Weaker social ties are linked to an increased dementia risk
Scientists are studying the effect of “social frailty” on memory loss—and testing whether AI companions can help.
As people age, frailty starts to creep in. Falls are more damaging and take longer to heal, muscles weaken, walking slows. And on top of physical frailty, people can also become “socially frail” as they age as connections to others fade away.
A new study, published in October in the Journal of Gerontology, finds that screening for social frailty might help doctors predict who will get dementia. The authors are now also working to see if an AI companion might help dementia sufferers by giving them an extra boost of social strength.
Physical frailty is easy to grasp, but social frailty is more complex. “Social frailty includes loneliness, but is broader than that,” says Suraj Samtani, a clinical psychologist at the Centre for Healthy Brain Ageing at the University of New South Wales in Australia, and one of the authors of the study. “Being socially frail looks like having fewer people in our social networks, but also critically, fewer people that we feel close to, or fewer people that we can rely on.”
While many people might be aware of the loneliness epidemic, they might not think of it as part of social frailty, or that social frailty itself is something that can be physically and mentally harmful, says Brea Perry, a sociologist at Indiana University Bloomington, who was not involved in the new study.
“The public does vastly underestimate the extent to which social connectedness factors are associated with morbidity and mortality,” Perry says.
(The reason dementia rates are rising is surprisingly simple.)
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The cognitive cost
A 2025 study estimated that there is a 42 percent risk of being diagnosed with dementia at some point after age 55. Dementia includes Alzheimer’s disease (which is the most common cause) and describes progressive symptoms of memory problems and cognitive decline.
Humans are social creatures, and in previous studies, Samtani and his colleagues have found good social ties benefit us as we age. In a 2023 study meta-analysis across 13 studies and nearly 40,000 people they showed that “people who had good social connections had half the rate of dementia compared to people who had poor social connections,” Samtani says.
In fact, Samtani recently advised actor Chris Hemsworth on the value of social connections for healthy aging in a new National Geographic documentary, A Road Trip to Remember. In it, Hemsworth uses the latest research to find ways to help his father, who has been diagnosed with early-stage Alzheimer’s disease. “Social connections slow down cognitive decline even for people who have been already diagnosed with dementia,” Samtani says in the documentary.
To further understand the connection between dementia and social frailty, clinicians need to know how to screen for social frailty. Scientists have developed five potential screening tools, but did not know which one could best predict dementia.
“Because social isolation is actually the biggest risk factor for dementia in late life, we should be screening for that,” Samtani says. In his latest study, Samtani and his colleagues took data over the course of 12 years from 851 seniors over the age of 70, all without dementia. The scientists scored the participants’ social frailty using different standards set by other studies. While each social frailty index had different questions, they also asked many similar questions, such as how much social activity someone got, how frequently they saw other people in person, how often they felt lonely, and what someone’s financial situation was like.
During the length of the study, 260 of the participants ended up being diagnosed with dementia. On average, across the different sets of social frailty measures, “we found that people who are socially frail, their risk of dementia was 50 percent higher than people who are not frail,” Samtani says.
(Chris Hemsworth talks reminiscence therapy and an epic road trip.)
Can you fix social frailty?
While social frailty may beget cognitive impairment, it’s also likely that cognitive impairment could weaken someone’s social networks. When it comes to social interactions, “it's definitely possible that people experiencing the early stages of dementia lose confidence,” Samtani says. “They might feel that they were embarrassed, and they might feel that they can't keep up with the conversation.”
Samtani sees this when he sees his older patients. “It's so human and understandable that if you can't trust your own memory and your thinking, that you would doubt yourself,” he says. This might make a person socialize less, leading them to lose their contacts and become more socially frail.
Social frailty indexes also don’t separate out exactly which issue—loneliness, financial precarity, social activity, or something else—might link someone’s social life and their health, Brea says. The measures “combine many different specific social mechanisms,” she says. “It is impossible to know what precisely is doing the ‘work’ of improving or preserving cognitive health.” So it’s not as simple as telling someone who is isolated to go out and socialize.
A doctor measuring someone’s social frailty “can give you a signal of risk, but it won't necessarily create a roadmap for you of what to do to mitigate that risk,” says Sachin Shah, an epidemiologist at Harvard Medical School who was not involved in the study.
