Medico-Legal Services

A standard pure tone audiogram is usually the starting point for any Medico-Legal hearing assessment.

All of our audiometry can take place in a sound-proof booth with TDH 39 headphones and will be preceded by an otoscopic examination. Testing will routinely include air conduction at 250 Hz; 500 Hz; 1000 Hz; 2000 Hz; 3000 Hz; 4000 Hz; 6000 Hz; and 8000 Hz. Bone conduction will be tested at 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz where required. Extended frequency testing up to 20,000 Hz can be arranged if required.

OAE’s can be recorded from a normally functioning inner ear in response to an acoustic stimulus. The OAE response is a frequency specific objective measure of cochlea function, meaning the inner ear function can be confirmed without the need for any responses from the client. The OAE response cannot be recorded if there is any middle-ear dysfunction, so testing is only performed if tympanometry confirms normal middle-ear function. If there a cochlea hearing loss greater then 30dB an OAE will usually be absent, meaning it is a good indicator of normal cochlea function, but does not provide hearing threshold information. The OAE can be an indicator of early noise or ototoxic damage to the inner ear, before a change in hearing threshold is measurable.

The ABR can be used to assess the integrity of the inner ear up to the auditory brainstem and can be used as an indicator for possible neurological conditions. It is also widely used as an objective indicator of hearing function. Unlike the OAE, the ABR can be used to estimate hearing thresholds and can be recorded even in the presence of middle-ear dysfunction. While an ABR is an indicator of the function of the hearing pathways up to the brainstem, it does not test the higher pathways up to the auditory cortex.

A summary report of the findings will be presented along with the results.

The CERA is used as an objective measure of hearing along the entire auditory pathway. For this reason, it is most commonly used for Medico-Legal hearing assessment. The CERA is an objective, frequency specific measure of hearing function. Passive cooperation is required from the client meaning (unlike the OAE or ABR) that it cannot be measured from a sleeping or sedated client. During a CERA we will commonly ask a client to read a book or to watch a subtitled film. Prior to a CERA assessment we will also carry out a pure tone audiogram.

A summary report of the findings will be presented along with the results.