Service delivery (neurological physics)

What do we do?

Having a tympanic membrane displacement (TMD)

The tympanic membrane displacement is simple, painless and non-invasive. A sensor is attached to your ear canal. You may hear a series of clicks or tones. The measurement takes up to 40 minutes. TMD is also used in ‘non-invasive intracranial pressure measurement’ (please see below).

TMD for non-invasive intracranial pressure measurement

We have over 15 years of experience in assessing intracranial pressure non-invasively within the NIPA (non-invasive intracranial pressure) unit, using the Southampton cerebral and cochlear fluid pressure (CCFP) analyser which detects brain pressures by measuring tympanic membrane displacement (TMD).

This technique is mainly used for assessing relative changes in pressure, for example, if you are having medical or surgical treatment used to regulate intracranial pressure. We can also detect abnormal brain pulsatility that may be innocent or require further investigation.

Following NIPA measurements, further investigation may be required if you are at risk of intracranial hypertension or hypotension and would benefit from short, medium or long-term serial pressure measurements. A non-invasive intracranial pressure measurement technique cannot replace lumbar puncture or surgical methods of intracranial pressure monitoring. However, it can assist where these techniques are inappropriate or when brain pressure needs monitoring with treatment or longitudinally over several months.