Altered Amplitude of Low-Frequency Fluctuations in Cognitive Impairment of Pediatric Bipolar Disorder: A Resting-State fMRI Study

Seventeen PBD adolescents in manic phase (male/female, 6/11) and remission phase (male/female, 8/9) and 17 age-, gender- and education matched normal adolescents (male/female, 5/12) were included in the study. The Stroop color-word test (SCWT), digit span test (DST), trail making test (TMT) and visual reproduction subtest (VR) were used to assess the cognitive function of the patients and the healthy controls (HCs). The amplitude of low-frequency fluctuations (ALFF) of the functional magnetic resonance imaging (fMRI) signals was evaluated to describe the resting-state brain activity. In the neuropsychological tests, the result of variance analysis showed values of SCWT, DST-B and VR of PBD patients were significantly decreased compared with those of the HCs (p < 0.05). Compared with the HCs (p < 0.01), significant increased ALFF values were found in left hippocampus (HIP) and right amygdala (AMYG) and decreased ALFF were found in right inferior temporal gyrus (ITG), left superior parietal lobule (SPL), left inferior occipital gyrus (IOG) and right calcarine fissure and surrounding cortex (CAL). Moreover, the mean ALFF of the right AMYG was positively correlated with the Young Mania Rating Scale (YMRS) score, the mean ALFF of the right ITG and right CAL were negatively correlated with the SCWT-B score and SCWT-C score respectively in PBD-mania patients (p < 0.05). PBD patients with manic phase and remission phase have broad impairment of cognitive functions, especially in executive function and visual perception. The abnormal resting-state neuronal activities of the AMYG, ITG and CAL may play a vital role in the cognitive impairment in PBD patients.