Altered spontaneous brain activity at attack and remission stages in patients with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS): Beyond stroke-like lesions.

Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) may cause whole-brain functional changes due to mitochondrial dysfunction. Our purpose is to comprehensively evaluate the alterations of spontaneous brain activity in MELAS patients at stroke-like episodes (SLE) attack and remission stages using resting-state functional magnetic resonance imaging. Forty MELAS patients at attack stage (n = 20) and remission stage (n = 20) and 22 healthy controls were enrolled in this study. We suggested that MELAS patients presented decreased spontaneous brain activities beyond the areas of stroke-like lesions (SLLs), with a downward trend from SLE attack stage to remission stage. In addition, the regional spontaneous activity of SLL, an inherent change in MELAS, was less than that in unaffected areas. Furthermore, the fractional amplitude of low frequency fluctuations value in left precuneus may be used as a promising neuroimaging biomarker for monitoring the disease status of MELAS.