Hearing, cognition and speech perception in aging: literature findings

Abstract

Purpose: These studies assess evidences in Literature about correlation between auditory abilities and cognitive functions on elderly. It was realized a systematic review of Literature, using articles published in the last two decades, researched in Medline, Scielo and Lilacs. It was picked prospective clinical and reviewed texts that refer to the correlation between audition and cognition. Each article was evaluated concerning to the level of evidence according to "Oxford Centre for Evidence-based Medicine Levels of evidence". It was found 38 articles among 2008 and 2012 that treated specifically aging auditory and cognitive aspects, being 11% national and 89% international. From studies about correlation and interactions between auditory abilities and cognitive abilities, 15% were about descriptive reviews of literature (level of evidence 3a); 65% were about case-control (level of evidence 3b); 3,3 % were about case-control studies with poor or not independent standard of reference (level of evidence 4); 3,3% were about validation cohort only in fragmented samples (level of evidence 3b); and finally, 10% were about validation cohort, with a good standard of reference, diagnostic criteria tested in a single clinical center (level of evidence 1b).  Few authors evaluated the correlation between hearing and cognition with adequate methods. The recommendation grade of the most of studies reviewed was B, which represents experimental or observational studies with fewer consistencies. It was observed that there are not formal protocols to assess the cognitive and central auditory abilities. Meta-analyze is difficult to have because of the variation of methods between these studies.