-In dementia with Lewy bodies (DLB) it is a major site of Lewy body pathology.[1] In Alzheimer’s (AD), amygdala-only Lewy bodies are present in ~40-60% cases[2] & it is a site of DLB & AD co-pathology propagation.[3]

-With improved resolution & tissue contrast, 7T MRI is ideally placed to measure amygdala subfields.[4]

METHODS:

 

RESULTS:

Participants: DLB (n=20, AD (n=25), controls (HC; n=19): well-matched for age & sex.

Left: faceted forest plot with lines representing 95% confidence intervals calculated using non-parametric bootstrapping (2000 resamples). Bars in red indicate P <0.05 for group comparisons using GLM (covariates: age, sex, education, total intracranial volume (TIV)) & subsequent type 2 ANOVA with LSD post-hoc tests

Right: Bubble plot showing Kendall’s tau correlations for volumes with Addenbrookes cognitive exam scores. Thick black outline indicates statistical significance PFDR<0.05

Plasma p-tau217 subgroup exploratory analysis: DLB (n=13), AD (n=17), controls (n=11). 100% of AD group & 69% of DLB group with plasma ptau217 conc. >0.4gl/ml.[9]. Below: box & whisker plots comparing whole amygdala volumes between those with/without raised plasma ptau-217

CONCLUSIONS:

Findings suggest presence of amygdala subfield atrophy in DLB which may contribute to cognitive deficits. Exploratory sub-group analysis suggests that AD co-pathology may drive amygdala atrophy in DLB.

REFERENCES & ACKNOWLEDGEMENTS:

1.Seyika et al. 2025; 2.Almeida et al. 2025; 3.Gawor et al. 2024; 4.McKiernan & O’Brien, 2017; 5.Hoopes et al. 2022;  6.Fischl et al. 2004; 7.Saygin et al. 2017; 8. Dale et al. 1999; 9. Ashton et al. 2025

We thank the participants for their generous and enthusiastic participation. 7T-DLB was primarily funded by Alzheimer’s Society grant: AS-CTF-17b-003. Ethical approval: Cambridge Central REC:16/EE/0418