Worldwide interest in SWIR: An increasingly popular method for measuring listening effort

20/4-2018

Measuring how good your hearing is, is not straightforward. Not only is it important that you hear the words, you also need to be able to understand and remember them. In 2008, a group of researchers at Linköping University decided to develop a new test, which takes this into account. This resulted in the so-called SWIR-test (sentence-final word identification and recall test), which is now used at Eriksholm Research Centre for research on listening effort.
Since then, the interest in both listening effort in general and the SWIR-test has increased, and this week thirty external researchers and clinical partners from all over the world gathered at Eriksholm Research Centre for a one-day workshop on the topic.

“Lately, a number of researchers from all over the world have shown interest in adapting the SWIR test in their local languages, and also in using pupillometry, a technique the size of the pupils, to measure listening effort. Therefore, we organized this workshop in order to gather the researchers and introduce to them to the research tools we use to measure listening effort,” explains Senior Research Audiologist Elaine Ng. She developed the SWIR-test during her PhD with Eriksholm-professor Thomas Lunner as one of her supervisors.

Conventional speech intelligibility tests do not represent real life

The workshop aimed to facilitate the adaptation of the SWIR test in new languages by standardizing the test procedure for development. So far, the test is available in Swedish, Danish, German, UK English, and Korean, while an Australian English version will soon be developed.
According to Elaine Ng, the increased interest in listening effort and specifically the SWIR-test is due to the limits of the conventional speech intelligibility tests that have been used in clinics and research for many years to evaluate hearing aid outcome.
“In clinics and research they usually do speech recognition tests, which means that the listener hears words and sentences and repeats them. That captures the audibility, but it does not represent real life situations. When you listen, you don’t just listen and repeat what I say. You have to understand what I say, and cognitive processes are involved in an ongoing discourse, such as interpretation of information, decision making, turn-taking and retrieving events from memory, rather than just listening. All these take more processing resources in the brain,” explains Elaine Ng.
It is an important part of speech understanding, how much effort you spend on actually hearing the words, and whether that leaves any brain capacity for processing and remembering them.
“Professionals are now thinking about adopting other ways of measuring listening effort. For that reason SWIR and also pupillometry have gained growing attention,” says Elaine Ng.

SWIR is showing the cognitive aspect

Elaine Ng started developing the SWIR test with Professor Jerker Rönnberg from Linköping University, Professor Mary Rudner from Linköping University, and Professor Thomas Lunner from Eriksholm Research Centre (in his Linköping University affiliation). The aim was to measure the cognitive benefits of hearing aid signal processing – meaning whether the hearing aid can help people spend less effort on listening, and thereby have more brain capacity for storing the information: remembering.
“We wanted to see the cognitive aspect. This is the essence of the test. You hear a sentence and then you remember,” says Elaine Ng.
In the test, the test subject is introduced to seven sentences. After each sentence, they are asked to repeat the final word. After the seven sentences, they are once again asked to repeat the final word of all seven sentences. This is a way of measuring performance and find out whether they use their remaining brain capacity, besides the capacity spend on listening, on remembering.