Social Withdrawal in Aging Tied to Shifts in Brain Networks

Medscape

3 days ago

There is a natural decline in sociability as a result of aging influenced by brain changes, new research shows.
'Our study suggests that age-related changes in the functional wiring of the brain may impair certain abilities needed to maintain social relationships,' the study's lead study author Yuet Ruh Dan, Duke-National University of Singapore Medical School, told Medscape Medical News .
The findings were published online on May 28 in PLOS One .
Sociability Critical to Health
Sociability, which is the capacity to communicate effectively, be socially assertive, and to manage emotions, is 'critical' for maintaining and promoting health, especially as we age, said Dan.
Research has linked sociability to increased functional connectivity in and between intrinsic brain networks. Overall, the default mode network (DMN), ventral attention network, and limbic structures have been the most strongly correlated with sociability.
The aging process also involves changes in intrinsic brain networks. Studies have shown that aging results in lower within-network connectivity, as well as greater between-network connectivity.
For example, Dan noted that connectivity between the frontoparietal and DMNs decreases with age change that has been linked to poorer self-esteem and memory. Meanwhile, connectivity between the limbic and insular regions increases with age and has been shown to activate in situations involving social exclusion, she added.
'Intuitively, poorer self-esteem and an increased sensitivity to exclusion may be linked to a decreased ability to communicate with others and regulate our emotions,' she said.
This study is among the first — if not thefirst — to directly examine the relationship between age-related changes in functional connectivity and sociability, Dan added.
The study included 196 healthy participants aged 20-77 years (mean age, approximately 38 years), with 34.2% identifying as female, drawn from the Leipzig Study for Mind-Body-Emotion Interactions dataset. For the analysis, researchers grouped participants into 5-year age brackets (20-25, 25-30, etc.), Dan said.
In addition, the researchers obtained resting-state functional MRI data. Participants completed the sociability subscale of the Trait Emotional Intelligence Questionnaire Short Form.
This six-question subscale measures social awareness, emotional management, communication effectiveness, and participation in social situations. The questionnaire is scored on a 7-point Likert scale ranging from 1 (completely disagree) to 7 (completely agree), with higher scores indicating higher levels of sociability.
Researchers also collected data using the NEO Five-Factor Inventory (NEO-FFI), which measures neuroticism, extraversion, openness to new experiences, agreeableness, and conscientiousness. They found a strong positive correlation between sociability and extraversion ( P < .001), highlighting a significant link between the two traits.
Researchers conducted network-based analyses to identify patterns of resting-state functional connectivity, grouping the data into an age-positive network (APN), which showed a positive correlation with age, and an age-negative network (ANN), which showed a negative correlation.
'Essentially, we found that with increased age, there is a group of functional brain networks that become more interconnected and a group that becomes less interconnected,' said Dan.
The subcortical-parietal connectivity and the within-limbic connectivity were the most negatively correlated in the ANN, while limbic-insular connectivity was the strongest positive correlation within the APN.
Within the positive connectivity network, ventral attention-somatomotor connectivity had the strongest correlation with age. Frontoparietal-DMN connectivity was the most negatively correlated with age.
Decreased Connectivity, Sociability
Both ANN and APN may contribute to decreased sociability, but it's not yet clear which plays the more dominant role, Dan said.
However, she and her colleagues have some theories. They propose that reduced connectivity between the frontoparietal and DMN regions may be linked to impaired cognition and lower self-esteem, 'thereby resulting in impaired social assertiveness, emotional regulation skills, and reduced sociability.'
Decreased connectivity of these regions could be linked to decreased sociability through impaired executive processing, they noted.
The study illustrates that as we age, 'it may not be just a lack of social contact opportunities that prevents us from forming and maintaining relationships but also an inherent change in the brain's functional wiring,' Dan said.
A mediation analysis showed the effect of age on sociability was fully mediated via both APN and AAN.
'Generally, these statistical results meant that the networks that become more connected, for example APN, as well as less connected, for example, ANN, with age can explain decreased sociability seen across the lifespan,' said Dan.
Dan emphasized that sociability is just one factor related to loneliness — and one that is relatively easy to measure — whereas loneliness itself is a far more complex and deeply subjective experience.
'Intuitively, people with lower sociability scores may be more likely to be lonely, as they may find it harder to maintain relationships. In this sense, increased sociability may be a risk factor for increased loneliness with age.'
Dan said she hopes these preliminary findings will spur more longitudinal research into these relationships and help inform efforts to support healthy aging.
She noted the importance of physicians recognizing that declining sociability may be a natural part of aging. 'Greater emphasis should be placed on community-based health promotion efforts,' she said.
The investigators did not analyze NEO-FFI personality trait variables, so 'we can't draw any conclusions about whether they were related to changes in brain connectivity or sociability,' Dan said.
She also noted that the sample was heavily skewed toward younger participants, which may limit the reliability of the findings for older adults. Additionally, grouping subjects into 5-year age bins may have introduced 'noise' into the statistical models.
Other limitations included an all-European study sample, and collection of sociability data exclusively via self-report, which may be less reliable than more objective measures like social network size.
Interpret With Caution
Commenting for Medscape Medical News , Dirk Scheele, PhD, professor of social neuroscience, Ruhr University Bochum, Bochum, German, said the paper addresses a 'relevant' topic.
'The general question of how social interactions and the desire for social engagement change with age is undoubtedly important, particularly given strong evidence that the risk of social isolation and loneliness increases with advancing age,' he said.
However, the underlying neural mechanisms remain 'surprisingly unclear,' he said. 'For example, no study to date has directly compared the neural substrates of loneliness or social isolation between younger and older adults.'
Although the study 'has the potential to inspire novel research questions,' its findings should be interpreted with 'considerable caution' due to several limitations, he said.
'Most notably, it's an entirely exploratory study without preregistration, and its cross-sectional design prevents conclusions about causal relationships,' he added.
Scheele also noted the 'sociability' construct was derived from a subscale of a questionnaire and 'encompasses multiple facets, such as emotion regulation and social awareness, that may belinked to distinct neural mechanisms.'