The impact of speech recognition testing on the association between cochlear implant and cognition
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Abstract
BACKGROUND: It has been suggested that there is a relationship between hearing loss and accelerated cognitive decline. Cochlear implants have been investigated as a possible means to slow this decline. However, the relationship between cochlear implant outcomes and cognition are complicated, and details regarding this association require clarification. The goal of the work is to evaluate whether speech testing in cochlear implantation impacts outcomes on its association with cognition.
OBJECTIVE: To assess the impact of speech recognition testing in noise and quiet on the relationship between cochlear implant outcomes and cognition.
METHODS: The project was performed as a literature review that followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The reviewed studies examined the association between cochlear implant outcomes and cognition in adult patients who were post-lingual deafened from January 1996 through May 2021. Studies that evaluated the relationship between cognition and cochlear implant in the adult population were included for review.
The included studies were further organized by the six cognitive constructs of: global cognition, memory/learning, controlled fluency, inhibition-concentration, verbal fluency, and visuospatial organization.
RESULTS: There were 2140 studies screened, of which 63 were included in our initial review. Out of the 63 studies that were examined, only 38 of them reported outcomes of associations between speech recognition scores and cognition and included in analysis. Outcomes reported from each study were separated based on whether the speech recognition testing was performed in quiet or noise.
There were 84 outcomes that evaluated the relationship between cochlear implant scores in noise to cognitive scores. There were 161 outcomes that evaluated the relationship between cochlear implant scores in quiet to cognitive scores.
The association between cochlear implant and cognition did not appear to be impacted by whether speech testing was performed in quiet or noise. When cochlear implant testing was performed in quiet, 29% of outcomes were found to have a positive association with cognition. The number of positive associations was 20% when cochlear implant testing was performed in noise.
When specific cognitive constructs were evaluated, the construct with the highest percentage of positive associations with speech recognition scores in noise was verbal fluency, while the highest percentage of associations with speech recognition scores in quiet was global cognition.
CONCLUSIONS: Speech recognition testing performed and quiet or noise, may not influence the association between cochlear implant and cognition. Future work should further evaluate this relationship to determine if there is an optimal speech recognition test that can clarify this association.