A new method for noninvasive measurement of short-term cerebrospinal fluid pressure changes in humans

Changes in cerebrospinal fluid (CSF) pressure were shown to be reflected by changes in tympanic membrane (TM) tension. Impedance audiometry measures mechanical tension on the TM and was used to detect changes during jugular vein compression in normal students. CSF and peri-lymph communicate through the cochlear aqueduct, permitting increases in CSF pressure to result in increased pressure on the stapes footplate. This is transmitted to the TM by the ossicles and detected by impedance audiometry. TM tension was also proportional to CSF pressure in cadavers, where CSF pressure was manipulated by saline injection through a lumbar puncture.