1. Neuroscience
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Poor coherence in older people's speech is explained by impaired semantic and executive processes

  1. Paul Hoffman  Is a corresponding author
  2. Ekaterina Loginova
  3. Asatta Russell
  1. University of Edinburgh, United Kingdom
Research Article
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Cite this article as: eLife 2018;7:e38907 doi: 10.7554/eLife.38907

Abstract

The ability to speak coherently is essential for effective communication but declines with age: older people more frequently produce tangential, off-topic speech. The cognitive factors underpinning this decline are poorly understood. We predicted that maintaining coherence relies on effective regulation of activated semantic knowledge about the world, and particularly on the selection of currently relevant semantic representations to drive speech production. To test this, we collected 840 speech samples along with measures of executive and semantic ability from 60 young and older adults, using a novel computational method to quantify coherence. Semantic selection ability predicted coherence, as did level of semantic knowledge and a measure of domain-general executive ability. These factors fully accounted for the age-related coherence deficit. Our results indicate that maintaining coherence in speech becomes more challenging as people age because they accumulate more knowledge but are less able to effectively regulate how it is activated and used.

Data availability

All raw data and code required to replicate the analyses are available at https://osf.io/8atfn/DOI 10.17605/OSF.IO/8ATFN

Article and author information

Author details

  1. Paul Hoffman

    Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE), Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom
    For correspondence
    p.hoffman@ed.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3248-3225
  2. Ekaterina Loginova

    Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE), Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Asatta Russell

    Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE), Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.

Funding

Medical Research Council (MR/K026992/1)

  • Paul Hoffman

Biotechnology and Biological Sciences Research Council (MR/K026992/1)

  • Paul Hoffman

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Human subjects: All participants provided informed consent and the study was approved by the University of Edinburgh Psychology Research Ethics Committee.(120-1415/3).

Reviewing Editor

  1. Elizabeth Jefferies, University of York, United Kingdom

Publication history

  1. Received: June 4, 2018
  2. Accepted: September 3, 2018
  3. Accepted Manuscript published: September 4, 2018 (version 1)
  4. Version of Record published: September 21, 2018 (version 2)

Copyright

© 2018, Hoffman et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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