SINGAPORE - A team of researchers here is embarking on a five-year study to determine the impact of vision and hearing loss on the risk of developing pre-dementia and its progression to dementia in Singaporeans.

The team will also look into whether standard treatments for vision and hearing loss, such as spectacles, hearing aids and cataract surgery, can reduce these risks. These are paid for by the participants.

This is the first local interventional programme on sensory loss and cognitive decline, said the National Neuroscience Institute (NNI) in a press statement on Tuesday. NNI is leading the study in partnership with the Singapore Eye Research Institute, Changi General Hospital and Lien Foundation.

The Steadfast Study plans to recruit 300 participants aged 50 and above who have hearing loss, visual impairment (including uncorrected long or short-sightedness), or both.

Recruitment is expected to start towards the end of 2023.

“Understanding how the presence and severity of individual and multiple sensory loss impact pre-dementia and dementia will help us develop screening tools to identify at-risk individuals,” said Associate Professor Adeline Ng, a senior consultant in neurology at NNI and the study’s co-lead.

One of the study’s aims is to develop a prediction tool to determine who is at higher risk of pre-dementia, or mild cognitive impairment, and who among those with pre-dementia are at greater risk of progressing to dementia, she said.

“In addition, 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,” she said.

Currently, one in eight Singaporeans is living with pre-dementia and nearly one-third of them will go on to develop dementia. 

Over three to five years, the study’s participants will undergo comprehensive vision, hearing and neuropsychological screening and testing by specialists and be referred for standard clinical care.

They will also get additional support, such as cognitive rehabilitation and psychosocial therapy, if needed. 

In the study, those identified as having a higher risk of cognitive decline can undergo brain stimulation therapy, a strength training programme for seniors called Gym Tonic or virtual reality therapy. Participants in the study do not have to pay for these.

The researchers will assess the effectiveness of the three non-invasive interventions in delaying the progression to pre-dementia or dementia. The use of these three programmes to delay pre-dementia or dementia is being piloted for the study.

Prof Ng said many factors are involved in cognitive decline, including ethnicity and social isolation, and in recent years, there is growing scientific evidence that sensory changes might also be interconnected with overall brain health and dementia.

She said a study on this, done in New Zealand, had shown that the risk of cognitive decline varied by ethnic groups, which is why they are gathering local data to ensure the findings are relevant for the Singapore population. 

About 180,000 adults here aged 60 and above have some form of visual impairment and this number is expected to double by 2030 as the population rapidly ages, according to the NNI statement.

Local data shows that about half of Singaporean adults in their 60s have hearing loss, and about 95 per cent of those in their 80s are affected by it.

The study marks a paradigm shift in how hearing loss is viewed: It is no longer just an impairment but a potential risk factor for a devastating disease, said Clinical Assistant Professor David Low, a senior consultant at Changi General Hospital’s department of otorhinolaryngology – head and neck surgery.

“Recent analysis of early studies suggests that the appropriate and timely management of hearing loss can lower the risk of dementia by as much as 10 per cent,” he said.

The study is supported by $4 million in funding from the Lien Foundation.