Poster No:
648
Submission Type:
Abstract Submission
Authors:
Jiya Shah1, Nhu Huynh1, Neda Rashidi-Ranjbar1, Nicolaas Verhoeff1, Meryl Butters2, Corinne Fischer1, Alastair Flint1, Nathan Herrmann1, Krista Lanctôt3, Benoit Mulsant1, Bruce Pollock1, Tarek Rajji4, Aristotle Voineskos5, Linda Mah6
Institutions:
1University of Toronto, Toronto, Ontario, 2University of Pittsburgh, Pittsburgh, PA, 3Evaluative Clinical Sciences, Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, Ontario, 4UT Southwestern, Dallas, TX, 5Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, 6University of Toronto, Toronto, ON
First Author:
Jiya Shah
University of Toronto
Toronto, Ontario
Co-Author(s):
Nhu Huynh
University of Toronto
Toronto, Ontario
Krista Lanctôt
Evaluative Clinical Sciences, Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute
Toronto, Ontario
Introduction:
Loneliness and social isolation in older adults increase risk of mortality and medical and psychiatric comorbidity, including depression and dementia [1-2], while psychological resilience, defined as the ability to recover from stress or adversity [3], may serve as a protective factor against negative health outcomes. The medial temporal lobe region is known to play a role in stress regulation [4] and has been linked to loneliness and social isolation [5], but few studies have examined the association between the medial temporal lobe and resilience. Moreover, the majority of research on the relationship between the medial temporal lobe and these constructs in older adults has been cross-sectional in design; thus, the directionality of these relationships is unclear. In the current study, we sought to determine whether medial temporal lobe volumes were predictive of loneliness, extent of social networks, and resilience during the recent COVID-19 pandemic in community-dwelling older adults who had completed structural magnetic resonance imaging (MRI) scans as part of research studies prior to the onset of the pandemic.
Methods:
The sample included 114 older adults (55 males, mean age 73 years, SD=5.6) who were enrolled in research studies and had completed a structural MRI scan prior to March 2020. Diagnoses included mild cognitive impairment (MCI, n=28), remitted major depressive disorder (rMDD, n=12), rMDD with comorbid MCI (n=28), or normal cognition with no psychiatric history (n=46). The research studies included an observational study of older adults with mild memory concerns and a clinical trial of transcranial direct current stimulation and cognitive remediation in MCI and rMDD. T1-weighted anatomical scans were acquired using a 3T (Siemens TIM, Erlangen, Germany) scanner at two sites (N=31 and N=10) and a 3-T GE MR750 Echospeed (General Electric, Milwaukee, WI) at a third site (N=73) at a mean interval of 1182 days (SD=559.1) prior to obtaining measures of loneliness (UCLA Loneliness Scale), social network diversity (Social Network Index) and resilience (Connor Davidson Resilience Scale) during the COVID-19 pandemic. MRI scans were preprocessed and analyzed using FreeSurfer 7.0 to extract regions of interest (ROIs) which included volumes of amygdala and hippocampus and thickness of entorhinal cortex averaged across both hemispheres. Multivariable regression modelling of loneliness, social network diversity, and resilience was conducted separately with each ROI as a predictor and covariates of total intracranial volume, age, sex, depression history, MCI diagnosis, living arrangement, scanner site, and time interval between scan and self-report measures.
Results:
Amygdalar volume was negatively associated with loneliness (β = -0.011, P =.048, adjusted R2= 0.13, F (9,104) = 2.90, P = 0.0042) while entorhinal cortical thickness was negatively associated with social network density (β = -1.52, P =.025, adjusted R2= 0.24, F (9,102) =4.89, P = 0.00019). In addition, amygdalar and hippocampal volumes were both positively associated with resilience (amygdala: β =0.0127, P =.0013, adjusted R2= 0.19, F (9,103) =3.99, P = 0.0002; hippocampus: β =0.0038, P =.025, adjusted R2= 0.15, F (9,103) =3.21, P = 0.0018).
Conclusions:
Reduction in amygdalar volume is associated with vulnerability to loneliness in older adults, while greater volumes of amygdala and hippocampus are associated with resilience in older adults, independently of age, sex, depression history and cognitive status. Limitations to the study include the use of a convenience sample and potential selection bias, the use of multiple scanners, and variability in the time interval between scan acquisition and self-report measures. The possible roles of both amygdala and hippocampus in psychological resilience are consistent with the neuromodulatory influence of the amygdala on the effects of stress hormones on hippocampal plasticity and reinforcement of adaptive behaviour in response to stress [6].
Disorders of the Nervous System:
Neurodegenerative/ Late Life (eg. Parkinson’s, Alzheimer’s) 2
Psychiatric (eg. Depression, Anxiety, Schizophrenia)
Emotion, Motivation and Social Neuroscience:
Social Cognition 1
Novel Imaging Acquisition Methods:
Anatomical MRI
Keywords:
Aging
Emotions
Limbic Systems
Memory
Neurological
Psychiatric
Social Interactions
STRUCTURAL MRI
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Other
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Patients
Was this research conducted in the United States?
No
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Yes
Were any animal research approved by the relevant IACUC or other animal research panel?
NOTE: Any animal studies without IACUC approval will be automatically rejected.
Not applicable
Please indicate which methods were used in your research:
Structural MRI
Behavior
Neuropsychological testing
For human MRI, what field strength scanner do you use?
3.0T
Which processing packages did you use for your study?
Free Surfer
Provide references using APA citation style.
1. Taylor, H. O. et al. (2018). Social Isolation, Depression, and Psychological Distress Among Older Adults. Journal of Aging Health 30, 229–246.
2. Guarnera, J. et al. (2023). The Impact of Loneliness and Social Isolation on Cognitive Aging: A Narrative Review. Journal of Alzheimers Disease Rep 7, 699–714.
3. Skalski, S. B. et al. (2022). Resilience and Mental Well-Being During the COVID-19 Pandemic: Serial Mediation by Persistent Thinking and Anxiety About Coronavirus. Frontiers in Psychiatry 12, 810274.
4. Mah, L. et al. (2016). Can anxiety damage the brain? Curr Opin Psychiatry 29, 56–63.
5. Hirabayashi, N. et al. (2023). Association Between Frequency of Social Contact and Brain Atrophy in Community-Dwelling Older People Without Dementia: The JPSC-AD Study. Neurology 101, e1108–e1117.
6. Hermans E.J. et al. (2024). Building Resilience: The Stress Response as a Driving Force for Neuroplasticity and Adaptation. Biological Psychiatry, Oct 22:S0006-3223(24)01700-1.
No