NEW TEST FINDS THE BEST HEARING SOLUTION

In an article published in Hearing Review, ORCA scientists develop a new repeat and recall test for mapping individual user needs.
Speech understanding is a complex process. It involves a multitude of mechanisms that start with the outer ear and go all the way into the brain. How every little mechanism along the way works and performs influences which kind of hearing solution your client needs. It can also help you give more personalised advice on tackling individual problems with speech understanding. 

Today’s speech tests can only take us so far

The success of real-life communication in noisy situations depends not only on listeners’ central auditory processing abilities, but also on their cognitive abilities and their motivation to engage in the communication.

Many speech tests today address some of the mechanisms involved in speech understanding. But often the cognitive mechanisms that have to do with working memory are ignored. Also, many of today’s tests use unrealistic test conditions, like testing at signal-to-noise ratios (SNRs) that are much lower than the ones that people are exposed to in real life.
 

The new repeat and recall test involves working memory

At ORCA-USA, Widex’s research facility in Chicago, scientists have developed a new repeat and recall test (RRT) that involves cognitive mechanisms. It combines a recognition task (repeat) and an auditory working memory task (recall). In the test, the listener is presented with sentences at different signal-to-noise ratios (SNRs), and the results are then assessed for how well the listener could both repeat and recall the sentences. 

The sentences are grouped according to five different topics: food and cooking, books and movies, music, shopping, and sports. 
What’s unique about this test is that the listeners are presented with two types of sentences: A high-context sentence which is semantically correct, and a low-context sentence which is syntactically correct, but makes no sense. 

The test also evaluates the listening effort and the time listeners are willing to spend in different SNRs.
 

In a high-context sentence it’s easy to guess a word if you hear most of the sentence, like “the boy ate a ca…” (cake). A low-context sentence is more difficult because these sentences are constructed to make syntactic sense but not semantic sense, like “the boy ate a ca…” (canoe).

What can this test conclude?

The recently published article presents the results from a recent study where the RRT was performed by normal-hearing and hearing-impaired listeners. 

Data shows that lowering the SNR affects the listeners’ repeat and recall scores and listening effort negatively. It also shows how hearing loss leads to lower repeat scores, but not necessarily lower recall scores, meaning that hearing-impaired participants were able to repeat fewer words than normal-hearing listeners, but they could still recall the same share of the words as the normal-hearing listeners. 

In fact, at the most favourable SNRs, hearing-impaired listeners had higher recall scores than normal-hearing listeners for sentences with high-context cues. This suggests that hearing-impaired people may use some rehearsal strategies in their everyday life, and that they use context much more actively than normal-hearing listeners to guess what’s being said.

There were significant correlations between repeat and recall scores and scores from dedicated speech-intelligibility and working-memory tests. This suggests that the RRT is a valid tool to assess both dimensions of speech understanding.

How does it benefit my practise?

By using the new RRT, hearing care professionals can obtain a more accurate and true-to-life profile of the individual hearing-aid user, including how they cope with speech in noise and whether any speech in noise issues are because of cognitive challenges. This is handy because many clients are likely to be older adults that may experience cognitive decline.  

The RRT can help you better understand the underlying causes of your client’s speech-in-noise difficulties. That includes whether those difficulties reflect issues with audibility, issues with the encoding, processing, and storing of speech information – or general issues with staying motivated to communicate in noisy situations.

The profile can be compared with the average profile of normal-hearing people or the profile of people with the same audiometric profile. The RRT may suggest individual changes both for the fitting and in your counselling. The researchers at ORCA in the U.S. are currently working to define the specific fitting and counselling strategies that best match different hearing profiles. 

How does it benefit the hearing aid industry?

From a research perspective, the new RRT helps us compare different hearing solutions while taking different aspects of hearing into account. Two different hearing solutions may offer the same repeat performance, but one solution may offer better recall performance than the other. And in that case, users won’t need to spend as much cognitive energy when trying to understand speech.  

Want to learn more?
Read the full study article

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