# Social Connection and Brain Function: From Measurement to Clinical Trials

## TL;DR

This paper explores how social connection affects brain health and dementia risk, emphasizing the need for clinical trials to reduce social isolation in older adults.

## Contribution

The paper introduces a symposium framework for understanding and addressing social isolation through targeted behavioral interventions.

## Key findings

- Social isolation contributes to 5% of dementia cases, more than physical inactivity or diabetes.
- Theoretical frameworks are essential for designing effective interventions to reduce social isolation.
- Conversational interactions can serve as cognitive stimulation to enhance cognition in isolated older adults.

## Abstract

Over five decades of gerontological studies have shown the negative impact of social isolation on health, including an increased risk of dementia. The most recent Lancet Commission on Dementia reported that social isolation contributes to 5% of dementia cases, higher than the 2% attributed to physical inactivity or diabetes. Reducing social isolation could significantly impact dementia prevalence. However, compared to other behavioral interventions like exercise and diet, fewer randomized controlled trials (RCTs) have been conducted on social isolation/connectedness. Social isolation is multifactorial, affecting cognition through various pathways, including tangible and intangible factors, multiple types of cognitive stimulation, and emotional bonding. Thus, RCTs require careful consideration of theoretical frameworks to clarify and identify the different potential mechanisms. This symposium aims to highlight key factors in developing behavioral interventions for social isolation/connectedness through four presentations: 1) Perry will discuss egocentric social network methodology to assess social connectedness, which operationalizes social bridging and bonding theories. 2) Yu will present the results of her systematic literature review on psychosocial and physiological pathways linking social isolation/connectedness to brain health. 3) Krendl will examine whether the theory of mind mediates the relationship between older adults’ social connectedness and cognition, both cross-sectionally and longitudinally. 4) Dodge will present the theoretical framework and findings from the I-CONECT project, which aimed to enhance cognition by providing frequent conversational interactions as cognitive stimulation among socially isolated older adults. Together, this symposium will offer critical components for developing targeted interventions that address social isolation/connectedness and support cognitive resilience.