Hearing loss linked to brain shrinkage

Hearing loss linked to brain shrinkage

New research has linked a loss of hearing with brain shrinkage as people grow older.

Most people's brain gets smaller over time, but according to scientists at the John Hopkins University in Baltimore, Maryland, and the National Institute on Ageing, shrinkage occurs more quickly in those who are deaf.

This in turn increases the risk of poor mental wellbeing, dementia and falls.

Researchers used data from the ongoing Baltimore Longitudinal Study of Ageing to compare the cognitive abilities of those with impaired hearing to people with without any problems.

Hearing loss has been linked to changes in brain structure previously, but according to Dr Frank Lin, assistant professor of the university's school of medicine and public health, whether the changes occurred before or after hearing loss is unclear.

Some 126 patients are currently involved in the Baltimore Longitudinal Study of Ageing, with each undergoing MRI scans every ten years.

In 1994, 75 per cent were deemed to have normal hearing while 51 had impaired hearing of at least 25 decibels.

D Lin and his team found that the brains of those in the second group have deteriorated more rapidly than those with normal hearing, losing an average of one cubic centimetre of brain tissue per annum.

The superior, middle and inferior temporal gyri – the brain structures which process speech and sound – were found to be the most affected parts of the brain.

However, Dr Lin said that the shrinkage could be caused by a lack of stimulation rather than hearing loss.

He added: "If you want to address hearing loss well, you want to do it sooner rather than later. If hearing loss is potentially contributing to these differences we're seeing on MRI, you want to treat it before these brain structural changes take place."

The team are now set to run tests to see if treating hearing loss has any affect association cranial problems.

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