Frequency-Dependent and Temporal Variability of Low-Frequency Fluctuations in Primary Sjögren's Syndrome Patients

Motivation: Primary Sjögren's syndrome (pSS) is an autoimmune disorder affecting multiple organs, including the nervous system, and is associated with cognitive deficits and "brain fog". Goal(s): Explore the alterations and characteristics of low-frequency fluctuation amplitude (ALFF) in pSS patients. Approach: Employ the ALFF method to assesse the frequency-dependent alterations within Slow-5 and Slow-4 frequency bands, and conduct dynamic ALFF (dALFF) analysis to probe the temporal variability. Results: The Fusiform_R in pSS patients exhibits abnormal ALFF values and anomalies within its two sub-bands. The Precentral_L and Frontal_Mid_R displayed abnormal increases restricted to the Slow-5 frequency band. dALFF analyses revealed abnormalities in Supp_Motor_Area_L of pSS patients. Impact: This study reveals that ALFF indicators demonstrate aberrant alterations in pSS, exhibiting characteristics of both frequency dependence and temporal variability, complementing traditional metrics and suggesting that ALFF could serve as a novel tool for investigating the neurological underpinnings of pSS.