Gait speed in Parkinson disease correlates with cholinergic degeneration.

Editors’ Note: Grabenhenrich and Roll critique the methodology and design in the study by Kerti et al. on the association between glucose metabolism and memory performance. The authors conduct additional statistical analysis to support their results. Neurology’s sometime neuromythologist and historian, William Landau, cites quotations from Parkinson’s historical monograph to comment on the article by Bohnen et al. on gait speed in Parkinson disease. The authors respond. —Chafic Karam, MD, and Robert C. Griggs, MD