Longitudinal changes in MEG-based brain network topology of ALS patients with cognitive/behavioral impairment: An exploratory study

In this longitudinal magnetoencephalography (MEG) study, we explored changes in brain network topology in amyotrophic lateral sclerosis (ALS) patients with cognitive/behavioral impairment (ALSci/bi), compared with the two extreme ends of the ALS behavioral variant of frontotemporal dementia (ALS-bvFTD) spectrum (ALS with only motor impairment and bvFTD patients without ALS). We recorded resting-state MEG at baseline and 5-month follow-up, analyzing frequency-band-specific functional connectivity and constructing the networks' backbone using the minimum spanning tree (MST). Our findings indicate that at baseline, ALSci/bi networks were more similar to ALS-pure motor than bvFTD in the theta band. At follow-up, ALSci/bi networks shifted toward bvFTD-like topology in the beta band. This suggests that ALSci/bi patients' brain networks evolve along the ALS-bvFTD spectrum, highlighting potential implications for disease progression.