Hearing loss and cognition in the Busselton Baby Boomer cohort: An epidemiological study
The work was conducted at the Busselton Health Study (m.h.); the Department of Psychology, University of Western Australia (r.s.b., p.d.); and the Ear Science Institute Australia (c.b-j., d.s.t., r.e.). This work was supported by the Office of Science and the Department of Health of the Government of Western Australia, the Shire of Busselton, Ear Science Institute Australia Inc., Lions Hearing Foundation of Western Australia Inc., and private donations. Mr. Brennan-Jones reports grants from Cochlear Foundation Ltd and the Lions Hearing Foundation of Western Australia outside the submitted work. Dr. Wesnes was until February 2014 an employee of Bracket Global, provider of the CDR System as a service in clinical trials. He currently runs a consultancy, which provides services concerning appropriate testing of cognitive function in clinical trials. Dr. Eikelboom reports nonfinancial support from Sonova Holdings Switzerland; nonfinancial support from Med-el, Austria; grants from Med-el, Austria; and personal fees and nonfinancial support from the National Health and Medical Research Council, Australia, outside the submitted work. The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Abstract
Objectives/Hypothesis
To determine the relationship between peripheral hearing loss (HL) in baby boomers (better-ear measure) and cognitive function, taking into account the impact of depression or cognitive reserve on this relationship and exploring binaural hearing.
Study Design
A prospective, epidemiology study.
Methods
Data from 1,969 participants aged 45 to 66 years were collected in the Busselton Healthy Ageing Study. Participants were assessed using pure-tone air-conduction thresholds at octave frequencies (250; 500; 1,000; 2,000; 4,000; and 8,000 Hz). Hearing loss was grouped using 1) pure-tone averages across 4 frequencies (500 to 4000Hz) in the better ear (BE4FA) or 2) latent profile analysis (LPA) using all thresholds from both ears. Cognition was tested with the Cognitive Drug Research System, verbal fluency, and National Adult Reading Test (premorbid-IQ). Regression was used to determine the impact of HL relative to no HL on age and education-adjusted cognition, controlling for mood, sex, and premorbid-IQ.
Results
According to BE4FA, 4.7% had mild (26–40 dB) HL; 0.8% had moderate (41–60 dB) HL; and 0.3% had severe (61–80 dB) HL. Based on the LPA, 20.5% had high-frequency HL; 7.8% had mid- to high-frequency HL; and 1.9% had significant HL across all frequencies. The HL group was not a predictor of cognitive performance in any domain using BE4FA and explained just 0.5% and 0.4% of variance in continuity-of-attention and speed-of-memory retrieval using LPA. Critically, those with the worst hearing did not differ cognitively from those with the best.
Conclusion
Hearing loss is not an important determinant of contemporaneous attention, memory, or executive function in middle-aged adults once age, education, depression, cognitive reserve, and sex are controlled.
Level of Evidence
4. Laryngoscope, 126:2367–2375, 2016
