FRIDAY, March 4, 2022 (HealthDay News) — For older adults without cognitive impairment, the presence of Alzheimer’s disease pathology is linked to memory impairment according to the Objective Memory Impairment Stage System (SOMI), according to research published online February 2, 2022. 23 in Neurology.

Ellen Grober, Ph.D., of the Albert Einstein College of Medicine in New York City, and colleagues examined the neuroimaging correlates of the SOMI system using data from 4,484 participants without cognitive impairment (mean age, 71.3 years) of anti-amyloid therapy in Asymptomatic Alzheimer’s Disease Study (A4). All participants had amyloid positron emission tomography imaging and a subset of 1,262 amyloid β-positive (Aβ+) participants had structural magnetic resonance imaging. Mean cortical Aβ standardized uptake ratio (SUVR) and volumetric measurements of the hippocampus, parahippocampal gyrus, entorhinal cortex, and inferior temporal cortex were compared between the five SOMI stages.

The researchers found that across the entire sample, an analysis of covariance showed that individuals at higher SOMI stages had higher overall amyloid SUVR while controlling for age, gender, education, and APOE4. Higher amyloid SUVR was observed in SOMI-4 and SOMI-3 subgroups than in SOMI-0 and SOMI-1 subgroups. Smaller hippocampal volume, entorhinal cortex, and lower temporal lobes were observed at higher SOMI stages, but no difference was observed between parahippocampal gyrus volume by SOMI stage. SOMI-4, -3 and -2 had smaller hippocampal volumes than SOMI-0 and -1. A significantly smaller entorhinal cortex and smaller inferior temporal lobe were observed for SOMI-4 compared to all other groups.

“These results suggest that this test can be used to improve our ability to detect cognitive decline at the stage before diagnosis of Alzheimer’s disease,” Grober said in a statement.

Several authors disclosed financial ties to biopharmaceutical companies, including Eli Lilly, which partially funded the A4 study, with in-kind support from Avid and Cogstate.

Summary/Full text