Hearing loss may be linked to mental decline: Study

Loss of hearing represents more than just difficulty hearing sounds. It can lead to social isolation and depression. A study suggests that hearing loss may also be linked to loss of memory and thinking skills.

In a study published in JAMA Internal Medicine, Johns Hopkins researchers found that declines in thinking skills happened faster during a six-year period among people with hearing loss than among those without it.

Among the nearly 2,000 volunteers, all over age 70, those with hearing loss we also likely to develop “cognitive impairment,” defined as a substantial reduction in the score on a key test called the Modified Mini-Mental State Examination.

The researchers estimated that it would take a hearing-impaired older adult just under eight years, on average, to develop cognitive impairment compared with 11 years for those with normal hearing.

This isn’t the first time that researchers have explored possible connections between hearing loss and brain function. Some saw what the Hopkins team saw, while others found no connection between hearing loss and thinking skills. The strengths of this study compared to earlier ones are:

• It included older people who had normal tests for memory and thinking at the start.

• All volunteers had standardized hearing tests performed by professionals.

• The same methods for testing hearing and brain function were used throughout the study.

Keep in mind that this study shows an association. It does not prove that hearing loss causes a decline in thinking skills. The work also raises a huge question: can treating hearing loss prevent or slow an age-related decline in brain function?

What’s the connection?

If hearing and thinking skills are truly connected, there are several plausible reasons that might be so.

Hearing loss can lead to greater social isolation, something to which older people are already prone, and social isolation is a definite risk factor for cognitive impairment and dementia.

Like impaired vision, diminished hearing can lead to less brain stimulation, another risk factor for a decline in thinking skills.

It’s also possible that by making the brain work overtime to process the signals it is getting from the ears, hearing loss pulls away energy from the “thinking” parts of the brain.

Harvard Health Publishing

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