Does cognitive function predict frequency compressed speech recognition in listeners with normal hearing and normal cognition?

Abstract

Objective: The aim was to investigate the relationship between cognitive ability and frequency compressed speech recognition in listeners with normal hearing and normal cognition. Design: Speech-in-noise recognition was measured using Institute of Electrical and Electronic Engineers sentences presented over earphones at 65 dB SPL and a range of signal-to-noise ratios. There were three conditions: unprocessed, and at frequency compression ratios of 2:1 and 3:1 (cut-off frequency, 1.6 kHz). Working memory and cognitive ability were measured using the reading span test and the trail making test, respectively. Study sample: Participants were 15 young normally-hearing adults with normal cognition. Results: There was a statistically significant reduction in mean speech recognition from around 80% when unprocessed to 40% for 2:1 compression and 30% for 3:1 compression. There was a statistically significant relationship between speech recognition and cognition for the unprocessed condition but not for the frequency-compressed conditions. Conclusions:The relationship between cognitive functioning and recognition of frequency compressed speech-in-noise was not statistically significant. The findings may have been different if the participants had been provided with training and/or time to ‘acclimatize’ to the frequency-compressed conditions.

Key Words::

• Frequency compression
• cognition
• speech-in-noise
• trail making test
• reading span test

Acknowledgements

Parts of this work have been presented at the International Hearing Aid Research Conference, Lake Tahoe, USA, August 11–15, 2010, and at the British Society for Audiology Annual Conference, Manchester, UK, September 8–10, 2010. The authors are grateful to the participants and to Thomas Lunner for providing a copy of the reading span test. Thanks to Piers Dawes for his comments on an earlier draft of this paper, and to Lisa Mendel and two anonymous reviewers for their helpful comments and suggestions.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.

This study was funded by an ESRC CASE PhD studentship in conjunction with Phonak AG.