Effect of Changes in Cerebrospinal Fluid Pressure on the Labyrinth in Terms of Tympanic Membrane Displacement

摘要

It is shown that a pressure change of 30 mm saline in the perilymph fluid can be detected by the tympanic membrane displacement (TMD) measurement system, as a change in the mean volume displacement and maximum inward volume displacement of the tympanic membrane during contraction of the stapedius muscle. The change in perilymphatic pressure, measured in terms of the reflex TMD, faithfully reflects the changes is cerebrospinal fluid (CSF) pressure brought about by controlled changes of posture. A patent cochlear aqueduct is the most probable route for this pressure transfer from the CSF to the perilymph fluid. However, at least 12% of the ears tested show no change in perilymphatic pressure with a change in CSF pressure. The technique can detect high intracochlear fluid pressures in patients with hydrops. The technique may have a significant bearing on the investigation of the time-course of forms of paroxys mal vertigo such as Meniere's Syndrome.