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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.

Obscure audio-vestibular disorders (TMD)

In the non-invasive intracranial pressure assessment (NIPA) unit, the team has experience understanding the signs and symptoms associated with intracranial hypertension, hypotension and obscure disorders of the middle ear. We combine this understanding with objective measurements made using the Southampton CCFP analyser, also known as the TMD analyser.

If a patient has the following symptoms, they may be referred to the NIPA unit for further investigation:

  • Hearing, balance and tinnitus problems of an obscure nature, for example, a Meniere’s-like symptom profile
  • Low-frequency whooshing or pulsatile tinnitus, especially if combined with imbalance, vertigo or brain fog
  • Aural or head pressure sensations
  • Unexplained low frequency or fluctuating hearing loss, especially if combined with any of the above symptoms
  • Persistent Eustachian tube function where a patulous (open) Eustachian tube may be a possible diagnosis.