Signs of Alzheimer's evident on imaging up to 15 years prior to symptom onset in Down syndrome population
Structural brain changes are evident on imaging more than a decade before the onset of Alzheimer’s symptoms in individuals with Down syndrome.
In fact, changes across the medial temporal lobe (MTL) regions are visible up to 15 years prior to diagnosis in some patients, according to new data published in the journal Brain. By identifying these changes prior to the onset of symptomatic neurodegeneration, providers may be able to initiate preventive therapies sooner, thus slowing disease progression and improving the quality of life for affected individuals.
“Our data indicate that structural MRI not only enables early detection of changes, but can effectively complement fluid biomarkers in predicting clinical status,” first author Alejandra Morcillo-Nieto, a researcher in the Neurobiology of Dementias group, and colleagues noted. “This is especially relevant in Down syndrome, where cognitive testing may be limited by baseline intellectual disability.”
For the study, experts analyzed the MRI scans and cerebrospinal fluid of two groups of participants—one with and one without Down syndrome—in addition to conducting thorough clinical and behavioral assessments in participants with confirmed Alzheimer’s diagnoses. The imaging used for the research was acquired from the Down-Alzheimer Barcelona Neuroimaging Initiative (DABNI), which provides long-term data.
The team focused their work on alterations of the medial temporal lobe (MTL). In doing so, they observed anatomical changes related to the progression of Alzheimer’s, starting with changes in the cortical thickness of the entorhinal cortex. Changes in the posterior hippocampus, anterior hippocampus and parahippocampus followed.
Strong correlations between posterior hippocampal volume and cerebrospinal fluid were evident as well. This finding had the highest predictive value for an eventual Alzheimer's diagnosis, with an accuracy of 86.3%.
“The approach allowed us to observe that the entorhinal cortex and posterior hippocampus are the first regions to show structural loss, even before symptoms appear,” the team explained. “Moreover, some regions like the parahippocampus initially show cortical thickening, possibly reflecting inflammatory or compensatory processes, before entering a phase of atrophy—although this is a hypothesis that should be confirmed in future studies.”
Although additional data on larger cohorts are needed to validate the group’s findings, they are hopeful that their work will lead to more timely diagnoses in this subset of patients, prompting earlier interventions that could improve their quality of life.
Learn more about the findings here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.