Fractional amplitude of low-frequency fluctuations (fALFF) changes in children with anisometropic amblyopia

This study aimed to explore changes in spontaneous brain activity in children with anisometropic amblyopia (CAA) using the fractional amplitude of low-frequency fluctuation (fALFF) analysis method and to determine whether anisometropic amblyopia is associated with changes in brain function. Resting-state functional magnetic resonance imaging data were collected from 16 children with anisometropic amblyopia (CAA group) and 10 healthy children (HC group). fALFF was used to assess spontaneous brain activity. Group differences in fALFF were analyzed using a two-sample t test, with age, sex, and head motion included as covariates. The statistical threshold was set at a voxel-level P  < .001 (uncorrected), combined with a cluster-level family-wise error correction at P  < .05. Partial Pearson correlation analyses, controlling for age and sex, were used to examine the relationships between fALFF values in regions showing significant group differences and clinical measures (best-corrected visual acuity of the amblyopic eye and magnitude of anisometropia) in the CAA group. Given the exploratory nature of the study, no correction for multiple comparisons was applied. Compared with the HC group, the CAA group showed higher fALFF values in the right middle occipital gyrus and left paracentral lobule. The fALFF value in the left middle frontal gyrus was lower in the CAA group than in the HC group. There were no significant correlations between clinical information and mean fALFF values in the CAA group. This study suggests that CAA may exhibit aberrant spontaneous brain activity within visual and frontal networks, as measured by fALFF. The absence of a direct correlation with standard clinical measures suggests that fALFF may capture distinct, network-level neural alterations in amblyopia. However, whether fALFF can serve as a reliable neuroimaging biomarker remains hypothetical and requires confirmation in larger, well-powered studies with comprehensive visual-function assessments.