Network based statistics associates increased connectivity to REM sleep disorder and hallucinations in early DLB

Dementia with Lewy Bodies (DLB) is a heterogeneous disease characterized by four core clinical features: visual hallucinations, REM sleep behaviour disorder (RBD), cognitive fluctuations and Parkinsonism. We study the relationship between these features and functional connectivity from high-density electroencephalographic data of 33 subjects with early-stage DLB and 21 healthy controls. We used two connectivity metrics averaged on the individual theta and alpha bands, defined by determining the individual theta-to-alpha transition frequency through the package transfreq. After showing that DLB determines a shift toward lower frequencies of posterior dominant rhythm and theta-alpha transition, we used Network Based Statistics to explore differential connectivity networks between subgroups of DLB patients with different features. We found that both visual hallucinations and RBD are associated with increased connectivity in early DLB patients mostly in the left hemisphere, while cognitive fluctuations and Parkinsonism appear to have a non-significant impact on functional connectivity metrics in our population.