Study suggests link between hearing loss and dementia

When elderly patients with dementia have difficulty communicating, it’s important to rule out whether hearing loss is an exacerbating factor, says a specialist at the Baycrest Centre for Geriatric Care.

Communication can become very difficult for patients with dementia. In order to set the patient up for success, difficulty with communication should prompt a hearing evaluation,” Dr. Tiffany Chow, a senior clinician-scientist, said Tuesday.

She was commenting on new research that suggests a link between dementia and hearing impairment. The study, which appears in the February issue of Archives of Neurology, shows that the risk of dementia appears to rise as hearing declines.

The study followed 639 people between the ages of 36 and 90 who did not have dementia in 1990. For the next four years, they were given cognitive and hearing tests. And they were then monitored for dementia until 2008. Of the 639 participants, 58 were diagnosed with dementia, including 37 with Alzheimer's disease.

By cross-referencing data, researchers found that the risk of mild hearing loss was linked to a slight increase in dementia risk, but the risk increased noticeably among those with moderate and severe hearing loss. For participants aged 60 and older, the risk of memory problems was strongly linked to hearing loss.

Chow said more studies need to be done to show whether hearing loss is an early sign of dementia or one of its risk factors.

But there is no doubt that hearing loss can make symptoms of dementia appear worse than they really are, she said.

When patients with hearing loss are assessed for dementia at Baycrest, a “pocket talker” is used — a microphone and headphones that eliminate all ambient noise and amplify the examiner’s voice.

It’s really amazing how patients who look like they have moderate to severe cases of dementia perk up and respond appropriately,” Chow said.

(Hearing loss) makes the symptoms appear worse. It makes the brain look like it has a more advanced case of dementia that it does have,” she added.

Chow has also encountered patients with hearing loss whose dementia is detected late because they have spouses who are accustomed to answering questions for them.

You have probably been around a couple where one of them can’t hear too well and the other person answers for them all the time,” she said.

Because one is so used to covering for the other, it becomes difficult to figure out when did the memory problems start.