Gray matter atrophy and freezing of gait in Parkinson's disease: Is the evidence black-on-white?

ABSTRACT Objectives The pathophysiology underlying freezing of gait (FOG) in Parkinson's disease (PD) is poorly understood. We tested whether gray matter (GM) atrophy contributes to FOG in PD. Methods Voxel‐based morphometry quantified GM atrophy in 106 patients who were classified as freezers (n = 30) or nonfreezers (n = 76). Well‐matched smaller subgroups were also studied. Balance, gait, and cognitive function were assessed, and we evaluated the relationship between GM, FOG severity, and symptoms associated with FOG. Results GM was significantly reduced in the inferior parietal lobe and angular gyrus in the matched freezers (n = 22), compared to nonfreezers (n = 22; P