Executive functions and working memory capacity in speech communication under adverse conditions

Abstract

Introduction: Working memory is assumed to play a major part in hearing and communication in everyday listening situations. Our working memory stores information, but in suboptimal listening conditions, interfering stimuli can lead to information only being partially stored, or even missed. Research suggests that a high working memory capacity (WMC) might not just be a result of a large store, but in addition good inhibitory control can facilitate working memory, and therefore aid in situations where focus on a target stimulus while ignoring distractors is needed.Objective: The aim of the present study was to investigate how individual WMC, cognitive inhibition, and lexical decision relate to listening to speech under adverse conditions in two separate groups: 46 young normally hearing (NH) and 40 elderly hearing-impaired (HI) individuals.Results: It showed that lexical access was of little importance for young NH individuals in a speech-in-noise test, but that high lexical decision-making was associated with lower signal-to-noise ratios for the elderly HI individuals. The results also showed that WMC was of importance for word recognition in a speech-in-noise test for elderly participants, when the 80% word recognition criterion was targeted, but not for the young NH individuals. Finally, results suggest that cognitive inhibition, as measured with the Hayling task, was important for young NH individuals when listening conditions are suboptimal.Conclusion: In conclusion, hearing loss is a strong contributing factor to declines in the ability to recognize speech in noise, and in order to assess speech-recognition-in-noise performance, individual differences in WMC and cognitive inhibition should be taken into consideration. Future research should include various age groups, with and without hearing loss, as well as measures of WMC, cognitive inhibition, and lexical access when assessing the ability to listen to speech under adverse conditions.