Dynamic Changes in Functional Network Connectivity Involving Amyotrophic Lateral Sclerosis and Its Correlation With Disease Severity

Background Aberrant static functional connectivity (FC) has been well demonstrated in amyotrophic lateral sclerosis (ALS); however, ALS‐related alterations in FC dynamic properties remain unclear, although dynamic FC analyses contribute to uncover mechanisms underlying neurodegenerative disorders. Purpose To explore dynamic functional network connectivity (dFNC) in ALS and its correlation with disease severity. Study Type Prospective. Subjects Thirty‐two ALS patients and 45 healthy controls. Field Strength/Sequence Multiband resting‐state functional images using gradient echo echo‐planar imaging and T1‐weighted images were acquired at 3.0 T. Assessment Disease severity was evaluated with the revised ALS Functional Rating Scale (ALSFRS‐R) and patients were stratified according to diagnostic category. Independent component analysis was conducted to identify the components of seven intrinsic brain networks (ie, visual/sensorimotor (SMN)/auditory/cognitive‐control (CCN)/default‐mode (DMN)/subcortical/cerebellar networks). A sliding‐window correlation approach was used to compute dFNC. FNC states were determined by k‐mean clustering, and state‐specific FNC and dynamic indices (fraction time/mean dwell time/transition number) were calculated. Statistical Tests Two‐sample t test used for comparisons on dynamic measures and Spearman's correlation analysis. Results ALS patients showed increased FNC between DMN‐SMN in state 1 and between CCN‐SMN in state 4. Patients remained in state 2 (showing the weakest FNC) for a significantly longer time (mean dwell time: 49.8 ± 40.1 vs. 93.6 ± 126.3; P