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A recent study provided key insights into brain degeneration in DLB, which may help clinicians better monitor this neurodegenerative dementia.

A recent study published in JAMA Neurology provided key insights into brain degeneration in dementia with Lewy bodies (DLB), which may help clinicians better monitor this neurodegenerative dementia.

DLB is a common cause of dementia. Although ¹⁸F-fluorodeoxyglucose–positron emission tomography (FDG-PET) imaging is a well-established cross-sectional biomarker of brain metabolism in DLB, little is known about how these brain changes develop over time.

Daniel Ferreira, PhD, and colleagues conducted a longitudinal case-control study to investigate longitudinal FDG-PET in prodromal DLB and DLB. They followed up 172 patients from the Mayo Clinic Alzheimer Disease Research Center and the Longitudinal Imaging Biomarkers of Prodromal DLB and DLB Program.

Of this cohort, 35 patients had probable DLB, 37 had mild cognitive impairment with Lewy bodies (MCI-LB). Individuals without cognitive impairment from a population-based cohort, matched for age and sex, were included for comparison. The mean age of the DLB and MCI-LB groups combined was 69.6 years; 66 patients (92%) were men and 6 (8%) were women. All patients completed between 2 and 8 FDG-PET visits, with a mean follow-up of 3.8 years.

The researchers found that brain degeneration begins early in prodromal DLB and worsens as the disease progresses. At follow-up, 18 patients (49%) with MCI-LB had progressed to probable DLB. Specifically, patients with MCI-LB had a quicker decline in FDG-standardized update value ratios (SUVr) in the posterior cingulate, occipital, parietal, temporal, and lateral frontal cortices than patients without cognitive impairment. Furthermore, the same regions showed greater metabolic decline in patients with DLB versus individuals without cognitive impairment, with the addition of anterior-middle cingulate, insula, and medial frontal orbital cortices.

Rates of change in FDG-PET in these brain regions were combined into a region of interest (ROI) labeled longitudinal FDG-PET meta-ROI. A faster decline in FDG-SUVr correlated with faster increase in Clinical Dementia Rating Sum of Boxes (CDR-SB) score across all ROIs, reflecting increased disease severity. In addition, a faster decline in FDG-SUVr in the meta-ROI was associated with a faster increase in CDR-SB.

In conclusion, the authors said, “Importantly, FDG-PET may be a contributing biomarker of neurodegeneration in the new staging systems of LBD-associated clinical phenotypes, and data reported in this study may facilitate operationalizing those systems in the clinical setting for biological staging of patients and mentoring of disease progression.”