Combined 64-channel EEG and PET evaluation of lecanemab efficacy: Two case reports

Lecanemab, an anti-amyloid-β (Aβ) monoclonal antibody, has shown potential in slowing Alzheimer's disease (AD) progression. We report divergent responses in two AD patients with similar backgrounds following lecanemab treatment. Subject 1 showed worsened daily functioning, increased Aβ/tau deposition, and elevated electroencephalogram (EEG) slow/fast wave ratios (>30%) in right fronto-occipital regions (Fp2/F8/O1). Subject 2 improved cognitively, with modest Aβ reduction, marked tau suppression, and mixed EEG frontal declines (F3/F7/O1/Pz) and parietal/occipital gains (P3/P4/T3/T6). EEG alterations corresponded with positron emission tomography findings, suggesting its potential for therapeutic monitoring. Multimodal analysis revealed region-specific lecanemab effects, supporting EEG's role in evaluating treatment efficacy.