Characteristic alterations of dynamic amplitude of low-frequency fluctuation in patients with post-stroke depression.

The abnormalities in static brain activity in patients with post-stroke depression (PSD) have been widely reported; the abnormal alterations and characterized clustering model of the dynamic neural activity in PSD remain enigmatic. We investigated dynamic neural activity abnormalities in patients with PSD with the dynamic amplitude of low-frequency fluctuation (dALFF) method. Imaging and clinical data from 25 patients with PSD and 28 without PSD collected from April 2020 to June 2023 were evaluated. The between-group comparisons of dALFF variance and state properties were conducted using a combined approach of sliding window and clustering analysis. The correlation coefficients between abnormal dALFF variance and ALFF in the distinguished regions (DRs) and depression severity of PSD were calculated. Compared with that in patients without PSD, decreased dALFF variance in patients with PSD was mainly located in lower dALFF variance in multiple emotion-related brain regions. The dALFF was clustered into four states in all patients. In particular, state 3 was the remarkably distinct state that dwelled for more time in the PSD group. There was a negative correlation between decreased dALFF variance in the right parietal cortex and Hamilton Rating Scale for Depression (HAMD) scores in patients with PSD. ALFF values in the DRs showed no correlation with the HAMD score. Our results suggest that patients with PSD showed characteristic alterations in dynamic regional neural activity, which might be regarded as potential neural mechanisms of PSD. This study demonstrates the dynamic features of neural activity in PSD, which may advance future neuroimaging studies.