EEG Synchronization Evaluation: A New Diagnostic Tool for Predicting the Progression of Alzheimer's disease.

Alzheimer's disease (AD) is known as a leading cause of dementia in elderly persons. It is a chronic neurodegenerative disorder characterized by progressive cognitive dysfunction. AD can disrupt functional connectivity in distributed cortical networks. The S-estimator, which is a measure of multivariate intraregional synchronization, was analyzed in this study. Twenty patients with AD and 20 age-matched controls were tested at baseline and after 1 year to evaluate the potential of synchronization to be a possible marker of AD progression. All the subjects had clinical evaluations and electroencephalography (EEG) at baseline and post 1 year. Hyposynchronization had an important effect in the medial temporal and frontal regions, while there were no significant effects for hypersynchronization. Hypersynchronized clusters changed more slowly with time (P = .067), whereas hyposynchronized clusters changed more quickly (P = .032). Hyposynchronized cluster-averaged S-estimator correlated negatively with progression of AD (r = -0.98769, P = .0103). In conclusion, the present study provides a whole-brain, AD-specific phenotype of temporal coordination in distributed cortical networks, which is an early diagnostic tool for progression of AD.