Hearing loss has been found to be almost twice as likely to affect elderly people with Parkinson’s disease.

A study, conducted by a Taiwanese research team, shows that incidences of Parkinson’s disease were 1.77 times more likely in a group of patients with hearing loss compared to a non-hearing loss group: 3.11 vs. 1.76 per 1,000 people respectively.

By using data from the Taiwan National Health Insurance Program, the Taiwanese research team has studied nearly 5,000 patients aged 65 or older, who were newly diagnosed with hearing loss between 2000 and 2010.

With a comparison group of nearly 20,000 people without hearing loss, the research team investigated the incidence of Parkinson’s disease by the end of 2010 in both groups.

How Parkinson’s affects the cochlea

It is well known that aging is related to hearing loss. However Parkinson’s disease also affects the cochlea, which is the sensory organ of hearing.

The important neurotransmitter dopamine, the absence of which causes Parkinson’s disease, helps to protect the cochlea from noise exposure. Inadequate dopamine can thus lead to damage to the cochlea and result in hearing loss.

About the study

The study was published in The European Journal of Neurology and was a collaboration between researchers from Taichung Tzu Chi General Hospital, China Medical University and College of Health Science in Taiwan.

Sources: http://www.ncbi.nlm.nih.gov and http://www.viartis.net