Auditory threshold, phonologic demand, and incident dementia

• Published in: Neurology Vol. 79; no. 15; p. 1583
• Main Authors: Gallacher, John, Ilubaera, Victor, Ben-Shlomo, Yoav, Bayer, Antony, Fish, Mark, Babisch, Wolfgang, Elwood, Peter
• Format: Journal Article
• Language: English
• Published: United States 09.10.2012
• Subjects: Audiometry, Pure-Tone; Auditory Threshold - physiology; Cognition Disorders - epidemiology; Cognition Disorders - physiopathology; Dementia - epidemiology; Dementia - physiopathology; Humans; Incidence; Longitudinal Studies; Male; Middle Aged; Risk Factors
• ISSN: 1526-632X
• DOI: 10.1212/wnl.0b013e31826e263d

This study was undertaken to investigate the association of auditory threshold with cognitive decline and dementia. The 1,057 surviving men of the Caerphilly cohort with audiometric data at baseline were followed for 17 years for cognitive outcomes. Pure-tone unaided audiometric threshold was assessed at 0.5, 1, 2, and 4 KHz at baseline and after 9 years. Incident dementia was assessed according to DSM-IV criteria, including standard criteria for vascular dementia and for Alzheimer disease. Cognitive decline was assessed by repeat administration of a cognitive test battery. Mean age-adjusted auditory threshold across both time points was associated with incident dementia and cognitive decline. After adjustment for premorbid cognitive function, the association with dementia was retained (odds ratio(0.5 KHz) = 2.67; 95% confidence interval, 1.38-5.18; p = 0.004). Stronger associations with cognitive decline were found for tests administered by interview than for those administered by computer. This study has found an association of auditory threshold with dementia and cognitive decline over a 17-year period. The mechanisms underlying this association are unclear and may include a prodromal effect of dementia on auditory threshold, an effect of auditory threshold on cognitive assessment, an effect of auditory threshold on cognitive loss, or a shared etiologic pathway between both.