For Samtani, that’s where AI might provide some help. Along with other scientists, he’s now looking at how a new AI companion could alleviate loneliness for seniors at risk.
(They sing to remember: The power of memory choirs.)
Meet Viv and Friends
“I’m so sorry, my dear. It’s just that my memory isn’t what it used to be.”
The phrase could be coming from anyone with a memory problem. But this one is coming from Viv, an AI companion. She’s part of Viv and Friends, one of six different characters created by the Centre for Big Anxiety at the University of New South Wales. The characters were co-designed with input from women living with dementia, and their conversations are also specifically designed with older people in mind, not pulled from a general chatbot or large language model (LLM).
Viv talks about her own cognitive symptoms and can also talk about other topics like gardening. But she’s not designed to fool anyone—an important aspect for people with dementia, who can become confused about who is around them. “They deliberately co-designed this character to look like a cartoon character,” Samtani says. “It looks like something that is from an animated show rather than a picture of a real person.”
Samtani is now trying to use Viv and her AI friends, who are loaded onto an iPad, to help people who already have dementia, and who are also isolated and socially frail.
So far, 12 of the residents in an Australian residential care home have used the AI companion during a five-week trial. “We had one woman who hadn't been visited by her family in the last three months, and she had a two-hour long conversation one day with the companion,” Samtani says. “And she just was so animated, so happy after that conversation, because she was talking to Viv about the beautiful connection she has with her sister, with her nieces.”
Viv and Friends are also trained for things like “handovers,” for patients with dementia. When a caregiver needs to leave, “they can include the AI companion for the last couple of minutes on the final topic of that conversation, and then hand over to it, so that when the person leaves, you can keep having that conversation,” Samtani says, avoiding some of the anxiety patients can experience.
Samtani hopes that the AI companions could help patients cope with other anxieties. Unlike some other LLMs that tend to agree with people, Viv and Friends is “designed to ask people how they cope with difficult situations, rather than just agreeing with whatever the person wants to do.”
As more of the population ages, there could be more augmentation required. “We are sort of staring down the barrel of a caregiver crisis,” says Shah. He notes that researchers should continue to experiment with AI companions, but at the same time, thinks it’s important to proceed as cautiously as possible for the sake of patient safety. He points out that a lot of AI efforts end up overhyped, and not always as useful as people might have hoped.
And of course, a pilot study of 12 people is only the first step. Samtani hopes the AI companion could eventually give patients daily cognitive quizzes to keep track of their abilities, and also give patients reminders on everything from taking medications to self-care, to help them remain independent.
“So let's say you want to make a tea,” Samtani says. “You have to boil the water first, get the tea bag, get the cup, pour things in in a certain order, and if you lose that order, you can't be independent anymore.” A patient might be embarrassed to admit to a caregiver that they can’t quite remember the steps. But Viv remembers, and she’s glad to help.
(The unexpected ways Ozempic-like drugs could fight dementia.)
Trying to Remember
When Viv and Friends are letting patients talk about their pasts, they are helping them with a form of reminiscence therapy, a psychological concept where people with memory problems recall memories from their lives as a way to improve mental wellbeing.
In “A Ride to Remember,” Hemsworth engages in reminiscence therapy with his father, taking a motorcycle road trip to places from their past and even recreating a former home with vintage materials.
Reminiscence doesn’t need to be quite that intensive, and many with later stages of dementia may not be able to see old friends or go back to places from their former lives. Instead, reminiscence therapy can be as simple as “looking at old photos together,” says Samtani in the documentary.
While reminiscence can be joyful, it can also get repetitive for caregivers. “People like staff might feel frustrated hearing the same conversation over and over again, but the AI companion is never going to feel that or express that,” Samtani says. The companions are an infinitely patient audience.
But he notes that AI can only assist human interaction. “We never want to replace that human contact,” Samtani says. After all, an AI could listen to reminiscence, but it wasn’t there to experience the memory, too. It can’t participate in the patient’s emotions, or bring up something else from the patient’s past—because it was never there.
Brea agrees that while AI companions might help patients, “it is critical that any AI companion augment real-world human interaction, not replace it. No technology-mediated interaction can substitute for face-to-face support.” Remembering with another person, after all, benefits everyone.
