Frequency-dependent, asymmetric, and dynamic alterations of white matter function in primary hemifacial spasm: a multiband resting-state fMRI study.

Primary hemifacial spasm involves central network reorganization, but white matter functional alterations remain unclear. We acquired resting-state functional magnetic resonance imaging data from 89 left-sided patients, 92 right-sided patients, and 124 healthy controls. Patients exhibited widespread abnormalities in tracts including the corpus callosum, superior longitudinal fasciculus, and corona radiata. Notably, this remodeling was highly asymmetric: left-sided patients primarily showed increased local neural activity in prefrontal pathways, whereas right-sided patients exhibited increased global network centrality across interhemispheric tracts. Furthermore, these alterations displayed distinct frequency preferences, and certain functional instabilities were exclusively captured by dynamic metrics rather than static analyses. These findings demonstrate that the disorder is associated with time-varying, frequency-specific, and asymmetric white matter functional reorganization, highlighting the value of dynamic and multi-frequency approaches in decoding its pathophysiology.