Ultrahigh-efficiency enhancedfour-wave-mixing in Si-Ge-Graphene photonic crystal waveguide

BACKGROUND AND OBJECTIVE Subjective memory impairment (SMI) is a preclinical stage prior to amnestic mild cognitive impairment (aMCI) along with the Alzheimer's disease (AD) continuum. We hypothesized that SMI patients had white matter (WM) network disruptions similar to those in aMCI patients. METHODS We used diffusion-tensor magnetic resonance imaging and graph theory to construct, ana- lyze, and compare the WM networks among 20 normal controls (NC), 20 SMI patients, and 20 aM- CI patients. RESULTS Compared with the NC group, the SMI group had significantly decreased global and local efficiency and an increased shortest path length. Moreover, similar to the aMCI group, the SMI group had lower nodal efficiency in regions located in the frontal and parietal lobes, limbic sys- tems, and caudate nucleus compared to that of the NC group. CONCLUSION Similar to aMCI patient, SMI patients exhibited WM network disruptions, and detec- tion of these disruptions could facilitate the early detection of SMI.