Hypersynchronized MEG brain networks in patients with mild cognitive impairment and Alzheimer's disease in Down syndrome.

INTRODUCTION The majority of individuals with Down syndrome (DS) show signs of Alzheimer's disease (AD) neuropathology in their fourth decade. However, there is a lack of specific markers for characterizing the disease stages while considering this population's differential features. METHODS Forty-one DS individuals participated in the study and were classified into three groups according to their clinical status: Alzheimer's disease (AD-DS), mild cognitive impairment (MCI-DS), and controls (CN-DS). We performed an exhaustive neuropsychological evaluation and assessed brain Functional Connectivity (FC) from magnetoencephalographic recordings. RESULTS Compared to CN-DS, both MCI-DS and AD-DS showed a pattern of increased FC within the high alpha band. The neuropsychological assessment showed a generalized cognitive impairment, primarily affecting mnestic functions, in MCI-DS and, more pronouncedly, in AD-DS. DISCUSSION These findings might help to characterize the AD-continuum in DS and in the population with typical development. Additionally, they support the role of the excitatory/inhibitory imbalance as a key pathophysiological factor in AD.