It has been established that subjects with MDD have dysregulation of neural oscillatory synchrony, but comprehensive information is limited. There is consistent support for increased synchrony in the alpha band, as evidenced by increases within single regions of alpha band power on quantitative electroencephalography (qEEG) [34]–[39]. Studies are inconsistent, however, in identifying which region(s) show this abnormality, with increases reported over the frontal or parietooccipital regions, either on the right or left [39]–[41]. One report found that patterns of alpha asymmetry fluctuated over the span of weeks in subjects with MDD as compared to normal controls [35], suggesting that disturbed synchrony in MDD may reflect a broadly distributed dysregulation [42]–[44]. Disturbed synchrony in other frequency bands has not been consistently reported.
