Because hearing is one of the five senses, hearing damage and hearing loss can have further-reaching effects that affect the other senses.
Whilst the best and clearest way to determine the scale of hearing loss is through audiology tests, there are other common telltale signs that someone who can hear is struggling more than they may be expecting.
One of the most common and yet most surprising is finding conversations more tiring as you have to exert effort to distinguish between different voices in a crowded area.
However, despite there being anecdotal evidence that listening more closely is more tiring, there had not been any scientific studies that confirmed this for sure until the middle of 2023, when two were published within just a few months of each other.
They found a connection between eye movements and focusing on listening, and what these studies highlighted may help with future hearing treatments.
Why Eye Movements?
Both papers, the first written by Claudia Contandini-Wright and her team and the second by M. Eric Cuit and Bjorn Herrman, both for the Journal of Neuroscience, focus on the behaviour of the eyes during “effortful speech listening” or times when someone pays attention to speech whilst listening.
The first paper focuses on pupil dilation, highlighting that when trial subjects were focusing on listening to noises that were difficult to parse, their eyes were noticeably larger, typically reflective with sensory arousal and cognitive processing, such as when someone is memorising information.
The second paper focused instead on the connection between eye movements and listening, with there being a typical connection between slower eye movements and increased focus.
This is, for example, why people blink less often when they are reading, and their eyes will move slower and they will blink less depending on how complex the text they are reading is.
This approach was transposed from reading to listening, with 26 young adults listening to several different sound files featuring both short sentences and longer spoken stories, an eye tracker reading their movements.
The findings revealed several interesting results.
The first was that there was a connection between focused listening and eye movement, highlighting the potential to study this further in auditory neurology, with less of the potential environmental disruptions found when trying to detect pupil size.
This also highlights the potential for tracking eye movements as part of hearing tests, as they can be used to detect difficulties of hearing in practical situations even if your ears have the capacity for hearing as determined through conventional pitch testing.
As this is an exceptionally early field of study, however, it is difficult to determine which eye movements relate to which cognitive hearing processes, which will require more study.
As well as this, whilst more effortful listening can be a symptom of hearing loss, it can also be exceptionally context-sensitive.
People will listen more attentively when processing complex or less clear sentences, as well as any speech in languages they are not necessarily fluent in.
These two papers are the beginning of a fascinating field of study, one that could produce a new approach to examining how people hear.