Comparison of Continuous Noninvasive and Invasive Intracranial Pressure Measurement--Celda Infusion Subprotocol

"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.