Adverse listening conditions disrupt executive processing of speech more for older adults with hearing impairment than for younger adults with normal hearing
2014 (English)Manuscript (preprint) (Other academic)
Speech recognition, especially in noise, has been associated with cognitive capacity, specifically working memory capacity. Cognitive spare capacity (CSC) is the residual cognitive capacity available for processing heard speech. Previously, we have shown that in young adults with normal hearing, CSC was not generally related to working memory capacity (WMC) and that CSC decreased in noise conditions. CSC was enhanced in noise by presence of visual cues, but in quiet, visual cues reduced CSC. In the present study, we investigated CSC in older adults with age-related hearing loss. Twenty-four adults performed the CSC Test (CSCT) and an independent battery of cognitive tests. In the CSCT, they listened to lists of numbers with and without visual cues in quiet, steady-state and speech-like noise at intelligibility levels approximating 90%. They recalled numbers according to different executive processing instructions (updating and inhibition) at two different memory loads. We predicted that CSCT performance would be reduced in noise and enhanced by visual cues in both quiet and noise, but not associated with WMC. The results confirmed our predictions. We also found that CSC was associated with episodic long term memory (LTM). A reanalysis with data from the previous study showed that the CSC of older adults was reduced compared to young adults especially in high load conditions, with an absence of visual cues and in speech-like noise. The older adults also performed worse on a battery of cognitive tests. These findings suggest that older individuals with hearing loss and lower cognitive skills are more susceptible to the increased demands in processing of speech that episodic LTM may constitute a processing bottleneck. On the other hand, higher CSC may also lead to efficient episodic LTM.
Place, publisher, year, edition, pages
Working memory, cognitive spare capacity, updating, inhibition, episodic long-term memory
IdentifiersURN: urn:nbn:se:liu:diva-104944OAI: oai:DiVA.org:liu-104944DiVA: diva2:700246