P1‐422: Reduced Long‐range Default Mode Connectivity Predicts Conversion to Alzheimer's Disease in Older Individuals With Down Syndrome
Year: 2019
Type: article
Study design: Observational Study
Abstract: Individuals with Down syndrome (DS) are at increased risk for developing Alzheimer's disease (AD) and have earlier symptom onset at an average age of 55, compared to age 80 in the general population. Determining preclinical biomarkers of AD is critically important for early diagnosis and effective intervention within this high-risk population and more broadly in the general population, but little is known about the biomarkers that may predict clinical onset in DS. Previous studies in non-DS individuals have shown weaker functional connectivity within the default mode network (DMN) and stronger functional connectivity within the medial temporal lobe (MTL) in cognitively normal older adults in the preclinical stage of AD (Sperling et. al, 2009; Westlye et al., 2011). However, few studies have investigated functional connectivity as a potential biomarker of AD in individuals with DS ages 40+. 15 non-demented older adults with DS (mean age 51.7±5.3, 47% women) underwent MRI, including a 1mm MPRAGE scan and a 3mm resting state fMRI scan, as well as clinical evaluation. Participants were followed for two years, returning to the clinic roughly every 12 months for neuropsychological testing and consensus diagnosis for AD. 4 participants transitioned to AD during follow-up. We hypothesized that older adults with DS who subsequently became demented would have weaker functional connectivity within the DMN and stronger functional connectivity within the MTL compared to those who remained cognitively normal during follow-up. Older individuals with DS who later developed AD had weaker antero-posterior DMN functional connectivity one year prior to conversion. We found no significant differences in connectivity within proximal DMN hubs or within the MTL. Antecedent hypoconnectivity between distant DMN hubs may predict future conversion to AD in older adults with DS.
Source: Alzheimer s & Dementia
Institution: University of California, Irvine
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2981207890