Listening effort in the European Population (LISTEN) (WC2013-030)


Starting date: 01/03/2014

Barbara Ohlenforst has finished a systematic literature review to the existing evidence regarding the effect of hearing impairment (Q1) and hearing aid amplification (Q2) on listening effort. A systematic search of five electronic libraries produced 46 articles. Those articles had to fulfill the PICOS strategy and we performed a quality rating based on the GRADE Working Group guidelines. Statistical evidence regarding Q1 was identified in 24 articles and in 29 articles regarding Q2. Overall, scientific evidence proposed that hearing impairment increases listening effort and that hearing aid amplification can reduce listening effort. However, the scientific quality was in general on a moderate level, and additional evidence may affect the current findings.

Barbara has finished the data collection for the first experimental study. In total 34 listeners with normal hearing and 30 listeners with hearing impairment were included. The study assessed the pupil dilation response to speech perception in degraded listening conditions (intelligibility between 0% and 100% correct) and in a clear listening condition. The participants also performed several cognitive tests including tests for linguistic abilities and verbal working memory. These functions have known associations with both speech perception performance and cognitive processing load (pupil dilation response) during listening. Finally, questionnaires assessing daily-life experiences and activities were administered, including scales assessing hearing disability, scales for chronic fatigue, and need for recovery. These questionnaires allow us to connect the lab-based data with daily-life functioning. The quality check of the behavioral data and pupillometry data has been performed. The data analysis will be continued and these data will result in at least one paper to be submitted for publication in a scientific journal.

The design of the future studies in progress. The experimental design is currently being developed and piloted at Eriksholm. Data collection will start in the beginning of 2016.


Yang Wang has finished a systematic literature review 1) of the existing evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2) discussing the relationship between hearing impairment and parasympathetic activity and 3) seeking evidence of possible connections between hearing impairment and pupil light reflex. The results demonstrated that the pupil light reflex could be used as a testing tool to assess the presence of parasympathetic dysfunction in people with hearing impairment. Maximum constriction velocity and relative constriction amplitude appear to be more consistently sensitive.

Yang has finished the data collection for the experimental study. These data consist of two parts. For part one, first a pilot study was conducted (finished on date 30-10-2015) to optimize the parameters for testing the pupil light reflex. Then, 27 listeners with normal hearing and 25 age-matched listeners with hearing impairment were tested in 8 conditions. Differences between the groups in their pupil reflex to light will indicate differences in their parasympathetic activation (part of the autonomic nervous system). This may suggest differences in their abilities to cope with prolonged or temporary stress. Currently, the data is analyzed. The first analyses suggest that participants with hearing impairment had a faster and bigger constriction in comparison with the normally hearing participants Part two consisted of a study that aimed to disentangle the separate contributions of the sympathetic and parasympathetic nervous system on the pupil dilation response to listening effort. The same listeners as those participating in part 1 of this study performed two speech perception tasks: one in complete darkness and one in ambient illumination levels. The difference in pupil dilation response between these two conditions will inform us about the parasympathetic contribution to the pupil dilation response during listening. Data is currently being analysed.  

Future study for Yang is currently being designed. The data collection for this study will start in the beginning of 2016.