The University of Southampton
University of Southampton Institutional Repository

How much can horizontal head movements influence the real-ear measurement accuracy of open-canal fittings?

Lau, Sean (2010) How much can horizontal head movements influence the real-ear measurement accuracy of open-canal fittings? University of Southampton, Institute of Sound and Vibration Research, Masters Thesis , 91pp.

Record type: Thesis (Masters)


The modified pressure with stored equalisation (MPSE) method of soundfield equalisation is universally recommended for use in clinical practice during the real-ear measurement (REM) verification of open-canal (OC) hearing aids. This is because the MPSE method deactivates the reference microphone for aided measurements and so is not susceptible to the leakage of amplified sound from the open ear canal when fitting OC devices. However, the deactivation of the reference microphone means that the MPSE method will be susceptible to errors resulting from head movements during aided measurements and the magnitude of such errors has not been well explored in the literature. Therefore, this study aimed to investigate how much small horizontal head movements can influence the accuracy of REMs when using the MPSE method.

Real-ear unaided responses (REURs) were measured in 28 participants at horizontal head deviations of 0°, ±5°, ±10°, ±15°, and ±20° azimuth relative to the two loudspeaker-to-client azimuths of 0° and 45°. The difference between the baseline REUR measured when no head deviation was made and the REURs measured for each head deviation was then calculated so that the magnitude of REM errors arising from these head movements could be determined.

Statistical analysis revealed no significant difference between the REM errors for the 0° and 45° loudspeaker-to-client azimuths. REM errors of typically less than 1 dB were obtained when no head deviation was made (i.e. 0° head deviation), indicating that no clinically significant errors are introduced when using the MPSE method provided patients keep their heads still. However, the REM errors were found to increase with increasing head deviation up to ±20° where the errors were typically less than 2 dB. The magnitude of these head movement induced errors are not clinically significant on their own but it is recommended that head movements are minimised as much as possible so that REM targets can be matched more accurately.

PDF P2705.pdf - Other
Download (1MB)

More information

Published date: 2010
Organisations: University of Southampton, Human Sciences Group


Local EPrints ID: 173757
PURE UUID: afcecd24-d54e-44a9-bf62-f1c93db03115
ORCID for Emma Mackenzie: ORCID iD

Catalogue record

Date deposited: 07 Feb 2011 11:36
Last modified: 18 Jul 2017 12:12

Export record


Author: Sean Lau
Thesis advisor: Emma Mackenzie ORCID iD

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton:

ePrints Soton supports OAI 2.0 with a base URL of

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.