When Hannah Guest graduated from The University of Manchester with a bachelors degree in Audiology she couldn’t have imagined that some years later she would be working as Postdoctoral Research Associate for the Manchester Centre for Audiology and Deafness. However, after completing her PhD here too she received the opportunity to conduct more research with the academics who had taught her during her undergraduate degree. Learn all about the fascinating research that she is involved in below…
Hi there, my name is Hannah Guest and I am a Postdoctoral Research Associate in the Manchester Centre for Audiology and Deafness. Being a PDRA means that I spent a few years getting a PhD with Professors Chris Plack and Kevin Munro and now I conduct research on various aspects of hearing.
The research that I do fits in with a broader programme of research that Chris Plack’s lab is looking at on subclinical hearing deficits. We study people who have broadly normal results on the standard hearing test, but who nonetheless seem like they might have something a bit unusual going on with some aspect of their hearing behind-the-scenes.
There are various reasons why this might be but chief among them is the fact that the standard hearing test, which is called the pure tone audiogram, really only looks at a persons ability to detect very quiet, very simple sounds in a silent background and when those sounds are happening one at a time. Human hearing in the real world is completely different from this as humans need to be able to not only detect sounds but understand what they mean, especially speech.
It also needs to do this when there are all kinds of sounds happening at the same time and at a whole range of different volume levels. Therefore, it’s not all that surprising really that someone could have actually fairly major problems with hearing in the real world, but still come out looking normal when given a pure tone audiogram.
My first involvement with this kind of research was with the scientific hunt for cochlear synaptopathy. Synaptopathy is a condition that we know exists in animals, where exposure to really loud sounds or ageing of the animal can lead to subtle damage to the nerve that connects the ear to the brain and crucially this condition wouldn’t show up on the standard hearing test.
Our lab was interested in finding out whether this could occur in young humans as well. My colleagues Gareth and Sam were looking at young humans with different levels to noise exposure, for example professional musicians or sound engineers or just people who do a lot of gigging and clubbing versus people who are much more low risk and tend not to expose their ears so much.
My corner of this research was looking to see if there there was any evidence of this condition in people who have hearing symptoms despite having normal results on the standard hearing test. Perhaps they have unexplained listening difficulties or maybe they have ringing in their ears known as tinnitus and again testing to see if there is evidence of synaptopathy in those individuals.
One of the things that’s really enjoyable about working in this kind of area, and I count myself very lucky, is that because we’re trying to measure a condition that is really subtle it means that we get to use a bunch of really sophisticated and varied measurement techniques to do that. Some of the time we’ll be using little ear buds in the ear to take direct measurements of the neural or mechanical response of the ear and then other times we’ll be designing really complex and challenging listening tasks that people are going to do over headphones in the lab.
Then on other occasions we’ll be taking measurements of the ongoing brain activity using little electrodes on the scalp. That degree of variety and innovation in the techniques that we use is really enjoyable.
Autism and hearing
Recently, we’ve started to look at subclinical hearing issues a bit more broadly so rather than just looking for evidence of a single underlying condition like cochlear synaptopathy, we’ve been trying to look at whether there are variations in real-world hearing abilities and real-world hearing experiences among people who have normal results on the standard hearing test.
In particular we’ve been looking in relation to the autism spectrum disorder. Are there areas where autistic people find that they have more listening difficulties than neurotypical people and are there areas where they seem to have enhanced abilities? This area appears to be somewhat under-researched therefore we’ve tried not to just dive straight in based on the hunches of the people in lab coats like me. Instead we’ve decided to engage with autistic individuals and the wider autistic community to see what they think should be the research priorities.
We’ve been conducting in-depth interviews and large-scale questionnaires to try and find out if there are elements of real-world listening that autistic individuals have noticed are problematic for them, or times when their hearing is particularly acute. We’re also looking to find out what they think we should be researching, and how they think we should be researching it. I think that’s been incredibly valuable as it means that when we get to the stage of gathering the hard data we will have done so by using research questions and methods that are most likely to gather something sensible.
I feel very fortunate to be working in a lab where we take the time to engage in these kinds of processes rather than diving in head first and ending up with research that perhaps isn’t as useful as it might have been had we actually engaged with interested and affected members of the public.