Other studies of coherence have used methods that differ from the current study, and have obtained disparate results. Knott and colleagues [37] found decreased coherence in MDD subjects compared to normal controls, but calculated coherence between a limited number of individual electrodes, a technique that may not characterize regional measures of brain activity as well as the electrode pairs in the present study [61]. Armitage and colleagues have examined coherence during sleep and shown that it is decreased among adolescents with MDD, and is a predictor of recurrence and risk of developing illness [72]–[74]. The relationship between sleep and resting awake state coherence is unknown.
