Isolation, communication difficulties, reduced alertness — hearing impairment or loss is a real challenge in daily life. Over time, it can also become a risk factor for cognitive decline. A team from the University of Geneva (UNIGE) analysed data from 33,000 older adults across Europe to examine the combined impact of hearing loss and loneliness on memory. They identified three distinct profiles based on the degree of social isolation and perceived loneliness. The findings show that hearing loss accelerates cognitive decline particularly among individuals who feel lonely, regardless of whether they are socially isolated. These results, published in Communication Psychology, support the case for early and preventive hearing care.

According to the World Health Organization (WHO), nearly 2.5 billion people will experience hearing loss or impairment by 2050. More than 25% of people over the age of 60 experience disabling hearing impairment. In addition to the social challenges it creates, this loss — or reduction — is linked to a significantly increased risk of cognitive decline in later life. That risk may be two to three times higher for those affected.

A joint team from the Lifespan Developmental Psychology Lab and the Cognitive Ageing Lab at the University of Geneva (UNIGE) set out to investigate whether the combination of hearing difficulties and feelings of loneliness — whether objectively measured or subjectively perceived — could be associated with accelerated memory decline in older age. ‘‘This is a relatively new approach,’’ explains Charikleia Lampraki, postdoctoral researcher in the Lifespan Lab at UNIGE’s Faculty of Psychology and Educational Sciences and first author of the study. ‘‘While some studies have suggested that this might be a promising avenue, very few research teams have actually explored it.’’

33,000 people studied
To conduct their analyses, the researchers drew on data from the large-scale SHARE study (Survey of Health, Ageing and Retirement in Europe) — a longitudinal survey launched in 2002 that examines the health and ageing of Europeans aged 50 and over.

“We used data from twelve countries, including Switzerland, representing a sample of 33,000 people,” explains Andreas Ihle, assistant professor at the Lifespan Lab and director of the study. Participants are surveyed every two years on various aspects of their daily lives — such as activities, social connections, and perceptions — and undergo tests on cognitive functions like episodic memory, using standardised exercises.

The UNIGE research team identified three distinct profiles related to the issue:

1. Individuals who are socially isolated and feel lonely
2. Individuals who are not socially isolated but still feel lonely
3. Individuals who are socially isolated but do not feel lonely

Isolation and deafness: an ‘‘explosive’’ cocktail
The scientists then examined whether these different profiles had different trajectories of cognitive decline, depending on the type of perceived isolation and the degree of hearing loss. ‘‘We found that people who were not socially isolated but who felt lonely saw their cognitive decline accelerate when they were deaf,’’ says Matthias Kliegel, a full professor in the Cognitive Ageing Laboratory in the UNIGE’s Faculty of Psychology and Educational Sciences, and co-author of the study.

These findings support the importance of addressing both hearing loss and the social and emotional dimensions of individuals in efforts to prevent cognitive decline. This is particularly crucial for people who are not socially isolated but still feel lonely — in such cases, simple hearing interventions, like using a hearing aid, may be enough to help them engage more fully in social life. “These individuals are already socially integrated, so it’s a matter of removing a sensory barrier in order to reinforce their engagement and protect their cognitive health,” concludes Charikleia Lampraki.