Abnormal amplitude low-frequency oscillations in medication-naive, first-episode patients with major depressive disorder: a resting-state fMRI study.

Background: Recent resting-state fMRI studies on major depressive disorder (MDD) have found altered temporal correlation between low-frequency oscillations (LFOs). However, changes on the amplitudes of these LFOs remain largely unknown.

Methods: Twenty-two medication-naive, first-episode patients with MDD and 19 age-, sex-, education-matched healthy controls were recruited. Resting-state fMRI was obtained by using an echo-planar imaging sequence and the fractional amplitude of low-frequency fluctuations (fALFF) was calculated to investigate the amplitude of LFOs in the resting state.

Results: Compared with control subjects, patients with MDD showed significantly decreased fALFF in right cerebellum posterior lobe, left parahippocampal gyrus and right middle frontal gyrus and increased fALFF in left superior occipital gyrus/cuneus (p<0.05, corrected for multiple comparisons). Further receiver operating characteristic curves (ROC) analyses suggested that the alterations of fALFF in these regions might be used as markers to classify patients with MDD from healthy controls.

Conclusions: These findings indicated LFOs abnormalities in MDD and the fALFF analysis might be a potential approach in further exploration of this disorder.