Normative models in neuroimaging learn the brain patterns of healthy
population distribution and estimate how disease subjects like Alzheimer's
Disease (AD) deviate from the norm. Existing variational autoencoder
(VAE)-based normative models using multimodal neuroimaging data aggregate
information from multiple modalities by estimating product or averaging of
unimodal latent posteriors. This can often lead to uninformative joint latent
distributions which affects the estimation of subject-level deviations. In this
work, we addressed the prior limitations by adopting the
Mixture-of-Product-of-Experts (MoPoE) technique which allows better modelling
of the joint latent posterior. Our model labelled subjects as outliers by
calculating deviations from the multimodal latent space. Further, we identified
which latent dimensions and brain regions were associated with abnormal
deviations due to AD pathology.

通过采用混合乘积专家（MoPoE）技术，我们提出了一种改进的范式模型，该模型利用多模态神经影像数据对联合潜在后验进行更好的建模，并计算从多模态潜在空间由于阿尔茨海默病（AD）病理而产生的异常偏差。