are based on the responses of the inner ear and middle ear to
      changes in ICP. The first method is TMD, which measures tiny movements of the ear drum, and
      the second is DPOAE, which is routinely used for newborn hearing screening.

      Adults with hydrocephalus, shunt malfunction, or other disorders of CSF circulation who have
      been recommended on the basis of standard clinical criteria to have CSF infusion testing are
      eligible.
    

Intervention name(s): Tympanic Membrane Displacement (TMD); DPOAE
Intervention type(s): Device; Device
Intervention description(s): The CCFP Analyser has a passive mode and an active mode. When used in active mode, the device generates a tone burst that is transmitted to the ear to elicit contraction of the stapedius muscle. The passive mode requires no stimulus or sound burst.
For each ICP level during the CSF infusion testing, the active mode will be used. Each condition comprises 13 stimuli of 0.3s duration.; DPOAE measurement uses a clinical acoustic probe to record the ear's response to two simultaneous tones. DPOAE measurements will be made for 13 tones. The total measurement time for each condition is 2-4 minutes.
Other intervention name(s): Marchbanks MMS-14 TMD Cerebral Cochlear Fluid Pressure (CCFP) Analyzer; Distortion Product Otoacoustic Emissions
Intervention model: Single Group Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Diagnostic
Keywords: ICP; Intracranial pressure; Hydrocephalus; Idiopathic normal pressure hydrocephalus; CSF; Cerebrospinal fluid; Noninvasive ICP