hearing and seeing impairment -50% chance of dementia

 A new study says losing function in both senses may put you at greater risk of dementia and cognitive decline years later. The research is published in the April 7, 2021, online issue of Neurology, the medical journal of the American Academy of Neurology. The study did not find such a link between losing just one of those senses.

“Depending on the degree of hearing or vision loss, losing function in your senses can be distressing and have an impact on your daily life,” said study author JinHyeong Jhoo, M.D., Ph.D., of Kangwon National University School of Medicine in Chuncheon, Republic of Korea. “But our study results suggest losing both may be of particular concern.”

The study looked at 6,520 people between the ages of 58 and 101. Visual and hearing impairment was determined by questionnaire asking about using glasses or hearing aids. People rated their hearing as “normal,” “reduced, but able to communicate without a hearing aid,” “difficult communicating with a hearing aid” or “no hearing at all.” People rated their sight as “normal,” “reduced, but able to view newspaper or TV without wearing glasses,” “unable to view newspaper or TV with glasses” or “no sight at all.”

At the beginning of the study, 932 people had normal seeing and hearing, 2,957 had either visual or hearing impairment, and 2,631 said they had both impairments.

Dementia was more than twice as common in the group with both impairments at the beginning of the study. In that group, 201 people out of 2,631, or 8%, had dementia at the start of the study, compared to 2.4% with one sensory impairment and 2.3% with no sensory impairment.

Researchers evaluated people’s thinking and memory skills every two years for six years using a test that includes word recall and recognition. Then they analyzed the relationship between having a hearing or vision impairment and dementia and having both impairments and dementia.

During the six-year follow-up period, 245 people developed dementia. Of the 1,964 people with both impairments, 146 developed dementia, compared to 69 of the 2,396 people with one impairment and 14 of the 737 people with no impairments. In addition, 16 out of 142 people who could not determine whether they had a sensory impairment developed dementia.

After adjusting for factors like sex, education and income, researchers found that the group with both hearing and seeing impairment were twice as likely to develop dementia than the group with normal sensory function. People with just one impairment were no more likely to develop dementia than those with normal sensory function.

In addition, the decline on thinking test scores was steeper among people with both hearing and vision impairment.

Jhoo says that further research is needed to explain why people with two impairments have a greater risk for dementia than those with one.

“Older people with only a visual or hearing impairment can usually still maintain social contact, so they may not feel be as isolated or depressed as people who have both impairments,” Jhoo said. “However, when someone has both impairments, that may increase the risk of isolation and depression, which previous research has found may affect dementia risk and thinking skills later on.”

A limitation of the study is that participants completed a questionnaire about their hearing and vision. Not having objective measures of people’s hearing and vison could have affected the study results.


The study was supported by Research of Korea Centers for Disease Control and Prevention.

Learn more about dementia at BrainandLife.org, home of the American Academy of Neurology’s free patient and caregiver magazine focused on the intersection of neurologic disease and brain health. Follow Brain & Life® on Facebook, Twitter and Instagram.

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The American Academy of Neurology is the world’s largest association of neurologists and neuroscience professionals, with over 36,000 members. The AAN is dedicated to promoting the highest quality patient-centered neurologic care. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer’s disease, stroke, migraine, multiple sclerosis, concussion, Parkinson’s disease and epilepsy.

3M on Trial for Failing to Protect SOLDIERS Hearing

3M on Trial for Failing to Protect Soldiers Hearing

Veterans claim that the 3M knowingly gave soldiers defective NOISE REDUCTION earplugs.

Julia Métraux

Health Writer

30 March 2021

1280px 3 M Building Maplewood Mn1

Image via Wikimedia Commons/Acroterion

The first trial began yesterday for multinational corporation 3M—for its defective military-issued earplugs. There are over 229,397 lawsuits from veterans and soldiers who claim that 3M knowingly gave defective earplugs to soldiers to use in combat. Two subsequent trials will take place in May and June.

“Combat Arms CAEv2” earplugs, sold by 3M-subsidiary Aearo Technologies, were designed for use by the US Military, and sold to the US government between 1999 and 2015. The Star Tribune reports that damages related to the faulty earplugs “could tally in the hundreds of millions of dollars, if not more, based on the outcome of other large mass tort cases in recent years.” The plaintiffs from the first trial are veterans, mostly between the ages of 30 and 49.

One plaintiff, U.S. combat veteran Dave Henderson, started to experience ringing in his ears and had trouble hearing people after using the Combat Arms earplugs in the field. Henderson told Reuters that “we had no choice but to use the 3M earplugs” because the soldiers “trusted that our equipment would work.” Henderson told Reuters that he has to sleep with a fan to help with the ringing in his ears, and sometimes cannot hear when his children are crying.

The plaintiffs claim that 3M knowingly hid product defects—namely that the CAEv2 earplug didn’t always fit properly—from the U.S. Department of Defense.  Aearo’s own laboratory tests, conducted in 2000, showed that the earplugs weren’t effective unless they were fitted “in a particular way.” According to Star Tribune, 3M claimed that it informed the military about “fitting issues”, but “in a 2018 report, the Army concluded that had the government known about tests […] it may not have purchased Combat Arms earplugs.” 3M also paid a $9.1 million penalty in a whistleblower settlement but did not admit liability. 3M also paid a $9.1 million penalty in a whistleblower settlement but did not admit liability.

Judge M. Casey Rodgers of U.S. District Court for northern Florida, who will hear all three consolidated claims, will not allow 3M to use the “government contractor defense”, which would potentially “offer protection from state law product liability actions arising out of a contractor’s compliance with a federal government contract,” according to the American Bar Association.

The key point in this trial is whether or not 3M knew that the Combat Arms earplugs were defective. Hearing loss is a major issue for veterans, and a costly service-connected injury for the VA. The U.S. Department of Veteran’s Affairs reported that  “more than 933,000 Veterans were receiving disability compensation for hearing loss, and nearly 1.3 million received compensation for tinnitus” at the end of the fiscal year of 2014.

Julia Métraux

Health Writer

Julia Métraux is a health and culture writer with hearing loss and a member of the Association of Health Care Journalists. Check out her portfolio.