Hear for health

Hearing impairment can create obstacles in engaging with others for children, adults and the ageing population.

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'Blindness separates people from things, deafness separates people from people' – Immanuel Kant

The World Health Organization considers participating in society as one of the three key parameters to healthy living and ageing, along with physical health, mental health, and security.

Hearing impairment can create obstacles in engaging with others for children, adults and the ageing population; many deaf children are academically behind their peers, and hearing difficulties in the elderly are related to cognitive decline in the elderly. Both these symptoms of hearing loss can cause frustration and social isolation leading to a poorer quality of life.  

More and more research into neural development, cognition and deafness, has revealed the negative correlation between hearing loss and cognitive skills. 

Dr Julia Sarant from the Department of Audiology and Speech Pathology has been working with hearing impaired children and adults for over two decades and understands all too well the complex partnership between the brain and the ears and what happens at a neurological and auditory level to communicate.

Many hearing impaired children continually fall behind their peers in language, speaking and social development by 40% per year, and without intervention they will never catch up. In older people, those with hearing loss are more likely to have dementia though it is unclear whether it is a cause or a risk factor. The results of the study on children were published in The Journal of Speech, Language & Hearing Research.

Thirty years ago, the bionic ear was invented by University of Melbourne scientists and engineers. The Melbourne-based team were leading the world in cochlear implants. Professor Graeme Clark was the first surgeon to insert a cochlear implant in a patient. The cochlear implant is the only treatment for those with severe to profound hearing loss.  

Professor Richard Dowell, Head of the Department of Audiology and Speech Pathology who holds the Graeme Clark Chair of Audiology and Speech Science and is the Director for Audiological Sciences at the Victoria Eye and Ear Hospital, is proud of the University's role in the history of the cochlear implant. 

'The University of Melbourne is where it all began for cochlear implants,' he said. 'And Melbourne remains a key international centre for research in the field.'

Others in the Department of Audiology and Speech Pathology are researching language skills development in children who have cochlear implants before twelve months of age. Results of a multi-centre Australian study led by Dr Shani Dettman show cochlear implants for eligible children younger than 12 months can improve listening and spoken language. With early intervention like this, hearing impaired children are able to catch up to their hearing peers. Dr Dettman's results were presented to an international audience in 2015. 

Hearing loss not only affects a child's neurological development at a young age, it is also associated with cognitive skills decline during the ageing process.  What is less clear is whether hearing loss causes the decline, or if hearing loss is a symptom of cognitive decline.  

This area of research is still relatively new as scientists from all disciplines strive to find the cause and treatment of cognitive decline.  

A study into hearing loss in ageing populations by Dr Sarant and her team is funded by a new Australian Research Council linkage project to investigate if treating hearing loss delays the onset of cognitive impairment. 

'Dr Sarant's new study on the relationship between restoration of hearing and cognitive abilities in the elderly may have significant impact on improving quality of life in our aging population,' said Professor Dowell.  

Hearing loss can cause social isolation, embarrassment, stress and depression as the individual adjusts to how they can participate in their new world. There is a direct causal relationship between hearing loss and poorer quality. With better hearing comes the ability for an individual to stay connected to their family and community, they can maintain their mental health and physical health. 

'Understanding the pathways that lead to cognitive impairment and identifying factors that affect this process in the elderly is a public health priority' said Dr Sarant. 

'There is a significant correlation between hearing loss and decline in cognitive function in the elderly. Whether hearing loss is a marker for early cognitive impairment or a risk factor that can be modified is unknown,'

The studies were conducted in partnership with The University of Melbourne's Department of Audiology and Speech Pathology, Cochlear Ltd and The Royal Victorian Eye and Ear Hospital

Findings from the study and the ARC grant application were based on strong evidence-based research analysis and data modelling by Professor David Harris, econometrics expert from Monash University. 

By Lisa Mamone