Seeing and hearing is remembering | MEDICUS 2024 Issue 1

Seeing and hearing is remembering

Credit: iStock.com / Edwin Tan

Could vision and hearing disabilities put you at risk of more serious health conditions such as dementia and cognitive decline?

Recent studies have pointed to a possible correlation, spurring the launch of a Singapore-based collaborative study, called the STEADFAST study, to determine whether there is a direct association between hearing and vision impairment and the risk of developing pre-dementia and dementia. Announced in October 2023, the five-year study will also investigate whether someone’s dementia risk can be lowered using widely adopted interventions for sensory impairments.

“Vision and hearing loss can usually be improved with spectacles, hearing aids and cataract surgery, offering the potential of readily available treatment strategies to prevent and delay the onset of dementia.”
Assoc Prof Adeline Ng

Importantly, the study, which brings together scientists from three institutions of the SingHealth Duke-NUS Academic Medical Centre, will generate Singapore-relevant data on the association.

“This is crucial as it could lead to a paradigm shift in how sensory loss is viewed, as it is no longer just an impairment but a potential risk factor for a devastating disease,” said Clinical Assistant Professor David Low, who is a senior consultant with the Department of Otorhinolaryngology, Head and Neck Surgery at Changi General Hospital and one of the site principal investigators of the study.

The study findings are likely to have wide-reaching impact on Singapore’s rapidly ageing population that includes a high proportion of individuals with pre-dementia and dementia as well as sensory impairments. Currently, one in eight Singaporeans is living with pre-dementia, and one-third of these individuals will go on to develop dementia. This is coupled with about 180,000 adults aged 60 years and older who have some form of visual impairment, a number that is expected to double by 2030, while 50 per cent of sixty-year-olds and 95 per cent of octogenarians live with some degree of hearing loss.

The STEADFAST team, comprising researchers and clinician-scientists from the National Neuroscience Institute, Singapore Eye Research Institute and Changi General Hospital, aim to recruit 300 participants aged 50 years and above who have hearing loss, visual impairment or both.

Over the course of the study, participants will undergo comprehensive vision, hearing and neuropsychological screening and testing by specialists in ophthalmology, ear, nose and throat (ENT) and neurology, and where needed, referred to standard clinical care.

Assoc Prof Adeline Ng is a co-lead of the STEADFAST study // Credit: Norfaezah Abdullah, Duke-NUS

“Vision and hearing loss can usually be improved with spectacles, hearing aids and cataract surgery, offering the potential of readily available treatment strategies to prevent and delay the onset of dementia,” said Associate Professor Adeline Ng, a senior consultant neurology at National Neuroscience Institute and a co-lead of the study.

For participants who are at higher risk of developing cognitive decline, the care team will provide additional support in the form of post-diagnosis and behavioural support, counselling, cognitive rehabilitation, and psychosocial therapy. These participants will also be given the opportunity to join one of three pilot interventions – brain stimulation using low intensity pulsed electrical currents; Gym Tonic, which is a safe and simple strength training programme for seniors; or virtual reality therapy. The three pilots will assess the effectiveness of these interventions in delaying the progression to pre-dementia or dementia.

“Contemporary data on the role of vision, hearing, and dual sensory impairment in dementia development and progression, are lacking in older adults,” pointed out Professor Ecosse Lamoureux, who is director of Population Research and Epidemiology at the Singapore Eye Research Institute and one of the site principal investigators of the study.

By focusing on the intricate interconnection between sensory abilities and brain health, the Steadfast study addresses this crucial gap and provide new strategies to help slow cognitive decline.

The five-year study is supported by a $4 million from the Lien Foundation, whose chief executive officer, Mr Lee Poh Wah, added: “We aspire to expand the local toolbox of drug-free, non-invasive interventions, thereby bolstering strategies to combat cognitive decline and dementia.”

Adapted by Sruthi Jagannathan from New study to investigate how vision and hearing loss contribute to the development of dementia in Singaporeans