This is a PhD studentship awarded to Dr Josef Schlittenlacher at University College London. Emma Foottit started her PhD in October 2025.
Background
A major problem in adjusting the settings of a hearing aid to a person’s hearing loss is the lack of good hearing tests. The standard hearing test, the audiogram, measures the ability to hear faint tones. While people are good at this task, that is, they provide consistent results when they repeat the test, the ability to hear faint sounds is of little relevance in daily life compared to understanding speech, enjoying music or perceiving sounds at the correct loudness.
People tend to struggle when judging loudness. When matching loudness for two different sounds, such as a high-frequency (high pitched) bird chirp and a low-frequency (low pitched) humming, a person will usually give different answers on different testing occasions. There is therefore a need for objective methods to measure loudness perception that do not involve conscious judgments made by the person being tested.
A promising candidate for this is reaction time. A person with normal levels of hearing will react faster to a sound the louder it is. This relationship between loudness and reaction time not only holds when varying sound pressure level (the decibel value of the sound), but also other factors of loudness including frequency or whether a sound is heard with one or two ears.
Aims
Emma will work to establish that reaction time is a valid measure for how loud sounds are for someone when they have hearing loss. Previous evidence has been promising but a more rigorous investigation is needed to use reaction time as a measure of loudness in clinical settings.
As part of the project, Emma will design and evaluate reaction-time hearing tests that could be used in the clinic. Compared to the protocol used in scientific experiments, these will be more time-efficient while still giving a good estimate of an individual’s loudness perception.
Research methods
The experiments will typically be completed by 20 participants with hearing loss. The main task in the test will be to press a button as soon as a sound is heard, followed by an assessment of how loud the participant thinks the sound is. Emma will vary the sound level and frequency of tones, as well as other aspects of the sound, called their spectral composition (think of the difference between the sound of a flute compared to a piano or traffic noise), to establish that the relationship between loudness and reaction time holds for factors that are highly important when setting up a hearing aid.
Emma will evaluate the new reaction-time hearing tests by using the results to set up a hearing aid and asking the participant about speech intelligibility and quality.
Benefit
The findings from this project will improve our understanding of the relationship between loudness and reaction time in people with hearing loss. The new reaction-time based hearing tests could be used directly in clinical practice to result in better hearing aid settings. By establishing the link for people with hearing loss, the results will also form a basis to develop further applications of the test, for example with cochlear implants.